Single battery won't last a day

[hutchman123]

Our new Reflection 367 BHS came with a single marine battery. We dry camp and run a generator while camping and do not have solar, yet. The battery won't even last a full day. I've had the battery load-tested by the battery dealer it tests fine. I cannot operate my refrigerator on propane/battery (no generator) for more than a few hours before the refrigerator low power alarm activates. I realize I'm going to need to ad solar, this 5th wheel came pre-wired for solar, and am looking into doing just that. I've considered adding a second battery and jumpering the two together. We had this exact configuration, two batteries-no solar, on our first travel trailer and the batteries would last a couple days. Lithium seems cost prohibitive but am open to everyone's thoughts/experience.
Thank you all!
2021 Reflection 367 BHS

[jkwilson]

What battery do you have?

[hutchman123]

Centennial
RV/Marine
DC27MF
MCA:890

[PappaJohn]

Have you checked the battery voltage when charged to make sure it is getting fully charged? Might also measure the battery voltage when the frig low batt light comes on.

[hutchman123]

Yes I've checked it when fully charged by using the Wall Panel inside the trailer. Not with a volt meter. It shows 12.3 which is fully charged according to the panel inside the trailer. I took the battery to the distributor and he load tested it twice and it tested good both times.
Good idea to test when alarm goes off. I'll do that. That'll take a few hours. I'm at home plugged in. I'll unplug and create the scenario you've suggested.
Thank you.

[PappaJohn]

Was the shore power connected when you measured that voltage? If you were on shore power then that voltage is too low. When the batteries are on float charge the voltage should be something like 13.4V. The voltage should be more like 14.4V during the active part of the charging. I don’t think your battery is getting fully charged.

[hutchman123]

Yes it was on shore power when I tested it. The wall meter only goes to 12.3. I'll test with a volt meter. Have to go borrow my son's...lol!

[Redapple63]

Centennial
RV/Marine
DC27MF
MCA:890

That battery is maybe 80 amp hours which means you have like 40 amp hours usable totally makes sense how quickly it dies.

I suggest at least 2 gc2 batteries for low cost entry to get you through the season. I would look into agm or Lifepo4 for long term.

Also double check the converter or generator is actually charging your battery. 12.3 represents about a 62% state of charge.

[PappaJohn]

Redapple is correct. The batteries 20hr rating is only 75Ahr. That is tiny. I agree that two GC2 6V batteries which are about 225Ahr is a much better solution.

[hutchman123]

Battery tests 12.63 volts with Multi Meter. Not plugged into shore power. Reads fully charged on wall panel inside trailer.