Battery & electrical questions

[coolmom42]

I have a 2014 Coachmen 21QB on a Chevy 4500 chassis, with an Onan 4KW generator.

*Does the generator have its own starting battery? If so, how is this battery charged? Or does the generator crank off the chassis battery? (I'm assuming it doesn't crank off the house battery, as that would kind of defeat the point of having a generator.)

*Does the generator charge the chassis battery?

*Does the chassis alternator charge the house battery? If so, how well?

*Does the battery isolator switch completely isolate the house battery and chassis battery from each other?

*Does the converter charge the chassis battery when the RV is plugged into shore power?

*On the side of the engine compartment, there is a 200 amp fuse. What is this for?

[IAMICHABOD]

Bordercollie wrote:
It would be good if RV manufacturers would include a placard that clearly states this kind of information including location of solenoid switches, fuses, reset buttons, etc. The proper operation of generator, converter/charger, transfer switch, chassis alternator, house and chassis batteries, etc., is critical to running air conditioning, furnace, fridge, microwave, water heater, interior lights, fans and entertainment devices.I wonder how renters figure this stuff out once the are out on the road.

They can easyly find most of it on Instructional Videos in many languages or Instructional Manuals also in many languages.

[Bordercollie]

It would be good if RV manufacturers would include a placard that clearly states this kind of information including location of solenoid switches, fuses, reset buttons, etc. The proper operation of generator, converter/charger, transfer switch, chassis alternator, house and chassis batteries, etc., is critical to running air conditioning, furnace, fridge, microwave, water heater, interior lights, fans and entertainment devices. I wonder how renters figure this stuff out once the are out on the road.

[Harvey51]

Thank you for finding it!
I still haven’t found the fuse that has voltage only when the engine is running. I have the E350 manual with names and numbers but it doesn’t seem to help. Just a matter of time, though. I should have saved a photo of the connection. I have some other DC problems (rear view camera). I will be 70 next month and I’m not as able as I was. Darn!

[IAMICHABOD]

Harvey51 wrote:
Slightly off topic, sorry. I set up an alarm for the house door steps that rings when the engine is running and the steps are down. Unfortunately it quit working and I’m having trouble fixing it. I initially found a fuse in the fuse box under the steering wheel that provided 12 volts only when the engine is running. Anyone have a fuse chart to help me find it again? A few years ago I posted the whole thing in this forum. I would appreciate a link to it.

Hey Harvey51,is This Old Post what you are looking for?

[Harvey51]

Slightly off topic, sorry. I set up an alarm for the house door steps that rings when the engine is running and the steps are down. Unfortunately it quit working and I’m having trouble fixing it. I initially found a fuse in the fuse box under the steering wheel that provided 12 volts only when the engine is running. Anyone have a fuse chart to help me find it again? A few years ago I posted the whole thing in this forum. I would appreciate a link to it.

[enblethen]

NAPA has their own brand of relays. If you buy named units, you will be paying more.

[CharlesinGA]

enblethen wrote:
The Cole Hersee style 200 amp is normally stocked at NAPA.

While some stores may stock the 24213, the web site makes it appear that it is a warehouse item for me at least. In any case, its $15 or more higher than Amazon delivering it to my door.

https://www.napaonline.com/en/p/TWR24213BX?partTypeName=Solenoid+Switch&impressionRank=39&keywordInp...

Charles

[CharlesinGA]

coolmom42 wrote:
I'm thinking that POSSIBLY the generator starts off the chassis battery--because one day I couldn't get the generator to start (think I just didn't prime it enough the first time) and cranked it multiple times with no luck. Then the chassis battery turned out to be dead, as in it wouldn't start the vehicle. As soon as I got the chassis battery jumped, and the engine going, the generator started right up.

So my thinking was that I ran the chassis battery down in attempts to start the generator. Still not sure if that's what happened.

By starting the engine, you then had the engine's alternator powering and charging all of the batteries, both the chassis and coach, so there is no telling at that point.

Charles

[pnichols]

DrewE's post above is why I have this boondock camping non-sun-dependent Plan C: If for some completely unforeseen and unfortunate reason both the coach battery bank and chassis battery should be low at the same time, we carry along a small portable generator that is pull started and can be used via a small stand-alone charger to charge coach and/or chassis batteries.

Being stranded way out there in a MH with no tow vehicle would be no fun. I've never yet experienced it, but don't have to in order to not want to.

[DrewE]

time2roll wrote:
I think I would prefer the generator starts from the chassis battery. Only trick is you need to make sure when the generator is running that the chassis battery is getting recharged.

I don't think it makes a huge difference in practice (assuming, as you mention, that whatever battery the generator runs from is charged when it is running). If the generator starts/runs from the house battery, and the house battery is sufficiently discharged that it can't start the generator, then starting the main engine of the motorhome will connect the batteries so the alternator can charge the house battery and the generator should then be able to start without much difficulty off of the combination of the dead house battery, the not dead chassis battery, and the engine alternator.

Ideally, of course, you shouldn't let any battery discharge so far that it is incapable of starting the generator.

[time2roll]

coolmom42 wrote:
I'm thinking that POSSIBLY the generator starts off the chassis battery--because one day I couldn't get the generator to start (think I just didn't prime it enough the first time) and cranked it multiple times with no luck. Then the chassis battery turned out to be dead, as in it wouldn't start the vehicle. As soon as I got the chassis battery jumped, and the engine going, the generator started right up.

So my thinking was that I ran the chassis battery down in attempts to start the generator. Still not sure if that's what happened.

I think I would prefer the generator starts from the chassis battery. Only trick is you need to make sure when the generator is running that the chassis battery is getting recharged.

[pnichols]

coolmom42 wrote:
I'm thinking that POSSIBLY the generator starts off the chassis battery--because one day I couldn't get the generator to start (think I just didn't prime it enough the first time) and cranked it multiple times with no luck. Then the chassis battery turned out to be dead, as in it wouldn't start the vehicle. As soon as I got the chassis battery jumped, and the engine going, the generator started right up.

So my thinking was that I ran the chassis battery down in attempts to start the generator. Still not sure if that's what happened.

FWIW, I think that my Itasca's coach batteries start the built-in Onan generator ... not the Ford's chassis battery.

Sometimes I charge the coach batteries via a little portable generator powering an external charger. I attach the charger's output cable allligator clips onto the Onan's starter power lugs that have 8 gauge cables on them leading underneath the coach floor headed straight for the coach batteries on the other side of the coach.

When I start the little generator the coach battery bank ammeter jumps right up, indicating that the coach batteries are receiving current from the external charger being powered by the portable generator. Hence, the coach batteries are wired to the Onan's starter via the 8 guage cables.

[pianotuna]

coolmom42,

It sounds to me as if the genny is starting from the chassis battery.

[coolmom42]

I'm thinking that POSSIBLY the generator starts off the chassis battery--because one day I couldn't get the generator to start (think I just didn't prime it enough the first time) and cranked it multiple times with no luck. Then the chassis battery turned out to be dead, as in it wouldn't start the vehicle. As soon as I got the chassis battery jumped, and the engine going, the generator started right up.

So my thinking was that I ran the chassis battery down in attempts to start the generator. Still not sure if that's what happened.