[kip51035]

I have a Futaba T6XA transmitter. the other day I went flying I turned the transmitter on and the voltage was 10.2V, I went flying, at the end of the flight it read 9.8V. Half an hour I went for a second flight. Start voltage was 10.1 and the voltage at the end of the flight was 9.6. An hour later the voltage was 10.2. This is a computer radio,which I am not use to yet. I have been running nicads since 1964 and this seems a little strange. I took it off charge this morning and it now reads 10.7V. The battery holds it's voltage really well. Does anyone have an explanation for this?

Kip

[Cougar429]

This sounds like you may have just had a pack that was not fully charged. What I believe is happening is the pack partially recovers once left to rest a bit.

Rewind it and see what it does.

[moo]

1) What is wrong with 9.6 Volts under load? (you should probably expect 11 Volts fresh off the charger with good batteries though)

2) The voltmeter may need calibration.

3) you may have one cell with low capacity.

[Spitball]

I wouldn't be unhappy with those readings - cells come back up a bit after resting, but I would keep a steady eye on them nonetheless.
Most computer radios draw about 200mA, which is a fair steady load on the 600/700mAHr cells used so I'd cycle the pack if you have the facilities, and see. NiCds are pretty predictable but NiMHs behave strangely sometimes! MHO.

[moo]

If you can, check the voltage under load of each cell individually. (I have some extremely sharp meter probes for this, including one designed to puncture insulation on a wire)

If you cannot, each half of the pack should be equal (also under load)

This will tell you if you have a bad cell.