VTPete
Senior Member
The symptoms:
While parked, my cabin battery would drain over time despite having nothing turned on and the power shut off. Also, although the battery would charge while driving down the road, it never charged properly while on shore power.
This took a while (over a year) for me to finally figure out. In the meantime, I ruined at least one deep cycle battery because I had left the refrigerator on 12v for several days while being plugged into shore power. (That should not have drained the battery!)
In the end, there were two separate things wrong with my old '96 Dodge based Roadtrek 190 popular - and chances are they're wrong with yours as well!
First, the isolator under the hood of the vehicle was allowing my cabin battery to essentially drain while it was parked - both the cabin battery and van's starter battery were trying to find equilibrium and honestly, my starter battery is old. So, the cabin battery was always slowly draining until it and the starter battery evened out. I checked the diodes on the isolator under the hood and it was definitely bad, so I replaced it and that solved the 'draining while parked' issue.
Next was the fact that while plugged into shore power, the 12v system never seemed to charge. As a matter of fact, when I plugged into shore power, I could see the voltage in the 12v system jump from about 12.4 volts briefly to above 13, but within seconds, drop back down to the resting voltage of the battery. Why did it take me two years to realize this?
Anyway, I fixed this by getting a nice new 120v to 12v converter - one that put out 55 amps rather than the original 32 and used modern electronics to charge the cabin battery. I bought the 55 amp model from here: Upgrade Kits for Magnetek/Parallax
Pulling out the old converter and plugging in the new one was pretty straight forward, but was made more difficult due to the tight fit of the cabinet it's held in. The most time was spent labeling the 12v wires so I'd put them back in the right order! PM me if you are thinking of doing this and need any help.
Wow, what a difference! Now, on shore power, I can flip the cabin's power button and see exactly what you'd expect! The voltage at the battery jumps up to a perfect 13.4 volts to charge - and it's also smart enough to jump up higher if necessary, or lower for a small amperage trickle charge. And, get this, all of the 12 volt appliances now have a bit more gusto! The lights are a bit brighter, the fans are a bit faster, and nothing dims or slows down when you turn on something else - the new 55 amp service (when plugged into shore power) is fantastic and totally apparent!
At this point, I don't think there's a single wall, wire, hose, pipe, window, curtain or light I haven't either replaced or fixed on this old lady - but with only 30,000 miles on it, it's worth it. She drives like new and the kids and I love camping in it! Hope this post helps someone out there!
While parked, my cabin battery would drain over time despite having nothing turned on and the power shut off. Also, although the battery would charge while driving down the road, it never charged properly while on shore power.
This took a while (over a year) for me to finally figure out. In the meantime, I ruined at least one deep cycle battery because I had left the refrigerator on 12v for several days while being plugged into shore power. (That should not have drained the battery!)
In the end, there were two separate things wrong with my old '96 Dodge based Roadtrek 190 popular - and chances are they're wrong with yours as well!
First, the isolator under the hood of the vehicle was allowing my cabin battery to essentially drain while it was parked - both the cabin battery and van's starter battery were trying to find equilibrium and honestly, my starter battery is old. So, the cabin battery was always slowly draining until it and the starter battery evened out. I checked the diodes on the isolator under the hood and it was definitely bad, so I replaced it and that solved the 'draining while parked' issue.
Next was the fact that while plugged into shore power, the 12v system never seemed to charge. As a matter of fact, when I plugged into shore power, I could see the voltage in the 12v system jump from about 12.4 volts briefly to above 13, but within seconds, drop back down to the resting voltage of the battery. Why did it take me two years to realize this?
Anyway, I fixed this by getting a nice new 120v to 12v converter - one that put out 55 amps rather than the original 32 and used modern electronics to charge the cabin battery. I bought the 55 amp model from here: Upgrade Kits for Magnetek/Parallax
Pulling out the old converter and plugging in the new one was pretty straight forward, but was made more difficult due to the tight fit of the cabinet it's held in. The most time was spent labeling the 12v wires so I'd put them back in the right order! PM me if you are thinking of doing this and need any help.
Wow, what a difference! Now, on shore power, I can flip the cabin's power button and see exactly what you'd expect! The voltage at the battery jumps up to a perfect 13.4 volts to charge - and it's also smart enough to jump up higher if necessary, or lower for a small amperage trickle charge. And, get this, all of the 12 volt appliances now have a bit more gusto! The lights are a bit brighter, the fans are a bit faster, and nothing dims or slows down when you turn on something else - the new 55 amp service (when plugged into shore power) is fantastic and totally apparent!
At this point, I don't think there's a single wall, wire, hose, pipe, window, curtain or light I haven't either replaced or fixed on this old lady - but with only 30,000 miles on it, it's worth it. She drives like new and the kids and I love camping in it! Hope this post helps someone out there!
