Charging system

[wtmtnhiker]

The coach has been sitting since last Oct 2017. My wife and I were going to head south last February but she got sick, she passed away in June.
I haven't decided whether to keep the motorhome or not but Thursday I took it out for an overnight just to see how it would be alone. The charging system is not working and the check engine light came on seemingly when the battery voltage got too low. When I turned off the lights and and AC the cel went out once the batteries recovered some on their own.
I have looked at the alternator and all connections seem fine. I tapped on it slightly to see if I could free up any potentially stuck brushes. Battery connections are good, clean and tight.
I wanted to try to figure out what I would need for a replacement alternator just in case but I do not see any tag or numbers on it anywhere. Any help or suggestions would be appreciated. Likely I'll need to take it to the garage.

2005 Holiday Rambler Ambassador 36PDD

[tiffy2000]

Sorry for your loss, I think there is a charge relay somewhere in the charging circuit. If it has a V belt it could be slipping enough that it wont charge, if you can turn the pulley by hand it is slipping

Norm

[oldave]

RVs have been made with every charging combination mentioned above
but many many do not charge the house when driving or the chassis
when on shore power .
Even if the OP had all those features they may not be operative now .

Really all he needs to be concerned with presently is why the alternator
is not charging the chassis batteries.
Then he can proceed to determine if other things are not right .
I think we can assume the batteries are ok since he was able to drive
3 hrs with accessories on before they began to wane .

If he has a volt meter and can determine if the alternator in putting
out approx 14v then trace the 14v to the rear elect bay where he may have
a solid state isolator .
If he has an isolator the alternator will probably feed the center post
and the house batt connected to one post and chassis batt to the other .
I can't include a picture but here is one on Amazon .

https://www.amazon.com/dp/B01A9I3GDA/ref=sspa_dk_detail_8?psc=1&pd_rd_i=B01A9I3GDA

[time2roll]

Virtually every RV charges the house battery from the alternator while in transit.

[tropical36]

RLS7201 wrote:

wolfe10 wrote:
Yes, in an emergency you can run the generator which powers your converter, charger or inverter/charger to charge (at least) the house battery bank.

On most coaches, it will NOT charge the chassis battery. So, to drive, you will need to either use your boost/combine switch or physically connect the battery banks-- you have to have the chassis battery at above 12 VDC while driving, as it powers the engine and transmission computers!

I'm just throwing this out for debate, but doesn't the engine ignition switch normally cause the isolator relay to close when the engine is running? If so the generator/converter will indeed charge the chassis battery while running down the road.

Richard

Could be and with my inverter/converter/charger, I'm most sure the Big Boy closes on the chassis, when the house batteries are at 13.3v or so, regardless of the ignition switch position.

[tropical36]

Nomadac wrote:
In my experience most engine alternators do not charge the House Batteries unless specific wired.

Are you saying that the engine alternator, won't charge the house batteries on a Travel Supreme or are just speaking in general?

[tropical36]

wolfe10 wrote:
Yes, in an emergency you can run the generator which powers your converter, charger or inverter/charger to charge (at least) the house battery bank.

On most coaches, it will NOT charge the chassis battery. So, to drive, you will need to either use your boost/combine switch or physically connect the battery banks-- you have to have the chassis battery at above 12 VDC while driving, as it powers the engine and transmission computers!

I guess, for some entry level models, but even with our old 98 gasser, the converter charger charged the chassis batteries, once the house was up to par. The alternator did so with the house batteries, as well as the chassis, as there was a time when the genset wouldn't turn over, but did so immediately after starting the engine.

[Nomadac]

In my experience most engine alternators do not charge the House Batteries unless specific wired.

[time2roll]

You need to put a voltmeter on the system. Alternator should put close to 14 volts into the chassis battery. Some voltage should get to the house battery. Unplug, fire it up and take some readings. Post the battery voltages.

If this seems daunting... get it into a trusted shop to verify operation.

[RLS7201]

wolfe10 wrote:
Yes, in an emergency you can run the generator which powers your converter, charger or inverter/charger to charge (at least) the house battery bank.

On most coaches, it will NOT charge the chassis battery. So, to drive, you will need to either use your boost/combine switch or physically connect the battery banks-- you have to have the chassis battery at above 12 VDC while driving, as it powers the engine and transmission computers!

I'm just throwing this out for debate, but doesn't the engine ignition switch normally cause the isolator relay to close when the engine is running? If so the generator/converter will indeed charge the chassis battery while running down the road.

Richard

[enblethen]

I doubt that it is the alternator.
Use battery disconnect switch to shut off coach battery system. Jump start the chassis. Use volt meter on chassis battery to get output from alternator. Or could use coach battery to start then throw battery disconnect for coach off. Test voltage. If rig will not run, it is not getting enough power to excite alternator.
DP is on what chassis and engine?

[Roadpilot]

I wonder if you could be more explicit what happened when. You mentioned you took the coach out for 3 hours and the check engine came on. I assume that was when you were driving but you also said you shut off some lights and the AC (air conditioner?) and the light went out.

Or did you drive somewhere and spend the night then in the morning start the coach and you had a check engine light? Were you plug in over night?

Anyway, if you could tell us the exact sequence of events it would help.

Sorry for your loss. We are in the NH Seacoast by the way.

[wolfe10]

Yes, in an emergency you can run the generator which powers your converter, charger or inverter/charger to charge (at least) the house battery bank.

On most coaches, it will NOT charge the chassis battery. So, to drive, you will need to either use your boost/combine switch or physically connect the battery banks-- you have to have the chassis battery at above 12 VDC while driving, as it powers the engine and transmission computers!

[tropical36]

wtmtnhiker wrote:
The coach has been sitting since last Oct 2017. My wife and I were going to head south last February but she got sick, she passed away in June.
I haven't decided whether to keep the motorhome or not but Thursday I took it out for an overnight just to see how it would be alone. The charging system is not working and the check engine light came on seemingly when the battery voltage got too low. When I turned off the lights and and AC the cel went out once the batteries recovered some on their own.
I have looked at the alternator and all connections seem fine. I tapped on it slightly to see if I could free up any potentially stuck brushes. Battery connections are good, clean and tight.
I wanted to try to figure out what I would need for a replacement alternator just in case but I do not see any tag or numbers on it anywhere. Any help or suggestions would be appreciated. Likely I'll need to take it to the garage.

2005 Holiday Rambler Ambassador 36PDD

You should be able to run the generator and for getting enough of a charge for driving it home.
Once there or even with where you're camped, the best thing is to remove the alternator, once verified bad and take it to NAPA or other for a match and also with possible having the originally pulley changed out.

[enblethen]

New Hampshire!
First guess is the battery froze sitting since Oct.
Battery shorted.
Remove battery and have it checked. Look for bulging in battery case.
Sorry for your loss!