I have just tried this with my Milwaukee 18v battery that has been dead for 4 years. It absolutely works beats paying $100’s of dollars in batteries. Thanks brother love your work….
What is occurring here is that the battery packs contain a fuel gauging and safety IC. The charger must communicate to this IC, before the battery can charge. If the battery gets to a low enough voltage, the IC will be unpowered, and unable to communicate. There is a way in most of these IC solutions to provide a slow charge path for a deeply discharged battery. The issue is that some manufacturers, because of their cell chemistry, don't want a battery which has dropped below about 1V per cell, to ever be used, as it can cause plating of the current collector materials into the carbon matrix, which can then become energized when the cell gets charged, resulting in shorts and localized heating, which can then lead to what is referred to in the battery industry as "rapid disassembly", more often called an explosion by consumers! If the battery reaches low voltage because it was stored uncharged, and left in that state for a long period, it would typically take multiple months, it may reach a low voltage. Such cells are usually safe to recharge, but to be sure you really need to get the info from the cell makers datasheet. The other reason the cells can reach such a low voltage, is because they are wearing out, and their impedance is increasing and capacity is starting to rapidly decline. This can cause a cell to go to zero volts during storage due to increased leakage currents within the cells. Such cells are typically unsafe to recharge! If you are going to do this, be very careful. Recovery of such packs is at a greater risk of catastrophic failure for the cells. Watch such packs carefully during charge, and even for half a day after the recharge. I have seen cells fail after such recovery charging as long as 8.5 hours after charging was complete. A single fire can cost you much more than the price of a replacement pack. I wanted to make sure people are warned of the potential consequences. Please be extremely careful. I highly suggest replacing such packs unless you know they were stored uncharged and left for a multiple months. Li based cells are fickle, they contain tremendous energy. When things go bad, they go bad quickly and violently. Please take this warning seriously. I would hate someone to lose someone they love to such a senseless accident!
“ but to be sure you really need to get the info from the cell makers datasheet. ” Lmafo, don’t even bother. If you can even find the original manufacturer and get a data sheet they NEVER have this information. They usually don’t even have actual capacity at various discharge rates or even temperatures sometimes they don’t even have the capacity which is insane. The data sheet says almost nothing beyond “what you want? It’s a BATTERY”.
@@leeabell183 My battery was not blinking defective; it was dead with no lights. I don’t know if it would work on one where the lights indicate there is a problem. Might be worth a try. By the way, my reclaimed battery is still working.
The wife here. My hubby ran away from home. Left me with some old Ryobi tools and DEAD BATTERIES. I'm so blessed to find this process. I have friends with working Ryobi batteries. Now I can fix mine. Thank you!
@@joegonzalez1941 Most men choose ugly women for their secretary for a reason(wife is insecure). Then I thought, if they were real men they would not chase a better looking woman. So there is th at. You probably won't agree with my unpopular opinion. Looks fade.
I have several 40V Greenworks outdoor power tools; mower, trimmer, leaf blower. About 3-4 years ago one of the expensive (more then $100 at the time. They've come down in price since then) 5 amp batteries stopped working. Wouldn't charge, wouldn't run. So, having nothing to lose, I took it apart. On top of the batteries is a circuit board. On the circuit board was a flat automotive fuse, soldered into 2 slots on the board. The fuse was blown. I unsoldered the fuse and pulled it out. Got a new one of matching amperage from my tool box, trimmed about 1/8" off of the blades so it would sit low on the board like the original, and soldered it in place exactly like the original. Worked perfectly. I'm still using that battery.
They do this with televisions, they do this with washer and dryers and microwaves. I know because I have replaced a fuse on all these in every single one was a Samsung. What a scam.
@@BillyP-49Chevy it's not a scam, it's a fuse. It protects the electronics. If there was no fuse it would have blown an expensive or difficult to replace component in the electronics when it could have been easily protected with an inexpensive and relatively easy to replace fuse. Almost every electric and electronic device has internal fuse protection with troubleshooting and replacement details in the owners manual.
@@rupertcornelius8924 You are partly right. The fuse certainly does protect the electronics. But in this case there is no mention of it in the owners manual or any literature, and it is in no way intended to be replaced if it blows. What they want to happen is for the owner to declare the battery dead, trash/recycle it, and spend >$100 on a new battery. THAT is the scam. The fuse should be in a fuse socket in a user-accessible location so when it blows it can be replaced.
Just came across this video and had a DeWalt 20v battery I was about to take to recycle it. Figured I’d give this a shot, and you just saved me a battery! Working again like a charm!
I did that scissors trick when I was 4 with a 120v outlet. Much more memorable. Now that I am an 61 with a EE degree I would recommend a fuse and alligator clips.
Ha ha! I did that same trick with a pair of wired toy “Rabbit ears”. I was 5 years old and was curious as to what would happen if I stuck those ears into a 120v outlet. Poof!!! One scared kid and a blown fuse. 😅
Ok, I have a 40v lithium battery for my Black & Decker weed trimmer. Over a year ago the battery was dead as any door nail. But I kept it for later recycling with other batteries. I saw this video and went to work to see if your jumper trick would work. I fully charged the good battery. Then I made my connections and gave it time. I came back in about 10 minutes and the "dead" battery was warm. I removed the wires and put that battery on the charger! It works! The red light started flashing. It's now working to be fully charged. I now have two 40v batteries to work with. Thanks for this great tip.
@@lindsayadams4905 My battery showed that it was recharging--green light-- but after a few minutes it got the flashing red light. I assume the battery is bad. But the trick did work when it showed no green light.
Totally works. Did it with Dewalt 40V yard tool batteries. Took about an hour to reach "threshold voltage" that the charger would recognize. Thanks man!
Wow, I'm glad I watched this. I have a bunch of new batteries that have been sitting around for years going dead. I am so glad I can revive them now that I'm able to use power tools again.
Nice tips, my addition would be to flatten your solid copper wire ends rather than forcing them in. Mechanically spread and damaged connector terminals inside the pack will also render it unusable in a much less fixable manner. It can overheat and melt the plastic around it in your battery pack and leave a burned pitted spot in your tool's contacts as well.
when you insert the battery into the charger it spreads the terminals apart to make a good connection. It's designed to handle this over and over again. Its a non issue.
Thanks for this tutorial, I tried it on my M18 red lithium, it sparked a little but all it took was less than a min and now its charging, this is awsome!!
I have a brand new hammer drill with a bad battery that I purchased. I'm glad I kept it. Just saw your video and tried it out. It's currently charging. Thank you for sharing the trick.
3-5 minutes might be generous. It can be a lot faster. I learned this last summer from a different video and listed much shorter times. So I tried what they said. 20v dewalt - I connected the wires for about 30 seconds and that was all I needed to have just enough juice to get the charger going. I'm glad people are sharing this information. Seems a shame for batteries to be getting tossed / recycled unnecessarily.
yes a few seconds is more than enough - it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first because the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuild BMS detects this condition and tells any devices which respect it to shut off power from it. the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
These cells don't actually reach zero. The charger will cut them off between 3 and 2.5 volts. They will not let you discharge them completely because it would likely catch on fire. What happens is the battery is charged up to 4 Volts. It is used till it hits its cutoff voltage around 3 volts then instead of charging it you put it into your bag for three or four days and the battery self discharges to less than 2.5 at which point you need to do what he says here to charge them. The reason I t takes so little time is that you are only bringing the battery from around 2.4 to 2.6 volts enough where it is recognized. If your battery hit zero you would never be able to charge it again. If a lithium battery ever reached a negative voltage it would quickly achieve thermal runaway. The battery packs don't look for negative voltage to stop charging. They test each set of batteries for the low voltage cutoff. You are right about the imbalance though it happens at much higher tha zero volts. I'm not sure how lithium batteries deal with imbalanced cells but in lead acid deep discharge batteries you overcharge them up to about 14 or 15 volts for a short time. This brings all the individual cells up to the same voltage.
For the 18volt dead battery, instead of wires or scissors to charge off of another 18 volt battery. Just use a typical 9 volt battery and place upside down on the prongs for about a min. Should send a charge to get it recognized by the charger. Super easy!
I did jumped the dewalt 18v xrp batterys according to your instructions for my dewalt 18v xrp batterys. And so far it worked. No errors on the charger. Time will tell. The 20v adapter puts every tool out of balance and too tall. And my problem is I purchased about 10 major 18v tools and really don't want to add an adapter. All my Dewalt 18v tools are still in their hard cases, most only used once. Thanks for the video.
I've had this issue before. In the past, I've just left the battery in the charger, and sometimes, after a few hours, the battery starts taking a charge. Perhaps the charger recognized a slight charge during the process. Will use your tips, though - much easier!
Yes cause even though charger doesn't recognize battery when dead to give charge, when u connect the dead battery the charger, the charger still gives a very small amount discharge naturally and after hours of that miniscule amount of electricity going to the battery, it gets it to the point where it builds up enough stored electricity to have the charger recognize it
I did it and it worked. 18 volt Makita. It did spark when I made contact (lithium batteries) but left only for 60 seconds and put it on the charger- it is charging! Thank you, thank you. Just bought two new batteries for $185- wish I saw this earlier.
Just seen the video, just tried it and it does work. I think this is the first time I’ve tried a hack I seen on a video and this did work. I had two of the exact 20v that crapped out when they were new. I just never threw them away. Thanks!
Gents. I'm with Brian. Be very careful when attempting to revive an LI batteries regardless of method. Have some sort of fire suit on when you take matters in hand. Use scissor techniquice in case you must quickly disengage or the explosion may disengage for you. You never know. Do this outside your house away from burnable materials as extra precaution just to be safe. Otherwise, happy recharging!!
I don’t have a solution but i DO have the same problem with one of my Ryobi batteries. It flashes the “maintenance charge” sequence (slow, gradual flashing).
I just did this to my completely dead 18V Milwaukee battery pack . It had 0.01V before I jumped it. It's now on the charger and had 19.21V after jumping it for about 4 minutes from my 2nd battery that had a full charge. This works!
Great video. Great comment section. To avoid any kind of battery fire due to over charging or failure. Get your self a metal garden shed run a 120v GFCI circuit to it and make a charging and battery storage set-up insde it for your rechargeable battries. Locate it as far as possible from occupied structures garages and any flamable materials. Dont ask how I know... a thief leaves the coat hangars, fire leaves nothing... I'm a retired Electrical Contractor. ✌️🙏😇 Stay Safe. ❤
Great idea. I would also suggest a smoke alarm, a cut off switch and a bucket of sand. Also - would a metal shed get hot in the sun and overheat the battery and charger?
This How to Home gentleman could be a millionaire with what seems to be hundreds of really good DYI ideas to save time (which is saving $$). Thanks to How to Home.
What a good and simple way of explaining how to revive these batteries! I am a retired electrical engineer and never gave this a thought. Keep up the good work!
The batteries are not being revived. li-ion, lipo and similar chemistry batteries once they are discharged below their lowest discharge voltage rating (normally around 2.2-2.5v per cell) they become useless. Yes you might get them to take a charge but, it'll never be 100% and the capacity is severely reduced.
I think those are rated as 80% capacity. You never get back to 100%. Anyway, use the battery until it can no longer takes a charge. Squeeze every volt out. @@Blueknight1960
yes a few seconds is more than enough - it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first before the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuilt BMS detects this condition and tells any devices which respect it to shut off power from it. the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
I learned about this tendency of rechargeable batteries needing this "jump starting" when I got a universal camera battery charger after I bought 2 used cameras that had been stored for a very long time and their batteries would not charge on the charger that came with the cams. It has a sort of "boost" function you can engage to charge a completely dead camera battery. Always good to know things like this.
I've never had to buy a battery, I use a plug! These types of batteries cannot be recycled so it's just adding to a pollution problem that IS KILLING our planet!
Thanks for the tip. Years ago I tried saving money by getting cloned DeWalt 18v batteries but they didn't quite fit properly. I took them apart and stuffed the guts into the original worn out batteries and they worked. Something about how the clones made them not fit the charger right, so changing out the cases worked. Worn out batteries have a faster flashing light indicating no more charge cycles left. Heavy use for ten years exceeded their charging cycles. This is also true for NIMH AA & AAA batteries. FYI, sometimes the issue is with bent connections. Look at the spacing of the metal tabs and compare to the charged battery, then slightly bend the tab to make a proper connection. I had this issue after loaning a tool to my brother in law. I bent the tab back and the tool worked again.
it was a little anxiety-inducing but just revived an 18v using the scissors method, thank you so much! living in the city without a car, jumper cables and insulated wires aren't something I have on hand.. so this really helped!
Wife likes all kinds of ambiance low power stuff around the house. I made her switch to rechargeable batteries due to how many she was going through. The problem with these devices is that they will suck a battery to 0. So i built a board to be able to jump-start them and get them to change easily. Works really well. I've also done this on car batteries, Zegway batteries, and many others threw the years. Never had an issue.
An excellent video. This illistrates the principle that a good battery sacrifices toward a dead battery. They will share the electricty equally. In the old days truck mechanics used this to start an exhausted battery.
I'd written off a nearly new grass strimmer because neither 18 volt battery would recharge. I actually purchased a replacement strimmer of higher voltage. Your demo got me using my DeWalt 18 volt battery to connect to each of the anonymous strimmer batteries in turn. Hey presto! I now have two working strimmers! Also the other of my two DeWalt 18 volt batteries had become unrechargeable so I applied your cure and now am back to having both available. Many thanks for taking the trouble to put out your fix for everyone's benefit [except perhaps for the battery manufacturer!].
I brought an impact driver yesterday and the charger would not charge the battery. I just tried this today and it worked. I only connected it for 10 seconds. Thank you!
You absolute legend! Had a Worx battery that had appeared dead after only a few months of owning. Luckily Worx replaced it within warranty. However I kept the dead one 'just in case'. It now lives thanks to this genius tip. Thanks again!
great video, I really appreciate the tips you shared! it's impressive how simple steps can make a big difference. but honestly, I wonder if all those methods really work for every type of battery. I've had mixed results with some brands, and sometimes it feels like a gamble. anyone else feel that way?
Never had this condition before, but I have had the charger say the pack is bad a lot. But I gotta add that a current limited power supply would be a better choice for this. The dead battery could overheat and die from the potential short circuit current draw if the dead battery cell is defective.
a few seconds is all it takes, it is indeed dangerous to do this for the stated 3-5 minutes. it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first before the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuilt BMS detects this condition and tells any devices which respect it to shut off power from it. the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
This is a brilliant idea. Thank you so much. Also, you've provided a very clear explanation of the situation and how to correct it. A breath of fresh air.
I’ve done this with Ego56v batteries and it does work. I had a battery that wouldn’t take a charge and registered a fault, ran the wires like he showed and it gave the “bad” battery just enough charge for the charger to recognize it as a good battery in need of charging.
While this does work, there is nothing to regulate the current when you connect the positive wire. There's always a chance with Lithium that you'll have a fire if you charge or discharge too rapidly. I recommend using a current limited bench power supply, or be ready to chuck the whole thing outside because it's on fire.
Probably a good idea to not just walk away from it while doing this. I don't even leave a battery on a charger any longer than it takes to charge it. I keep checking on it and when charged it comes out of the charger and unplug the charger.
@@tsmartinI know you can leave Bosch, DeWalt, and Milwaukee in the charger since they implement a charge protection timer. Ryobi still doesn’t last I checked. RTFM
Man- this tip Saved me a trip back the store for yet another tool replacement! So glad I saw this and had plenty of Romex from my remodel available! Worked like a charm. Thx!!!
I've done this before. one way for the manufacturers to prevent this issue is to have a jumpstart button on their chargers. I suppose that would be counter profitable because they can't sell more batteries that way…
For once it's actually got nothing to do with making more money. These batteries can be dangerous when handled by fools. Including the numb nuts that made this video.
Not really because once you drain one of those batteries down too low, they become worthless. Yes you might get them to take a charge but, the capacity of the cells will be too low to be of any use.
@@Blueknight1960 As I stated to another such comment, I jump-started a battery about 2 years ago and have used it many times since...never having to jump-start it again. It had been unused when it previously went completely dead (from lack of use), so admittedly that may be a factor. But it may not be a factor as well. I only know that it's operated as well as any new battery I ever owned for two years now, and I use my tools heavily...auto repair and home maintenance.
If the batteries are any good they should hold a charge on the shelf as it were…. I have probably 20 DeWalt batteries in my collection and the only ones that go dead on their own are the ones that i know are weak… I have a 9 ah 60v that’s in my chainsaw and 2 years on the shelf and it still shows 3 bars
FYI - if batteries sit on the shelf unused they undergo a process called self-discharge. See wikipedia topic "battery self-discharge" for details. I have several Ryobi tools each with a battery and I rotate thru them so a battery doesn't sit unused for months on end. A lead-acid car battery can also self-discharge over time if left unused but also after years of use the chemistry degrades so they no longer hold much of a charge and need replacing. A table in the article notes lead-acid batteries self-discharge around 4-6% a month and eventually won't have enough charge to crank the engine. Lithium-Ion self-discharges 2-4% month and eventually won't have enough charge for the charger to recognize the battery as good. So the trick in this video seems like a good way to give a still-good battery a kick so the charger will charge it. But you will know if the battery is really degraded when it only runs the tool for a few minutes after "full" charging.
Not necessarily true, lithium holds onto its charge for a very long time. The only reason they self discharge here is because the BMS system is usually parasitic and requires a tiny bit of power to keep itself alive. The difference is that the lead acid discharge is because of its chemistry, and the lithium is because of its BMS. Does it really matter? No, but it is not a flat rate, a lithium battery with the same BMS but twice as large as another will bleed through the BMS twice as slow.
I just. Got through watching your video and did exactly what you did. And now I'm recharging one more date battery. Thank you for your video. Now do both the berries have to be the same size? 2 Same thing Do the same thing
Maybe the battery was aging out? I did this several months ago to a 20v dewalt and it seems to be working just fine. I just do not jobs (not contractor) so it would be hard for me to tell if it had a few percent less charge but if so it is not obvious. I have used it for a number of misc jobs since I charged it and have not yet had to recharge it.
Each pack has 5 cells to make up its voltage 18v/20v. The BMS cuts off charge when one of the 5 reaches 4.15v. So open battery and either discharge all to same voltage or use likes of a tp4056 and individually charge each of 5 cells to 4.15 v Also note the discharge curve of lithium ion batteries shows that from fully charged they drop from 4.15v to around 4v in first 4% of discharge. Then slowly drop down to around 3.2 v and if kept in use again the curve drops like falling off a cliff
The 20v and 18v are actually the same voltage. They each have 5 cells in series. Normally the cells are specified by their nominal voltage of 3.7v so 5x is 18.5v. However at full charge the cells are at 4.2v, so 5x is 21v. But there isn't much capacity between 4.1 and 4.2v, and it is better for the usable lifetime of the battery to not charge it up all the way, so 20v is a nice round number pretty close to the typical upper limit.
correct, that's why Dewalt has the 20V MAX * and if you go to the fine print it says " *Maximum initial battery voltage (measured without a workload) is 20 volts. Nominal voltage is 18. "
this is true if they are both lithium ion batteries but the 18 volt batteries shown in this video are nickel cadmium and are a very different technology
Great information. I tried this with two old batteries, got one to work and accept a charge but the second wouldn't accept a charge and just shows a rapid flashing light on the charger. Any tips on a battery fix for the the rapid flashing light?
Thanks for the info. My experience is that 'heat' kills any battery no matter what type and letting batteries go 'dead' and then leaving them partly charged is also bad news. Some batteries also dislike being anything other then constant topped especially gasoline car batteries. i tend to leave them on trickle charge and have a desulfator in my car engine compartment and plug it in whenever i think of it and my batteries last 10+ years. The charger is on a xmas light timer and runs about 15 to 30 minutes/day so the battery water levels don't go down from the constant heat of charging. My ipod is plugged in all the time and so it lasts an incredibly long time. If i have a particularly long continuous drain like mowing a lawn with an electric mower, i will go till the battery seems done and not try to force it beyond that and then put the battery in the basement in a cool place but not the fridge, for at least an hour so it completely cools down. Then i find the coolest place in the house like the floor in the basement (again not the fridge) and put them on charge and charge till it is done and leave it in the charger for awhile after, (i set the alarm on my ipod to remind me) and then let the batteries cool for at least an hour or three, and then use them. My batteries last a long time with doing this. NiCad batteries are supposed to be used till they are drained down or they will get a memory and will not top off properly, but the problem is that if they get too low they will short and the only way to revive them is to give them a blast of juice say from a lead acid car battery to break the short and then they will recharge. I would not try that with a lithium battery. (That's why Teslas are called "blow up cars".) The memory problem with NiCads IMO is more mythical than true and i've read articles that basically dis that practice basically because any weak cells will die first and thus reverse, so in our aircraft they have to drain (cycle) each cell separately and have a charger that electronic monitors it and shut off the draining at exactly the right voltage before recharging. In the 1970's?? The Canadian guv in their infinite wisdom forced all aircraft owners to install a Li powered "emergency locator transmitter" system in all aircraft to cut down on their very expensive search and rescue costs of locating downed aircraft. Very good idea but not well thought out. The Li batteries started blowing up and basically blowing the tail off of the aircraft. (ELTs are usually placed in the tail as it sustains less damage in a crash) Aircraft don't work properly without a tail for some reason...😏 Same as the "blow up Teslas" Another 'feature' on one device i have is that if the Li battery sits, say all winter with no use, the battery will discharge a certain amount (i forget why) so i never leave it on the device and charge it periodically. Basically i know this info from lots of articles in RC aircraft magazines on charging, combined with listening to mechanics.
Ni cad has been replaced with nickel metal hydride batteries. they don't have the memory effect. lead acid batteries like being kept fully charged. lithium batteries last the longest when used between 20% and 80% charge. They make LIFEP04 batteries which don't catch on fire and have a much higher cycle life. the draw back is the maximum current draw is at their amp hour rating. The charge current is at a quarter of the amp hour rating..
In case you don't have a second battery to jump start the dead battery, I did the same thing using my car battery and a set of jumper cables. I had to clip a piece of wire onto one end of each jumper cable so I would have something small enough to fit into the grooves on the Dewalt battery. I used an old guitar string because I had one handy. I only jumpered them together for less than a minute. The 12-14 volt car battery shouldn't cause any harm to the 20V battery...and it didn't. I have used that rescued battery for about 2 years since then and never had to jump start it again.
Very cool! I wasn't looking for this information, but I'm glad it popped up in my search for when I (eventually) run into this problem!! Thank you. You also explain things very well.
I did this only once but the battery that I charged is still working fine about 2 years later. I use it often too. When it was dead it had never been used before. It was purchased, then sat unused for several years causing it to lose all of its' charge. Possibly that is a factor in why it has worked so well since I charged it??? I don't know.
@veganpotterthevegan it's much cheaper and you can always fix them even when Dewalt discontinue them. But then again I expect a vegan to be overwhelmed by a simple task.
Beware - this trick can definitely work if the problem is that all cells have a too low voltage. However if all cells but one are good and one cell is dead short - which definitely commonly happens too - it's an easy way to start a fire. To prevent this, chargers for n-cell batteries tend to refuse to charge when the measured voltage is smaller than the fully charged voltage of (n-1) cells. Some chargers are more clever than this and look at the charge/discharge curve to detect this condition more reliably - these chargers will have better chances at reviving a dead battery. Thus, when doing this, best do it outdoors, with no flammable material nearby, and also thoroughly test the battery afterwards - either by fully charging, discharging and recharging once to see if it gets a good charge (on a single cell short you likely will have an "empty" - as in, too low voltage - battery soon after use again) or fully charging, discharging a bit (like a minute of power drilling into the air) and checking its voltage to see if it is near its design voltage (if it has a single cell short, it will go below design voltage very soon after charging and even drawing a small amount of energy from it).
Yes but those chargers also blink in a way showing that something is wrong. This method would only introduce enough power so that the charger can recognize it and either start charging it again like normal or if there is an issue, at that point would blink, usually rapidly, to let you know there is an issue and needs to be replaced.
I have a battery that the Dewalt charger shows as charged (solid light) but it won't power any of my tools. I was told it may have one dead cell. Have you come across that? I haven't tried this trick on it because I was afraid it may not be safe. Looking to buy another spare battery instead.
Dude, you need to mention that if the two scissors touch, you gd ot a dead short. The good battery could explode or catch fire. Somebody is gonna start a fire and sue you. You need a little safety disclaimer...lol
I've got a small pile of dead batteries at work that I'm going to try this on. At least two of them are behaving exactly like what you show in the video, some of them are Makita 18v, and when you put them on the charger, the charger indicates a fault in the battery, but I don't know if it's a similar issue or not, and this seems like a good place to start troubleshooting.
I just got a brand new 14.4 volt dewalt with two batteries and charger. Never used to put totally dead. Purchasing one cheap battery on Amazon and will try to get my old ones going.
I watch your video and tried it on two car batteries using un insulated wires about a month ago. Since then, I am really enjoying it up here in heaven.😀
This video just resurrected my old 14.4V Snap-On 3/8 Impact. It's been in the bottom drawer of my tool box since about 2007. Both batteries were dead and the charger read them as faulty. I hooked one of them up to my 12V car battery charger set on 2 amps, and after 5 minutes the Snap-On charger would read it and apply a charge. Now while the one battery is on the charger the other is on my car charger.
Didn't work with a 40V Ryobi and I'm sort of glad it didn't. I too have seen Li Ion batteries melt down. After I played around with these cures, I set the batteries outside in fear of burning the home down. I love the cordless tool, but Ryobi 40vs are just too sensitive to this issue. The replacement cost is now reaching $200. It's nearly always cheaper to buy an entirely new tool. Which is why I now have three string trimmers.
Have you ever run into this issue? Did you end up just replacing the batteries?
I wonder if this could be done with RC batteries?
As long as you're using an identical battery pack to try this and they are rechargeable, you should be fine. @@jc2200
I still have my dead batteries, so I'm going to try this. You're awesome. Thank you so much. I'm going to try this now.
I didn't replace them because I had already seen the 700 OTHER videos that explain this procedure on you tube.
@andys5562 cool. But that’s definitely an exaggeration 😂
I have just tried this with my Milwaukee 18v battery that has been dead for 4 years. It absolutely works beats paying $100’s of dollars in batteries.
Thanks brother love your work….
I am gonna try this as well with my Milwaukee M18 battery
Agree, not cheap. Escpecially higher volt ones.
A-@@cornelisgoedegebuur
this is very scare, my cat is sad
@@grahamcracker659
What is occurring here is that the battery packs contain a fuel gauging and safety IC. The charger must communicate to this IC, before the battery can charge. If the battery gets to a low enough voltage, the IC will be unpowered, and unable to communicate. There is a way in most of these IC solutions to provide a slow charge path for a deeply discharged battery. The issue is that some manufacturers, because of their cell chemistry, don't want a battery which has dropped below about 1V per cell, to ever be used, as it can cause plating of the current collector materials into the carbon matrix, which can then become energized when the cell gets charged, resulting in shorts and localized heating, which can then lead to what is referred to in the battery industry as "rapid disassembly", more often called an explosion by consumers!
If the battery reaches low voltage because it was stored uncharged, and left in that state for a long period, it would typically take multiple months, it may reach a low voltage. Such cells are usually safe to recharge, but to be sure you really need to get the info from the cell makers datasheet. The other reason the cells can reach such a low voltage, is because they are wearing out, and their impedance is increasing and capacity is starting to rapidly decline. This can cause a cell to go to zero volts during storage due to increased leakage currents within the cells. Such cells are typically unsafe to recharge!
If you are going to do this, be very careful. Recovery of such packs is at a greater risk of catastrophic failure for the cells. Watch such packs carefully during charge, and even for half a day after the recharge. I have seen cells fail after such recovery charging as long as 8.5 hours after charging was complete. A single fire can cost you much more than the price of a replacement pack.
I wanted to make sure people are warned of the potential consequences. Please be extremely careful. I highly suggest replacing such packs unless you know they were stored uncharged and left for a multiple months. Li based cells are fickle, they contain tremendous energy. When things go bad, they go bad quickly and violently. Please take this warning seriously. I would hate someone to lose someone they love to such a senseless accident!
Excellent analysis
Absolutely true Brian. Lithium ion cells are far too unpredictable for messing about with. If they lose their charging ability replace them.
Thanks for your technical advice Brian. Very good information
u are right on point.
“ but to be sure you really need to get the info from the cell makers datasheet. ”
Lmafo, don’t even bother. If you can even find the original manufacturer and get a data sheet they NEVER have this information. They usually don’t even have actual capacity at various discharge rates or even temperatures sometimes they don’t even have the capacity which is insane. The data sheet says almost nothing beyond “what you want? It’s a BATTERY”.
The scissors trick is jankiest of solutions in the best way. Love it!
Wow! I tried it on a Ryobi 40W battery with speaker wire and the technique worked. Thanks.
Was it blinking defective or nothing at all? Mine is blinking defective and I wonder if I should try this
@@leeabell183 My battery was not blinking defective; it was dead with no lights. I don’t know if it would work on one where the lights indicate there is a problem. Might be worth a try. By the way, my reclaimed battery is still working.
The wife here. My hubby ran away from home. Left me with some old Ryobi tools and DEAD BATTERIES. I'm so blessed to find this process. I have friends with working Ryobi batteries. Now I can fix mine. Thank you!
Who needs a man around the house anyway with plenty of batteries on charge 😂
@@21stcenturycaveman33 Or youtube. Hey at least he left some tools.
Tell your hubby don't come back and your keeping the tools
He ain't coming back, ran off with the cute secretary 😅
@@joegonzalez1941 Most men choose ugly women for their secretary for a reason(wife is insecure). Then I thought, if they were real men they would not chase a better looking woman. So there is th at.
You probably won't agree with my unpopular opinion. Looks fade.
I have several 40V Greenworks outdoor power tools; mower, trimmer, leaf blower. About 3-4 years ago one of the expensive (more then $100 at the time. They've come down in price since then) 5 amp batteries stopped working. Wouldn't charge, wouldn't run. So, having nothing to lose, I took it apart. On top of the batteries is a circuit board. On the circuit board was a flat automotive fuse, soldered into 2 slots on the board. The fuse was blown. I unsoldered the fuse and pulled it out. Got a new one of matching amperage from my tool box, trimmed about 1/8" off of the blades so it would sit low on the board like the original, and soldered it in place exactly like the original. Worked perfectly. I'm still using that battery.
They do this with televisions, they do this with washer and dryers and microwaves. I know because I have replaced a fuse on all these in every single one was a Samsung. What a scam.
@@BillyP-49Chevy it's not a scam, it's a fuse. It protects the electronics. If there was no fuse it would have blown an expensive or difficult to replace component in the electronics when it could have been easily protected with an inexpensive and relatively easy to replace fuse. Almost every electric and electronic device has internal fuse protection with troubleshooting and replacement details in the owners manual.
Is that what they call ‘planned obsolescence’?
@@rupertcornelius8924 You are partly right. The fuse certainly does protect the electronics. But in this case there is no mention of it in the owners manual or any literature, and it is in no way intended to be replaced if it blows. What they want to happen is for the owner to declare the battery dead, trash/recycle it, and spend >$100 on a new battery. THAT is the scam. The fuse should be in a fuse socket in a user-accessible location so when it blows it can be replaced.
@@redfo3009 Not so much planned obsolescence as planned premature failure.
Just came across this video and had a DeWalt 20v battery I was about to take to recycle it. Figured I’d give this a shot, and you just saved me a battery! Working again like a charm!
Still working?
@@couchpoet1 it is! Works as well as the other two I have.
I did that scissors trick when I was 4 with a 120v outlet. Much more memorable. Now that I am an 61 with a EE degree I would recommend a fuse and alligator clips.
I second the fuse and alligator clips. You REALLY don't want to see a Li battery fire inside your house or garage.
What size fuse would you suggest?
30 amp most likely. As thats around the max output of a samsung high output cell
Ha ha! I did that same trick with a pair of wired toy “Rabbit ears”. I was 5 years old and was curious as to what would happen if I stuck those ears into a 120v outlet. Poof!!! One scared kid and a blown fuse. 😅
I wish you had done this video. ❤️
Ok, I have a 40v lithium battery for my Black & Decker weed trimmer. Over a year ago the battery was dead as any door nail. But I kept it for later recycling with other batteries. I saw this video and went to work to see if your jumper trick would work. I fully charged the good battery. Then I made my connections and gave it time. I came back in about 10 minutes and the "dead" battery was warm. I removed the wires and put that battery on the charger! It works! The red light started flashing. It's now working to be fully charged. I now have two 40v batteries to work with. Thanks for this great tip.
I just did the same thing! Amazing!!
@@lindsayadams4905 My battery showed that it was recharging--green light-- but after a few minutes it got the flashing red light. I assume the battery is bad. But the trick did work when it showed no green light.
Door nails may be dead but door screws are very much alive
Totally works. Did it with Dewalt 40V yard tool batteries. Took about an hour to reach "threshold voltage" that the charger would recognize. Thanks man!
Wow, I'm glad I watched this. I have a bunch of new batteries that have been sitting around for years going dead. I am so glad I can revive them now that I'm able to use power tools again.
Let me know if thatvworks
Nice tips, my addition would be to flatten your solid copper wire ends rather than forcing them in. Mechanically spread and damaged connector terminals inside the pack will also render it unusable in a much less fixable manner. It can overheat and melt the plastic around it in your battery pack and leave a burned pitted spot in your tool's contacts as well.
when you insert the battery into the charger it spreads the terminals apart to make a good connection. It's designed to handle this over and over again. Its a non issue.
My procrastination finally paid off! Have several of these batteries in garage intending to go to recycling. Yay!! Thank you!!!
Thanks for this tutorial, I tried it on my M18 red lithium, it sparked a little but all it took was less than a min and now its charging, this is awsome!!
I have a brand new hammer drill with a bad battery that I purchased. I'm glad I kept it. Just saw your video and tried it out. It's currently charging. Thank you for sharing the trick.
3-5 minutes might be generous. It can be a lot faster. I learned this last summer from a different video and listed much shorter times. So I tried what they said. 20v dewalt - I connected the wires for about 30 seconds and that was all I needed to have just enough juice to get the charger going. I'm glad people are sharing this information. Seems a shame for batteries to be getting tossed / recycled unnecessarily.
Yeah, completely depends on the battery. Sometimes shorter can work as well. Appreciate the input!
yes a few seconds is more than enough - it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first because the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuild BMS detects this condition and tells any devices which respect it to shut off power from it.
the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
These cells don't actually reach zero. The charger will cut them off between 3 and 2.5 volts. They will not let you discharge them completely because it would likely catch on fire. What happens is the battery is charged up to 4 Volts. It is used till it hits its cutoff voltage around 3 volts then instead of charging it you put it into your bag for three or four days and the battery self discharges to less than 2.5 at which point you need to do what he says here to charge them. The reason I t takes so little time is that you are only bringing the battery from around 2.4 to 2.6 volts enough where it is recognized. If your battery hit zero you would never be able to charge it again. If a lithium battery ever reached a negative voltage it would quickly achieve thermal runaway. The battery packs don't look for negative voltage to stop charging. They test each set of batteries for the low voltage cutoff. You are right about the imbalance though it happens at much higher tha zero volts.
I'm not sure how lithium batteries deal with imbalanced cells but in lead acid deep discharge batteries you overcharge them up to about 14 or 15 volts for a short time. This brings all the individual cells up to the same voltage.
@j
😊lrinc1420
These types of batteries don't get recycled. Green ain't all that friendly!
For the 18volt dead battery, instead of wires or scissors to charge off of another 18 volt battery. Just use a typical 9 volt battery and place upside down on the prongs for about a min. Should send a charge to get it recognized by the charger. Super easy!
👍
Do you have to match the + and - on the 9v to certain sides of the battery your sending the charge to?
That is an intelligent question since it is definitely a DC battery@@jmar8507
Do a video, I'd like to see you do that... before I try it.
@@jmar8507this
Give a new meaning to scissoring
😂 You'll have a blast💥🤣
It frekn worked!!! Have about 10+ completely new but dead Milwaukee batteries and did this, they're now charging!!
WOW, It worked on my 18v Black & Decker dead battery. Fully charged and holds charge well. Thank you for the tip. Super.
You are very welcome! Really glad to hear it was helpful to you. Thanks a lot for the feedback!
Thanks! You just saved me money. I was just about to get a replacement for a battery I thought was dead. Thanks again.
I did jumped the dewalt 18v xrp batterys according to your instructions for my dewalt 18v xrp batterys. And so far it worked. No errors on the charger. Time will tell. The 20v adapter puts every tool out of balance and too tall. And my problem is I purchased about 10 major 18v tools and really don't want to add an adapter. All my Dewalt 18v tools are still in their hard cases, most only used once. Thanks for the video.
Awesome! Glad to hear it was able to help. Thanks a lot for the feedback Doug!
EE? Eat Everything?!
I've had this issue before. In the past, I've just left the battery in the charger, and sometimes, after a few hours, the battery starts taking a charge. Perhaps the charger recognized a slight charge during the process. Will use your tips, though - much easier!
That’s what I did on 2 lightly used older Milwaukee 20’s.
Yes cause even though charger doesn't recognize battery when dead to give charge, when u connect the dead battery the charger, the charger still gives a very small amount discharge naturally and after hours of that miniscule amount of electricity going to the battery, it gets it to the point where it builds up enough stored electricity to have the charger recognize it
Awesome video. Thanks!😊
I did it and it worked. 18 volt Makita. It did spark when I made contact (lithium batteries) but left only for 60 seconds and put it on the charger- it is charging! Thank you, thank you. Just bought two new batteries for $185- wish I saw this earlier.
Hey. I tried this on a dewalt flex volt and it worked. You’ve saved me $200🤙 Thanks so much. Great video 🙏🏻
Just seen the video, just tried it and it does work. I think this is the first time I’ve tried a hack I seen on a video and this did work. I had two of the exact 20v that crapped out when they were new. I just never threw them away.
Thanks!
Gents. I'm with Brian. Be very careful when attempting to revive an LI batteries regardless of method. Have some sort of fire suit on when you take matters in hand. Use scissor techniquice in case you must quickly disengage or the explosion may disengage for you. You never know.
Do this outside your house away from burnable materials as extra precaution just to be safe. Otherwise, happy recharging!!
Very helpful... any suggestion for a blinking charger and the battery isn't charging?
I don’t have a solution but i DO have the same problem with one of my Ryobi batteries. It flashes the “maintenance charge” sequence (slow, gradual flashing).
Super advice thank you, I have done this a few times, recently on those solar lights that gets too low during winter and can't charge in the spring
I just did this to my completely dead 18V Milwaukee battery pack . It had 0.01V before I jumped it. It's now on the charger and had 19.21V after jumping it for about 4 minutes from my 2nd battery that had a full charge.
This works!
Great video. Great comment section. To avoid any kind of battery fire due to over charging or failure. Get your self a metal garden shed run a 120v GFCI circuit to it and make a charging and battery storage set-up insde it for your rechargeable battries. Locate it as far as possible from occupied structures garages and any flamable materials. Dont ask how I know... a thief leaves the coat hangars, fire leaves nothing...
I'm a retired Electrical Contractor. ✌️🙏😇 Stay Safe. ❤
Great idea. I would also suggest a smoke alarm, a cut off switch and a bucket of sand. Also - would a metal shed get hot in the sun and overheat the battery and charger?
This How to Home gentleman could be a millionaire with what seems to be hundreds of really good DYI ideas to save time (which is saving $$). Thanks to How to Home.
I wish haha. You are very welcome! Really glad to hear you are finding so much value in the channel! Thanks a lot for all the great feedback Robert!
What a good and simple way of explaining how to revive these batteries!
I am a retired electrical engineer and never gave this a thought.
Keep up the good work!
The batteries are not being revived. li-ion, lipo and similar chemistry batteries once they are discharged below their lowest discharge voltage rating (normally around 2.2-2.5v per cell) they become useless. Yes you might get them to take a charge but, it'll never be 100% and the capacity is severely reduced.
I think those are rated as 80% capacity. You never get back to 100%. Anyway, use the battery until it can no longer takes a charge. Squeeze every volt out. @@Blueknight1960
@@Blueknight1960 A reduced capacity is far better than a zero functioning brick.
yes a few seconds is more than enough - it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first before the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuilt BMS detects this condition and tells any devices which respect it to shut off power from it.
the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
Is there a way to do this without another good battery, Say a power supply or a stack of 9 volt batteries?
Thanks for the great advice. I tried it today on two what I thought were dead Milwaukee 18v batteries. Both are now on the charger.
I learned about this tendency of rechargeable batteries needing this "jump starting" when I got a universal camera battery charger after I bought 2 used cameras that had been stored for a very long time and their batteries would not charge on the charger that came with the cams. It has a sort of "boost" function you can engage to charge a completely dead camera battery. Always good to know things like this.
Oh wow, wished I had known this a few years ago, would have saved me lots of money in new batteries. Thank you!!
You're welcome! Really glad to hear you liked it. Thanks a lot for the feedback!
I've never had to buy a battery, I use a plug! These types of batteries cannot be recycled so it's just adding to a pollution problem that IS KILLING our planet!
Hi, Just watched your battery revival video. Question: If you have only one 18v battery, could you use a 12v power supply to 'jump' the dead battery??
I haven’t had this issue yet. But I’m glad you showed how to jump start as a first test of a battery’s health!
D😮ttd
Thanks for the tip. Years ago I tried saving money by getting cloned DeWalt 18v batteries but they didn't quite fit properly. I took them apart and stuffed the guts into the original worn out batteries and they worked. Something about how the clones made them not fit the charger right, so changing out the cases worked. Worn out batteries have a faster flashing light indicating no more charge cycles left. Heavy use for ten years exceeded their charging cycles. This is also true for NIMH AA & AAA batteries.
FYI, sometimes the issue is with bent connections. Look at the spacing of the metal tabs and compare to the charged battery, then slightly bend the tab to make a proper connection. I had this issue after loaning a tool to my brother in law. I bent the tab back and the tool worked again.
it was a little anxiety-inducing but just revived an 18v using the scissors method, thank you so much! living in the city without a car, jumper cables and insulated wires aren't something I have on hand.. so this really helped!
Tries it on a newer dead battery - worked like a champ !!!! thank you for the video
Wife likes all kinds of ambiance low power stuff around the house. I made her switch to rechargeable batteries due to how many she was going through. The problem with these devices is that they will suck a battery to 0. So i built a board to be able to jump-start them and get them to change easily. Works really well. I've also done this on car batteries, Zegway batteries, and many others threw the years. Never had an issue.
An excellent video. This illistrates the principle that a good battery sacrifices toward a dead battery. They will share the electricty equally. In the old days truck mechanics used this to start an exhausted battery.
I'd written off a nearly new grass strimmer because neither 18 volt battery would recharge. I actually purchased a replacement strimmer of higher voltage.
Your demo got me using my DeWalt 18 volt battery to connect to each of the anonymous strimmer batteries in turn.
Hey presto! I now have two working strimmers!
Also the other of my two DeWalt 18 volt batteries had become unrechargeable so I applied your cure and now am back to having both available.
Many thanks for taking the trouble to put out your fix for everyone's benefit [except perhaps for the battery manufacturer!].
I brought an impact driver yesterday and the charger would not charge the battery.
I just tried this today and it worked. I only connected it for 10 seconds.
Thank you!
I wish i had seen this before I bought a new drill battery. Thanks so much for the tip, and you always have good info.
Keeper trick. I always keep old battery's waiting for a trick like this. Many Thank you's.
You absolute legend! Had a Worx battery that had appeared dead after only a few months of owning. Luckily Worx replaced it within warranty. However I kept the dead one 'just in case'. It now lives thanks to this genius tip. Thanks again!
Perfect timing. I just had a 20v dewalt stop charging for some reason. Can’t wait to try this
great video, I really appreciate the tips you shared! it's impressive how simple steps can make a big difference. but honestly, I wonder if all those methods really work for every type of battery. I've had mixed results with some brands, and sometimes it feels like a gamble. anyone else feel that way?
This is one of the most useful videos I have ever seen. Thanks for posting.
You're welcome! Really glad to hear you liked it. Thanks a lot for the feedback!
Ones it work on lithium batteries?
Never had this condition before, but I have had the charger say the pack is bad a lot. But I gotta add that a current limited power supply would be a better choice for this. The dead battery could overheat and die from the potential short circuit current draw if the dead battery cell is defective.
Did you mean the Good battery could die?
a few seconds is all it takes, it is indeed dangerous to do this for the stated 3-5 minutes.
it is nothing to do with the explanation he gave, it is about individual cell polarity reversal which occurs when a lithium 'bank' (group of cells) approaches 0v of charge : as if the cells are not perfectly balanced (they can't ever be) then one cell will reach zero first before the others, and that cell ends up with a NEGATIVE voltage (or reversed polarity) -- the inbuilt BMS detects this condition and tells any devices which respect it to shut off power from it.
the hot 'jump' technique to the battery+/- terminals forces those flipped cells back into positive voltage levels by overpowering them. BRIEFLY! a few seconds is all it takes. any more can be dangerous.
This is a brilliant idea. Thank you so much. Also, you've provided a very clear explanation of the situation and how to correct it. A breath of fresh air.
Just tried this and it really worked well first time. I had some small alligator clip leads which made it really easy. Totally impressed!
I tried the trick and it worked as the video clip shows. Thank you.
You're welcome!
I’ve done this with Ego56v batteries and it does work. I had a battery that wouldn’t take a charge and registered a fault, ran the wires like he showed and it gave the “bad” battery just enough charge for the charger to recognize it as a good battery in need of charging.
Nice. We seem to replace a lot of B&D batteries for our weedeater(s) - I'm trying this next time!
While this does work, there is nothing to regulate the current when you connect the positive wire. There's always a chance with Lithium that you'll have a fire if you charge or discharge too rapidly. I recommend using a current limited bench power supply, or be ready to chuck the whole thing outside because it's on fire.
Probably a good idea to not just walk away from it while doing this. I don't even leave a battery on a charger any longer than it takes to charge it. I keep checking on it and when charged it comes out of the charger and unplug the charger.
@@tsmartinI know you can leave Bosch, DeWalt, and Milwaukee in the charger since they implement a charge protection timer. Ryobi still doesn’t last I checked. RTFM
Thank you for taking the time to do the step by step resurrecting of the battery
Man- this tip
Saved me a trip back the store for yet another tool replacement! So glad I saw this and had plenty of Romex from my remodel available! Worked like a charm. Thx!!!
I've done this before. one way for the manufacturers to prevent this issue is to have a jumpstart button on their chargers. I suppose that would be counter profitable because they can't sell more batteries that way…
For once it's actually got nothing to do with making more money. These batteries can be dangerous when handled by fools. Including the numb nuts that made this video.
Ingenious! Love this! Thank you so much for the wonderful tip! Gonna save people some serious bucks!❤
Not really because once you drain one of those batteries down too low, they become worthless. Yes you might get them to take a charge but, the capacity of the cells will be too low to be of any use.
@@Blueknight1960 As I stated to another such comment, I jump-started a battery about 2 years ago and have used it many times since...never having to jump-start it again. It had been unused when it previously went completely dead (from lack of use), so admittedly that may be a factor. But it may not be a factor as well. I only know that it's operated as well as any new battery I ever owned for two years now, and I use my tools heavily...auto repair and home maintenance.
@tim9430 don’t try and give them actual facts Tim, many of them don’t like facts 😂. Appreciate the input.
If the batteries are any good they should hold a charge on the shelf as it were…. I have probably 20 DeWalt batteries in my collection and the only ones that go dead on their own are the ones that i know are weak… I have a 9 ah 60v that’s in my chainsaw and 2 years on the shelf and it still shows 3 bars
FYI - if batteries sit on the shelf unused they undergo a process called self-discharge. See wikipedia topic "battery self-discharge" for details. I have several Ryobi tools each with a battery and I rotate thru them so a battery doesn't sit unused for months on end. A lead-acid car battery can also self-discharge over time if left unused but also after years of use the chemistry degrades so they no longer hold much of a charge and need replacing. A table in the article notes lead-acid batteries self-discharge around 4-6% a month and eventually won't have enough charge to crank the engine. Lithium-Ion self-discharges 2-4% month and eventually won't have enough charge for the charger to recognize the battery as good. So the trick in this video seems like a good way to give a still-good battery a kick so the charger will charge it. But you will know if the battery is really degraded when it only runs the tool for a few minutes after "full" charging.
Not necessarily true, lithium holds onto its charge for a very long time. The only reason they self discharge here is because the BMS system is usually parasitic and requires a tiny bit of power to keep itself alive. The difference is that the lead acid discharge is because of its chemistry, and the lithium is because of its BMS. Does it really matter? No, but it is not a flat rate, a lithium battery with the same BMS but twice as large as another will bleed through the BMS twice as slow.
i used your trick today and it worked fine. Had a hyper Tough battery for a saws all that was dead. Thanks!!!
I just.
Got through watching your video and did exactly what you did. And now I'm recharging one more date battery. Thank you for your video.
Now do both the berries have to be the same size? 2 Same thing
Do the same thing
I've done this before but, although the batteries will then "charge", at least in my case, they were able to hold very little power.
Maybe the battery was aging out? I did this several months ago to a 20v dewalt and it seems to be working just fine. I just do not jobs (not contractor) so it would be hard for me to tell if it had a few percent less charge but if so it is not obvious. I have used it for a number of misc jobs since I charged it and have not yet had to recharge it.
I would expect different results depending on the age and wear ofnthe revived battery
Each pack has 5 cells to make up its voltage 18v/20v.
The BMS cuts off charge when one of the 5 reaches 4.15v.
So open battery and either discharge all to same voltage or use likes of a tp4056 and individually charge each of 5 cells to 4.15 v
Also note the discharge curve of lithium ion batteries shows that from fully charged they drop from 4.15v to around 4v in first 4% of discharge. Then slowly drop down to around 3.2 v and if kept in use again the curve drops like falling off a cliff
@@patomahony9747 Thanks!
Storing flat batteries will ruin them.
You can also use a spade connector for the 18v one
What is a spade connector?
I agree, much safer. A short piece of wire with 2 female connector at the ends.
The 20v and 18v are actually the same voltage. They each have 5 cells in series. Normally the cells are specified by their nominal voltage of 3.7v so 5x is 18.5v. However at full charge the cells are at 4.2v, so 5x is 21v. But there isn't much capacity between 4.1 and 4.2v, and it is better for the usable lifetime of the battery to not charge it up all the way, so 20v is a nice round number pretty close to the typical upper limit.
@Sylvan_dB Thanks. I appreciate knowing the details of "why".
correct, that's why Dewalt has the 20V MAX * and if you go to the fine print it says " *Maximum initial battery voltage (measured without a workload) is 20 volts. Nominal voltage is 18. "
this is true if they are both lithium ion batteries but the 18 volt batteries shown in this video are nickel cadmium and are a very different technology
@@jbbolts no they are not. Ryobi changed from nicad many years ago and no mainstream tool brand has been nimh.
@@Sylvan_dB except the ones in this video are dinosaur dewalts
It worked !!! It really worked. Thank you so much. I'm a single gal just trying to overcome obstacles like this ! And I did it !!!!!
I was just able to make this happen on a 20v porter cable battery. Excellent stuff!!! Thank you so much for the video.
Thank goodness I searched for "scissoring videos." This was helpful.
😂
Nice 😂
🤣
😮
🤦♂️
Thanks for helping me to save money once again!
You ROCK Brother!!!
You’re very welcome! Really glad you found it helpful. Thanks a lot for the feedback!
THAT'S AWESOME!!! It's just like boosting a car battery with another car battery. Thank you one million times!!!
Great information. I tried this with two old batteries, got one to work and accept a charge but the second wouldn't accept a charge and just shows a rapid flashing light on the charger. Any tips on a battery fix for the the rapid flashing light?
WOW!! What a simple yet brilliant video. Thank you!
Very nice. Never would have thought of using scissors.
What if red light continues to flash and no change to green after 20 minutes? Is it unrechargeble battery?
@maryreyes9926 yes. That is letting you know something is actually wrong with the battery and needs to be replaced.
Thanks for the info. My experience is that 'heat' kills any battery no matter what type and letting batteries go 'dead' and then leaving them partly charged is also bad news. Some batteries also dislike being anything other then constant topped especially gasoline car batteries. i tend to leave them on trickle charge and have a desulfator in my car engine compartment and plug it in whenever i think of it and my batteries last 10+ years. The charger is on a xmas light timer and runs about 15 to 30 minutes/day so the battery water levels don't go down from the constant heat of charging. My ipod is plugged in all the time and so it lasts an incredibly long time.
If i have a particularly long continuous drain like mowing a lawn with an electric mower, i will go till the battery seems done and not try to force it beyond that and then put the battery in the basement in a cool place but not the fridge, for at least an hour so it completely cools down. Then i find the coolest place in the house like the floor in the basement (again not the fridge) and put them on charge and charge till it is done and leave it in the charger for awhile after, (i set the alarm on my ipod to remind me) and then let the batteries cool for at least an hour or three, and then use them. My batteries last a long time with doing this.
NiCad batteries are supposed to be used till they are drained down or they will get a memory and will not top off properly, but the problem is that if they get too low they will short and the only way to revive them is to give them a blast of juice say from a lead acid car battery to break the short and then they will recharge. I would not try that with a lithium battery. (That's why Teslas are called "blow up cars".) The memory problem with NiCads IMO is more mythical than true and i've read articles that basically dis that practice basically because any weak cells will die first and thus reverse, so in our aircraft they have to drain (cycle) each cell separately and have a charger that electronic monitors it and shut off the draining at exactly the right voltage before recharging.
In the 1970's?? The Canadian guv in their infinite wisdom forced all aircraft owners to install a Li powered "emergency locator transmitter" system in all aircraft to cut down on their very expensive search and rescue costs of locating downed aircraft. Very good idea but not well thought out. The Li batteries started blowing up and basically blowing the tail off of the aircraft. (ELTs are usually placed in the tail as it sustains less damage in a crash) Aircraft don't work properly without a tail for some reason...😏 Same as the "blow up Teslas"
Another 'feature' on one device i have is that if the Li battery sits, say all winter with no use, the battery will discharge a certain amount (i forget why) so i never leave it on the device and charge it periodically.
Basically i know this info from lots of articles in RC aircraft magazines on charging, combined with listening to mechanics.
Ni cad has been replaced with nickel metal hydride batteries. they don't have the memory effect. lead acid batteries like being kept fully charged. lithium batteries last the longest when used between 20% and 80% charge. They make LIFEP04 batteries which don't catch on fire and have a much higher cycle life. the draw back is the maximum current draw is at their amp hour rating. The charge current is at a quarter of the amp hour rating..
In case you don't have a second battery to jump start the dead battery, I did the same thing using my car battery and a set of jumper cables. I had to clip a piece of wire onto one end of each jumper cable so I would have something small enough to fit into the grooves on the Dewalt battery. I used an old guitar string because I had one handy. I only jumpered them together for less than a minute. The 12-14 volt car battery shouldn't cause any harm to the 20V battery...and it didn't. I have used that rescued battery for about 2 years since then and never had to jump start it again.
Very cool! I wasn't looking for this information, but I'm glad it popped up in my search for when I (eventually) run into this problem!! Thank you. You also explain things very well.
Been doing this for years, however the dead battery doesn’t ever fully recharge or last as long as it should.
I did this only once but the battery that I charged is still working fine about 2 years later. I use it often too. When it was dead it had never been used before. It was purchased, then sat unused for several years causing it to lose all of its' charge. Possibly that is a factor in why it has worked so well since I charged it??? I don't know.
Just replace the cells inside.
@@StopWars420unless you have nothing to do, the time to change cells out isn't worth the cost savings.
@veganpotterthevegan it's much cheaper and you can always fix them even when Dewalt discontinue them. But then again I expect a vegan to be overwhelmed by a simple task.
@itsallinyourheadbiotch never said it's hard clown. But time is money. I have a lot more money than time for something so inexpensive
Beware - this trick can definitely work if the problem is that all cells have a too low voltage. However if all cells but one are good and one cell is dead short - which definitely commonly happens too - it's an easy way to start a fire. To prevent this, chargers for n-cell batteries tend to refuse to charge when the measured voltage is smaller than the fully charged voltage of (n-1) cells. Some chargers are more clever than this and look at the charge/discharge curve to detect this condition more reliably - these chargers will have better chances at reviving a dead battery.
Thus, when doing this, best do it outdoors, with no flammable material nearby, and also thoroughly test the battery afterwards - either by fully charging, discharging and recharging once to see if it gets a good charge (on a single cell short you likely will have an "empty" - as in, too low voltage - battery soon after use again) or fully charging, discharging a bit (like a minute of power drilling into the air) and checking its voltage to see if it is near its design voltage (if it has a single cell short, it will go below design voltage very soon after charging and even drawing a small amount of energy from it).
Yes but those chargers also blink in a way showing that something is wrong. This method would only introduce enough power so that the charger can recognize it and either start charging it again like normal or if there is an issue, at that point would blink, usually rapidly, to let you know there is an issue and needs to be replaced.
I have a battery that the Dewalt charger shows as charged (solid light) but it won't power any of my tools. I was told it may have one dead cell. Have you come across that? I haven't tried this trick on it because I was afraid it may not be safe. Looking to buy another spare battery instead.
Dude, you need to mention that if the two scissors touch, you gd ot a dead short. The good battery could explode or catch fire. Somebody is gonna start a fire and sue you. You need a little safety disclaimer...lol
Everything at your own risk wtf are you going on about.
Part of the stupid label generation
Thanks 😊
Fantastic info! I have several dead batteries that I am going to try this out on.
Wow! I will definitely try this. I have a couple that are dead and I figured there might be a way to revive them. Thank you!
I've got a small pile of dead batteries at work that I'm going to try this on. At least two of them are behaving exactly like what you show in the video, some of them are Makita 18v, and when you put them on the charger, the charger indicates a fault in the battery, but I don't know if it's a similar issue or not, and this seems like a good place to start troubleshooting.
I just got a brand new 14.4 volt dewalt with two batteries and charger. Never used to put totally dead. Purchasing one cheap battery on Amazon and will try to get my old ones going.
Just tried it on my Dewalt 2ah stack that died after a few months. Now I can recharge it. Thanks for the tip
Thank you for your selfless dedication
Just did mines and it's charging now great 👍 information thank you 👍😎
Just helped me fix one of my dead craftsman batteries. Thank you.
I watch your video and tried it on two car batteries using un insulated wires about a month ago. Since then, I am really enjoying it up here in heaven.😀
😅😅😅😅
thank you so much for sharing, I have a couple of dead batteries and I will try it. 9:53
This video just resurrected my old 14.4V Snap-On 3/8 Impact. It's been in the bottom drawer of my tool box since about 2007. Both batteries were dead and the charger read them as faulty. I hooked one of them up to my 12V car battery charger set on 2 amps, and after 5 minutes the Snap-On charger would read it and apply a charge. Now while the one battery is on the charger the other is on my car charger.
Cool. Some of the best tips I've seen recently. Batteries can be expensive. Thanks so much.
Didn't work with a 40V Ryobi and I'm sort of glad it didn't. I too have seen Li Ion batteries melt down. After I played around with these cures, I set the batteries outside in fear of burning the home down. I love the cordless tool, but Ryobi 40vs are just too sensitive to this issue. The replacement cost is now reaching $200. It's nearly always cheaper to buy an entirely new tool. Which is why I now have three string trimmers.
Thank you, that helps alot and makes sense of not registering with the charger, worked for my ham radio batteries as well
Worked on my 20v Craftsman lithiums!
SERIOUSLY, thank you!
I just tried this using an 18 volt hitachi to jumpstart a 20v craftsman and it worked!
I absolutely LOVE the scissors trick for 18v batteries! Gonna get right on it. Thank you!!!!!