OpenTube

The Ultimate M18 Battery Test

Doctor Lefthandthread

5,424 views

Is your Milwaukee M18 Battery not charging and showing a flashing light? Don't toss it just yet. In this video I will show you how to restore balance to a pack and test the battery afterwards with a load tester.
The items required are linked below
lipro B6 Charger https://amzn.to/4nfPtPx
load tester https://amzn.to/4nIfruS

Disclaimer
working with lithium-ion batteries can be dangerous I am not responsible for any damage or injury resulting from attempts to follow the procedures in this video

11 Comments

@doctorlefthandthread Creator 1 year ago Pinned

The items required are linked below
lipro B6 Charger https://amzn.to/4nfPtPx
load tester https://amzn.to/4nIfruS

@daveh4106 9 months ago

I like the magnet trick. People also use them to hold the tabs in place when spot welding batteries - prevents shorting cells.

@pcfixerr 1 year ago

A fine example of what can go wrong Doctor! Your testing proves that cells which go WAY too low will definitely lose capacity and that is why manufacturers specify a low limit for their cells :)

@michaelkennedy-j6v 9 months ago

Another great video I think you should take the time to show how you were setting up the charger as I believe many do not know!!

@OzCreationsAU 9 months ago (edited)

If the cells went flat (one P group), it will happen again, one of the cells is dead (prob a heater as well), needs to be replaced, or it's just going to go dead again, or worse start a fire during use or charging cycle.

@george-oc7303 9 months ago

Iv the same charger and it keeps saying battery low voltage

@thomasmillward3353 9 months ago (edited)

So I had 2 dead cells, replaced them and have 3.9 v on all cells but battery is still not charging (solid green on charger) any help thanks

@SorosTheKingMaker 9 months ago

3.4ah is better than 0

@MarkSadler-w8c 9 months ago

You are using a balancing charger to charge one bank of cells. Is there a reason you don’t do a full balance on the battery pack? I know you have to make a lot more connections, but with your magnet trick, shouldn’t be too hard.

@AverageDadsOffroad 6 months ago

I have the same load tester and setup it the same way you did for a 5.0 battery. I ran the test and it shut off early, instead of running to the set 12.5v cutoff, I'm assuming the BMS cut it off at around 14.7v. I was at 3800mah. Has this happen to you before? I would like to attempt the full load test. Any suggestions?

@MrZimmaframe 9 months ago

I bought 2 Milwaukee faulty batteries the other day. One had a loose cell connection , and then other needs 2 new cells at some point.

I spot welded the loose connection back on, checked the cell bank voltages and they were all spot on at 4.09 eachv, I put it on the charger to reset it, and it worked. Fully charged it and let it rest to 20.2v. Used it on my impact and then left it on my impact on my workbench, and it flashes one bar again, no loose connections, it resets each time I put it on my charger, but after using it again a few times it flashes 1 red bar. Do you think a new PCB would fix this issue?