Battery Life in Hours

[jpjulian]

Our new Mobile Suites came equipped with two 6 volt batteries and a 1000 watt inverter. We spent one night dry camping at a casino and during the night an alarm went off and it was discovered the batteries were nearly spent. As far as I am aware, the only 120v appliance running off the inverter is the refrigerator. I would think we should have more capacity than about 12 hours of use before the batteries go south. What should we expect in battery life should we decide to another overnight without an electric hookup?

Joe

[jplante4]

Battery "life" is measured in reserve capacity, which is how long in minutes it takes a fully charged battery to reach 50% state of charge (about 12.2 volts) at a discharge rate of 25 amp-hours. A pair of typical flooded lead acid 6v golf car batteies have about 400 minutes RC, so less than 7 hours.

I inspected a Travel Supreme coach last year that was all electric; oven, stove, fridge. The heat was Aqua-Hot. It had 8-6V batteries, 2-2000 watt inverters and a 12.5kw generator. I'll bet that it would not go the night with the heat on.

[garyemunson]

Most RVs I have seen with residential fridges use a 4 battery setup. 2 batteries are the norm for units with a gas fridge. You should not need to upgrade the charger/inverter/converter. It is obviously big enough for the 120 VAC you need and should have no problem charging a couple extra batteries. Remember, when you are dry camping, there are a lot of other electricity draws. Watch TV? Satellite receiver box, furnace fan if it's cold, smoke and CO detectors, water heater control circuit, lights, maybe more stuff. 12 hours on 2 batteries sounds about right.

[TomG2]

Residential refrigerators (AC only) are not the best setup for parking lot "camping". A friend simply uses a chest type cooler. Much cheaper than replacing batteries that are ruined by be being totally discharged often. She plugs in and enjoys her huge refrigerator at the campgrounds.

[Padlin]

I'd try it again, just make sure the batteries are topped off at the start of the night. If you get a repeat then the batteries don't hold enough for your overnight use and look into adding the extra 2 batteries that theoldwizard mentions were an option at purchase.

[MrWizard]

turn off the ice maker function when using inverter power
check to make sure your water heater is OFF or on propane
is this a combo inverter & charger
or a stand alone inverter
IF stand alone be sure to turn off the circuit breaker for the converter

or you have an endless loop drain

my residential 8cuft only used 100w, aka 9 amps at 12v,

I don't buy into the 700w, statement
its hard to believe, that you are using more than 300w for fridge cooling, and it should be cycling, Not a continuous draw

[JimK-NY]

jpjulian wrote:
.... As far as I am aware, the only 120v appliance running off the inverter is the refrigerator. I would think we should have more capacity than about 12 hours of use before the batteries go south. .........

Joe

Sounds like you already learned what to expect. The idea of getting more than 12 hours is wishful thinking.

[theoldwizard1]

jpjulian wrote:
Our new Mobile Suites came equipped with two 6 volt batteries and a 1000 watt inverter.

Looking at a brochure, it appears that 5er has at least a 22 cu ft side by side refrigerator with bottom freezer. Very nice but those can draw up to 20A !

I also noticed that the manufacturer offer an upgrade inverter with 4 batteries ! I hope you won big at the casino because you will be spend your winnings on this upgrade !

[theoldwizard1]

2 things to check.

When were the batteries last "fully" charged and by what means ? How do you know they were fully charged ?

Second, a 1000W inverter could, in theory, draw over 80 amps ! Highly unlikely if the refrigerator was the only thing running. What are the specs for current draw from the refrigerator ? An "average" 18 cu ft residential refrigerator drams about 6-8A @120VAC or roughly 700-800 watts, when it is running. It really depends how many minutes per hour it runs. If you shop around, there are some refrigerators that take less.

You really should invest in a AC-DC clamp on ammeter. There are many out there to choose from that are less than $100. I have this one this one.

[jpjulian]

It is a residential fridge. No propane option.

Joe

[marcsbigfoot20b]

Check the draw on that fridge and do the math.
Switch it to propane unless hooked up or on solar.

[Lwiddis]

Battery life is measured in cycles and depth of discharge. Ah, the joys of a residential fridge! What is your residential fridge amp draw? What is the capacity of the batteries? What was the state of charge when you went to bed?