@@paulirumbin1541 no you is ignorant! I am Wright. The Utuber has no klue what hes talkin bout. I've been a major master electrician for 79 years and I can tell you paralleling series only ads resistence while lowering ohms. No extra power is created.
I am new to you. I think you are priceless. Probably one of the best teachers I have seen on TH-cam. Very thorough, to the point and also a great sense of humor. I have learned so much from you, and am grateful. Thank you so much.
My partner has a lot of tools, so when he needed a circular saw, I ordered this one for him as a Christmas gift. th-cam.com/users/postUgkxYDKeIjKLOfcwTgdin7TtCutsz4MbIc43 He is incredibly happy with the purchase. He stated that he likes that it is powerful, but still easy to use and cuts very well. He mentioned that it is important to know the right tools for the job at hand, and this compact saw has been exactly what he needed for a variety of projects at his rental properties and renovations. He also appreciates the battery packs, as stated, he owns a lot of DEWALT tools, so he is able to always keep batteries charged as needed.
This is a great idea and so simple. Im building an ebike and are using powertool batteries but thought i would need to stack the batteries ontop of each other. Your way is way more efficient for space. Plus my 36 volt system would only need 2 chargers which i already have instead of swapping the batteries over or buy more chargers. I would just use threaded rod and nuts on the top to hold them together. Another great use would be to make your own powerwall this way.
You did not need to join the balancing connections with as heavy of wire. Since your cells are in a 6S5P configuration you could have kept a single strip down each of the balancing leads since very little current should ever flow. The most positive and most negative connections are the only connections that need to carry a large amount of current. The balance leads ensure that no one parallel set of cells goes over or under the preset voltage in the balance circuit. If one set goes lower than the rest the balance circuit will cut the power as soon as the lowest set of cells in the parallel string reaches the cut off voltage. The next time it is charged the balance board will ensure that all each set is at approximately the same charge voltage when fully charged. Since one pack can deliver 20A you can assume that the drill is not able to draw over that 20A in normal operation so as long as all your most positive and most negative connections can handle that 20A it won't matter that the pack can deliver 100A since the drill and even the balance board were not designed to go over the 20A. This pack as long as it is not damaged will likely outlast the drill since now the cells will not be abused near as much as they will share the current draw rather than one set having to provide the full 20A each string will now only have to provide 4A of current.
Those strips are carrying the current of the extra battery packs. He did not connect the main positive and negative terminals of the extra batteries. The strips will be used to balance also.
@@draytonPW I think what he is saying that he could have just joined all of the end teminals + and - from each of the 5x battery packs only, instead of joining all teminals of all cells within each of the battery packs. Either way I probably would have done it the way he did it for structural integrity none the less.
I know this is old video but I'm planning on doing something similar. Looking back would you now construct these in a different fashion? I recently bought many of the Kobalt 1.5ah battery packs(2 for $15) and now plan on putting 10 together for 15ah packs (24 volts each). I'll wire these in series to create 48 volt packs for our trikes. I am currently using smaller versions and they work great! The smaller versions were created with not taking the cases off but keeping them intact and jumping the terminals with custom cables to create 48 volt packs. I charged the packs by taking the cables apart (a pain) with four Kobalt chargers. I want to make the new packs similar to yours but thought you might have other ideas on how to construct them. Thanks for all your thought provoking videos and entertaining humor!
TL;DR: This is a long comment. I go into detail about multi-cell packs and at the end voice my concerns for mechanical, (not electrical) safety. So there's quite a few things going on here. that are advantageous, though maybe don't take it all the way to 5P configuration due to practicality and weight. -First: You're pentupling the capacity. This means longer run-time. -Second: You're minimizing voltage-drop. 18650 cells may be rated to give a peak output of 20A, but they sag like crazy at that current level and heat very quickly. The maximum output is "maximum current for 1 minute before catastrophic failure" or somesuch. Add more parallel cells, minimize voltage drop, get more continuous wattage out of the battery. Some of the drill motors are capable of pulling 80A+ peak (stall current) if the motor controllers let them. How manufacturers think that a 1P battery pack is even REMOTELY capable of handling that kind of current, I have no idea. The general rule-of-thumb when it comes to Lithium-based batteries is limit current to 1/4 "rated" maximum to preserve the health of the cell. Any more and you're damaging it internally every time you discharge. -Third: You're extending cell life by reducing both charge and discharge current-per-cell by a significant margin. Cells will survive far more cycles if charged at 0.5 to 0.2 their C-rating. Assuming a half hour charge and 2Ah cells, the charger likely outputs 4A. That means that now you're charge less than an amp per cell, which will significantly lower the load both in discharge and charge cycles. The only concerns I have are that the tabs need to be doubled on the end connections for load-bearing, (balance current is far less than charge or discharge current, so the middle connections can be a single strip; end connections need at least two since the full current of the pack charges/discharges through them). Balancing is done by charging through the entire pack, and bleeding off energy into a resistive element from the cells that are close to maximum voltage, while the others catch up. In essence balance charging is where the higher-voltage cells get charged "slower" than the lower voltage cells. Additionally, I'm concerned about structural integrity of the cells. Foam and tape are not good enough in an industrial environment; dust can still get in, metallic objects can easily pierce the covering and short something. I'd at least take some corrugated plastic material and wrap the sides to help protect from these sorts of dangers. Further, dropping or bumping the bottom of the pack while it is attached could cause the adhesive tape between parallel packs to come loose, or worse, break the solder points or put stress on them. In a worst-case scenario that's a recipe for a short and catastrophic failure. The best would be to 3D print a new case that covers the full size of the pack, (if you have such a resource available to you).
@Eitan did you know for sure that the circuit balance each line of the series? I haven´t seen a balancer included on the packs, it could be great they started implementing this on consumer electronics, specialy laptops. I also think that those wires will get undersized, but depending on the load required they could be safer that way... If he is willing to reinforce the wires i would suggest him to use a termal resistor / fuse in serie that will open circuit on over currents, just to be safe and avoid fire (every pack from respected manufacturers include one or leave a thin pad that will fuse).
@Matias D.B. All consumer packs have balance circuits for each cell in a series configuration. Balancing will occur regardless of however many parallel elements are in the pack. The only possible danger is if you have mis-matched cells that have very different resistance values or very different states of charge. Different states of charge will cause one cell to discharge into another when you solder them together. Different resistance values will cause one cell to discharge and charge at a different rate, causing one cell to be "weak" vs. it's parallel companion(s). Fusible links are a thing, and definitely help, but may be cost-prohibitive for this DIY-minded build. That of course assumes that the people doing this sort of modification know anything about battery building and treat their modified packs with care.
Do you have some general rules you would recommend for how to Charge and Discharge battery pack? Frequency of charging, how low can you go before charging them back up, etc? How do we get longer life out of batteries in general?
With the new 21700 cells there are now OEM batteries available with only 10 cells and 18 Volt 8 Ah. For cordless drills you normally don't need such big batteries, but other tools like circular saws or chain saws can benefit from it. You should never use soldering to connect lithium ion batteries. Even if you solder fast to limit the amount of heat going into the battery they will be damaged, especially at the negative terminal. All commercial packs are spot welded. Spot welding is the only recommendable connection method for round cells.
I disagree. Have you ever soldered a Li-ion battery and damaged it? I have been using these Kobalt packs on my ebike and it's been 1.5 years and still kicking. In fact, I solder ALL of my Li-ion batteries for everything (so far) and haven't seen any single cell that fails. Your assumption doesn't have any real facts to back it up. Commercial packs are spot welded because it saves time.
A few points to consider before using such mod: a. With this configuration the balance charger treats a whole series of 5 batteries as a single cell so it won't detect a failure in a single battery on such array. If one cell will fail it will overheat and damage the other batteries or even explode from the accumulating heat. b. The added weight makes it impractical to work with. c. I can't be sure that the motor can handle continuous torque that can be achieved through this mod. Overall - nice concept but should be made at least with battery charge management for each cell and some good heat spread in some way.
Not genius at all. In fact it didn't even make sense. He was correct in calling that Battery 10 AMp hour. However he was incorrect calling it a 100 V. It is still only twenty four volts.
bruh, when did he say 100V? 17:33 he said 100A. the battery could deliver a maximum of 100A at 24V. doesn’t mean the engine will draw 100A when it’s working. probably much less. Wall sockets (in eu at least) can deliver 16A,230V usually with a circuit breaker when exceeding 16A, it doesn’t mean your devices will draw the max amount..
cool I thought I was the only one to do this. I used x4 1.5ah packs making a 6.0ah. once I got it together I put a layer of tape around the cells then put the case together then used clear silicone in a caulk tube to make the cover. I smoothed it out with a straight edge and let dry. it's a little hefty but it's great for my grinder.
FORGOT IMPORTANT THING! With multilayer battery you must have NTC temp feedback for every layer!!! While charging bottom ones can get hot without controller board knowing it and they can get damaged!
Sure, if he weren't charging a 5p pack with a charger meant to charge one cell individually. The cells are receiving 1/5th the current they normally would, what makes you think any of them are ever going to get hot? If it comes down to a cell failure, a temp sensor isn't going to help anything once the cell goes short-circuit.
I remember seeing your first video about kobalt batteries yeeeears agoooo and I made this as well for my E bike. Works with original charger still too xD Keep up the great vids!
The problem you're going to have is that the BMS will still shut down at the original overcurrent setpoints, and may even error out if it detects charge current but too long a charge time. The BMS has to know what the capacity of the pack is, so if it thinks it's still a 2A pack and sees 2A of charging current for more than a couple of hours, it might just disable itself.
I built two 7s10p packs from Samsung 26c cells. I run them in series for my bike, and parallel for my Worx string trimmer. So either 52ah in parallel or 26ah in series.
Can you please do a video about converting a Kobalt cordless-to-corded battery adaptor. It was be nice to have that adaptor for all Kobalt cordless tools. never runout of battery.
I do like your work mate... very concise and informative. The solar oven was a goodun too. All the best and I'll be looking out for your next work and what you do with the big bad battery pack
when you wire them in parallel it is not amps, it is capacity. since you dont raise voltage, tool will probably draw the same amp. maybe more batteries will make it a notch stronger but again, tool wont draw like 5 times more amps :) but I see endings are thicker than middle ones(middle ones are just used for balancing-charging i think) so if you make something equal width to endings, it should be enough.
@@johnrhodes3350 I don't. 18650 lithium batteries usually can give around 4-5 amps even when shorted. MNaybe better battery will give more. but it depends more on your tool. when you have unlimited source maybe it draws 5A at max. then it would be better to use 2 or more such batteries in parallel because they would sustain voltage longer if they need to give 2A instead. but your tool won't draw 10 A even if you connects 100 batteries in series because it also depends on input voltage and circuit inside tool. does your phone draw 10 amps when you connect to 5V 10A power supply? no. Capacity is Ah or mAh. but current depends on more than just capacity. There is this C value, internal resistance, load, motor inductance, other resistances in circuit, electronics design... so, no, nobody confuses anything. and those mah/Ah values also depend on how much current you draw. They are given for certain calues 1C for example. if a battery is rated 4Ah at 1C then it means it can give 4A for one hour. But if you draw 4C, then it may be rated even below 1Ah. Faster you draw, lesser its capacity. and yes their internal resistance prevents at some point so it is not infinite amps even when shorted thus you can't empty a battery in a second like you do with capacitors. we clear?
Very nice setup. Really nice and clean soldering done. For your screws, you could of used all-thread and then put an end on it with a washer. I agree with a comment below about putting a new label on. Especially if you made some smooth sides and made it look like it "manufactured" that way ;)
Vuaeco, the load/charge/discharge circuit is managing all of the rest of the batteries packs? The problem could be is that the BM is rated for 1 pack - it does not know the overall resistance with the other batteries inline.
how do you balance charge the battery? yes the factory charger balance charge the top pack but theres no way the charger is going to detect each of the added cell to balance them. This is going from a 6 cell to 30 cell pack.. unless you wire up the added cell to a balance board and the the charger can support 30 cell charging... This thing will blowup.
yes, when you run them in parallel you double the capacity but keep the same volt. when you series the battery your double the volt but keep the same capacity.
The way he strapped the batteries together as the charger balances the top pack it will balance every cell below that cell because each pack is strapped cell by cell vertically. So it will balance charge each pack correctly - unless he didn't solder something correctly. Which i think his craftsmanship is quite good so that should not be a problem.
Wow and i spend 450$ for a 48v battery+charger . i wonder if you could add another 5 of those in series to make it 48v battery. not that your bike needs it but yeah. Thanks for the great video. thumbs up. NVM that won't work cause you'll need a different charger and different circuit for the batteries. Very cool none the less
In this way not only will the battery last longer but it will not get as hot, it will not see as many cycles, and each string of cells will last longer because they are being less abused with high current draw. In this config instead of each cell in the string needing to supply the full 20A, each cell in each string of cells only has to provide 4A so they will not get near as hot. If he also chooses to charge the battery when done each day it may only be at half capacity rather than a full discharge so all of the cells will see a much larger number of charge cycles so the single battery could last a far longer life.
Because it reduces stress on the batteries, making them last longer. Also, you can increase the amount of torque the tool can make as well as reducing the voltage droop that happens. Basically, this means you can deliver higher voltage and higher current to the tool. Both of which will increase the final output that you get. If you need an example, look at how much torque a Li-ion powered drill can produce as opposed to a Ni-Cd powered one. Because Li-Ion can produce significantly more current whilst also maintaining a higher per-cell voltage, it can produce a decent increase in the tool's torque. Oh... and not to mention that each cell gets charged at a significantly lower current on the stock charger. This isn't exactly a good thing if you just want to be able to use the tool as fast as possible because your charge time takes a significant hit, but because you're doing a slow charge on the cells, it reduces the stress on the cells during charging and means that they should be able to withstand more charge.discharge cycles before wearing down significantly.
The added bulk and weight make this ridiculous for a screw gun. But he said the actual intention is to use it on other projects he's planning. The "added lifetime" is negated by the fact it's 5 times the amount of batteries purchased just all at once. If one battery lasts 3 years that does not mean this thing will work 15 years. Then you'd get much of the performance enhancement with a stock 4.0Ah from the store. Another thing to consider is there is a maximum boost possible as the tools regulate the power coming in.
When you buy a cordless tool like this it is common to get 2 batteries in the kit when it is on sale. When I last bought a cordless tool system each tool came with a charger and 2 batteries on sale. So it is entirely possible you could have a ton of these low capacity batteries laying around when you buy all the tools in the system as separate kits. These 2Ah batteries are only good for about 250-450 cycles before they fail. Depending on how often you use the tool they may last less than a year if cycled 2-4 times each day or they may last 5 years if only used occasionally. By combining the packs each set of cells could potentially see a much longer cycle life in the neighborhood of 1000-2500 cycles if the pack is less often fully drained. Sure you would have to wait longer for a full charge but with Lithium batteries, it really doesn't hurt them to charge more often when not in use. You can buy 6Ah packs for the real contractor professional grade tools that are maybe 2-3 lbs but they don't seem all that ridiculous compared to the weight of even the corded tools in that same category. My corded rotary hammer drill weighs 7 lbs and the corded reciprocating saw I have is a good 8.5 pounds. Even my older screw gun that uses a NiMh 24v battery is 5.5 lbs and I would consider that light by quality tool standards. Adding an extra pound or two to a tool can actually make the tool nicer to use. So far my experience with lithium batteries has led me to the conclusion that a pack made from quality cells should last well over 10 years provided the cells have cycle life left and have not been abused. It really does depend on how hard the batteries are used and abused as to how long they will realistically last. Some of my corded tools are over 50 years old and still going strong. I still have the first cordless tools I bought back in the mid to late 80's and they are still fully serviceable. I have moved on to aftermarket batteries for them but the tools still work just fine over 30 years later.
Thats funny, I bought a bunch of Kobalt 2.0s to use the cells in some of my other tools packs. Its a very good deal, 10$ per amp/hr or 2 watts per dollar. Other companies charge at least double, and they use the same cells. One thing I find interesting is, I bought 9 Kobalt packs, the first one had Sanyos like yours, but all 8 after that had Samsung 20r's.
Yep, Kobalt has the cheapest batteries in all power tool companies. They used to have Sanyo cells. I've never seen Samsung 20R on the Kobalt though. Maybe it's the newer 2.0 batteries.
Good video bud keep up the good videos quick question how mach the battery you used worth. Link if you have from where you got them from. And how many ah discharge they get up to. Ty keep up the good videos.
I know this video is a little old. But at least in Australia, Milwaukee makes a 9Ah battery you can just buy off the shelf, and its about a third of the size of this. Still, pretty good video.
I've built an 10S10P battery for my ebike based on the lg cells from ebay. I got them for $150 which is great for 100 LG cells. The thing is that I have a $100 hobby charger but I want to build one for an uncle but the charger is expensive. It seems that I'll look into getting a 36/40v charger and one pack and wire them up and make a 22 Ah battery for an ebike. This may be a good way to have a cheap and reliable balancing charger. I also built a spot welder so there is no worries there.
Your video is great man! I watch videos like these however I don’t think I am capable of doing this myself however would love to for my e300 currently SLA battery scooter.
Great build! You didn't mention it ... but you probably did it. When you put cell packs together you should make sure each packs voltage is within .1 or 1/10 of a volt of the other. If you don't do this when you solder those strips onto the sides it can cause a lot of current to flow between the attached packs. This can cause damage to the cells in the packs. Liked !!
Very creative. Neat idea. But, for me it's way to heavy. I have a 4 ah battery now and was thinking of getting a 2 ah battery just to keep the weight down on my 1/4" impact wrench. Down the road I may get a 6 ah if I find the need, but for now, my 4 ah is perfect for long runs. Barry
Good video presentation. Would like to see a followup video showing if the extra current from the parallel arrangement will hurt the original charger circuit components or the the battery balance board. It may be damaging to the balance protection board which was only meant to balance 1 battery not 5. Make a comparison of a regular battery and the 5 banger on current or heat measurements of the charger and balance pcbs with the cases removed. We want to see if the extra batteries will cause over work of the circuits and cause heat damage to the power FETs, transistor, or cell balancing resistors over the longer charge and run times.
Love your videos. I see that you use these to run your scooters. Curious... would 4 of these, running parallel to 48v, power a Golf Cart? Or would it fall short in discharge or kW?
Could not find any info on the motor. It's a 36v cart with a 275amp controller. It look like the aH rating would be too high (I'm a newbie to all of this). Each lead battery is 6v 225Ah. Doesn't that mean I would have to have over 100 of those Kobalt batteries?
Each of the Li-ion cell is capable of handling 20A. I have 5 in parallel in this pack so that's 100A for each pack. If you put 2 packs in parallel, that's 200A max. So 3 in parallel would be able to handle 300A. But because these are small and low capacity, you might want to put more packs in parallel to increase your range (and Amps ratings as well at the same time)
Not necessarily the first 10AH battery pack you can buy on the market... BUT, it is the first 10AH tool battery quite simply because you can't air-mail li-ion batteries with such insanely high capacities, and for manufacturers, it's cheaper and much faster to ship by air than water. No denying though, that battery pack MUST give you a pretty decent life and won't be subject to the same amount of stress as the stock ones since you're spreading the load across more cells. ergo... a better battery life and the longevity is increased significantly.
It's an Accuteck ShipPro W-8580 110lbs capacity, resolution 0.1 oz. Very accurate scale. I got it on ebay. Amazon and many other online merchants have it too.
Very nice but what are the measurements. Trying to build a battery pack and I might have to go down to 8 Ah to put it in ezip scooter with out modifying it.
The major current will be from positive to negative. there will be very little cross current. only balancing current. You only need small wire strip at each connection. 8 cross connections instead of 10.
It's not just the positive and negative terminals that are in parallel. Think of it as a single giant 24V battery with 6 giant cells connected in series to produce 24V. If you can imagine that, you will see how important that is to connect every single cell in parallel, not just the end terminals.
OK, very impressive. So how many of these Kobalt 24v would I need to power a electric Ford Ranger truck with a 96volt requirement. And how would I need to wire them up? I know 4 x 24 is 96volts. But I also know I will need to go several rows of 4s to get the ummm, duration the miles requirement for the day before recharging.
i think im gonna make a 100 Ah battery pack for my cordless drill, it would be able to stand up by itself from the floor, no table needed when im not using it, joke aside good job
well deserved TU + sub. awesome job fun film. it must weigh about 50 pounds :-) your next one should be three times longer and make it into guinness world records.
Perhaps you should have drawn a circuit diagram of the battery connections and checked the specs of the control boards that control charging and power to the tool(s) to support your statements. If you want some pointers, then see AvE on TH-cam. He tells you what the pixies(voltage & current) are doing, and what controls them.
Should put the DeWalt circuit board on opposite side so you can used on either drill that battery must weigh alot. You should just made it 125 volts. Put a Gfi on it portable power.
You know those regulators were meant to regulate the charge of one of those packs, youd have to have a way to hook them up in parallel also to make sure the thing doesnt over head and explode im a noob but i know 1 thing dont fuck with li ion they explode nicely
in your other video if you dont know why the circuit boards are so complicated i ask you kindly refrain from doing this and teaching people to do this because someone will end up dead or severely bored. They are so complicated because they have to make sure a lot doesnt go wrong, stable voltages, how much voltage/amperage over the charge time and so much more
Great teaching, I learn a lot, can I do the same with dwalt batterries, or how about using usb adapters cap and conect them in series, like you did on the newest videos?, this is my plan, 2 (20v 5 ah) in parallel to make 10 ah conected in series with another 2 (20v 5ah) in parallel conected to a 12v 2ah in series to complete 52v 10ah for my ebike motor 1000w 48v, with that work? Thanks!
Does the BMS limit the discharge current or does it only have a low voltage cut off? If u try to pull a lot of amps from a parallelled pack using one board, eg for a high power ebike battery. Would it still only allow the delivery of 1 cell?
I looked at that also. The smallest threaded rods at my local hardware store was size 10. I need size 6. So that didn't work. Plus, with a threaded rod, you'll need to make a cap by welding or use a lock nut. That either sticks out too much or would come loose eventually.
You are stupid. There is no more power. It only last longer.
It is absolutely MORE POWER! Original 2A/H battery is only 48 watts. With this set up, hes getting 240 Watts. Watts IS Power!
Bigger batteries can handle a higher discharge rate.
This is crackhead stuff
@@PatChapp yes u are Crack head. Learn how electric motors work.
@@paulirumbin1541 no you is ignorant! I am Wright. The Utuber has no klue what hes talkin bout. I've been a major master electrician for 79 years and I can tell you paralleling series only ads resistence while lowering ohms. No extra power is created.
@@ricktruman1416 what?
I am new to you. I think you are priceless. Probably one of the best teachers I have seen on TH-cam. Very thorough, to the point and also a great sense of humor. I have learned so much from you, and am grateful. Thank you so much.
My partner has a lot of tools, so when he needed a circular saw, I ordered this one for him as a Christmas gift. th-cam.com/users/postUgkxYDKeIjKLOfcwTgdin7TtCutsz4MbIc43 He is incredibly happy with the purchase. He stated that he likes that it is powerful, but still easy to use and cuts very well. He mentioned that it is important to know the right tools for the job at hand, and this compact saw has been exactly what he needed for a variety of projects at his rental properties and renovations. He also appreciates the battery packs, as stated, he owns a lot of DEWALT tools, so he is able to always keep batteries charged as needed.
Respect to the quality kraftsmanship
And the sticker at the end.... bro you da man!!!
Great video
This is a great idea and so simple. Im building an ebike and are using powertool batteries but thought i would need to stack the batteries ontop of each other. Your way is way more efficient for space. Plus my 36 volt system would only need 2 chargers which i already have instead of swapping the batteries over or buy more chargers. I would just use threaded rod and nuts on the top to hold them together. Another great use would be to make your own powerwall this way.
Ur a very creative genius with a sense of humor!
Old but Gold. Very helpfull Video !!
You did not need to join the balancing connections with as heavy of wire. Since your cells are in a 6S5P configuration you could have kept a single strip down each of the balancing leads since very little current should ever flow. The most positive and most negative connections are the only connections that need to carry a large amount of current. The balance leads ensure that no one parallel set of cells goes over or under the preset voltage in the balance circuit. If one set goes lower than the rest the balance circuit will cut the power as soon as the lowest set of cells in the parallel string reaches the cut off voltage. The next time it is charged the balance board will ensure that all each set is at approximately the same charge voltage when fully charged. Since one pack can deliver 20A you can assume that the drill is not able to draw over that 20A in normal operation so as long as all your most positive and most negative connections can handle that 20A it won't matter that the pack can deliver 100A since the drill and even the balance board were not designed to go over the 20A. This pack as long as it is not damaged will likely outlast the drill since now the cells will not be abused near as much as they will share the current draw rather than one set having to provide the full 20A each string will now only have to provide 4A of current.
Those strips are carrying the current of the extra battery packs. He did not connect the main positive and negative terminals of the extra batteries. The strips will be used to balance also.
@@draytonPW I think what he is saying that he could have just joined all of the end teminals + and - from each of the 5x battery packs only, instead of joining all teminals of all cells within each of the battery packs. Either way I probably would have done it the way he did it for structural integrity none the less.
Absolutely love this project. I would pay good money for one of these 10 amp batteries to use on my scooter 😭
I know this is old video but I'm planning on doing something similar. Looking back would you now construct these in a different fashion? I recently bought many of the Kobalt 1.5ah battery packs(2 for $15) and now plan on putting 10 together for 15ah packs (24 volts each). I'll wire these in series to create 48 volt packs for our trikes. I am currently using smaller versions and they work great! The smaller versions were created with not taking the cases off but keeping them intact and jumping the terminals with custom cables to create 48 volt packs. I charged the packs by taking the cables apart (a pain) with four Kobalt chargers. I want to make the new packs similar to yours but thought you might have other ideas on how to construct them. Thanks for all your thought provoking videos and entertaining humor!
TL;DR: This is a long comment. I go into detail about multi-cell packs and at the end voice my concerns for mechanical, (not electrical) safety.
So there's quite a few things going on here. that are advantageous, though maybe don't take it all the way to 5P configuration due to practicality and weight.
-First: You're pentupling the capacity. This means longer run-time.
-Second: You're minimizing voltage-drop. 18650 cells may be rated to give a peak output of 20A, but they sag like crazy at that current level and heat very quickly. The maximum output is "maximum current for 1 minute before catastrophic failure" or somesuch. Add more parallel cells, minimize voltage drop, get more continuous wattage out of the battery. Some of the drill motors are capable of pulling 80A+ peak (stall current) if the motor controllers let them. How manufacturers think that a 1P battery pack is even REMOTELY capable of handling that kind of current, I have no idea. The general rule-of-thumb when it comes to Lithium-based batteries is limit current to 1/4 "rated" maximum to preserve the health of the cell. Any more and you're damaging it internally every time you discharge.
-Third: You're extending cell life by reducing both charge and discharge current-per-cell by a significant margin. Cells will survive far more cycles if charged at 0.5 to 0.2 their C-rating. Assuming a half hour charge and 2Ah cells, the charger likely outputs 4A. That means that now you're charge less than an amp per cell, which will significantly lower the load both in discharge and charge cycles.
The only concerns I have are that the tabs need to be doubled on the end connections for load-bearing, (balance current is far less than charge or discharge current, so the middle connections can be a single strip; end connections need at least two since the full current of the pack charges/discharges through them). Balancing is done by charging through the entire pack, and bleeding off energy into a resistive element from the cells that are close to maximum voltage, while the others catch up. In essence balance charging is where the higher-voltage cells get charged "slower" than the lower voltage cells.
Additionally, I'm concerned about structural integrity of the cells. Foam and tape are not good enough in an industrial environment; dust can still get in, metallic objects can easily pierce the covering and short something. I'd at least take some corrugated plastic material and wrap the sides to help protect from these sorts of dangers. Further, dropping or bumping the bottom of the pack while it is attached could cause the adhesive tape between parallel packs to come loose, or worse, break the solder points or put stress on them. In a worst-case scenario that's a recipe for a short and catastrophic failure. The best would be to 3D print a new case that covers the full size of the pack, (if you have such a resource available to you).
@Eitan did you know for sure that the circuit balance each line of the series? I haven´t seen a balancer included on the packs, it could be great they started implementing this on consumer electronics, specialy laptops. I also think that those wires will get undersized, but depending on the load required they could be safer that way... If he is willing to reinforce the wires i would suggest him to use a termal resistor / fuse in serie that will open circuit on over currents, just to be safe and avoid fire (every pack from respected manufacturers include one or leave a thin pad that will fuse).
@Matias D.B. All consumer packs have balance circuits for each cell in a series configuration. Balancing will occur regardless of however many parallel elements are in the pack. The only possible danger is if you have mis-matched cells that have very different resistance values or very different states of charge. Different states of charge will cause one cell to discharge into another when you solder them together. Different resistance values will cause one cell to discharge and charge at a different rate, causing one cell to be "weak" vs. it's parallel companion(s). Fusible links are a thing, and definitely help, but may be cost-prohibitive for this DIY-minded build. That of course assumes that the people doing this sort of modification know anything about battery building and treat their modified packs with care.
Do you have some general rules you would recommend for how to Charge and Discharge battery pack? Frequency of charging, how low can you go before charging them back up, etc? How do we get longer life out of batteries in general?
CELLS IN PARALLEL. EVERY SHORTED INTERNALLY WILL RUIN ANOTHER 4.
With the new 21700 cells there are now OEM batteries available with only 10 cells and 18 Volt 8 Ah. For cordless drills you normally don't need such big batteries, but other tools like circular saws or chain saws can benefit from it.
You should never use soldering to connect lithium ion batteries. Even if you solder fast to limit the amount of heat going into the battery they will be damaged, especially at the negative terminal. All commercial packs are spot welded. Spot welding is the only recommendable connection method for round cells.
I disagree. Have you ever soldered a Li-ion battery and damaged it? I have been using these Kobalt packs on my ebike and it's been 1.5 years and still kicking. In fact, I solder ALL of my Li-ion batteries for everything (so far) and haven't seen any single cell that fails. Your assumption doesn't have any real facts to back it up. Commercial packs are spot welded because it saves time.
A few points to consider before using such mod:
a. With this configuration the balance charger treats a whole series of 5 batteries as a single cell so it won't detect a failure in a single battery on such array. If one cell will fail it will overheat and damage the other batteries or even explode from the accumulating heat.
b. The added weight makes it impractical to work with.
c. I can't be sure that the motor can handle continuous torque that can be achieved through this mod.
Overall - nice concept but should be made at least with battery charge management for each cell and some good heat spread in some way.
Absolutely genius. The home made screws! You channel deserves to be known world wide.
Not genius at all. In fact it didn't even make sense. He was correct in calling that Battery 10 AMp hour. However he was incorrect calling it a 100 V. It is still only twenty four volts.
bruh, when did he say 100V? 17:33 he said 100A. the battery could deliver a maximum of 100A at 24V. doesn’t mean the engine will draw 100A when it’s working. probably much less. Wall sockets (in eu at least) can deliver 16A,230V usually with a circuit breaker when exceeding 16A, it doesn’t mean your devices will draw the max amount..
cool I thought I was the only one to do this. I used x4 1.5ah packs making a 6.0ah. once I got it together I put a layer of tape around the cells then put the case together then used clear silicone in a caulk tube to make the cover. I smoothed it out with a straight edge and let dry. it's a little hefty but it's great for my grinder.
Very cool brother... Don't ever listen to the haters...
Outstanding buddy learning more thanks again for the great ideas take care stay safe 😊😊😊😊
FORGOT IMPORTANT THING! With multilayer battery you must have NTC temp feedback for every layer!!! While charging bottom ones can get hot without controller board knowing it and they can get damaged!
Sure, if he weren't charging a 5p pack with a charger meant to charge one cell individually. The cells are receiving 1/5th the current they normally would, what makes you think any of them are ever going to get hot? If it comes down to a cell failure, a temp sensor isn't going to help anything once the cell goes short-circuit.
Matthew Walsh 1
yes youre right but if one cell gets hot charger cant know that to turn charging off but yours point is good
yes and a 10 amp charger also.....the next thing is that the top board is not going to last too long because it will not handle the current for long.
capacity has nothing to do with board on top. tool will still draw same amount of current.
500 Wh 24v battery pack. Very nice!
I remember seeing your first video about kobalt batteries yeeeears agoooo and I made this as well for my E bike. Works with original charger still too xD
Keep up the great vids!
Excellent work!!!THANK YOU!👏🌟
Dude, I'm seriously in love with your voice. It took me a while to place it, but you remind me of Hank Hills neighbor from Laos on King of the Hill.
You mean the guy from La Ocean? :D
I like this guy his accent is priceless.
Yes sir. Only President Trump can put a price on an accent.
@@vuaeco WOW DUDE! thats the funniest comment i ever heard! Thank you!
"O honey, that's why you not have boifrand"
The problem you're going to have is that the BMS will still shut down at the original overcurrent setpoints, and may even error out if it detects charge current but too long a charge time. The BMS has to know what the capacity of the pack is, so if it thinks it's still a 2A pack and sees 2A of charging current for more than a couple of hours, it might just disable itself.
Two and a half years later it's still working. And it's still working now.
Build a house on 1 charge... 😆 🏠 awesome
Is it dangerous if you double it again to a 20ah?
love it. but will it cost more to buy the new battery pack then individual battery?
greetings from *_THE PHILIPPINES_*
So it does still stay 24 volts because of the circuit board correct??? That was awesome I never thought about trying that!!!
I built two 7s10p packs from Samsung 26c cells. I run them in series for my bike, and parallel for my Worx string trimmer. So either 52ah in parallel or 26ah in series.
Did it extend the run time of the Worx string trimmer. I was thinking of doing the same thing. Do you have any pics of how you did it?
Really good job, love the homemade brass screws.
every powertool owners wet dream. a pack that will last all day.. i want to do this to my makita radio :D
Can you please do a video about converting a Kobalt cordless-to-corded battery adaptor. It was be nice to have that adaptor for all Kobalt cordless tools. never runout of battery.
I wonder how long that custom 10ah battery will run the Kobalt 24v fan for
I do like your work mate... very concise and informative. The solar oven was a goodun too. All the best and I'll be looking out for your next work and what you do with the big bad battery pack
Simple beautiful upgrades!!!! *MO POWA* my tools will love these.
when you wire them in parallel it is not amps, it is capacity. since you dont raise voltage, tool will probably draw the same amp. maybe more batteries will make it a notch stronger but again, tool wont draw like 5 times more amps :) but I see endings are thicker than middle ones(middle ones are just used for balancing-charging i think) so if you make something equal width to endings, it should be enough.
Sailor OnDaTea exactly what I was thinking
Don't confuse A with Ah
@@johnrhodes3350 I don't. 18650 lithium batteries usually can give around 4-5 amps even when shorted. MNaybe better battery will give more. but it depends more on your tool. when you have unlimited source maybe it draws 5A at max. then it would be better to use 2 or more such batteries in parallel because they would sustain voltage longer if they need to give 2A instead. but your tool won't draw 10
A even if you connects 100 batteries in series because it also depends on input voltage and circuit inside tool. does your phone draw 10 amps when you connect to 5V 10A power supply? no.
Capacity is Ah or mAh. but current depends on more than just capacity. There is this C value, internal resistance, load, motor inductance, other resistances in circuit, electronics design...
so, no, nobody confuses anything.
and those mah/Ah values also depend on how much current you draw. They are given for certain calues 1C for example. if a battery is rated 4Ah at 1C then it means it can give 4A for one hour. But if you draw 4C, then it may be rated even below 1Ah. Faster you draw, lesser its capacity. and yes their internal resistance prevents at some point so it is not infinite amps even when shorted thus you can't empty a battery in a second like you do with capacitors. we clear?
Well, that was fun, thanks for the video. pierre from New Mexcio
Very nice setup. Really nice and clean soldering done. For your screws, you could of used all-thread and then put an end on it with a washer.
I agree with a comment below about putting a new label on. Especially if you made some smooth sides and made it look like it "manufactured" that way ;)
Vuaeco, the load/charge/discharge circuit is managing all of the rest of the batteries packs? The problem could be is that the BM is rated for 1 pack - it does not know the overall resistance with the other batteries inline.
how do you balance charge the battery? yes the factory charger balance charge the top pack but theres no way the charger is going to detect each of the added cell to balance them. This is going from a 6 cell to 30 cell pack.. unless you wire up the added cell to a balance board and the the charger can support 30 cell charging... This thing will blowup.
Exactly my thoughts. Ain't gonna go
Down well with the home insurance when your explaining what caused the house to burn down.
thought the same, also isn't the formula e batteries much higher capacity?
yes, when you run them in parallel you double the capacity but keep the same volt. when you series the battery your double the volt but keep the same capacity.
yeah, i know that. I was saying that the formulae batteries have more capacity.
The way he strapped the batteries together as the charger balances the top pack it will balance every cell below that cell because each pack is strapped cell by cell vertically. So it will balance charge each pack correctly - unless he didn't solder something correctly. Which i think his craftsmanship is quite good so that should not be a problem.
I'll take my (stock) DeWalt 20v/60v 9ah pack any day of the week. Way more compact, and more flexible. Good project, though!
I noticed you left 1 BMS on to manage the charging and safety. will it be the same for one as for them large bank?
Wow and i spend 450$ for a 48v battery+charger . i wonder if you could add another 5 of those in series to make it 48v battery. not that your bike needs it but yeah. Thanks for the great video. thumbs up. NVM that won't work cause you'll need a different charger and different circuit for the batteries. Very cool none the less
if you have 5 batteries of 2 Ah, what's the point to join them together? Is it to difficult to change the battery when needed?
In this way not only will the battery last longer but it will not get as hot, it will not see as many cycles, and each string of cells will last longer because they are being less abused with high current draw. In this config instead of each cell in the string needing to supply the full 20A, each cell in each string of cells only has to provide 4A so they will not get near as hot. If he also chooses to charge the battery when done each day it may only be at half capacity rather than a full discharge so all of the cells will see a much larger number of charge cycles so the single battery could last a far longer life.
Thanks for answering. Your answer was complete and accurus.
Because it reduces stress on the batteries, making them last longer. Also, you can increase the amount of torque the tool can make as well as reducing the voltage droop that happens. Basically, this means you can deliver higher voltage and higher current to the tool. Both of which will increase the final output that you get. If you need an example, look at how much torque a Li-ion powered drill can produce as opposed to a Ni-Cd powered one. Because Li-Ion can produce significantly more current whilst also maintaining a higher per-cell voltage, it can produce a decent increase in the tool's torque.
Oh... and not to mention that each cell gets charged at a significantly lower current on the stock charger. This isn't exactly a good thing if you just want to be able to use the tool as fast as possible because your charge time takes a significant hit, but because you're doing a slow charge on the cells, it reduces the stress on the cells during charging and means that they should be able to withstand more charge.discharge cycles before wearing down significantly.
The added bulk and weight make this ridiculous for a screw gun. But he said the actual intention is to use it on other projects he's planning.
The "added lifetime" is negated by the fact it's 5 times the amount of batteries purchased just all at once. If one battery lasts 3 years that does not mean this thing will work 15 years. Then you'd get much of the performance enhancement with a stock 4.0Ah from the store. Another thing to consider is there is a maximum boost possible as the tools regulate the power coming in.
When you buy a cordless tool like this it is common to get 2 batteries in the kit when it is on sale. When I last bought a cordless tool system each tool came with a charger and 2 batteries on sale. So it is entirely possible you could have a ton of these low capacity batteries laying around when you buy all the tools in the system as separate kits.
These 2Ah batteries are only good for about 250-450 cycles before they fail. Depending on how often you use the tool they may last less than a year if cycled 2-4 times each day or they may last 5 years if only used occasionally. By combining the packs each set of cells could potentially see a much longer cycle life in the neighborhood of 1000-2500 cycles if the pack is less often fully drained. Sure you would have to wait longer for a full charge but with Lithium batteries, it really doesn't hurt them to charge more often when not in use.
You can buy 6Ah packs for the real contractor professional grade tools that are maybe 2-3 lbs but they don't seem all that ridiculous compared to the weight of even the corded tools in that same category. My corded rotary hammer drill weighs 7 lbs and the corded reciprocating saw I have is a good 8.5 pounds. Even my older screw gun that uses a NiMh 24v battery is 5.5 lbs and I would consider that light by quality tool standards. Adding an extra pound or two to a tool can actually make the tool nicer to use.
So far my experience with lithium batteries has led me to the conclusion that a pack made from quality cells should last well over 10 years provided the cells have cycle life left and have not been abused. It really does depend on how hard the batteries are used and abused as to how long they will realistically last. Some of my corded tools are over 50 years old and still going strong. I still have the first cordless tools I bought back in the mid to late 80's and they are still fully serviceable. I have moved on to aftermarket batteries for them but the tools still work just fine over 30 years later.
Thats funny, I bought a bunch of Kobalt 2.0s to use the cells in some of my other tools packs. Its a very good deal, 10$ per amp/hr or 2 watts per dollar. Other companies charge at least double, and they use the same cells. One thing I find interesting is, I bought 9 Kobalt packs, the first one had Sanyos like yours, but all 8 after that had Samsung 20r's.
Yep, Kobalt has the cheapest batteries in all power tool companies. They used to have Sanyo cells. I've never seen Samsung 20R on the Kobalt though. Maybe it's the newer 2.0 batteries.
Good video bud keep up the good videos quick question how mach the battery you used worth. Link if you have from where you got them from. And how many ah discharge they get up to. Ty keep up the good videos.
$20 each from Lowe's. Discharge rate is 100A (20A each).
One charge now lasts the life of the tool!
I know this video is a little old. But at least in Australia, Milwaukee makes a 9Ah battery you can just buy off the shelf, and its about a third of the size of this. Still, pretty good video.
Yes but it still costs twice as much as this even though it has 33% less run time than this.
This is awesome nicely done!
I've built an 10S10P battery for my ebike based on the lg cells from ebay. I got them for $150 which is great for 100 LG cells. The thing is that I have a $100 hobby charger but I want to build one for an uncle but the charger is expensive. It seems that I'll look into getting a 36/40v charger and one pack and wire them up and make a 22 Ah battery for an ebike. This may be a good way to have a cheap and reliable balancing charger. I also built a spot welder so there is no worries there.
His accent kept me watching lmao
Ikr jackie chan knows batteries
#metoo😂
What’s with all the racists? This is great info.
I guess this is a good "Because I can type project. as far as your screws use all thread cut it to length and use lock nuts to cap the end.
Your video is great man! I watch videos like these however I don’t think I am capable of doing this myself however would love to for my e300 currently SLA battery scooter.
Great build! You didn't mention it ... but you probably did it. When you put cell packs together you should make sure each packs voltage is within .1 or 1/10 of a volt of the other. If you don't do this when you solder those strips onto the sides it can cause a lot of current to flow between the attached packs. This can cause damage to the cells in the packs. Liked !!
I don't understand please give an example excuse me for my ignorace
This was helpful, thank you
Very creative. Neat idea. But, for me it's way to heavy. I have a 4 ah battery now and was thinking of getting a 2 ah battery just to keep the weight down on my 1/4" impact wrench. Down the road I may get a 6 ah if I find the need, but for now, my 4 ah is perfect for long runs.
Barry
Very nice job. Great idea. Thanks.
i love this new "genius" who had an inspiration and wants to share their "knowlege"
5mm copper bus strips are compared with 15mm nikkel strips right ??
That's a lot of sows, I never seen soo many sows altogedder. Love you videos.
Gr8 video, wot was the price
Good video presentation. Would like to see a followup video showing if the extra current from the parallel arrangement will hurt the original charger circuit components or the the battery balance board. It may be damaging to the balance protection board which was only meant to balance 1 battery not 5. Make a comparison of a regular battery and the 5 banger on current or heat measurements of the charger and balance pcbs with the cases removed. We want to see if the extra batteries will cause over work of the circuits and cause heat damage to the power FETs, transistor, or cell balancing resistors over the longer charge and run times.
EnergyCrafts no it works i am using 72 volts 3 5cell deep x3
Your awesome man I can only dream about doing some this stuff got the no how just broke and evil people come around me
Love your videos. I see that you use these to run your scooters. Curious... would 4 of these, running parallel to 48v, power a Golf Cart? Or would it fall short in discharge or kW?
4 of these in 2S2P config can handle 10KW at 48V. I figure they might be capable! What's the rating of your golf cart motor?
Could not find any info on the motor. It's a 36v cart with a 275amp controller. It look like the aH rating would be too high (I'm a newbie to all of this). Each lead battery is 6v 225Ah. Doesn't that mean I would have to have over 100 of those Kobalt batteries?
Each of the Li-ion cell is capable of handling 20A. I have 5 in parallel in this pack so that's 100A for each pack. If you put 2 packs in parallel, that's 200A max. So 3 in parallel would be able to handle 300A. But because these are small and low capacity, you might want to put more packs in parallel to increase your range (and Amps ratings as well at the same time)
Fast and good product
beautiful job
Not necessarily the first 10AH battery pack you can buy on the market... BUT, it is the first 10AH tool battery quite simply because you can't air-mail li-ion batteries with such insanely high capacities, and for manufacturers, it's cheaper and much faster to ship by air than water. No denying though, that battery pack MUST give you a pretty decent life and won't be subject to the same amount of stress as the stock ones since you're spreading the load across more cells. ergo... a better battery life and the longevity is increased significantly.
Would a 40 ah stacked run a 85 lb thrust 24 volt trolling motor.
can i do this with dewalt batteries ?
Yes. It's basically the same thing.
So you taped some cells together, but what about the balancing? And the thermal protection?
'Work out using my tool'.....Oh my that is a big tool you have there
I need to make something like this for my Ryobi One+ angle grinder!
hi i like your weighing scales, where did you get it?
It's an Accuteck ShipPro W-8580 110lbs capacity, resolution 0.1 oz. Very accurate scale. I got it on ebay. Amazon and many other online merchants have it too.
vuaeco thank you. great video by the way :-)
Very nice but what are the measurements. Trying to build a battery pack and I might have to go down to 8 Ah to put it in ezip scooter with out modifying it.
The major current will be from positive to negative. there will be very little cross current. only balancing current. You only need small wire strip at each connection. 8 cross connections instead of 10.
It's not just the positive and negative terminals that are in parallel. Think of it as a single giant 24V battery with 6 giant cells connected in series to produce 24V. If you can imagine that, you will see how important that is to connect every single cell in parallel, not just the end terminals.
So how many miles did u get from this
Very great love your work your very resourceful. Congrats. Please continue love your projects thumbs way up
Ingenious, very cool
OK, very impressive. So how many of these Kobalt 24v would I need to power a electric Ford Ranger truck with a 96volt requirement. And how would I need to wire them up? I know 4 x 24 is 96volts. But I also know I will need to go several rows of 4s to get the ummm, duration the miles requirement for the day before recharging.
i think im gonna make a 100 Ah battery pack for my cordless drill, it would be able to stand up by itself from the floor, no table needed when im not using it, joke aside good job
You can drill a whole week continuously non stop without having to recharge it.
Its not too dificult 2 keep it in hand?
Well done, really good video! :)
well deserved TU + sub. awesome job fun film. it must weigh about 50 pounds :-) your next one should be three times longer and make it into guinness world records.
Perhaps you should have drawn a circuit diagram of the battery connections and checked the specs of the control boards that control charging and power to the tool(s) to support your statements. If you want some pointers, then see AvE on TH-cam. He tells you what the pixies(voltage & current) are doing, and what controls them.
now i dont need to go to gym anymore haha :)
Should put the DeWalt circuit board on opposite side so you can used on either drill that battery must weigh alot. You should just made it 125 volts. Put a Gfi on it portable power.
So funny when you put it on the drill! Hahaha! "Wow look at dis"
You know those regulators were meant to regulate the charge of one of those packs, youd have to have a way to hook them up in parallel also to make sure the thing doesnt over head and explode im a noob but i know 1 thing dont fuck with li ion they explode nicely
in your other video if you dont know why the circuit boards are so complicated i ask you kindly refrain from doing this and teaching people to do this because someone will end up dead or severely bored. They are so complicated because they have to make sure a lot doesnt go wrong, stable voltages, how much voltage/amperage over the charge time and so much more
Great teaching, I learn a lot, can I do the same with dwalt batterries, or how about using usb adapters cap and conect them in series, like you did on the newest videos?, this is my plan, 2 (20v 5 ah) in parallel to make 10 ah conected in series with another 2 (20v 5ah) in parallel conected to a 12v 2ah in series to complete 52v 10ah for my ebike motor 1000w 48v, with that work? Thanks!
That's a real stretch... I doubt it would be Stable
Are there a way to just connect them on parallel without removing the cases? thanks
yes, you can make these slide in connectors and wire them in parallel: th-cam.com/video/4o0dBpYcWwE/w-d-xo.html
Does the BMS limit the discharge current or does it only have a low voltage cut off? If u try to pull a lot of amps from a parallelled pack using one board, eg for a high power ebike battery. Would it still only allow the delivery of 1 cell?
Instead 10ah, 4ah would be better. Less weight. Still good video. Enjoyed watching it ♥️
Where the screws hand made and batteries in parallel?
Yes, screws were hand made as nobody was selling it. And batteries are in parallel. It's a 6S5P pack.
Consider using threaded rod the next time you need long screws.
I looked at that also. The smallest threaded rods at my local hardware store was size 10. I need size 6. So that didn't work. Plus, with a threaded rod, you'll need to make a cap by welding or use a lock nut. That either sticks out too much or would come loose eventually.
Your solution was elegant.
Could the battery you made the 12 volt 10 amp fit into the tray of a the battery tray of a razor e325
what if you made a backpack that had 50 amps hours in it and then it wouldn't be as heavy
Pretty Cool 😎
So where did you buy the screws?
Will your charger balance the 5 packs when charging?
It should same circuit board.
can you use copper wire instead of the nickle strips? or will that not work?
You can use copper wire. But it needs to be thin enough to be put back into the plastic case or it won't fit.