AOG - Battery/alternator/starter problem----solved :)

[JordanGrant]

FIXED! See post below for the final resolution.
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Airplane On Ground.
Currently stuck in Elko, NV with weather AND maintenance problems. I don't think even VAF can help me with the weather, but maybe you can give me some ideas on my maintenance problem. Here's the narrative:
-Flew from Boulder City, NV to Burley, ID on Friday. 3 hrs, No problems.
-Flew local sortie on Saturday, about 0.8 hrs, no problems.
-Flew from Burley, ID to Elko, NV today. 1.5 hrs, no problems.
-Attempted to fly from Elko to Las Vegas, but turned back due to weather. Total flight time 2.5 hrs on that leg.
-After landing back at Elko and trying to fire up - the battery is dead! Or at least, something is wrong and the battery can't spin the engine. The local FBO tried charging the battery for me for about 1.5 hrs at 2-3 Amps. Tried it again, same problem - won't spin the prop. Acts like it's a dead battery when trying to crank, but otherwise still reading 12+ volts.
-The battery is a PC680 that I bought new in March at the Madera Formation Clinic (thanks Slick), so it's barely been used.
-The electric system showed about 13.3V the whole flight (my system loses about a volt to the sensor, so that should have been a charging voltage of about 14.2 at the battery).
-My ammeter reads current on the main alternator output wire. It showed pretty normal output/demand during the flight (about 15 amps) except for one oddity. At one point I showed a spike to a very high amperage (in the 40s). I've had odd ammeter readings before (in the 100's! and dropping offline) and have chocked it up to something with my sensor. Regardless, I turned off my strobes and nav lights to start shedding load, and the reading went back down to normal, so I just left that off for the remainder of the flight - figuring I'd troubleshoot it later. All was back to normal at that point.

So, if you've read this far - thanks - here's my question:
Is there a failure mode of anything else in the starting system (i.e. Skytec starter, starter solenoid, etc) that would look like a low-powered battery? I'm going to try charging up the battery again tomorrow morning and hopefully I can get out of here, but I'm worried it might be something else and I might have to troubleshoot. I'm going to try and check the resistance from the battery through to the starter as well to see if I have any kind of problem there.

Any ideas you have are appreciated,

[Mike S]

Try checking the starter solenoid aka contactor.

After that, look for wiring issues and do not forget the ground path.

How many hours on the plane, how long (if ever) since replacement of the starter or starter solenoid??

Good luck..........

[JordanGrant]

Airplane has been flying for 8 years (January 2006) and has 550 hrs. The starter is a Sky-Tech. Both the starter and solenoid are original - never been replaced.
The solenoid seems to work - the starter does engage and move the prop (a little bit).
I'll remember to check the ground path resistance back to the starter as well.

Thanks Mike!

[Mike S]

The solenoid has a set of contact points in it that will eventually burn, and cause high resistance or just fail altogether.

This would be my first place to look based on what you have described.

Take a look at this thread.

http://www.vansairforce.com/communit...ad.php?t=90977

Try shorting the start solenoid if possible. At least it will rule it out or confirm.

[Mike H]

I have had the exact same problem in my Cherokee 180. Skytec light weight starters have an additional/redundant solenoid that is starter mounted. The contacts inside of the solenoid become pitted and burned and will cause such high resistance that it appears that the battery is failing due to shorted cells or loss of capacity. New solenoid from Skytec fixed it twice. After the second time I traded it in to the factory for an in-line model which has a much lower failure rate and is the best starter that I have ever used. Do you have the light weight starter?

[JordanGrant]

Mike, you may be on to something there. Conveniently, there is an Autozone across the street from the FBO if I need to replace the solenoid!

[JordanGrant]

Mike Hammond,
Yup, SkyTech 149-12PM lightweight starter. Hopefully its just the solenoid. I really don't think its the battery at this point.

[Mike H]

Unfortunately you cannot jump this solenoid due to the proximity to the propeller. Try and borrow a serviceable starter to get you home and then send the light weight in for repair, Skytec will give you credit for exchange towards a new or rebuilt in-line unit which may be the last starter you ever buy. If you chose to keep running the light weight unit I would recommend purchasing a spare solenoid from Skytec and keeping it in the plane.

[Mike H]

I am not sure if the integral solenoid has an automotive application. You may want to call a skytec and let them know of your problem (they won't be surprised) and see if they can give you a automotive cross reference so that you can try and get a replacement locally.