Batteries vs Inverter

[alphamale49]

How to distinguish between bad batteries and a bad inverter or something else: I seldom use the inverter outlets. I am usually plugged into 30 amp shore power. And usually the battery indicator will read 13.something, like 13.5 or whatever. Yesterday the indicator started reading 12.7 or thereabouts. With the help of a more knowledgeable friend, we disconnected the battery and charged it overnight. Not all the way but it tested above 13 before I became impatient. It is now back down to 12.7. Of course I had no lights, radio, TV antennae overnight. And incidentally I could not get the refrigerator to switch over to propane, it stayed off as well as the refrigerator lights. I am guessing it is the inverter that is bad as that would cost the most money to fix. (snark, snark) I have a supplemental 7 year warranty with the dealer which involves driving 1000 miles to the dealer to have them look at it. The batteries are two years old, the 1000 watt pure sine wave inverter came with my brand new 2017 International Serenity. Is there further testing I can do or should I just buy two new batteries and see if that solves the issue? Thanks.

[Adventure.AS]

12.7 volts is 100% SOC for rested batteries. Is your “Use” switch on?

[TouringDan]

If you were plugged in and had no 12v power, the problem would be your converter (battery charger), not your inverter. The inverter converts 12v dc to 120v ac.

Dan

[alphamale49]

First of all let me apologize. My friend now says he misspoke and the problem may be with the converted, not the inverter. And I am really confused if you are not. The switch is set to 'use' and the little light is on. I always have it set that way.

[TouringDan]

I don’t see a problem. Does everything work? Here is a voltage table. You want to keep your batteries above 50% SOC (state of charge). I would get a volt meter and mount it permanently.

Dan

[alphamale49]

I am plugged into 30 amp shore power, the battery is reconnected and the switch set to 'use' Everything works, the indicator now says 12.9. So maybe there never was a problem? But why did the indicator always say 13.5 before I manufactured this crisis?

[LDM]

Sound like your converter slow it charging rate back as the batteries are getting close to full charge. That is what it should do. When plug in to shore power you are getting the charging rate on your battery. If you want to get Just battery rate un plug from shore power.

[TouringDan]

Originally Posted by alphamale49

I am plugged into 30 amp shore power, the battery is reconnected and the switch set to 'use' Everything works, the indicator now says 12.9. So maybe there never was a problem? But why did the indicator always say 13.5 before I manufactured this crisis?

Because the converter was charging the battery and the charging voltage at the converter was 13.5 volts. The charging voltage needs to be higher than the battery voltage for the batteries to take a charge. If you want to know the battery voltage when you are plugged in you need to unplug your Airstream or unplug your converter.

Dan