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

[TomG2]

Dometic CF-018DC Portable Freezer/Refrigerator. Holds enough for a day or two dry camping.

[jplante4]

Lwiddis wrote:
Two choices if you want to continue to dry camp, more batteries with a big solar system or install an RV fridge. Possibly to use only when dry camping?

3 choices actually. Dometic just came out with an AC/DC - no propane - compressor fridge. We got one at the store and ran it off a fully charged battery for 40 hours (until the battery read 11.7 volts).

Fridge

[Optimistic_Para]

jpjulian wrote:
The only thing running on 120v via the inverter was the fridge. The furnace was on as was the water heater on propane. An alarm went off around 3am and it was an alarm for the inverter for low dc power. I need to learn more about the systems I guess.
Joe

Propane fired furnaces use a surprisingly lot of 12 volt dc to run. There have been lots of posts by people who wake up in the middle of a cold night because their furnace is off. They had a single battery, and it drew the battery down so low the furnace couldn't operate. Adding a second battery solves this problem for them. I'm not sure how much power a propane hot water heater draws, never heard of one of them killing a battery the way a furnace can.

If you want to run a furnace AND a fridge overnight, you are definitely gonna need a bigger battery bank.

BTW, this is the reason that catalytic heaters are so popular with RV'ers. Unlike a furnace, they don't use any power at all.

[time2roll]

Exactly what alarm went off? If that is the propane detector complaining of low voltage the batteries were overly discharged. 4x would put you up where they were fully spent. 6x batteries would give some breathing room. Or you need to figure out how to conserve some energy... run a generator, or plug into something.

[Veebyes]

Out of the factory you are probably woefully under powered in battery bank capacity. Do you have space to increase it? My last 5er, an Alpenlite 34RLR Ltd., had 6 6V batterys & a 2000W inverter charger. One heckuva setup for an out of the factory 5er.

You need to fully understand what you have & what you need to have to power it all. Lots of good advice, including turning the fridge off at night & not opening the door. During a nice cool night it will not lose much chill at all. I used to do this onboard my boat which had 2 small 12V fridges.

For increasing battery bank capacity consider changing the type of battery used. Wet cells need ventilation. AGMs can be put anywhere. They can be put inside somewhere. Put them in the basement area. Put them in the living area as is commonly done in the marine applications.

In the meantime make sure that your inverter is not powering anything else major

[htss]

Something else to consider is something I read in Trailer Life's article on batteries from last month (May's issue), the higher the load the less capacity you will get out of the battery. In other words, if you are drawing 50 amps from you battery you will get less capacity than drawing 10 amps. Take a look at the chart on page 78 if you have the magazine.

[MrWizard]

I got kicked at the casino, but that's beside the point. It is a 20 cu ft fridge and if I read right is supposed to draw on 5 amps. The furnace was on and water heater on propane. The inverter is dedicated exclusively to the fridge, not to the tv or any other a.c. appliance, or so we were told. The batteries should have been fully charged, if I read the panel correctly, as this was our 3rd night of use since purchase and the prior 2 were connected to 50A.

Joe

thats 5a at 120v aka 600w

thats 50a at 12v from the batteries into the inverter to make 5a 120v out to the fridge

this power conversion confusion has come up a lot lately

general rule, if ts 120v multiply amps by '10' to get DC battery amps used by the inverter

we had another thread recently new RV residential fridge on inverter, drawing 45 amps

same thing, his was listed at 6a 120v aka 720w,
inverter use was 540w to power fridge aka 45 amps

he was using less than the listed power (which is usually the Max limit)
but its quite a shocker when you think that is 5a battery power and find out its NOT

[mike-s]

jpjulian wrote:

theoldwizard1 wrote:

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 !

I got kicked at the casino, but that's beside the point. It is a 20 cu ft fridge and if I read right is supposed to draw on 5 amps. The furnace was on and water heater on propane. The inverter is dedicated exclusively to the fridge, not to the tv or any other a.c. appliance, or so we were told.

Joe

That 5A would be at 120V. So about 600 watts. At 12V, that's 50 amps. Unless you have LED lighting, each fixture will likely draw 1-2 amps. The furnace is going to draw a few amps when running. Your 2 batteries are probably around 200 amp-hours. Way before the batteries are fully discharged, their voltage under load is likely going to drop below the inverter's minimum input voltage, so it will shut off. That's assuming they were fully charged to begin with, and that won't happen driving down the road or with the common WFCO converter most manufacturers use.

[jpjulian]

garyemunson wrote:
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.

The only thing running on 120v via the inverter was the fridge. The furnace was on as was the water heater on propane. An alarm went off around 3am and it was an alarm for the inverter for low dc power. I need to learn more about the systems I guess.

Joe

[jpjulian]

goducks10 wrote:
If you plan on doing a lot of dry camping then having 4 6V batteries are necessary. I'd also opt for solar.

We don't plan on dry camping often, but would like the single overnight option. As for the 4 6v option, I would have jumped at it if it were on the dealer lot. I've tried to figure where the other 2 batteries would go as the battery tray only has room for 2, not 4. The major expense would be the 2500 watt inverter.

This is a brand new unit to us; we are not newbies, so we have a learning curve with the new unit.

Joe

[jpjulian]

theoldwizard1 wrote:

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 !

I got kicked at the casino, but that's beside the point. It is a 20 cu ft fridge and if I read right is supposed to draw on 5 amps. The furnace was on and water heater on propane. The inverter is dedicated exclusively to the fridge, not to the tv or any other a.c. appliance, or so we were told. The batteries should have been fully charged, if I read the panel correctly, as this was our 3rd night of use since purchase and the prior 2 were connected to 50A.

Joe

[Lwiddis]

A little more study prior to purchase would have alerted you to the residential fridge...issues. Two choices if you want to continue to dry camp, more batteries with a big solar system or install an RV fridge. Possibly to use only when dry camping?

20 amps, Wizard? Wow

[goducks10]

If you plan on doing a lot of dry camping then having 4 6V batteries are necessary. I'd also opt for solar.

[theoldwizard1]

As crazy as this sounds, most residential refrigerators will keep things "cold" for 12-24 hours WITH NO POWER if the door(s) are closed.