Originally Posted by
BarracudaHockey
A123's are very hardy cells and put up with a fair amount of abuse. They have no memory and you can store them fully charged w/o issue. Indeed I charged up some stuff for an event next weekend when I got home Sunday afternoon and put everything in the trailer. All I have to do Saturday morning is pull in, unpack, and fly.
To answer your question I monitor the amount of charge being put back in after a given flights. If it changes much then I cycle the pack on a discharger to determine capacity.
When A123's first appeared I obtained a large number harvested from Dewalt packs . Most were used. I just charged them all up with my Celpro 10 charger. Some have sat in my garage that sometimes hits 140 d. in the summer. Thats been seven years. Most when I pull them out are still charged. Some have been bad but then they were used cell to begin with.
I used a pack of nine made up to resemble a radial engine to power a Lazy Ace. I got about 400 6 minute flights before I had to replace them. The current while in flight was about 20-30 amps.
There is no practical way to measure and know the power left. You just have to keep track of your flight time.
If you have a decent transmitter you can program it to do that for you