DeWalt FlexVolt Battery Pack Disassembly (Video#2)

[@_RocketRooster]

Man did DeWalt make the flex volt battery packs difficult to work on! I'm working on one now with one dead cell on the bottom middle and like yours I've just about got to disassembly the entire pack! What a thorn in my side this is! I'm sure thankful of your videos!

[@stanimir4197]

difficult as in - totally not meant to but send 'em to the bin? I consider them (flexvolt) a mistake running the 54v tool (15 in series) up to the thermal cut off. Then removing it and switching to 5s3p to balance themselves on their merry way w/o any current limiting. Other than that the pack looks amazingly well built mechanically aside the water ingress.

[@_RocketRooster]

@@stanimir4197 I've determined the flex volt isn't worth the money they cost! They just don't hold up in rough conditions!

[@johnhill3507]

Love your channel, thanks for your work on these videos, I enjoy and learn for free

[@ThriftyToolShed]

Thanks for your kind comment! So glad you enjoy them!

[@br4morse7]

The Samsung 20S is a very good cell! It has a max continuous discharge rate of 30amps. Compare that to the Samsung's 25R, the cell of choice for almost every 5ah power tool battery, you can only draw 20amps continuous from it. Forget about that flex volt mess! I'm cannibalizing the cells from the first 6ah flexvolt I get my grubby mitts on.

[@clydedecker765]

Some time I'd like a little better description of the "nickel" strips and their ties and function. You gloss over the whys and wherefores pretty good. I am assuming they are the interconnections to make series or parallel banks... and how they are connected to a "bus" of some kind to make switching arrangements. Once you've "torn" them loose - how to repair/replace them to remake their function again. Then there's "silicone potting" what is it and why is it so hard?

[@ThriftyToolShed]

The Nickel strips are the ties across the cells. They are tied in many configurations through many manufacturers. We see them most commonly tied the cells from positive of one to the negative of another to create a series cluster of cells if you will. The most simple of this is a single layer of 3 cells for example all 3 joined from positive to negative giving you a nominal 12V from end to end. This would be a 3S 1P pack. 3 cells in series and only 1 set. To double the capacity of the same exact cell type simply add another set just like this in parallel. So the strips again used to join across those to be in series with the first set. So now 3S 2P. Same 12V but double capacity. We typically spot weld these nickel strips on the ends of the cells. Soldering is not desirable because it can heat up the cells and cause damage. I have done it, but in that video I explained to heat it quickly and cool it quickly, still much better to spot weld for sure.yhe potting is as Nils mentioned, it's a protective coating to help with moisture ingress to help eliminate corrosion from happening and also it helps with vibration/shock on the components if dropped etc. Hope it helps, thanks for your comment!

[@jdmccorful]

A good book for reference is : "DIY Lithium Batteries, How to build your ownBattery Packs" by Micah Toll. . I purchased a copy some years back from Amazon. It will help you alot with understanding the mechanics involved with Li. pack building. Check it out.

[@bryanhenderson8413]

Great job thanks!

[@ruinunes8251]

It is so frustrating how just one cell makes one entire pack useless.

[@ThriftyToolShed]

Indeed! That is why I usually don't buy the largest capacity packs. We can absolutely get more current to a device with them and of course more run time, but also more head ache and more money. The lower capacity packs are usually too low of capacity to be useful in a broad range of tools and they have to work so hard to run a tool it can burn them out quickly. I usually as a rule of thumb go for the middle of the capacity range. As an example the Milwaukee M18 the 5ah is my favorite tool packs and also EGO 56v 5ah pack is my usual go to. Seems to work for a little longer with less issues anyway! Thanks for your comment!

[@ruinunes8251]

@@ThriftyToolShed Agree with you. My biggest Ryobi battery is 5.0Ah and the Milwaukee M12 is 6.0Ah. It is good enough for me. I assume the best way to extend the life of these large battery packs is not overheating them.

[@davidbarker3591]

And what cool is if you are swapping out all cells, you can get rid of the 25R's and go with Molicel 3000mAh cells with a CDR of 20 amps, so now you have a 6ah instead of 5ah.

[@ThriftyToolShed]

I do like the Molicel 2800 and 3000mah a lot so far. Great capacity and still lots of current output!

[@jdmccorful]

Do you have faith in the repair, and I'm not questioning your skill? Looking at the price on internet markets used run anywhere from $80 and new Dewalt $128 or up to $300. I follow your coment on its heat disapation problem. Just thinking out loud. Thanks for the look.

[@ThriftyToolShed]

Usually the repair will get much more life out of it. Of course the best repair would be to replace all cells with brand new, but that is not much cheaper sometimes than new pack price. I usually don't have much invested in attempt to get pack back running. I keep many tested good cells from other donor packs etc. Sometimes it may not be worth it.

[@jdmccorful]

@@ThriftyToolShed I follow your lead.