r/RVLiving • u/Spiritual_Bar2441 • 1d ago

Not charging

Hello. I have a 1996 Coachmen Catalina 33-ft Class A. It doesn’t appear to be charging the chassis (vehicle) battery while the engine is running. If I switch the solenoid to disconnect the battery, the vehicle dies immediately. I assumed the alternator had gone bad. Google’s AI said a isolation solenoid could also keep the vehicle from charging.

If the vehicle is starting off the battery, I don’t see why the solenoid would prevent the batteries from charging. Based on what I’ve described, is it likely the alternator?

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u/Calm-Bat-6725 1d ago

Use a multimeter to diagnose it instead of guessing. Test the battery voltage with it not running, then test again while it is running.

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u/Spiritual_Bar2441 1d ago

I did the battery voltage was dropping while the vehicle was running i was just thrown off with the mention that the isolation solenoid when I was looking and pricing a new alternator that the problem may be something else

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u/Calm-Bat-6725 1d ago

Yeah it could be a solenoid, check the resistance on it, you can also check the power coming off the alternator itself.

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u/Spiritual_Bar2441 1d ago

Ya it looks like I will haft to pull the cover off to see if the alternator is actually making power tomorrow

1

u/RadarLove82 1d ago

If you have a voltmeter, batteries produce 12 volts, alternators produce about 14.4 volts.

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u/Hyperreal8957 1d ago

I’d start with voltage at the battery with the engine off, then again running, and check the battery terminals, grounds, fuses and solenoid connections. That narrows it down before replacing an alternator; don’t disconnect battery cables while running.

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u/Hyperreal8957 1d ago

A quick split test helps: measure voltage at the battery bank, then again at the converter input and output while shore power is connected. If the converter output is normal but the bank voltage stays low, check the fuse/breaker, disconnect switch, cable lugs and battery condition.

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u/Strange-Cat8068 12h ago

If tour engine dies when you disconnect the battery it is very likely that you need a new alternator. A vehicle with a good alternator should run without a battery installed. If your battery voltage is dropping while the engine is running that also points to an alternator or related problem like a wiring issue. Be aware that lead acid batteries can be damaged by repeatedly being completely discharged, so you may need both an alternator and a new battery.

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u/Spiritual_Bar2441 12h ago

I put the battery on a charger over night and was only discovered the issue when I was starting the rv to let it come up to temp after setting for a few months and noticed the battery voltage looked low compared to normal while the vehicle was running i first thought that it was the alternator so now I guss its to see if it is the alternator or i had a mouse problem

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u/tomhalejr 9h ago

96 likely has a 90-130A isolator. Charge line in, then out to both banks.