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Topic: Starting the generator from inside (Read 908 times) previous topic - next topic

Starting the generator from inside

Today we had another power outage, makes 3 this year, and after 5 minutes I went out to the coach to start the AC. I pushed on the dash switch to start the generator but it did not start. I then started the coach, let it get up to full PSI, then pushed the start switch and it started. Turned the coach engine off, generator stayed on and ACs were engaged.

Why did the generator not start the first time but it did the second? Could it be a battery issue? Or something else?  I have an inexpensive cigarette lighter V meter, it showed 12.4/12.5 before cranking, so a little low but enough to start the 8.3. I would expect the 10KW generator to start if it can start the coach.

Re: Starting the generator from inside

Reply #1 –
Start with checking the cables to the generator starter.

Re: Starting the generator from inside

Reply #2 –
Jason, are there two cigarette lighters in the dash?  If so, I believe the left one is chassis batteries and the right one is house batteries.  This is how my 2003 U320 is set up.  I have a voltage meter in both.  When you try to start the generator, which one dips?  I wonder if your generator starts from chassis or house batteries...and what that voltage was.  Something to investigate.

Re: Starting the generator from inside

Reply #3 –
Thanks Keith, I'll check and report back.

Re: Starting the generator from inside

Reply #4 –
Quote from: WS6_Keith –
JI wonder if your generator starts from chassis or house batteries.

On Jason's 2000 the generator starts from the house batteries unless someone has changed it for some reason. With the engine running the alternator was putting out enough to help start the generator through the isolator. (IF the electrical system is OEM) or through the boost switch if you had it on.

Mike

Re: Starting the generator from inside

Reply #5 –
The generator needs little power to start and I think it was designed for lower voltage starts. The first year of Coach ownership we operated the generator off a old Red top battery without any issues. There were no storage batteries. 

Re: Starting the generator from inside

Reply #6 –
My 2 cig lighters are top/bottom orientation. The top is house, the bottom is coach. When I unplugged from shore, waited a couple minutes and then tried to start the generator, the volts went down to 7-8. I was almost certain I needed to replace them though and will add a Victron and possibly solar. I will start another thread for that

Re: Starting the generator from inside

Reply #7 –
1) I haven't tested this system and this can depend on the battery but a drop to 8V during a start sounds extreme.  I would expect closer to a drop to no less than 10V as a WAG.  But I would also not expect high accuracy from a cigarette type plug in meter.  Best to do a proper load test.  If you can get the vehicle or battery to many auto parts stores they'll do one for free. 

2) When it "wouldn't start" was it turning over at all, producing clicks or just nothing happened?

3) The switch can go back/get dirty contacts and either work intermittently or only when pressing really hard.



Re: Starting the generator from inside

Reply #8 –
On our U300, the side lighter plug is house and the dash plug is engine battery so you need two voltmeters to see the condition of both banks. Our generator needs juice from the house batteries. When you start the main engine, both banks get charged so that's probably why your generator didn't start the first time.

This is also why I put in twin voltmeters where the AUDIT display used to be.

Pierce

Re: Starting the generator from inside

Reply #9 –
Gene- I load tested them last year, they don't hold a charge. I put them on a desulfator too, didn't work. One was bulging badly, I removed that single last year and am down to 2. There was a thread on that. I have not traveled anywhere this year and normally we stay in campgrounds, so it's not too critical. Glad to know where power comes from and the ability to start the generator makes sense after I started the coach.

Re: Starting the generator from inside

Reply #10 –
Quote from: Jason –
My 2 cig lighters are top/bottom orientation. The top is house, the bottom is coach. When I unplugged from shore, waited a couple minutes and then tried to start the generator, the volts went down to 7-8. I was almost certain I needed to replace them though and will add a Victron and possibly solar. I will start another thread for that

So which one dropped to 7-8?  I'm assuming the top, the house batteries?  Do you have a boost switch, which ties the chassis and house batteries together?  If so, you may be able to use that to get enough juice to start the generator without having to start the engine.

Re: Starting the generator from inside

Reply #11 –
Quote from: WS6_Keith –
So which one dropped to 7-8?  I'm assuming the top, the house batteries?  Do you have a boost switch, which ties the chassis and house batteries together?  If so, you may be able to use that to get enough juice to start the generator without having to start the engine.

Yes it was the top. Boost is not working, Keith R identified that during the PPI. It's on the todo list to investigate and fix.

Re: Starting the generator from inside

Reply #12 –
Quote from: Jason –
Yes it was the top. Boost is not working, Keith R identified that during the PPI. It's on the todo list to investigate and fix.

Very easy to diagnose with a voltmeter:

One large lug will have chassis battery voltage. The other large lug will have house bank voltage.

With boost switch off, the two voltage will be different.

With boost switch on voltage should be exactly the same, because in essence, the boost switch on make the two banks into one large one.

If switch on does not work as above, locate the one or two small terminals.  If one, it will be the 12 VDC positive from the boost switch and the ground will be from the body of the solenoid contact with good ground.  If two, one will be the positive, the other the ground.

Basically, a 5 minute troubleshooting exercise.

Let us know what you find.

Re: Starting the generator from inside

Reply #13 –
Thanks Brett, looks like the solenoid is bad. With boost off, the solenoid terminals both show different voltage. When switched on, after the click, the passenger side registers voltage but the driver side goes registers microvolts. Unsure which side is coach/house.  From searching, it looks like 77-90000-100 is the part # to get.

Re: Starting the generator from inside

Reply #14 –
Quote from: Jason –
Unsure which side is coach/house.

Sounds like your house bank is on the way out and probably has lower voltage.  Use the front volt meters to determine which is higher/lower and match that up with the measurements at the solenoid. 

Re: Starting the generator from inside

Reply #15 –
Quote from: Jason –
Thanks Brett, looks like the solenoid is bad. With boost off, the solenoid terminals both show different voltage. When switched on, after the click, the passenger side registers voltage but the driver side goes registers microvolts. Unsure which side is coach/house.  From searching, it looks like 77-90000-100 is the part # to get.

No, activating the boost switch will not cause one of the large lugs to read very low voltage.  It is still (or actually should be) connected by that large-gauge cable directly the it's battery bank.

Might try again with the voltmeter-- may not have had a good ground when you got the very low voltage reading.

Again, if the solenoid is not working, the large lugs will continue to read differently.  If it works, with the boost switch on, the readings will be exactly the same.

Re: Starting the generator from inside

Reply #16 –
Ah, I misinterpreted, I tested the small studs on the solenoid, which would be the 2nd part you mentioned.  Retesting, with a good ground, the solenoid is good and I must have a burnt out boost light. However, the boost function does not work because the house batteries are bad.

Let me explain my investigation and if someone thinks different, please advise.  With the inverter/charger off, I turned on a interior light, this quickly drew the house batteries to 9V. My starter batteries are about a month old and register 12.76. With the boost on, the combined volts drops to 12.3/12.4 which is not enough to start, and with more load on the house batteries, that number will lower.
 

Re: Starting the generator from inside

Reply #17 –
The house bank voltage is likely below that at which the smart inverter/charger will even attempt to charge them.

If you know they are shot, just replace them.

If they may just be deeply discharged but not too old, use a "stupid" charger, jump from another battery/vehicle or if you can get the engine started, let the alternator bring up voltage to where the inverter/charger on shore power or generator will take over.