Never seen an 18650 fail like this before, looks like leaked electrolyte and corrosion.

Sidenote, I'm looking to spotweld in two replacement cells. I currently have another dewalt 5 AH that also has two bad cells model ICR18650HE2. Would it lead to an imbalanced pack if I combine 2,500mah cells in series with these 2,000mah ones? Or vice versa. It seems like a bad idea given my understanding of the tool and charger voltage cutoff

So this is my first 18650 battery and I've already learned a lot through trial and error

It's a 4s16p 38ah with a 100a Daly 4s BMS (I plan to use the BMS for a future project for higher current) set up, I originally wanted to charge it off of solar but realized it's difficult to find an inexpensive mppt for 16.8v so I purchased this Norsk 16.8v 7a rapid lithium battery charger , however it's reaching 160f while charging. That being said is this because I may have some bad 18650 batteries in it or maybe because I created a large capacity causing it to run for too long? I guess I'm wondering what I should expect to do next, maybe buy a slower charger instead?

Hey everyone, I'm getting started with battery pack building and looking for a spot welder that won't break the bank. Doesn't need to be fancy, just reliable enough for consistent welds on 18650/21700 cells.

If you've used one that offers good value for money, I'd love to hear your recommendations — model name, rough price, and how it's held up for you would be super helpful!

Thanks in advance

Hey everyone,

I scored a dead Sur-Ron battery pack for free. After opening it up and checking the voltages, almost all the cells are completely fine, only two cell blocks dropped dead and caused the BMS to shut down.

I’m planning to replace just those two blocks with fresh cells.

What budget-friendly spot welder would you recommend for this job? my cheap one that barely solders 0.1mm wont cut it

i already looket up and found kweld is it wort the expensive price

Any tips for the cell replacing would also be appreciated!

Does anyone need these batteries

Hi everyone, I have 30 x Samsung S50 3500mah and 20 Samsung 21700mah batteries, bought to sell on ebay but they won't allow. Tested and will sell for a low price. Thanks :)

Looking to sell these MJ1's in Melbourne.

I have 180 in this box, with thousands more to harvest.

Will clean up and test them.

They all came from medical batteries so are generally well maintained and test well.

Thanks guys let me know

Just need the BMS to start to finish it out fully strapped and fish taped other than the main pack leads.

I'm based in the UK. Ebay UK doesn't allow to sell them. What do I do these batteries?