Hi Everyone,
I'm a newbie to the RV thing and I recently went in on an 84 Huntsman with a friend which we picked up in NY and drove to CA. I'm quickly falling in love, but on her maiden voyage across the country we ran into a few electrical problems...
It started with us having problems keeping the coach battery charged, then over the course of a couple days the electrical system was on the fritz then eventually the alternator went out, engine stalling at low RPM, battery and brake dash lights on. A new alternator seemed to fix the problem and got us to CA where I've since done a quick and dirty investigation. The battery isolator (3 terminal) is charging the chassis battery but not the coach battery: 14.5 V across chassis battery, 11.9 V across the (probably bad) coach battery.
My theory for why this happened:
- The coach battery was damaged after sitting around for years with infrequent charging (the RV went through ~5 years of very little use before we got our hands on it)
- We killed the battery for good after a couple charge cycles
- The dead coach battery started putting a big load on the alternator causing it to overheat and burn out
- At some point one of the diodes in the isolator also burnt up due to the high load
Does that make sense?
I have also read a few other threads about battery isolators and it seems like "Toyota RV's need a 4 terminal isolator" is a common theme, but the isolator in there is a 3 terminal. Could that be part of the problem? Do I need to replace my old 3 terminal with a 4 terminal? I still don't fully understand why the 4 terminal isolators are preferable.
My other worry is that some other short/electrical issue caused the alternator to go in which case replacing the battery and the isolator won't actually fix the issue.
Any and all help is appreciated,
John