Being a newbie to racing, I'm buying alot of used batts from sponsored and/or unsponsored fellas at my club (RCOttawa
As such, some packs are good, some are soft. After seeing a battery discharge chart showing the discharge curve, I started thinking that I could generate these curves using datalogging equipment I use for my work.
At this time, I am able to monitor and record the voltage of each cell in a pack as well as the pack total 4 times a second. I do this using a 30A linear discharge (Indy 0-30) discharging each cell individually, and I can also do the exact same measurements discharging the pack at 30A using a Indy Reactor 30.
So, I got the curves (and found some bad cells), I have the data....what I am missing is a little more information to help me match my used cells to be able to use my RC dollars as wisely as possible.
I'm not sure how to calculate runtime for each cell. I can figure out the runtime to any voltage, but I don't know what the industry standard is for this. At what voltage is the battery considered dead...1.1V? 1.0V, 0.9V?
Internal resistance - I know the average volts over a certain period of time, I know the discharge amps, should I simply use V=Amps x Resistance?
I realise that there is a possibility that some professional matchers will consider my questions taboo. I simply happen to have equipment that gives me the data. I just want to mess around - this is what the hobby is all about right :P
Once my 4 1/2 year old and yet to be born child are off on their own, I'll stick to used batts and do what I can with them.
Any input/information is greatly appreciated.