Hi, Dave,
First off, many thanks for sharing your RV wisdom with us in your columns. It is greatly appreciated!
My RV has a Whirlpool residential refrigerator, model WRS571CIH204. (Manual says it’s energy efficient—low amp draw but will run more.) Progressive Dynamics Pd4560 WI converter system, Progressive Dynamics 1800-watt inverter, BMPRO JAYCOMMAND, 400 watts solar, 30 MPPT controller and two 250 AH Go Power! LiFePO4 batteries. The batteries were added in 2024.
We dry camp in the Adirondack Mountains at least once a year. Everything worked fine in 2024. We had to run a generator a few times during our 12-day stay due to lack of solar just to keep batteries full. In 2025, in the same park, we had trouble going 24 hours without running the generator to charge the batteries.
I thought the fridge was drawing excessively, but it is only drawing 1.8 amps; however, it does run a lot (as the manual states). We ended up unplugging the fridge at night to have enough power to run the furnace. The batteries would fully charge off the generator power, but there seemed to be a big draw from something.
Refrigerator draw at 1.8 amps
When we got home, I checked the fridge draw—still 1.8 amps. When getting the camper ready for storage I had everything off and unplugged, but there was still a 6.8 amp draw on the batteries. Time didn’t allow any further testing.
I realize there is still power going to the inverter, converter and JAY COMMAND. I will check draw to each when it comes out of storage.
My questions are:
#1 – What would be an acceptable draw with everything else off?
#2 – Would a 12-volt fridge of equal size use less power than a 120-volt residential fridge and inverter setup?
Thank you for any advice you can give me. —Roger, 2023 Jayco Eagle 321RSTS fifth wheel
Hi, Roger,
There are several variables that come into play when trying to determine 12-volt power demand when dry camping, how long batteries should last before needing to be recharged, and if solar panels can keep up with the demand.
Batteries and solar panels
First, let’s look at your setup for batteries and solar panels. You have 500 amp hours (Ah) available with the Go Power! batteries. Those can be drained to almost 100% state of charge (SOC), unlike flooded lead acid (FLA) batteries, that should only be drained to 50%.
500 Ah typically would be a reasonable amount of 12-volt power reserve. However, with only 400 watts of solar capacity, it might not be able to provide enough charge to the batteries. The typical “rule of thumb” I have gotten from Go Power! is you need 200 watts of solar capacity for every 100 Ah of battery reserve. I doubt you need 1000 watts, and since your first year indicated you could get by with the setup you had with an occasional generator burst, it might be fine.
Residential refrigerator
And, finally, let’s take a look at the residential refrigerator, which is supposed to draw only 1.8 amps per hour, which you verified during the pre-trip period.
Mike Sokol did a test for RVtravel.com a few years ago with a 100 Ah lithium battery, comparing a residential refrigerator with a 12-volt compressor-driven model. In a controlled 70-degree room, the residential refrigerator running through a 1800-watt inverter was able to run only about 12 hours.
A 12-volt compressor-driven refrigerator running through an inverter could run about 24 hours. A 12-volt compressor-driven refrigerator running directly through the 12-volt source could run almost 40 hours. Keep in mind this is without anything else running in the rig. It was just a static test of the refrigerator.
This test shows that not only is the residential refrigerator a huge draw on the 12-volt battery reserve, but the inverter is also an energy hog.
What caused the change in power drain
You stated that your rig could previously run 12 days with only a few charges by the generator, but now you have trouble getting 24 hours from it. So, something has “kicked” on to drain the batteries.
The first thing I would look at is the residential refrigerator. Check to see if it might be on an automatic defrost cycle. I have run into this before, as the defrost feature actually uses heating coils to defrost the evaporator fins and will drain a battery down in no time.
Some refrigerators have the feature of turning it off or on, while others have it programmed to automatically come on. If your refrigerator is drawing 1.8 amps, it might be in just the normal operating mode and the defrost kicks in when you don’t realize it.
The 6.8-amp draw is also concerning if everything is shut off—which, of course, isn’t the case. I would start pulling 12-volt fuses to see if you can identify what might be drawing. Then start turning off the breakers, as it might be a 120-volt outlet pulling through the inverter with something plugged in.
You might also enjoy these posts from Dave
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- Why does the RV refrigerator work on LP but not on 120-volt power?
- How to disable auto defrost on an RV residential refrigerator
- Why does RV 12-volt refrigerator noisily cycle hourly?
- Should we run the RV refrigerator and the roof A/C between trips?
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Towable with four 100 AH lithium batteries. Two batteries are Go Power batteries supplied by the dealer. About once a year, the Go Power batteries will trip themselves off line. The other two batteries will continue to provide power and I don’t realize anything is wrong until I run out of power in half the time (which gets exciting).
The Go Power batteries have a combination status light / reset button. When the batteries go into a “tripped” state the light will blink. Push the reset button and the battery will act normally.
It appears the batteries are tripping out on cold temps (freezing temps)?
May want to check and make sure both of your batteries are on line.
Good information as usual
Something I have come to understand better since I installed a Victron Smart Shunt is that when your 120 volt device is using 5 amps, the battery is seeing approximately 50 amps of draw. When you convert 12 volts DC to 120 volts AC through your inverter you have to multiply the amps from the battery. When your 120 volt converter is charging at 12 volts you divide the amps. If your converter is using 5 amps it is probably putting out about 50 amps to your battery. There is always a bit of loss through whatever device is doing the converting or inverting.