alternator output upgrade

[Lubek]

I am considering the cost-benefit analysis of upgrading the alternators on my 1966 PA30 from 35 amp to 70 amp. The driver for my consideration is the math; if one has an engine malfunction at night in winter, flying an approach with radios, heater fans, landing lights and lowering the gear, the power drain should overload the standard 35 amp alternator on the remaining operative engine.

I'd appreciate input/comments from others on the cost/benefit of the upgrade.

[N3322G]

Hi, I noticed this is your first post. Welcome.

Let me try to help by sharing what we've experienced. In the 40 years of the twin I have - the electrical system has been the most frequent problem - not huge but enough to make us design our renovated panel to have triple backup for an approach environment. The number one culprit has been alternators - again not huge but enough to notice - wires come off, belts not adjusted correctly - stuff like that.

I guess the benefit would be greater if you fly a lot of the night situation you described - sort of like - how much insurance do you want. That being said, my 39 has the 70 amp alternators and does run quite fine on just one.

Hope this helps.

[Lubek]

[Alan Cheak]

[md11flyer]

[Lubek]

[Lubek]

[9089P]

Hi Barry,

Not to confuse this too much, but regarding the singles, the 180's and the 250's could come from the factory with either 35 or 50 amp generators. The 260's came with 70 amp alternators. Otherwise I agree with Gary that 50 amps should be enough power in the event of an emergency. I also agree that it is unlikely that you have 35 amp alternators.

Good luck, Don