The International Cessna 170 Association

I still have a generator on my C-145 in my 1951 C-170A. I am considering having the engine overhauled and would like to know what the latest guidance is for the various alternator options to use or not to use. Any current or recent comments on this subject would be greatly appreciated.

Also, can I use a higher amp output alternator (35 Amp) or must I stick to a lower amp rated unit? If it helps, my aircraft serial number is 20216.

I just had the Plane Power ER14-50 alternator installed in 62C two months ago at the time of my recent top overhaul, replacing the old 35amp generator that was on the engine. My A&Ps have performed a number of the conversions and have nothing but good things to say about them. The generator was starting to fail and the choice became a no-brainer. In the two months since it has performed very well - it's great having "power" at all RPMs.

I already had a system that was capable of generating 35amps, though with my landing and nav lights LEDs I really didn't draw that much current, even with the strobes on. The alternator came with a new regulator. So, the wiring from the alternator to regulator to battery, etc. will all be new. I think the answer to your "can I increase the amps to 35" question likely has to do with the condition and gauge of the wiring behind the panel and whether it can safely handle the electrical load. I say that from a standpoint of ignorance, however, and trust that others who respond and have a deeper understanding will be able to be more specific and offer more thoughtful guidance.

Some early C-145 engines didn’t have dampened crankshafts and aren‘t eligible for higher power generators or alternators. If your engine is still a C-145 and has a D in the serial number, it is eligible for a generator/alternator upgrade. I’m fairly sure all of the O-300 engines came with dampened crankshafts and are also eligible.

I upgraded mine in 1990, so I don’t recall my reasoning, but I went with the Skytronics 50-amp Jasco alternator and solid state regulator. It had about 1000 hours on it when I had it overhauled with all he other accessories at engine overhaul time, and about 600 hours since with no issues. The only other maintenance has been replacement of the drive coupling rubber dampers and cup every 500 hours. Upgrading to 50 amps did require increasing the alternator output and cockpit supply wiring from 10awg to 6awg, and changing the ammeter to accommodate the higher output.

I think switching to an alternator also requires a couple extra circuit breakers be installed too.

You are correct, Stephen - the mechanics did install a new circuit breaker as well as a switch for the alternator.

I have both. I have the 35A gen in my 170, and the Jasco/Skytronics alt in my 172.

From an operating standpoint they are both invisible to the pilot because modern avionics and lighting does not require huge increases in generating capacity. The only advantage from a practical standpoint (IMO) ...is the few pounds of weight savings. Per pound, that is an expensive conversion.

AND, the Jasco alternator requires sending it back to Jasco every 1000 hours for rebuild. No one sells replacement parts for Jasco... only Skytronics will work on it. A Jasco/Skytronics conversion will pay for TEN 35A generator exchanges.

I only have the Jasco because the previous owner already converted my 172. If I were to select an alternator for upgrade, I think I’d select the Cessna/Ford/Prestolite Service-Kit version because it’s what Cessna did and because of the many automotive alternator rebuilders/parts supplies.

But I’ve got too many other things to spend money on than an alt conversion when my gen works just fine. YMMV

My aircraft had the Plane Power 60 amp alternator in it when I bought it.

No complaints so far. There is a manual Alt. Field switch in the panel now with an amber light to tell you if/when it is not working. The only time I've seen it on is when I accidentally hit the switch and turn it off....

This is the way to go:

BC433-H 30 Amp Gear-Drive Alternator

Vertical wrote:This is the way to go:

BC433-H 30 Amp Gear-Drive Alternator

Its not for certified aircraft...experimental only according the literature. (Besides, why would anyone want to give up 35A for 30A which is only available at “cruise” power settings?)

There is an STC pushed through by the swift crowd.

It’s substantally lighter. Put one on a friends 170b. He is extremely happy. I know of folks putting the smaller models. (8 amps I think) on cubs under field approval.

Very light, simple and reliable. .

We have a tiger moth on the airport that has a generator out on the wingstrut and has a small propellor on it . Wind driven generator . When people ask him about it he tells them it’s his auxiliary motor in case of when the big motor stops . I have seen aviation “experts” and others get suck into that one but it makes us hangar rats smile .

Replaced the factory installed generator with the Plane Power ER14-50 alternator kit during June 2019. Was not a difficult install. Very happy with the results, especially when the battery is being charged while taxiing.