[MikeZ]

A couple of years ago I upgraded my 79 P337 alternators to 65 amp to accomodate electric AC.... ended up putting in a Riley engine driven AC and I'm COOL now..... but the alternators don't start charging till well over 1500 RPM..... this has occasionally been a REAL problem......

anecdote: The other hot day on the ramp at TEB, after a long hot taxi, waiting among the jets for IFR departure..... rear engine starts to cook, I'm try keeping the RPM down, so no charging.... hmmm....temps coming up....shut down radios..... still temp is too high on rear engine.....shut down rear engine..... OK, cleared for takeoff.... uh oh.... try to fire up rear engine.... no voltage left in battery, so radios lose frequencies.... there I am rolling onto the active with no rear engine and no radios..... oh shit......

I 180 and taxi off with no radio contact, lucky it was clear.... jets all around me.....somehow I start my rear engine, rev the front, get my frequencies back on the radios (had to reboot) call tower, and tell them what happened.... they say OK, GO..... so I did ....

SO, back at the shop, put a new battery in..... it was two years old anyway....

but really, if the alternators charged at lower RPM it would not have put such a load on the battery. The old standard alternators kicked in earlier. The regulators on the front firewall don't seem to be adjustable. Or is there a way?

Any ideas or comments?

Next time I'll shut down sooner, keep the temps down.....but it would be nice to generate some charge at lower RPM....