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Will shore power work if house battery is completely dead?

Posted: Wed May 16, 2018 10:39 pm
by 8Track
I'm sure this is a rookie question but I've looked through the forums and couldn't find a similar issue. I've had my b190 (1999) for about a month now and I could tell from the beginning that the house battery was going to need replacing because the interior lights were dim and wouldn't last long even after a bit of driving. I've had it plugged up to shore power a couple of times and it worked great and was able to test the A/C and fridge.
About a week or two ago everything in the cabin just stopped working and couldn't get anything to power on and the systems monitor above the stove was so dim you could barely see it. I also can't get the genny to fire up but that might be an unrelated issue. I figured that the battery bit the dust but decided to hold off on replacing it because I'm looking into buying a used lithium setup from craigslist. Anyways, I tried to hook up to shore power today and I'm still getting nothing. I was under the impression that when you're plugged into shore power, it bypasses the house battery setup and you're drawing current directly from shore power source. Is that not the case? If not that, I figured it would possibly charge the battery -which it's not doing. I also checked the fuses and they all seem to be fine- unless there's some hidden that I don't know about.
While plugged into shore, the systems monitor brightened up but it was incorrectly reading the tank levels and propane levels which has got me worried. I hope this is as simple as just having a dead house battery? I'm unable to access a battery charger until this weekend but I was hoping someone might be able to shed some light on this so I'm not worrying through the rest of week. Any ideas?

Re: Will shore power work if house battery is completely dea

Posted: Thu May 17, 2018 3:39 pm
by skater
I think it's likely your converter is bad and putting out a low voltage. The battery could also be bad (being undercharged won't help), but I wouldn't be surprised to find your converter is toast. Try unplugging the shore power, disconnecting the battery, then plugging in again and see how it works. Do you have a multimeter? You should be seeing somewhere in the 12-14 volts range.

But if you're planning to go with a lithium battery, you'll need to replace the converter anyway, assuming you still have the original one. The original converter will cook batteries pretty quickly by overcharging them if you don't monitor it very carefully.