Engine only starts when jumped

[Steven]

I put a new Odyssey PC310 battery in my CTLS in March. It struggled to crank the engine fast enough and after about 3 weeks could no longer start the engine. The PC310 generates 310 peak amps. Fortunately the engine easily started using an auto jump starter (1800 peak amps). I flew the plane over to the dealer and they installed a new Super B lithium battery which delivers 450 peak amps. That worked for 3 months, albeit I thought the battery was struggling a bit to crank the engine fast enough. Then last Saturday, the very next day after a 2 hour flight, the battery could not start the engine, cranking it just a little bit.

 

I fully charged the battery using its specially designed battery charger, but that didn't help. I also thoroughly cleaned the battery terminals, but to no avail.

 

The jump starter can still start the engine, so the plane is heading back to the dealer in about 2 weeks. It's a 5 year old CTLS with about 360 hours engine time.

 

What could the problem be ???

 

1) Bad wiring ?

2) Corroded terminals ?

3) Bad starter motor (runs degraded and needs more amps to work) ?

4) Bad starter solenoid ?

5) Two consecutive bad batteries ?

6) Alternator is not adequately charging the battery ?

 

Any other ideas or guesses as to the most likely cause ?

 

Is there any harm in using the auto jump starter till the problem is resolved ?

[CT4ME]

The One thing you didn't mention tends to be the single biggest problem as far as electrical problems go.... grounding. I'm not sure it's related... but you can bet it's related just on the number of problems fixing the grounding has fixed.

tim

[Steven]

I did get about 6 high and low current alerts on the flight before the battery failed .... but those may represent the avionics circuit, not the starter motor circuit. It's a very familiar problem to me. About 2 years ago I was getting loads of those alerts and the mechanic finally fixed it by tightening a loose ground wire.

 

A good ground connection is essential when jumping the plane. I had successfully used the exhaust pipe as a ground for the jump starter, but on 2 occasions it did not work. I moved the grounding clamp to the front tire bolt and that worked great. The metal was much cleaner, but it still surprised me how sensitive an electric connection is to dirt and corrosion.

[Roger Lee]

Two things here. First you need to put a meter on the charging circuit out of the reg/rectifier. Next I would install a ground setup like the one shown in the maint. section. That will end any issues or or suspicions about grounding. It sounds like you are not charging your battery. The way to check the circuits for this reg/rec is in the Rotax Heavy maint. manual under electrical. I don't believe it's the starter that is last on my list, but not charging is #1. It sounds like a poor connection. It may be connecting, but barely.

[Steven]

Roger - thanks for your input which I'll pass along to my mechanic at Flight Design headquarters in Woodstock CT when I bring him my CTLS in 2 weeks.

 

I have long been suspicious that my batteries are not getting fully charged, but that may not be the only problem here, since I fully charged the lithium battery using its specially designed charger and yet it barely cranked the engine a 1/4 turn even after the charge ..... I hooked up the charger using the jumper wire from the plane, but that should be sufficient right ? I don't have to put it directly on the battery terminals do I ? In any event the charger light went from yellow to green indicating fully charged and the lithium battery is supposed to charge much more quickly than an old type lead acid battery. I left the charger on it for over 12 hours.

 

It will be interesting to find out what the problem(s) turn out to be. I'll keep you and the board posted.

 

By the way, the maintenance manual states that the engine should not be jump started. Why is that ? Can an overload of amps damage the circuitry or starter motor ? Or is it just saying that one shouldn't be flying without a good battery and not that a jump start could do any damage ?

 

I sure like the jump start since it works so well and is dependable, although I don't like getting out of the plane with the engine running to disconnect the jump starter. It makes me a little uneasy and it's windy out there with the prop spinning. Too bad there's no jump start wire inside the plane ..... that would be perfect ! It would be simple to run a wire right through the firewall for that purpose, but I don't think it's legal under FAA certification.

[Roger Lee]

This may be something different than a battery charging condition. Has this plane ever had a prop strike? With at least one plug out of each cylinder is the prop easy to turn over or does it have some friction and a little stiff to turn? This may be a starter problem too. You need to put a meter on it at start and see how many amps it's pulling. Should be around 70 +/- amps.

[Steven]

Roger - thanks for the suggestions. I'll relay them to my mechanic. No - my plane has never had any prop strikes beyond insects. haha

 

I'm surprised to hear the starter needs only 70 amps to crank the engine. That's a small amount relative to my lithium battery peak amps of 450. Yet it can't crank the engine !

[Jim Meade]

Running overspeed can also put the crankshaft out of spec. Remember, these are composite cranks.