lml@lancaironline.net Mailing List Archive

Ronald: That's probably because you're not generating 100a during taxi and you are draining the battery during taxi with the AC running. Your battery is supplying the AC amps during idle. When you runup it will boost the amps and voltage again which is recharging the battery and supplying the AC so you'll get the higher amps (85). I think I would look at whether there is a net drain on the battery and how much you wish to exercise the Alternator this way relative to the rated capacity. Typically, I've seen manuals suggesting that 70-80% of the rated current for the alternator is a good maximum output in steady state and I just don't know how hot that thing will get on the ground producing 85 amps. You could try to reduce the load on the battery to a minimum by turning off secondary loads until you are on your way and the battery is back up and the alternator has come off the highest loads.

Breaker limits can move over time and open after extended periods at or near the rated current. It may be close to its rated capacity or it may be failing on the safe side. I would test it or replace it with the proper rating and see if that changes anything. I would not continue to reset it without establishing the cause because many headlines have come from resetting circuit breakers. They are cheap and easy to work with. Come by the hangar if you want to talk about it.

Paul

Spruce Creek

In flight when the AC is running (cruise) my amps are around 44amps. Sometimes it goes to 60amps, this is when the AC kicks in again.

The puzzling part is, why it goes all the way to 85amps and than goes back again on the run up? I hope to trigger some Ideas here.
I am having problems that my breaker from the AC pops after about 15-20min after start.

Many thanks == Ronald