Boondocking with DC fridge.

[camp chef]

Every year we camp off grid for a few weeks during the summer and fall.
In the past with a propane/electric fridge I carried 1 extra deep cycle battery to connect with 1 deep cycle battery and between a small solar panel and running my Honda generator for a couple hours I was able to keep up. Even with furnace use.
We bought a Coachmen C with the DC fridge this year, I bought a 2000 watt solar panel and run the generator, but the fridge keeps drawing my 2 NAPA 8231 (800mca) batteries to 50% charge every day, even with full sun.
We don’t use any other appliances or lights except 1 LED light at night and some water pump usage.
Do I need a bank of lithium batteries to power a fridge?
I wish I had the old style now.
Any suggestions for what I need to do to keep up in the fall with furnace usage?
Thanks
Bob

[Mark_K5LXP]

Guessing you mean 200W, not 2kW solar.

A bigger battery won't solve your deficit problem. You either need more panel, or less draw. If a 200W panel only keeps up to 50%, sounds like you need at least another 200W.

Mark B.
Albuquerque, NM

[DavidEM]

Originally Posted by Mark_K5LXP

Guessing you mean 200W, not 2kW solar.

A bigger battery won't solve your deficit problem. You either need more panel, or less draw. If a 200W panel only keeps up to 50%, sounds like you need at least another 200W.

Mark B.
Albuquerque, NM

Maybe more than 200W. I would fill the rooftop with as much solar as will fit, but also double the battery capacity.

That will cost a few bucks and may not be worth it. You could just double the battery capacity and run the generator more. You need enough batteries to run the fridge through the night until you can start up the generator in the morning. But you will probably be running your generator two hours in the morning and two more at night with your existing solar capacity.

The specs for those NAPA batteries don't give an amp hour rating and they have no filler ports so they are what is called sealed lead acid. Not good for deep cycle use. If you can fit them in someplace, the cheapest solution would be four golf cart batteries wired in series/parallel. Or for more money, four 12V Group 31 AGM batteries and for about the same money, a pair of 100 Ah LiPO4 batteries.

In any case you will probably have to upgrade the charge in your converter to 80 amps to limit generator run time. If you go Li make sure it has such a battery setting.

And finally, I wish the RV industry would be honest about 12V fridges. They have their advantages but as you found out to your dismay, they are not great for boondocking.

David

[IAlreadyGot1]

The 12V refrigerator will consume more electric energy than a propane refrigerator. The former uses a 12V compressor that may run 10-12 hours each day and draw ~7A. That’s 70-84A’s that need to be restored to the battery. The Napa battery is rated at 105Ah, times 2 gives you 210Ah. So it’s easy to see how they’re being drawn down to 50%.

Unfortunately, the Napa battery isn’t a true deep cycle battery, but you may as well continue using them until you notice a decline in performance. Replacing them with 2, 6V GC2 batteries would up capacity a bit to say, 225-240Ah’s. A second 200w panel would help significantly. Some generator run time to charge may still be required on cloudy days.

[camp chef]

Yes, my mistake, 200 watt.
I am used to amperage , not watts.
So on the best days of clear sun and panel at a right angle to the sun I get 10.4 amps.
Isn’t 200 watts equal to 16 amp?
This renogy panel is heavy and being glass it is fragile, I carry it on the bed.
Really don’t want to lug 2 of these around.
I have no room for 4 golf cart batteries.
I would have to weld up a frame under the coach to carry them so they don’t gas us out.
I do have room under the dinette for lithium batteries.
Seems cheaper to sell the fridge and put an old style gas/ electric one in.
As I said, I barely keep up without running the furnace , so when I run the furnace too I need 600 watts of panels and 6 batteries?

I had no problems before I bought this camper.

[DavidEM]

I went through much of the same analysis as you when the new Thor Axis I purchased was delivered with a compressor fridge, not the absorption fridge as advertised. Fortunately, the dealer had one with an absorption fridge that came in the same day as mine, so they graciusly let me swap. Why Thor built one with a compressor fridge and another with an absorption fridge is beyond me. Maybe supply chain issues (we hear that often today as an excuse for mistakes).

Had I had to accept the RV with a compressor fridge I knew I would have to spend a couple of thousand on Li batteries, a charger swap out and maybe more solar panels, although we always camp in shady spots. It would probably have limited my no generator running time to two days, whereas now I can go for four.

I was very familiar with compressor fridges and their power requirement, having used them on boats over the last twenty years. A 10 cu ft DC compressor fridge will use about 75 amp hours daily, more in warm weather. A residential fridge can use double.

So, it sounds like your non refrigeration DC loads are small. So maybe your best bet is to replace it with an absorption fridge, particularly since you already have a propane system in place. All you have to do is tee into an existing connection and run a new hose to the new fridge.

The problem will be getting it through the door, in and out. Some have had to go through a window. And then you will have to see how you can install outside louvers on the bottom and a vent on the top. It may not work. Ease of installation and particularly location is one of the big benefits of DC fridges.

Good luck.

David

[darnold9999]

Something that might help is to find the absolute lowest setting on your thermostat that will keep your freezer to the temperature you want. I found with my boat DC fridge that trying to get to the temperature where ice cream is frozen and hard, as opposed to where water is frozen, makes the compressor run much much more often and draws a significant amount of extra power with very little to show for it. I found that 200w was not enough to run the fridge all day and the fridge and furnace at night. In fact it was barely enough to run the fridge 24 x 7 and this is a 4 cf fridge. Just put in 400w of solar and now everything works. (I have about 400ah of battery so that was never a problem.)

[440scout]

Maybe I missed it but there was some talk about how many amp hours the fridge uses in an average day. Or how that translates to what a clamp on amp meter would show while fridge is running. Here's what I saw for amp usage on my Norcold 18 cu ft propane electric fridge while running it on 120 volt electric through an inverter while stopped at a rest area along the highway for lunch in central Colorado. The inverter display showed 42 amps from the batteries to the inverter just to run that fridge but, with 6-200 watt solar panels on the roof putting out just over 52 amps, it was enough to keep up with the fridge and charge the batteries. But, let's say its December parked in the same place, the sun is low on the horizon, I would be lucky to see 20 amps. My point is, add more solar. Put it on the roof and don't worry about. Most Solar panel manufacturers guarantee their panels to hold up to at least one inch diameter hail stones so they're not as delicate as you may think. If you decide to add more solar try to get a solar charge controller to handle the amps and maybe more in case you add more solar. Good luck!

[IAlreadyGot1]

Originally Posted by camp chef

Yes, my mistake, 200 watt.
I am used to amperage , not watts.
So on the best days of clear sun and panel at a right angle to the sun I get 10.4 amps.
Isn’t 200 watts equal to 16 amp?
This renogy panel is heavy and being glass it is fragile, I carry it on the bed.
Really don’t want to lug 2 of these around.
I have no room for 4 golf cart batteries.
I would have to weld up a frame under the coach to carry them so they don’t gas us out.
I do have room under the dinette for lithium batteries.
Seems cheaper to sell the fridge and put an old style gas/ electric one in.
As I said, I barely keep up without running the furnace , so when I run the furnace too I need 600 watts of panels and 6 batteries?

I had no problems before I bought this camper.

A 200 watt panel will typically charge at about 12-14A in full sun. On a good day you might get 60-80A of charge. On a bad day it could be as low as 10A.

There are some portable 200W panels with built in charge controllers, which are actually 2, 100W panels connected with a hinge. They fold to about 36” x 28” x 3” and fit into a padded case. Much easier to manage than a single 200W panel.

If you frequently park where there is good solar exposure, adding solar may be worth the effort. If you park in the trees, a propane refrigerator might be your best bet.

Your new camper has a refrigerator that consumes more electricity than the refrigerator in your previous camper. That’s the issue, not the RV. You can’t make the 12V refrigerator use less electricity and even of you increased battery capacity, it would still be necessary to increase your charging capability. That means more solar or more generator run time. Or ditch the refrigerator for a propane unit.

[mr.tommy]

A single 200watt solar panel isn't much. Even in the best of conditions it will only produce around 120watts of charging power. Maybe a tad more. Depends on the panel though. If your existing panel has a MC4 connector, just buy another good 200watt, portable, foldable, light weight panel. Plenty of choices out there. Just remember all solar panels are not created equal when gathering power from the sun.

I have 3 - 200watt portable solar panels, very good grade panels and when wired in series on a good day I'll get about 450watts out them combined for charging at the peak of the day. Less in morning and late afternoon of course.

[runamuck]

sounds like there would be less headaches and expense by switching back to dual fuel fridge.

[camp chef]

Switching back is probably not something that can be done easily.
The fridge is in a slide out so no way to create a vent on the roof.
I guess I just have to carry more panels and add batteries.
Listened to the sales pitch when we bought the camper about how the DC fridge was superior to the old style one.

Thanks for the replies.