O-290-D Alternator Conversion

[8359]

I dug through the forum last night, looked through the STC and 337 List. I saw the documented alternator conversion for the C85, 90 and O200, but nothing listed for the O290D.

Has anyone done this?

I saw a few STCs listed for Pipers with the motor, but I assume the STC would have to be for the 120/140 specifically to apply to me. I guess this leaves the 337 route. Is it best to start with the C85/90/O200 as a guide?

On my last two flights my battery has been draining and hasn't been able to keep up. I had no lights on, only a radio and transponder running. It seemed like every time I was transmitting the voltage would take a hit and it wasn't able to recover. (very busy airspace here in SoCal, unavoidable).

I'm trying to re-charge my battery manually and try again to see if maybe it was just weak, but I'm not sure that's the case. The battery is a Gill from 2015 (previous owner installed).

Any help/input would be much appreciated.

Thanks.

[4004]

Tamer, it will help the gurus that will respond if you will give additional info of your present configuration, generator amps, etc - it could be that your present system needs a good checkout but agreed an alternator is the way to go. "In the interest of safety" the FAA shouldn't have a problem with a field approval. Could be that you can increase your generator size- a lot of 120/140 OEM size generators went from 12/13 amps up to 35 amps. In addition, generators have current regulators, which possibly needs adjusting in your case. 2c

[8359]

Thanks for the feedback. I will dig through the books tonight and try to figure out what's in there now. It was done by the previous owner. I just purchased the airplane this month.

[V529]

I'm guessing you have a generator? It's probably either a low amerage unit, or not working at all. Your radios (unless you have really old units) take almost no energy, except during transmissions. The Transponder uses the most juice. Running no lights? your generator should be able to keep up.

Several things. Have your generator system checked out. It may be simpler to just install a larger generator.

Contact Gus Warren here in Michigan, he has the McKenzie STC's for the Lyc engines and could probably help with figuring out an alternator install.

Research Plane Power, B&C and Sky Tec, who are the three leading lightweight Alternator/starter providers. They may have a ready made STC (yes it has to apply to the airframe not the engine) for your application.

The Field approval route is a tuff row to hoe these days.

[6643]

Look under the cowl. Whatever is there should have a data plate on it.

Sounds like something isn't performing up to snuff. It is against the regs to install equipment that is normally used continuously that increases the load on the electrical system to more than 80% of the generating capacity. In other words, your charging system should be able to keep the battery charged. If you start off OK and things go down hill through the flight then you're not charging the battery. (Don't you have an amp meter? What is it telling you?)

Generator and alternators are airframe components, so seeking a field approval (there is no "337 route", what you'll need is a field approval) you would be best to start with an approved setup for the 120/140 and substitute similar parts that are approved for the O290. It's unlikely you'll ever find an STC for a O290 in a 120/140 as the combination is so rare.

[8359]

Thanks for the feedback, very helpful.

The generator is a Delco Remy 1101899, 20amp model. Seems a little low.

I have a Narco MK12E radio, from what I can tell it's in the 5+amp range for transmission power. I fly out of KSNA, so I spend a lot of time on the ground idling waiting to take off and also a lot of time talking to ATC. I do have an amp meter and it was barely keeping it positive. The voltage would drop and then spike back up every time I would transmit. Things do start out fine, seems to be about the 20-30 min mark where it goes downhill. I have a newer transponder, Garmin GTX 327, I believe it's spec'd at 2-3amps draw.

I'm going to charge the battery for a few nights (Gill 12V) then go to the runup area and measure the voltage at full power and see if the generator is doing it's job. There is a chance the battery was just running a little low and then it couldn't keep up. I know they like to stay topped off.

I'm open to the idea of installing a larger generator, I guess I'll have to see if there's a drop in replacement. (If I go this route I assume it also requires field approval?)

Do you have Gus Warren's contact information?

I'll checkout the others you mentioned. I know I have a Skytec starter and it works great.

Thanks for the help, I apologize if these are elementary questions, this is my first airplane, just trying to figure it all out.

[4004]

Field Approvals are "personal" with each FSDO - lot has to do with FSDO experience level and responsibility acceptance of FSDO individual and proper preparation of 337 - cover all the bases.

As consensus, do dillegnt diagnostics on your current system. As Victor pointed out - kinda strange with your limited load that your generator (assuming) can't keep up. Also, don't trust just the logs, per John C., look for the dataplate on the generator- if it's a DelcoRemy, probably 1101899 20 Amp, 1101900 35Amp or 1101915 50 Amp - these are the approved for your 0-290 - someone may have installed an earlier smaller 12/13 Amp and not found in the logs . If you wanted to upgrade your generator, it looks like the FAA TCDS database no longer list the 0-290 engine, however, if you look at the 0-235s TCDS and under "Electrical", you will note that you are referred to "Lycoming Service Instruction 1154" - and FAA approved document listing all engines, starters, alternators combinations some no longer Lycoming supplied - scroll on down to Table 5 - and voila, you'll find generators and a listing for the "290 series " engines and listing the three DR numbers I mentioned above.

Having said that, if you needed/wanted to upgrade your generator system , discuss with your A&P - I see no reason why, wirh the appropriate wiring, fuse/CB, and regulator upgrade, all could be done with just a logbook entry. IIRC over the years, when the the 120/140 generators were upgraded, that additional approvals were not required.

Now, when 'the smoke has cleared" on your situation -- I have a 1101915 Delco 50 Amp generator, belt driven with pulley, and I think I still have the regulator, in my hangar that I removed from my Bonanza many years ago when I upgraded to an alternator via a field approval for my own fabricated system, including the mounting brackett. Coordination with my FSDO contact for advanced start for the field approval 337, "make it look good"!!

I'd have to look for regulator but know where the generator is - had about 500 hours since OH and working great! Yours for shipping.

Big Edd
moxcart1@wmconnect.com PS See you have been online since I started this - at 90 years in 15 days - extremely slow key puncher!!
One would think the 20 amp should be sufficient if your getting that - easily checked.

[6643]

Generator control units (voltage regulators in the vernacular) also provide over current protection to the generator. If you have the original 13 amp regulator then it won't matter what generator you install, it will be limited to 13 amps. So, what regulator do you have?

Generators will not charge at idle, so, assuming the battery is charged, you can get a handle on your load simply by turning everything you normally use on at idle and observing the discharge rate. (If it doesn't make sense, there could be something wrong with the indicator. Wouldn't be the first time...)

If you're near that 80% number, and you spend a lot of time on the ground idling and transmitting, you need 4 minutes at cruise for every minute on the ground to make up the deficit (in theory; practice is always worse...) Transmitters are not included in the load calculations as they are intermittent use, so your reality is that much worse.

[8359]

Big Edd,

Thanks for the detailed response. I may take you up on that offer for your old generator, I'm going to do some testing this week and report back. I think you may have seen by now, but mine is the 20amp unit. I know if should have enough juice, but I think between all the idling (can be up to 10-15min before I'm cleared for takeoff) and transmissions, I'm just draining the battery before it even gets a chance to start. I think keeping the battery topped off before flights will prove important as well.

If you have a copy of your field approval you're willing to share, I'd love to see it.

John,

Thanks for the lead. I'll take a look at the regulator tonight and see whats in there. I will do some testing and report back with the results.

In the meantime, if I go with an alternator conversion, I think the kit from Plane Power is the way to go. It's around $800 and includes all the brackets, regulator, etc.

Thanks everyone for the help.

[8359]

I was able to do some testing today. The generator appears to be working without a problem. At idle the voltage drops or maintains depending on what is switched on, and once I get above 1000RPM the battery starts to charge at a significant rate.

I think the major problem here was that I was used to being able to just flip on the radio, transponder, etc as soon as the engine is running. Then I have a solid 15 min of idling and running all those electronics. This gave the generator no time to energize and drains the battery. Then I'm dealing with a system that's already behind and can no longer keep up.

I'm also realizing these batteries like to stay topped off. I can either spend a few extra minutes in the runup to top it off before switching on all the electronics and/or I can try to keep it charged. I bought a solar battery tender and will keep that hooked up when I'm not flying. I think with all the sun we get in SoCal, keeping it on the dash will at least keep my voltage up so I can start with a full battery.

I'm still a little worried about longer decent from altitude at idle, but I think if I do my do diligence in the systems operation, I should be okay.

Link to the solar tender:
https://www.amazon.com/gp/product/B004Q83TGO/