I see a lot of folks sharing potentially dangerous advice on reviving deeply discharged tool batteries. Here's a much safer way to do it.
TL;DR if you don't want to watch the whole video:
- Charge the pack at 300mA max up to 15-6V while monitoring for safety
- Check that each cell is balanced at around 3v each (give up if not)
- Let rest overnight in a safe place
- Check that the cells held their voltage and balance (give up if not)
- Charge at 300mA up to full (21V) while monitoring for safety
- Check that the cells are in balance at around 4.15v (give up if not)
- Let rest overnight in a safe place
- Check that the cells held their voltage and balance (give up if not)
- Perform a couple full speed discharge and charge cycles in a safe area
- Check their balance again
- After all that, I generally consider it safe to use normally
- Try it AT YOUR OWN RISK, batteries can be very dangerous!
UPDATE: This battery did in fact end up fully recovering and is happily powering tools again.
I've enjoyed doing electronics tinkering for many years now and decided to try recording some of what I do and sharing it for fun. My own lower quality @bigclivedotcom knock-off. (Go check out his channel if you love electronics stuff).
This is very early on in me trying to record stuff at the worktable and I know a lot of it isn't great - yet! I edited tons out because I ended up rambling and repeating myself a bunch. I need more practice, but I'll get better.
If anyone has helpful advice to improve as I eventually share more videos, please feel free to comment. I'm not committing to any schedule or anything, just sharing as I go and hopefully, I'll improve the setup and editing along the way.
Some of the tools I use: (nothing sponsored/affiliated)
Filmed on an Android Revvl 4+
Bench Power Supply: Ruideng DPS5005 https://rdtech.aliexpress.com/
Hot Air Gun: Yihua 8858
Clamp Multimeter: UNI-T UT210D
Battery Charger: XTAR VC4SL
Adjustable CC Load: MakerHawk Electronic Load Tester 150W
3D Printer: Creality CR-10S
Soldering Iron: Weller WLC100 40W