I can't believe it's not possible for us to boondock!

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MN Blue Skies

MN Blue Skies

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We have a 2021 Jayco Eagle 321 RSTS 5th wheel. According to DH the problem is that we can't store enough electricity. We have two Honda 2000 watt generators. We have a single AGM 105 amp hour battery. DH doesn't think we have enough reserve in order to keep things charged overnight. BTW we have a residential frig.

As I said, I can't believe we can't boondock with our new 5th wheel. Somehow we managed to boondock with our old 2012 Cougar 5th wheel.

Thanks for your technical advice.
 
Options:

1. Turn off the fridge
2. Add batteries

You can do a deep dive into Wh's used, battery efficiency, charge recovery and maybe supplemental solar but at the end of the day a 100Ah battery is pretty light for a residential fridge plus usual house loads.

Mark B.
Albuquerque, NM
 
Get a bigger battery bank so that you don't have to run the generator all night. There is a wide variation on how much power a residential refrigerator draws as it depends on the model, size, as well as the ambient temperature, having said that a typical double door residential refrigerator in a typical household setting will draw around 5,000 watts of total power in a 24 hour day. This is a ball park figure, but close enough for general estimations, It might be 3,000 or 4,000 watts on the low side. Your single 105 AH AGM battery contains about 1260 watts of electricity, after considering conversion losses of a typical inverter it is more like 1,100 watts, which means you would need to run your generator about every 6 hours to recharge that battery, actually a bit less as the battery will take a few hours to charge, during which time the generator can also power the refrigerator.
 
MN Blue Skies said:
BTW we have a residential frig.
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And there is your problem. I stayed away from those.

But there are many people who like them. But I would rather waste my juice in other ways when boondocked.

BTW, open the refrigerator door and see if you can find the amps (or watts) it draws. They usually say where the door seats closed.

-Don- Auburn, CA
 
The fridge will also cycle. Plug in a watt meter to get real world numbers. But I agree that 1 lead acid will not be enough.
 
Our unit came with a residential fridge and two batteries. I've added two more, and 200 watt of roof mounted solar. We also have a 160 watt portable panel we can move around to catch the best sunshine. On a good day, we don't need the generator. At worst, we run it for a couple of hours in the evening.
 
I have a residential fridge also. I set some ice in there to keep it from running so often. That seems to help me make it thru the night.
 
TonyL said:
Our unit came with a residential fridge and two batteries. I've added two more, and 200 watt of roof mounted solar. We also have a 160 watt portable panel we can move around to catch the best sunshine. On a good day, we don't need the generator. At worst, we run it for a couple of hours in the evening.
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And don't you turn off ice maker overnight Tony?
 
We have four coach batteries; residential fridge, microwave, TV, computer, vairous charging devices for tablets and phones, CPAP. We can boondock all night, but need to charge in the a.m. since we don't conserve, but do turn off the ice maker.

My advice (as others also advised), get another battery - and if you think one more is enough, then get two more 12 V or a full set of four - deep cycle 6 volt batteries... and use the original 12 V as a spare for the towing vehicle.
 
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Isaac-1 said:
Get a bigger battery bank so that you don't have to run the generator all night. There is a wide variation on how much power a residential refrigerator draws as it depends on the model, size, as well as the ambient temperature, having said that a typical double door residential refrigerator in a typical household setting will draw around 5,000 watts of total power in a 24 hour day. This is a ball park figure, but close enough for general estimations, It might be 3,000 or 4,000 watts on the low side. Your single 105 AH AGM battery contains about 1260 watts of electricity, after considering conversion losses of a typical inverter it is more like 1,100 watts, which means you would need to run your generator about every 6 hours to recharge that battery, actually a bit less as the battery will take a few hours to charge, during which time the generator can also power the refrigerator.
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A bit of a correction to this...

Volts x Amps = Watts

This is how

12v x 105a = 1260w

As a battery discharges, the voltage drops. Once it gets below a certain voltage, 12v devices will not work properly. Some systems will actually shut the device off rather than risk damage to the device caused by low voltage. As such, you will never get the full amp-hrs out of a battery

In reading these forums, I have seen it estimated that a FLA battery will drop below its usable voltage once it gives up about 50% of its amp-hrs. An AGM is a fancy FLA. A lithium battery can reportedly give up about 80% of its amp-hrs before dropping below its usable voltage.

With that, the OP can only access about 630 watts at 12v from a 105 amp-hr FLA.
 
Drawing 50% from a AGM battery is to maximize its cycle life, and is not a limit on its immediate capacity, so while low voltage cutoff of an inverter is an issue, this is more of a problem at higher amp loads, so while you are right that you will not get the full 1260 watts out of a 105AH battery, you will get a lot more than 630 watts (exact amount depends on load, model of inverter, etc. but should be on the order of 1000-1,100 watts or so of actual available power), it will just come at the price of reduced cycle life, something that few RV owners need to worry about, as their batteries will tend age out before they cycle out unless they are full timers that camp off grid a lot.

p.s. the simplest solution to this is to get a portable power bank and plug the refrigerator into it, something like a https://www.amazon.com/Anker-A1780-Power-Storage/dp/B09XM7WDZ2/ This would give you 2048 watt hours of quickly rechargable LiFePo4 batteries with a built in inverter, that would in theory give you enough power to run your refrigerator for 10-12 hours or more, and then be able to recharge to 80% capacity in about an hour and a half from one of your 2000 watt generators without overloading it (it would be pulling about 1,500 watts from the generator while recharging, leaving enough extra to run the fridge, some lights, etc. at the same time). There are cheaper ways to accomplish this with your built in battery bank, but such a portable power station may have other uses for you outside the RV.
 
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tlmgcamp said:
a FLA battery will drop below its usable voltage once it gives up about 50% of its amp-hrs. A lithium battery can reportedly give up about 80% of its amp-hrs before dropping below its usable voltage.
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"Usable voltage" is strictly defined by the powered device, not the battery. If you have a device that cannot operate over the *specified* output voltage range of a given battery, then you have an application problem, not a battery one. I can't speak for all RV equipment but in looking through the documentation for mine, and empirical testing over time, everything works across the entire voltage range of lead acid batteries as originally equipped. So it can be done.

In the case of lead acid, delivered Ah is dependent on current drawn so there will be less delivered Ah at higher draws. This can be fairly closely predicted through using the published or calculated Peukert constant for a given battery. Achieving a balance between bank size and loads/run time is again an application decision.

Mark B.
Albuquerque, NM
 
Residential refrigerators vary widely in the amount of power they use. Plug it into a killawatt meter. Let it run for a day or two. You really need to find out how much power you suck up in a 24hour period all total. In the past, I have plugged a 30 amp rv into a killawatt meter using an adapter. You have enough battery to turn on a few lights and run the water pump for a bit. At the least, you need to double up on your battery (I would lean towards quadrupling). BEFORE you get sucked into the "lithium is the holy grail of batteries" hoopla, you need to see how many batteries you need (and kill a few battery banks, killing/replacing lead acid batteries is much cheaper than killing lithiums). AGMs come the closest to "forget about it" batteries.

I have gelled sealed lead acid (SLA) deep cycle batteries (6v) because they are mounted on the roof of the truck camper. It's the equivalent in weight of having a dead body on the roof (120LB). I need another "dead body" to run the little 7CF residential refrigerator 12/7 thru the winter nights as the truck camper is never plugged in. We also have the refrigerator on a timer so it cycles on/off on our preferred schedule (non-perishables are kept in it until we go grocery shopping). When we go camping in it, we leave the refrigerator on longer.

I actually ignored the people here and on other forums. I did my own research to find the batteries that would work best in that situation AND that was affordable. Also, when you add a couple batteries to your bank, go spend a weekend in a campsite with utilities but don't hook up. Do a dry camping test run. This will allow you to plug in and fill/dump tanks as needed. It's better to find out that you fell short of your goals with hookups handy than find out in the middle of nowhere.

I'll add this link but you probably won't use it. Lots of good info but he commits the heresy of advocating against lithiums. And I do believe that lithiums are a science religion. More people will believe that there is no God than believe that lithiums are not the "bestest battery e-ver" or use slave or semi-slave labour to mine the lithium, or believe that they have limited recycling programs (there are far more batteries to be recycled than there are places to recycle the actual battery "Most of the lithium battery scrap in the US comes not from end-of-life used EV batteries... but in the form of manufacturing scrap from battery producers."). Personally I have read enough documentation to decide that lithium batteries are not an industry that I want to support. My choice, my values, my money. And I don't give a flying fig what people on forums say. I fully expect to be either ignored or attacked for what I just posted. Do your own research to decide what works best for you.
 
I got one of those Kill-A-Watt meters when they first came out and one of the first things I did was plug it into the 2nd refrigerator in the laundry room to see how much a month it was costing me to keep sodas cold or whatever. I let it go a month and while the result now escapes me I recall the number was pretty close to the energy guide label number that was still stuck to the side of it. So maybe instead of trying to extrapolate the nameplate power draw of a given fridge in RV service, maybe start with the energy guide number since it's more representative of "typical" use factoring in duty cycle.

Mark B.
Albuquerque, NM
 
Batteries age - adding one battery and "just making it till dawn without the ice cream melting" means that in one-two years, it won't make it to dawn...

If you want to be comfortable - and skip the physics and phase of the moon, do the power upgrade to four.

You get what you pay for.
 
jackiemac said:
And don't you turn off ice maker overnight Tony?
Click to expand...
We only run the ice maker when we are hooked to city water, which invariably means electric hook up as well. Therefore there's no battery drain. If it's a colder night, we do alter the refrigerator temperature so that it doesn't need to run as much during the night.
 
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