Hi Bill,
I'm always glad to be wrong when it is in the other person's favor.
I can't give you data for a residential fridge--but I did post results for an absorption fridge running off the batteries for 24 hours. As you may know (or not), an absorption fridge uses 200 watts per hour--a heck of a lot more than all but the very biggest residential units.
The twenty four hours consumed 2.4 kwh. I was able to do this on just three (all I had at the time) group 29 batteries--of unknown age (but probably five years old) with the assistance of 256 watts of solar. It is true that nothing else other than the inverter was on.
I've since bumped up to 875 amp-hours of battery bank, so at 2.4 kwh per day I'd certainly not be at 50% overnight.
I do know that Mr. Wizard's residential fridge runs about 1 kwh per day if I remember correctly.
Unlike most RV folks I run as much as possible on 120 volt power. That includes cooking and water heating. And I do have data on starting the water heater from ambient temperatures up to the first cycle. It takes about 90 minutes @ 1200 watts so uses about 3.6 kwh. It cycles back on in about 4 hours and consumes a further 0.5 kwh. After that--my battery bank is still not at 50%. I did this test at night so that solar would not be assisting the battery bank.
Those are the only two tests I can remember at the moment, running on battery power alone.
I'd be interested do know how you recharge your bank each day to 100% state of charge. It would be kind of you to share the make of AGM's you have, and the inverter you use. I assume it is a pure sine wave unit.
Bill.Satellite wrote:
No, the batteries are new. The first set which lasted 10 years did the same. Not sure why folks insist on telling others what their RV is or is not doing or how their equipment is or is not working. Do you know what kind of fridge I have, how large, what it's power consumption is? The 8D batteries are also 225 AH so that would be 900 AH and they still hit 50% over night. Yes, lots of other stuff running 24/7 as well like my DVR and numerous other 120V chargers and clocks and who knows what. The inverter itself is also not 100% efficient so there goes more power. The reality is that's the power my coach consumes with good AGM batteries. YMMV and you are certainly welcome to post the results of YOUR batteries in YOUR coach and YOUR household frige.
