How not to kill a DeWalt flexvolt battery prematurely

One of my flexvolt battery packs died. Dissecting it, trying to re-use the cells. And figuring out why specifically just three cells at the bottom of the pack failed.

[JeffGeerling]

Heh, I go online and buy the right security bit and wait a week for the bit to arrive, and then the battery sits for 6 months next to the unopened bit... Matthias defeats the security with a nail and a hammer and moves along with his day.

[quirlmaster]

There is nothing more Matthias Wandel then bandsawing a battery appart. I love it!

[apagg]

Respect for that root cause analysis. I hope some Dewalt engineers are fans and realize.

[Anonymousee]

This deserves to be on the main channel. If others knew that they should throw all their batteries onto the charger periodically, it could save a lot of resources. I occasionally lost a battery in early spring (when work ramped back up) and didn't know why, but maybe that won't happen now that I will charge the full batteries before use.

[skatastic]

me: I'll just buy the "security" torx bits to open it. Matthias: I'm gonna break it. Good job.

[fredriklinge]

Best advice for these batteries - thank you for investigating Matthias! I’ve had a barely used 12Ah FV battery die this way, and warranty is only 12 months.

[plywoodcarjohnson]

This level of genius is beyond me. Congratulations!

[RiGGeN]

thanks matthias for the information, i have 2 flex volt batteries that i hardly ever use, with this information you may have save my batteries and a lot more from other users.

[paulf]

Great investigative work to uncover the reason for the middle cells draining!

[georgesilverhawkstrailcame]

I agree completely. Very nice work here, this has been a very informative and educational video. With any lithium-ion cells (flashlights, headlamps, lanterns, power tools, power bank, etc.), I always put the batteries on the charger to top them off before using. I was just telling my son why he should do the same…. this conversation was just a week ago. I will share this video with him.

Have a great day,
George

[ironhead]

I had a 40V battery for my Ryobi brand lawn blower /weed whacker combo die, just like what you explained! I haden’t used it for a while. I checked the charge, 3 bars. So I used it normally (usually ~2 bars to complete the yard). Near the end of my work, it died and would no longer accept a charge! What you explained perfectly matches my experience.

[iwayini]

Thanks for the video. I managed to replace a cell in a Makita battery which was much easier to dismantle and fix than Dewalt. I landed up building a spot welder as well which has come into into use quite frequently now for the battery packs.

[aaronalquiza]

It's magical that you uploaded this video just as i was having a balance issue with one of my $300 battery packs from Milwaukee.

[stoffel]

Found your videos yesterday. Now im hooked. You explain stuff that even a kid can understand it. Keep it up.

[juneritchie]

This is a real eye-opener, as they say, that will impact how I handle my batteries going forward. Thanks!!

[willierants]

This is a great video for a number of reasons. 1. Battery packs are outrageously expensive. 2. The more packs we save all the better for everyone and landfills except battery manufacturers.

[JBALLMORE]

Very informative. I've heard so many say that batteries can go flat if you store them incorrectly. Now I at least know that I should charge my stored batteries before using them.

[Friday-cp]

Excellent info. I try to store all my batteries fully charged, but now I think I'll add a routine charging of I don't use them for awhile. Thanks for the info!

[Fekillix]

I remember this being a big thing on the earliest Makita batteries (10 years ago). But then the issue was probably resolved, as I've never heard about it or dealt with a dead Makita battery since. I still have 8 year old Makita batteries in use.

[MRrwmac]

Matthias, That is some very good Dewalt battery information! Glad you decided to figure it out!
Hope you and your wonderful family have a great year in 2023.