Engine wouldn't start

[Dale Walker]

Hello fellow Beaver lovers. I have a question, that has me a little stumped. I took the coach down to have a new tail pipe installed, I parked it in the shop thinking I was going to work on the fuel sending unit, (hasn't come yet) when my SIL called and asked me to move it. Well, to my surprise it wouldn't start, so plugged it in to 110 outlet, thinking it would charge the batteries over night, but, lo and behold they weren't charged. It has all kinds of power on the Chassis batteries, and the Generator started up and runs fine. I shut off the generator, and jumped the Coach batteries and the engine, (C-9) started right up, so the question is, why??


Thanks in advance.

[Gerald Farris]

Dale,
I can not answer your question without more information. First, what was the charging voltage at the chassis batteries when you were plugged into shore power? Second, assuming that the charging voltage was adequate at the chassis batteries, what is the CCA test ratting or load test ratting on your chassis batteries?

Gerald

[Dale Walker]

Gerald, the chassis batteries, tested at 12.6 V. The coach batteries, were completely flat, only the dash lights worked, the manifold heater worked, but when you turned the key, the only thing you heard was a rattling sound from the starter solenoid, not the usual snap, snap, as if the starter was trying to engage. Since then, we put a charger on the coach batteries, and the engine started right up. After that happened, I have a sense that it needs the coach batteries hot for it to start? Is that possible? I don't understand why it wouldn't start on just the chassis batteries alone?

Thanks

[Gerald Farris]

Dale,
The coach engine starts from the chassis batteries only, and the condition of the house batteries has nothing to do with starting the engine.

If the house batteries were completely discharged after the coach was plugged into a 120 volt outlet overnight, either you did not have a hot outlet, you did not have the inverter set to charge the batteries, or you have an inverter with an inoperative charging circuit.

From your description, it sounds like you had a partially discharged chassis battery bank in that it had enough of a charge to start the small generator engine but it was inadequate to start the coach engine that requires about four times the necessary energy level, and you just need to determine why your batteries were not fully charged. However, if you could answer the questions in my earlier post, I could give you a more definitive answer of where to look.

Gerald   
 

[Dale Walker]

What has me puzzled, Gerald, is why did the dash light up, the manifold heater cycled, but the Aladdin system didn't work either. It seems to me that the coach batteries should be separate from the chassis batteries, but in this case it isn't. I'm not new, to MH's this is my 5th coach, but of course this is the most complicated of the bunch. What I'm going to do tomorrow, is I'm going to turn off the coach battery switch, and see if it will start? Something seems very fishy.

[Dale Walker]

Well, as I said, I turned off the coach battery switch and it started right up. Turned off the salesman switch, and it started up! For the life of me, I have no idea what happened. The day it wouldn't start, we put a battery charger on the coach batteries and it started.

Gerald, in answer to the size of the batteries, the chassis batteries are 950 CCA, the coach batteries are 120 min. @ 75 amps.

[Gerald Farris]

Dale,
Like I said earlier, it sounds like you had partially discharged chassis batteries, and all you need to do is determine why they were not charged if the coach was plugged into shore power.

The chassis batteries can have a sufficient charge to operate numerous low amperage draw systems in the 20 to 30 amp range like lights, radio, or wipers just like fully charged batteries, but when the 500 amp surge is needed to start a large diesel engine, they can not deliver and that is what causes the noise at the starter motor.   

Gerald