Hello All. I'm experiencing a voltage issue in the 73' Barth 25'. I get a low voltage error on my new Norcold fridge when hooked to shore power, either in the 110V or LP mode. I don't get the error when running off of the batteries. When I check the voltage at the fridge while on shore power, I get 10.5-11.0 volts, and 12.5+ when on battery. So I don't suspect wiring or ground to be the main issue. The wiring seems a bit odd to me (by modern standards)as the shore power comes directly to a residential type 110V breaker panel which feeds all the 110v circuits. The convertor /charger is plugged into a receptacle. The convertor/charger is connected to the house battery and also contains 4 fused connections to the 12V circuits. Under shore power it isolates the battery and switches to provide the 12v via an internal transformer. The unit is B-W model 3230UL 30 Amp. May be a replacement at some point. The literature in my book shows a progressive dynamics PD-710.
I've done research and can't seem to find a direct replacement for the existing unit except for the convertor/charger units that come with power distribution both 110v and 12v. Any suggestions ?
Thanks,
Mark

1970's RV wiring was very primitive by today's standards.

The convertor/chargers like yours apparently isolate the house battery from the 12V circuits while on shore power. It looks like your charger is producing low output.

Those old style units' DC voltage was poorly regulated and filtered, by today's standards. This was early in the days of solid state regulator design. Over/under voltage and AC ripple (hum) were common. (I think maybe this was why they isolated the battery to prevent overcharging it with the crude converter?)

If your DC voltage is that low there is a problem. Considering the age I would be tempted to remove the convertor/charger. Due to the early design and obsolete components it is not worth repairing. When you remove it you just tie the all 12V circuits to the house batt all the time.

Replace the converter with a modern charger like the Progressive Dynamics (or equivalent). You can get them in 30, 40, or 60 amps. Then just leave the charger connected all the time. Your house battery will always be perfectly charged and never need water, and your house voltage will be strong and steady.

My 86 Regal had the OEM convertor in it and it always overcharged the batteries. I could not leave it connected at all times. I replaced with a 40A Progressive Dynamics unit. Left it plugged in all the time, never added water in 3 years. 12V steady and strong.

My 97 Monarch had a ginormous 2000W/200A invertor/charger. I never used the inverter. I replaced it with a 60A PD, again with good results.

The newer designs are far better at controlling the voltage and will extend the life of the batteries they serve.

Steve, Thanks for the response.
I'm going with a Progressive Dynamics PD4135 which is a panel mount. If I went with one of the deck mounted units I was still going to have to add a 12V distribution panel. The old unit is a PITA to service as well. It is located under the bathroom closet floor. You have to remove a floor section and inspect the glass fuses with a flashlight and a mirror. Almost impossible to remove and replace a fuse.

Thanks again.

I replaced the old converter/charger this weekend with a new 35amp Progressive Dynamics unit. The old unit dying was a blessing in disguise. I chose not to plug the new one in as there is only one circuit breaker for all receptacles and one for the A/C so I opened the breaker box to do the wiring.
Man was this thing a time bomb ready to catch fire. 47 years and its probably never been opened. Really no reason to. There must have been a 1/2" of dust inside there. One overload or a loose breaker and poof...
If you have one of these old units, do yourself a favor and take a look inside.