MinotRich

I have a 600 mah Futaba rx pack that sat over the winter without being charged. When I have cycled it through 10 charge/discharge cycles, the average discharge capacity I am getting is 507 mah. If my math is correct, this equates to 84% of the rated battery capacity. Is this pack still safe to fly?
How low ( in mah discharge reading) should a battery pack be allowed to get before it is considered past it's usefull service life and should be discarded? I don't want to wreck a perfectly good airplane just because I was stupid.

Rodney

The numbers you are getting may be okay. To what voltage is your discharger discharging the batteries? If it is 1.1 volts/cell you will get less mah out than if the cutoff voltage is 0.9 volts/cell. What is the discharge rate? If it is higher than 0.2C you will get a lower mah out than when discharging at a lower rate. In order to answer your question acuratelly, one would have to know what the values were when the pack was new and tested after the correct forming charges were made. Another test you might want to make is to see how well the pack holds a charge. If you charge it and let it set for a couple of days, is the resulting mah much less than when you do an immediate discharge test? If so, the battery may be on the way out. If you only loose about 5% the battery is probably fine.

Rodney gets an A+ for this one. He must have stayed awake during Battery 101. Red S. The Battery Clinic

JNorton

My Feedback: (2)

Congratulations on your test score Rodney. [sm=thumbup.gif]

mbba2002

My Feedback: (10)

I would just buy a new battery cheap insurance. Batteries have gotten better and with higher capacity 2500 NIMH pack same size as you original pack but 4 times the capacity. You can make a new pack for $10.