When is your LIPO going bad?
 

I have a Gravity Hobby 5000mAH 40C battery that I have been using in my Jammin SCRT10 with the Havoc Pro/HV4.5 power. I had a battery lead fail on me a short the power and ground which discharged the battey a lot very fast. There was no external damage and each cell was still above 3.0v when I checked it. It was warm (about 105 DegF) so I changed it and it took about 3500 mAH.

I tested it in my truck and it was working OK no real issues. Then at the last big race I was noticing some issues that indicate that the voltage was dropping below either the LIPO cut-off or the input cut off. I have also noticed that the battery is always warm after 5 minutes and everything else is warmer too.

Could my Lipo be damaged such that the internal resistance is higher requiring more current draw or lower voltage? It seems that this is what is happenning.

Lipo doesn't tolerate being shorted, especially a long duration short like you've experienced. Voltage was prob lower than 3v while it was shorted.

Little doubt its damaged, surprised you did not find that the capacity fell off as well. Seems like once lipo media gets really stressed, voltage/amp character seems to change. Bigger voltage depressions for same current and lipo doesn't perform like it did.

It took about 8 cycles to start seeing issues. I'm going to right this one off and get another 5000/40C or better.

IMHO :sweat:
The lower the I.R. the better the battery is.
When I get a new battery the first thing I want to know is what the voltage and Internal resistance is before I use it.
I keep tack of those two thing and how many mah's I used every time I use my battery's.
I think when the I.R. goes up it gets hotter when being used and charged, keeping track of temperature can also tell you a lot.
The charger I have shows the I.R. when charging or dis-charging.
I've had lipo's I.R. and balance go down and some went up after 4 or 5 uses.

I hope that helps you a little :sweat: