The original 6ah/ "2ah @54v" have been very problematic for us. I always encourage flexvolt users to upgrade to atleast the 9ah/3ah or if they can swing it, the 12ah/4ah. Superior cells. 18650 cells are ok. But if you want the power, the 9ah and 12ah batteries both use 21700 cells. The difference in power alone is more than worth it. Same way with the fatter packs on the 18v line or 20v max as dewalt calls it. The 3ah, 6ah, and new 4ah and 8ah packs are 21700 cell batteries.

I'm a huge fan of the sexy flexy line. But I've had too much trouble with their 20v max batteries and tools, and the 6ah/2ah flexy batteries.

I've never had the same issues with milwaukee fuel tools and the m18 or m12 batteries for some reason. The warranty process is what pushed me from buying more dewalt for now. 7 months and 4 brand new dewalt 10 inch wet saws later just to get a proper working saw is crappy. And is why I pretty well run fuel everything except the bigger tools, like miter saws, big flexy grinders, table saws tile saws. Hopefully dewalt will update their warranty policy. I have sent in Milwaukee tools for little crap and the warranty is only 2nd to Hilti. Heck we found a 3 year old impact wrench that intermittently wouldn't impact, was damp, and in the back of a work truck we bought at auction.  I sent it in (without a reciept or anything at that.) Got a brand spanking new one back in less than a week. No questions asked. Might not be a big deal for diy or weekend warriors, but it was a huge deal as a builder. @DeWalt hopefully you see these posts and can come up with more reasonable solutions for defective tools and batteries. We have a pretty fat stack of bad batteries at the shop, that have little use, and some didn't make it through a single charge cycle...but the 1 year warranty period is up. Nedless to say, i check the dates when buying new dewalt tools, tool kits, and batteries from anywhere now... Ok, off my soapbox, thanks for the video! 👍💯
And again....Come one dewalt, I want to proudly recommend you like back in the nicad tools days! When you dominated. Warranty is a make it or break it deal for us that spend a few thousand on tools each year! 🤙

As you can see, the 9.0ah is a good bit bigger than the 6.0ah. that's because the 9.0ah uses larger 21700 (21mm across the top, 70mm tall) cells, where the 6.0ah uses 18650 (18mm across the ends, 65mm tall) cells. As for voltage, both of the different cell sizes should be right about 4v with a full charge and no load. Running voltage with a load should be in the 3.6v range. It's important to note that DeWalt's 20v and 60v batteries drop down to around 18v and 54v respectively under loads, so that's why they're called Max. A DeWalt 20v pack has the same cells and voltage under load as any other 18v lithium ion pack, but DeWalt markets the max voltage to make them sound better. The Flexvolt packs each have 15 cells in rows of 5, each row is in series making approx 18-20v. The rows are connected in parallel or series depending on what tool they're connected to. If you look at DeWalt's batteries in Europe, they actually rate the Flexvolt as 18v/54v, maybe because of some regulation or something. I've actually never seen a Flexvolt battery open before, looks very complex and very hard to fix without shorting something out. But that's the price to pay for a dual voltage battery. Thanks for teardown video!

The cells in these batteries should measure between 3.0 and 4.2 volts under normal circumstances. From my experience cells between 1-3 volts will charge back up and become useable again but most chargers won't charge them. You will need to use a dc power supply to charge them up to at least 3v before the regular charger will work.  If the cell is below 1v it is dead and will not accept a charge so basically trash.

My 60 V battery got wet now won't charge what should I do

here is a tip
try using a cell and give it a few seconds jump to that cell, and measure again, if it drops like a rock, then cell is bad
jumping it too long might heat up and burn
so make sure when you do the jump
touch the cable and good cell, pull it out if it heats up too quick.

if it is good, try to slow charge it with .50 Amp to get it up to 3.2V then balance charge all cells, then discharge them all then bring them up evenly.

i use either icharger or skyrc q200 charger

DeWalt uses 18650 HB4 batteries. This mean they are 4.2 Volts, 30 Ah batteries. On August 1, 2019 they can be bought online for $5 or less, if you buy case lots.

Exact same cell is reading 0 on mine too. Must be drawing more power from that one cell

Jumper the positive and negative from a fully charged good battery to that one and then try it

Need put cap to battery to shutdown for 1 each 3-batteries

Try putting a jumper wire to delete that one cell.  ?  Whats there to lose.  I have a couple dead ones if you drop them they go bad instantly.   I dropped one from about 18 inches off the ground and that was it.

Puedo cargar una bateria de 6 amperes con una cargador normal dewalt??

Hello there.. can you do a repair on a 9.0 ah the assembly is different and my battery needs a cell repair but the process is complicated. Thanks

Pushing the top cap from underworked for me on many batteries. It needed a sharp pin through one of the top holes and press down. Don't press it too much and not exactly on edge otherwise will hiss and the gases and the electrolyte can come out there. Happened to me and after hissing got back sealed and the pressure released. A small and hard screwdriver and enlarging the side holes all around worked for me many times. Usually can be tested if this is the safety cap with an ohmmeter. If It does not display any continuity in this issue. Most of the time will work after releasing the pressure or pushing it down all around for a while. The issue is that it can happen very often after this since probably that cell overheats. You can as well connect plus and minus with a wire for a lower voltage. Not sure how the BMS will respond but at least all the rest of the cells will be able to output their power. For sure the battery will be weaker and will need charging often. Any battery even not holding charge must let the charge pass through. Some batteries just got overheated and the gases push the safety cap in a position that disconnects the battery completely. The cells can be harvested for other projects. Will be a waste to just throw it in the bin. Most of them will be good for flashlights, e-cigarettes, and so many other applications. I built a power wall with these cells from laptop batteries with the same issues.

2016 is the year the batteries were made means old stock

Obviously the two batteries that have the black top came together in the two pack. They would have a yellow one in the same package as the black😂🤦‍♀️

hello, can you help me find a board for a flexvolt devalt 60volt battery, since the microcircuit is out, the board now does not take charge?

If it cant be fixed you can use those cells if you pry them out

It’s a shame there are so many bad DeWalt Flex Volt batteries. I have REALLY old DeWalt batteries and have never had a battery failure UNTIL the Flex Volt series.

18650s should be 4.2 volt per battery

It's always the same cell that breaks down. Dewalt designed this so that we end up in Home Depot to buy another one. There is really no feasible repair on these batteries.