LiPo Test

[mikiek]

I smoked some hardware by connecting batteries with the wrong harness. They were 6S and I plugged them into the Zelos 36 OOB harness. After a few snap, crackle, pops and some smoke I took a look at what was left. Besides the components, the cable on one of the batteries was partially melted. The other battery has no visual signs of damage.

So I'm wondering how to tell if the 2nd battery is still good. Is a test just as simple as a volt meter? Do I risk plugging it in to my smart charger and get the stats from that?

[boatsrnew2me]

i would check it with a volt meter ,if it only has some cable damage it may in fact be ok . only way to know is to test it . if the lipo had suffered any real damage it would have puffed up right away .

[Fluid]

Things which could have happened include tabs becoming unsoldered, which can often be determined by a total voltage check, or the use of a cell checker. You do have one of the latter, right?

https://www.offshoreelectrics.com/pr...y-Cell-Meter-7


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[mikiek]

Yes Fluid - I do. It's part of the charger. I'm a little nervous about plugging a potentially damaged battery into it. The way my luck has been going I would end up frying that. I'll find my volt meter and try that first.

The LiPo is not puffed. If it's just the cable do you cut off the old and replace? If yes, do you solder the new cables or use an electrical connector? If solder, I assume you would not use a resistance solderer for this application?

I know these are elementary questions but I still ranked in the noob column. I appreciate all comments. I'm learning (the hard way )

[boatsrnew2me]

can you post a picture of said lipo? that would be of great help

[srislash]

You will need a decent (80 watt) solder iron for the connectors or any wire to be soldered. I am wondering where the battery lead was damaged and if maybe you can solder the connector on at that point. First of course is to do the cell check. A small one such as Fluid linked is REALLY handy in the field box/bag.

Shawn

[mikiek]

Thanks for asking. That made me do a closer inspection of the "melted" insulation. Turns out it wasn't the insulation at all. It was the "Do Not Pull" label that went FUBAR. Maybe some good news.

Here's a few pix - it's hard to get good angles. The 2 batteries on the left were in the boat when I smoked it. The battery on the right is new, never used, same brand.

DSC01957.JPG

DSC01958.JPG

DSC01959.JPG

DSC01960.JPG

DSC01961.JPG

I'm still trying to dig up my volt meter.

[TheShaughnessy]

cant really see anything from that pic
here is a video i made a while back when i came across a similar situation. I TAKE NO RESPONSIBILITY FOR YOUR INJURIES ATTEMPT AT YOUR OWN DISCRETION. OUT SIDE ON CONCRETE IS THE BEST PLACE TO DO THIS.
https://www.youtube.com/watch?v=SO1gjtnHQ6M
https://www.youtube.com/watch?v=WqWD4EzkOE0

[Mxkid261]

Those look alright to me. If they were mine I would just check them with my cell checker. If they look good on that I would probably run them through a cycle on the charger, outside obviously. If they balance out and don't puff I'd say your good to go.

[mikiek]

Mxkid261 - my cell checker is a function of the charger. That's why I've been asking these questions first. I don't want to risk blowing a $200 charger by plugging in a damaged battery. I'm not sure if it would, but given the fiascos I seem to keep having I'd like to be reasonably sure it'll be OK.

[srislash]

They are most likely just fine. It is REAL hard to reverse current from a battery once she be a flowin'. I thought maybe you did that when you said you melted the leads but they really do look fine. I think you just really over exerted the ESC's..

[mikiek]

srislash - I believe you are right. I still haven't found the volt meter, but I did plug the batteries into one of those little tester units and the numbers look OK for both. So at least thru the balancer cable things are good. A little bit of good news

I'll plug them into the charger in the morning when I can watch them and set it for storage mode. I guess that would tell me if the leads are good.

[Mxkid261]

You should invest in a small handheld cell checker they're pretty convenient. I always have a handful laying around. You can get a 4 pack of cheapies on amazon for $11 or a nicer one like Fluids link. I like the cheap ones with the alarm, a couple of my boats I don't run low voltage cutoff (LVC) so I rely on it.

[TheShaughnessy]

if you didn't fry the balance wires then that means all the tabs are still connected, which would lead me to conclude that the main leads are fine.

[mikiek]

I do have one of the cell checkers. That's what I used to first test the batteries yesterday. I went ahead and put them on the charger today. It did not complain and I was able to put the batteries in storage mode.

What tabs are you referring to?

[TheShaughnessy]

the tabs underneath the shrink wrap and foam and tape that are used to solder the individual cells together. here is a picture to show you what i mean.single cell lipo,tabs circled.jpg
your 4s pack is four 1s packs connected in series. Its common for these tabs to disintegrate if the battery is shorted out. If this was the case and you connected it to your smart charger you would get an error stating there is not a battery connected. A circuit needs to be closed for electrons to flow and if a tab comes unsoldered then the circuit is open.

This is just for future reference since it seems you are out of the woods on this one.

[mikiek]

Just the kind of information I need. Thank you!

I have yet to tear into a pack to see how they are put together.