Cordless tools are power-hungry beasts. They can easily peak consume up to 40A from the battery. I wouldn't advise using those 5.000 mAh cells. They are designed for high capacity at low currents, like 10A max. Above this current demand, they will heat quite rapidly, and their capacity will go down significantly. The best 21700 Li-Ion cells for cordless tools are those with 3 to 4 Ah capacity since they can withstand currents as high as 40A without any issues.
I am building a 21700 pack to go along with my 18650 packs. I am building it with 10 Samsung 50S 21700 cells. It took me six hours to charge them up from 3.56 volts to 4.20 volts. I then tested them for capacity and the averaged over 5000 ah. That should create a 10 ah pack.
The trick to making a good replacement pack is to get good, name brand 18650 cells that have a high amp discharge rating. The originals are something like 20amp discharge rated. The higher the mah, the lower the discharge amp rating. The higher the discharge amp rating, the better the tool will preform. A lower rated discharge amp rating will be ok for a drill maybe, but not for a circular saw or an angle grinder. Any 18650 cell that claims to be 6000mah, just know that it's not, and even if it was the discharge amp rating on it would be maybe 1 or 2 amp discharge. So straining the tool will cause the battery cell to overheat and likely cause the tool to shut down.
The genuine DeWALT 10Ah battery has a slightly larger case for the Samsung INR21700-50S cells. They have extra cooling requirements compared to the 6Ah and 8Ah packs. Both 6Ah and 8Ah have the same shell that is smaller than the 10Ah battery’s shell despite all three having the same 2P5S 21700 configuration. 8Ah has Samsung INR21700-40T.
@@justinholmes5614 Glad to help. I tore into mine a few weeks ago and I couldn’t find that info before. :) I believe the board circuitry is adjusted for the 85°C temperature requirement of these cells (from the INR21700-50S datasheet). It has the same PCB as my 8Ah pack but the board is marked for different configurations… perhaps populated differently for each? Not sure. There is also a large fuse that isn’t present on the 6Ah and 8Ah packs. FWIW, I found a set of unbalanced cells in my bad one but after bringing that segment up and running both batteries in the lawnmower this pack still loses power faster than my good one and gets ridiculously hot (good one is just warm). The mower now quits with the good pack only missing one bar and the bad one still having one bar, likely because the mower detected the imbalance and is attempting to prevent over-discharge. Sure enough, I checked and the cell imbalance was worse than before, likely because those cells overheated. I’m now doing a days-long refresh cycle on the bad segment but I doubt it will help. It’s been taken apart with test leads to my smart charger for a few days now. :)
I chargers any pack battery to 4.2 volts before I build the pack. The reason that I do is so I can test them for capacity capacity of the cells - some lithium battery manufactures lie. I bough some batteries that were rated at 3999 ma and they tested out at a nominal 2550 and change, which is why I buy Samsung batteries, now. They always test out slightly above their stated capacity. I tested out some Samsung 50S cells today and they tested out 4,998-5002. Can’t beat that for consistency, can you? You need to warn any viewer to put the positive and negative leads on the inside part of the tab on the plug, otherwise you will not get the cover to go on the plug. That is the voice of experience.
The nickel you used is not made for the amount of amps flowing through these packs! Use the nickel that comes with the kit, and use a spot welder that can weld the thicker nickel!
Here it comes the debate of soldering cells. Thickes strips more expensive spot welder or you risk bad connections. I went soldering route where you heat the battery for literally 1 second. There're videos proving that soldering, if done properly doesn't harm cells.
I chargers any pack battery to 4.2 volts before I build the pack. The reason that I do is so I can test them for capacity capacity of the cells - some lithium battery manufactures lie. I bough some batteries that were rated at 3999 ma and they tested out at a nominal 2550 and change, which is why I buy Samsung batteries, now. They always test out slightly above their stated capacity. I tested out some Samsung 50S cells today and they tested out 4,998-5002. Can’t beat that for consistency, can you?
Great video! Thank you. I have purchased couple of cases for 18650 and 21700 batteries and successfuly built all of them. I'm having issue with 18650 5-6 ah batteries. When I'm using tool that have big drainage for example circural saw my case start burning and melting from heat.I think this is caused by strips on + and - terminal which are soldered to a cable like on original battery. I'm not sure where is issue if I'm using wrong nickle strip or its too thin. Did you had similar issue?
Sorry for a late reply! Please be extra cautious!!! I have not experienced that before. When I am using my battery with the dewalt heat gun, the battery do get warm but definitely not hot to touch. When it gets any warmer, the battery will thermally cut off, meaning I just need to leave it for a few minutes to cool down then I can use the tool again.
Lose connections do generate resistance therefore increasing the temperature. Please be extra careful!! May I ask did the wires get melted or was it just the case that has melted. The reason why I am asking is because if the wires have melted this could be because the wires itself weren't thick enough or the pcb that meant to be protecting the battery pack wasn't doing its job. Might worth getting a different battery case!
Would say could be several issues. I build my own, cause I have some high draw tools that where overheating my 5ah batteries in minutes, and it was annoying. I got the 10*21700 kit, and built it using samsung 40t3 cells. The kit came with steal strips, not nickel. I used my own 0.2mm pure nickel strips, and used 12awg wire to connect the + and - leads. Also on these kits the + and - terminals are not copper like on the real dewalt batteries so that could also be a heat issue. But due make sure your cells real rating at the current draw you need is high enough, and that the nickel strip is thick enough. My 0.2mm nickel strip is only rated for 7.5amps, so in my 8ah battery that would be 15amps, if you need more, you would have to double up the nickel strips, or use copper strips, dewalt uses nickel plated copper strips. Copper is rated like 4x of nickel.
No one, and I mean no one makes a 18650 4, 5, or 6 ah cell that can handle the load that a power tool demands. You want a cell that can handle at least 20amp discharge (more if it's anything other than a drill/driver). The best you can do on a reasonably priced high discharge 18650 cell is around 2800 milliamp hours (2.8ah). You can go higher than 2800mah if you're willing to pay a huge increase in price.
You need to buy 2 spot welders folks! Because when the batteries in the first spot welder fails you'll need the second spot welder to spot welder new batteries into the first spot welder.
I bought a knockoff DeWalt pack from ebay and I noticed its not as solidly constructed as an original. Do you think it would be safe to fill it with epoxy to firm things up?
Great video, but I am looking to build a 15*18650 Dewalt battery. I already have the case and cells, but I am unsure on how to wire it! I have built many batteries, but always 5 cell or 10 cell batteries. I'm looking to step it up to a 15 cell now. If a video exists, would someone please direct me to it? If no one knows of a video, it would be great to see one made! Thanks!
Check out the amp capacity for different strips, both Nps and pure nickel.. As long as you don't draw more than the upper limit of capacity, you're fine. On a higher discharge battery like this, pure nickel would be a better choice.
Unfortunately i will not and cannot recommend using a traditional soldering iron, there are friendly-priced spot welders available online. Here is one: amzn.to/3xJrujG
You say “don’t get them hot they will explode” You do realize how hot those Dewalt butteries get when you use them right?!? Like the charger literally has a overheat fuse and light built in… Just wondering if these custom batteries are safe to use in a work type environment? Lmk thanks!
Yes for sure a certain amount of risk will exist and this is just a video of me sharing the process of creating a DeWALT replacement battery. I did run it for a prolong period of time with the DeWALT heat gun, there was a few thermal shut down but was not a huge problem. In fact, with the thermal shut downs, I do believe the battery is safe to use in normal circumstance. However I will not and cannot take any responsibility in any case of accident or incident as I am just sharing personal experience. Thanks again!
just to be clear, soldering onto the cells itself is bad, but soldering onto the nickle strip on the the cell is okay? is this because the nickle protects the cell?
Sorry for the confusion, you should always try to avoid soldering on a cell. However, in certain circumstances, this procedure is inevitable for example soldering the wire to the strip.
In my understanding, the balance leads transfer very little power. Just weld Nickle tabs to the battery tabs, fold them over the edge and carefully solder. The heat is dissipated before it significantly can heat the battery. That's how Dewalt does it on the factory packs.
Why did you reverse the polarity configuration of the pack? Standard DeWalt packs have the positive at the front of the pack and the negative at the other end of the pack. When you are doing something use the KISS method - keep it simple, stupid. The screws on my 21700 pack were 10 torx.
That's a good overview of the process! I'd run an extra length of the strip to solder the balance wires to, minimising heat load into the cells, and I'd spend more and get genuine samsung cells - I've no idea what capacity you've measured under load here, but I suspect if you put this on something really power hungry like a router or angle grinder you'd burn those cells out really fast . On that subject, have you load tested this and what capacity reading did you get? As a reference £60-£70 for a 5ah 18v pack is the price we pay here in the UK, and if you used genuine samsung 21700-40T cells for an 8ah pack I suspect you'd be paying just over £100 for a true 8ah pack.
That's an excellent suggestion, doubling the strip, I will keep that in mind for future improvement. I've tested it with a dewalt heat gun and after leaving it on for 15-20mins, the battery went up to 35 to 40ish degrees and the overheat protection kicked in which I thought was pretty impressive as the entire setup was pretty cheap. However you do have a good point, end of the day it is definitely better to stick with the original batteries, instead of self-made or third-party ones. FYI: I am going to use it for another month or so before I summarise my opinion on making a self-made battery. The only con atm is that I don't think this battery will survive in a harsh job site environment. THANK YOU FOR LEAVING SUCH A WELL-ROUNDED COMMENT! Really appreciated!!!
@@k-30creator20 you are welcome! I am giving serious thought to doing the same as here in the UK the 8ah packs are, frankly, a ripoff. The smaller packs are quite close to the cost to DIY, but by the time you've imported an 8ah pack you're paying £165, which is a £65 premium.
Cordless tools are power-hungry beasts. They can easily peak consume up to 40A from the battery. I wouldn't advise using those 5.000 mAh cells. They are designed for high capacity at low currents, like 10A max. Above this current demand, they will heat quite rapidly, and their capacity will go down significantly. The best 21700 Li-Ion cells for cordless tools are those with 3 to 4 Ah capacity since they can withstand currents as high as 40A without any issues.
I am building a 21700 pack to go along with my 18650 packs. I am building it with 10 Samsung 50S 21700 cells. It took me six hours to charge them up from 3.56 volts to 4.20 volts. I then tested them for capacity and the averaged over 5000 ah. That should create a 10 ah pack.
The trick to making a good replacement pack is to get good, name brand 18650 cells that have a high amp discharge rating. The originals are something like 20amp discharge rated. The higher the mah, the lower the discharge amp rating. The higher the discharge amp rating, the better the tool will preform. A lower rated discharge amp rating will be ok for a drill maybe, but not for a circular saw or an angle grinder. Any 18650 cell that claims to be 6000mah, just know that it's not, and even if it was the discharge amp rating on it would be maybe 1 or 2 amp discharge. So straining the tool will cause the battery cell to overheat and likely cause the tool to shut down.
The genuine DeWALT 10Ah battery has a slightly larger case for the Samsung INR21700-50S cells. They have extra cooling requirements compared to the 6Ah and 8Ah packs. Both 6Ah and 8Ah have the same shell that is smaller than the 10Ah battery’s shell despite all three having the same 2P5S 21700 configuration.
8Ah has Samsung INR21700-40T.
These are the details I needed. Thank you for sharing this info.
@@justinholmes5614 Glad to help. I tore into mine a few weeks ago and I couldn’t find that info before. :) I believe the board circuitry is adjusted for the 85°C temperature requirement of these cells (from the INR21700-50S datasheet). It has the same PCB as my 8Ah pack but the board is marked for different configurations… perhaps populated differently for each? Not sure.
There is also a large fuse that isn’t present on the 6Ah and 8Ah packs.
FWIW, I found a set of unbalanced cells in my bad one but after bringing that segment up and running both batteries in the lawnmower this pack still loses power faster than my good one and gets ridiculously hot (good one is just warm). The mower now quits with the good pack only missing one bar and the bad one still having one bar, likely because the mower detected the imbalance and is attempting to prevent over-discharge. Sure enough, I checked and the cell imbalance was worse than before, likely because those cells overheated. I’m now doing a days-long refresh cycle on the bad segment but I doubt it will help. It’s been taken apart with test leads to my smart charger for a few days now. :)
I chargers any pack battery to 4.2 volts before I build the pack. The reason that I do is so I can test them for capacity capacity of the cells - some lithium battery manufactures lie. I bough some batteries that were rated at 3999 ma and they tested out at a nominal 2550 and change, which is why I buy Samsung batteries, now. They always test out slightly above their stated capacity. I tested out some Samsung 50S cells today and they tested out 4,998-5002. Can’t beat that for consistency, can you? You need to warn any viewer to put the positive and negative leads on the inside part of the tab on the plug, otherwise you will not get the cover to go on the plug. That is the voice of experience.
The nickel you used is not made for the amount of amps flowing through these packs! Use the nickel that comes with the kit, and use a spot welder that can weld the thicker nickel!
Here it comes the debate of soldering cells. Thickes strips more expensive spot welder or you risk bad connections. I went soldering route where you heat the battery for literally 1 second. There're videos proving that soldering, if done properly doesn't harm cells.
I chargers any pack battery to 4.2 volts before I build the pack. The reason that I do is so I can test them for capacity capacity of the cells - some lithium battery manufactures lie. I bough some batteries that were rated at 3999 ma and they tested out at a nominal 2550 and change, which is why I buy Samsung batteries, now. They always test out slightly above their stated capacity. I tested out some Samsung 50S cells today and they tested out 4,998-5002. Can’t beat that for consistency, can you?
Have a link for the case that uses the 21700 cells?
I would advise LT42A, P45B, T39 or T42 cells.. You need higher continuous discharge rate than the 10-15 these offer.
Great video! Thank you. I have purchased couple of cases for 18650 and 21700 batteries and successfuly built all of them. I'm having issue with 18650 5-6 ah batteries. When I'm using tool that have big drainage for example circural saw my case start burning and melting from heat.I think this is caused by strips on + and - terminal which are soldered to a cable like on original battery. I'm not sure where is issue if I'm using wrong nickle strip or its too thin. Did you had similar issue?
Sorry for a late reply! Please be extra cautious!!! I have not experienced that before. When I am using my battery with the dewalt heat gun, the battery do get warm but definitely not hot to touch.
When it gets any warmer, the battery will thermally cut off, meaning I just need to leave it for a few minutes to cool down then I can use the tool again.
Lose connections do generate resistance therefore increasing the temperature. Please be extra careful!! May I ask did the wires get melted or was it just the case that has melted. The reason why I am asking is because if the wires have melted this could be because the wires itself weren't thick enough or the pcb that meant to be protecting the battery pack wasn't doing its job. Might worth getting a different battery case!
Would say could be several issues. I build my own, cause I have some high draw tools that where overheating my 5ah batteries in minutes, and it was annoying. I got the 10*21700 kit, and built it using samsung 40t3 cells. The kit came with steal strips, not nickel. I used my own 0.2mm pure nickel strips, and used 12awg wire to connect the + and - leads. Also on these kits the + and - terminals are not copper like on the real dewalt batteries so that could also be a heat issue. But due make sure your cells real rating at the current draw you need is high enough, and that the nickel strip is thick enough. My 0.2mm nickel strip is only rated for 7.5amps, so in my 8ah battery that would be 15amps, if you need more, you would have to double up the nickel strips, or use copper strips, dewalt uses nickel plated copper strips. Copper is rated like 4x of nickel.
No one, and I mean no one makes a 18650 4, 5, or 6 ah cell that can handle the load that a power tool demands. You want a cell that can handle at least 20amp discharge (more if it's anything other than a drill/driver). The best you can do on a reasonably priced high discharge 18650 cell is around 2800 milliamp hours (2.8ah). You can go higher than 2800mah if you're willing to pay a huge increase in price.
Where did you get the dewalt battery housing and indicator ? can you provide the link ?
campaign.aliexpress.com/wow/gcp/tesla-pc-new/index?UTABTest=aliabtest377151_530968&src=google&src=google&albch=shopping&acnt=708-803-3821&slnk=&plac=&mtctp=&albbt=Google_7_shopping&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=17858129175&albag=&trgt=&crea=en1005005094635795&netw=x&device=c&albpg=&albpd=en1005005094635795&gclid=CjwKCAiA9NGfBhBvEiwAq5vSy8eg-Ss1ceUjaLjgZy6EYDQ6org5YLDHyawLywunssROdppFtiCQVxoCLI0QAvD_BwE&gclsrc=aw.ds&aff_fcid=f0b87390892c4ddb8923233721832f66-1677028873756-01393-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=f0b87390892c4ddb8923233721832f66-1677028873756-01393-UneMJZVf&terminal_id=922908fd10c2456e916aa33e3172fc2c&wh_weex=true&wx_navbar_hidden=true&wx_navbar_transparent=true&ignoreNavigationBar=true&wx_statusbar_hidden=true&bt_src=ppc_direct_lp&scenario=pcBridgePPC&productId=1005005094635795&OLP=1085100208_f_group2&o_s_id=1085100208
Above is the link to the case ~ it seems like the availability is going down at the moment, I will keep all of you updated! Thanks!!
Uuuuu. In the dewalt your paying for the chip in the batters to prevent accidents.
The chip in the battery don't save it from low voltage, that's in the tool, mabey the chip your talking about preventing accidents is for charging?
You need to buy 2 spot welders folks! Because when the batteries in the first spot welder fails you'll need the second spot welder to spot welder new batteries into the first spot welder.
Not if the batteries are soldered onto the board like on my spotwelder.
Hi mate what gauge solder did you use? Thanks 🙏👍 1.0mm???
I bought a knockoff DeWalt pack from ebay and I noticed its not as solidly constructed as an original. Do you think it would be safe to fill it with epoxy to firm things up?
could you put the links where you purchased all the parts from thanks
Great video, but I am looking to build a 15*18650 Dewalt battery. I already have the case and cells, but I am unsure on how to wire it! I have built many batteries, but always 5 cell or 10 cell batteries. I'm looking to step it up to a 15 cell now. If a video exists, would someone please direct me to it? If no one knows of a video, it would be great to see one made! Thanks!
Where did u get your batteries?
Excellent video!! I'll have to see if I can get these here in the States.
Thanks!!
Great video! but where do you buy the case itself?
At the moment, it seems like there aren't any available in the UK. I will keep on checking and update you.
@@k-30creator20its almost Christmas am still waiting for ur update
@@aquakey9834 They are available on Amazon, but don't know if they will deliver to the UK. Also available on Ebay.
what heat temp did you use on the heat gun
where did you get the BMS?
Also, is it not better to use pure nickel strips?
I am not sure. Please tell me more ~ learning every day.
Check out the amp capacity for different strips, both Nps and pure nickel.. As long as you don't draw more than the upper limit of capacity, you're fine. On a higher discharge battery like this, pure nickel would be a better choice.
For example .2 × 8mm pure nickel-6.5A, .2 × 8mm nickel plated steel-4.6A.
Can the batteries be connected with traditional soldering iron? I do not have a spot welder, and that kills be budget for cheap battery rebuild.
He mentioned that they cannot
Unfortunately i will not and cannot recommend using a traditional soldering iron, there are friendly-priced spot welders available online. Here is one: amzn.to/3xJrujG
You can just gotta do it right
Great vid btw :) good job!
Thank you for your support!!! Appreciated!!!
You say “don’t get them hot they will explode”
You do realize how hot those Dewalt butteries get when you use them right?!?
Like the charger literally has a overheat fuse and light built in…
Just wondering if these custom batteries are safe to use in a work type environment? Lmk thanks!
Yes for sure a certain amount of risk will exist and this is just a video of me sharing the process of creating a DeWALT replacement battery. I did run it for a prolong period of time with the DeWALT heat gun, there was a few thermal shut down but was not a huge problem. In fact, with the thermal shut downs, I do believe the battery is safe to use in normal circumstance. However I will not and cannot take any responsibility in any case of accident or incident as I am just sharing personal experience. Thanks again!
just to be clear, soldering onto the cells itself is bad, but soldering onto the nickle strip on the the cell is okay? is this because the nickle protects the cell?
Sorry for the confusion, you should always try to avoid soldering on a cell. However, in certain circumstances, this procedure is inevitable for example soldering the wire to the strip.
In my understanding, the balance leads transfer very little power. Just weld Nickle tabs to the battery tabs, fold them over the edge and carefully solder. The heat is dissipated before it significantly can heat the battery. That's how Dewalt does it on the factory packs.
Hell yea dewalt
Why did you reverse the polarity configuration of the pack? Standard DeWalt packs have the positive at the front of the pack and the negative at the other end of the pack. When you are doing something use the KISS method - keep it simple, stupid. The screws on my 21700 pack were 10 torx.
Is it xr compatible
Nah fuk all dat imma solder my batteries lol
That's a good overview of the process! I'd run an extra length of the strip to solder the balance wires to, minimising heat load into the cells, and I'd spend more and get genuine samsung cells - I've no idea what capacity you've measured under load here, but I suspect if you put this on something really power hungry like a router or angle grinder you'd burn those cells out really fast . On that subject, have you load tested this and what capacity reading did you get?
As a reference £60-£70 for a 5ah 18v pack is the price we pay here in the UK, and if you used genuine samsung 21700-40T cells for an 8ah pack I suspect you'd be paying just over £100 for a true 8ah pack.
That's an excellent suggestion, doubling the strip, I will keep that in mind for future improvement. I've tested it with a dewalt heat gun and after leaving it on for 15-20mins, the battery went up to 35 to 40ish degrees and the overheat protection kicked in which I thought was pretty impressive as the entire setup was pretty cheap.
However you do have a good point, end of the day it is definitely better to stick with the original batteries, instead of self-made or third-party ones.
FYI: I am going to use it for another month or so before I summarise my opinion on making a self-made battery. The only con atm is that I don't think this battery will survive in a harsh job site environment.
THANK YOU FOR LEAVING SUCH A WELL-ROUNDED COMMENT! Really appreciated!!!
@@k-30creator20 you are welcome! I am giving serious thought to doing the same as here in the UK the 8ah packs are, frankly, a ripoff. The smaller packs are quite close to the cost to DIY, but by the time you've imported an 8ah pack you're paying £165, which is a £65 premium.
I really doubt those are 5000mah batteries. Look up project farms test on cheap junk cells that claim high mah, they are nowhere near what they say.
There will be a testing video on this battery coming out soon ~ wait for it ~ you might be right
LMAO :) 5000 mah cells. You're lucky if those fake cells don't catch fire :)
got to give it a try :) All seems fine atm