Solar for heat and fridge

[Bobo_Wickersham]

I keep my RV inside the attached shed. I live in Charlotte NC. We do not experience long periods so sub-freezing temps. I’m trying to prevent winterizing. I DO NOT want the auto gen to come on as I don’t want to run the generator.

I ordered a 400w solar kit for the top of the shed. The shed gets significant sunlight during the day.

Is 400w enough solar to power something to keep the bays from freezing or what would you guys do to get power to keep some heat to prevent winterization?

[Jim_HiTek]

Where you are, I'd just pour RV antifreeze in the drains, fill the water tank (water has a high thermal energy - takes a loooooonnnnnggg cold snap to freeze a full tank). Looking at your rig, I 'think' that it's newer (it would be best if you put the details of the rig in your signature), which means it's using the newer PEX plumbing...that stuff has a high tolerance to freezing so really, a few days at 20 F during the night isn't going to bother it much. Just leave the water pump off, open all faucets and shower heads, maybe drain the pipes. This assumes it warms to well over freezing during the day. Blowing out the pipes is also an easy way to prepare for cold takes maybe 30 minutes. When you're ready to roll, only takes 5 minutes to have water again.

The 400 watt idea is fine. That's around 20 amps replenishment for the batteries...which would power 2 or 3 100 watt light bulbs you put in the wet compartments. I'd avoid having anything else on...400 watts is not much when the inverter is drawing 25 amps plus just to supply the 2.5 amps those three 100 watt bulbs are using @120 volt, and then that would be during the day. It's at night when it gets cold that you have no sunshine. Pretty sure you know that.

Do put thermostats on those 100 watt bulbs so they shut off when it reaches 45 F in the compartments. On at 35 F, off at 45 F is what they usually are rated at.

[Bobo_Wickersham]

Originally Posted by Jim_HiTek

Where you are, I'd just pour RV antifreeze in the drains, fill the water tank (water has a high thermal energy - takes a loooooonnnnnggg cold snap to freeze a full tank). Looking at your rig, I 'think' that it's newer (it would be best if you put the details of the rig in your signature), which means it's using the newer PEX plumbing...that stuff has a high tolerance to freezing so really, a few days at 20 F during the night isn't going to bother it much. Just leave the water pump off, open all faucets and shower heads, maybe drain the pipes. This assumes it warms to well over freezing during the day. Blowing out the pipes is also an easy way to prepare for cold takes maybe 30 minutes. When you're ready to roll, only takes 5 minutes to have water again.

The 400 watt idea is fine. That's around 20 amps replenishment for the batteries...which would power 2 or 3 100 watt light bulbs you put in the wet compartments. I'd avoid having anything else on...400 watts is not much when the inverter is drawing 25 amps plus just to supply the 2.5 amps those three 100 watt bulbs are using @120 volt, and then that would be during the day. It's at night when it gets cold that you have no sunshine. Pretty sure you know that.

Do put thermostats on those 100 watt bulbs so they shut off when it reaches 45 F in the compartments. On at 35 F, off at 45 F is what they usually are rated at.

Thank you Jim. This is very informative.

I like your light bulb idea. Seems to be the easiest. Just plug 2-3 100W bulbs in the bays (near any plumbing lines) and have the bulb come on at 45 degrees Fahrenheit? I also have heated floors, tank heaters, basically all of the options you can get on the coach. Should any of those options be on too or would any of those be a better idea than the bulbs?

It seems Iike you know a lot about the electrical components of the Newmar. How do I turn off all of the loads on the house batteries so the auto gen (I have it set to turn on at 12.1v) never turns on? I turn off the master power switch above the passenger chair when I leave it for an extended period of time but there still is a load from something. I turn off all major appliance fuses in the fuse box too.

[Breezy2006]

I see your area does not get below 32 degrees for long. The most expensive thing you are exposed to is your Aquahot. I’d put a bulb in that compartment. If the lows are low 20s for more than a few hours you should have a backup plan. Can you supply electricity to your shed? The electric elements would give you 20-30 degrees of heat in the 20s.

[Bobo_Wickersham]

Originally Posted by Breezy2006

I see your area does not get below 32 degrees for long. The most expensive thing you are exposed to is your Aquahot. I’d put a bulb in that compartment. If the lows are low 20s for more than a few hours you should have a backup plan. Can you supply electricity to your shed? The electric elements would give you 20-30 degrees of heat in the 20s.

No unfortunately I can’t get power to the unit. Well, I might be able to but it would be the spring before it could happen.
I live 3 minutes from the coach. If it’s going to be sub 20’s I could go over, turn on gen, tank heaters, floor heaters, ac2, and let the engine run for a while. That should distribute enough heat to sustain it for a while?

[Jim_HiTek]

All those heating pads are to keep your tanks from freezing while you're living in it. Those tanks are perfectly fine with 1" of liquid in the bottom. But, to be safe, add RV antifreeze to the grey and black tanks. And the toilet. And all drains, remember the washer if you have one. Remember to repeatedly operate the toilet foot pedal to drain it. If it's going to get really cold, I disconnect the water line from it and operate it a few more times. Usually those connections are easy to undo. Oh, and remove your undersink water filter if you have one. Drain it and reinstall.

No need for floor heat. There is a way to shut off your auto-start, check your book, it'll tell you how. Might be a multi-position switch on the dash.

The bulbs would be plugged into outlets that turn ON at 35 F, and OFF at 45 F. Amazon carries them.

So what you'd have, is the 400 watt panel feeding a solar controller, and that would be wired to your house batteries. Then you would get a high efficiency MSW 600 watt INVERTER to connect directly to those batteries. MSW (Modified Sine Wave) because the light bulbs don't need no fancy schmancy Pure sine wave. That inverter would output 120 volt AC and that would power your 3 - 100 watt light bulbs through the thermo outlets. Disconnect the grounds to the Chassis batteries but keep a wrench and gloves in the battery compartment so you can reconnect them when you start the engine. (That may also knock out the auto-start to the generator - depends).

Yes on flipping off all of the Circuit Breakers. There will still be draws on the batteries...engine and tranni memories, dash radio memory, the steps, the CO and Propane detectors. And sometimes the inverter if you have one or two. Try to disconnect fuses for those devices.

What I typically recommend is just disconnecting all the battery grounds and only use 120 volt AC devices power by an extension cord. In your case, you just bought those solar panels and probably want to use them...they need to go to batteries so different plan is necessary. What I'd do since it's a new installation is put the solar panel up, route it to the solar controller than to the house batteries that I've disconnected the grounds and power leads from the RV so they are stand alone. Then I'd run power wires from the batteries to a new 600 watt inverter and from there to an extension cord for the lights.

I know, it's getting complicated and I'm long winded but there's soooo much to consider! And you only have 400 watts. During the day. So all other loads need to be minimized.

BTW, it's recommend that you DO NOT start the engine, gas or diesel, unless you are going to drive for 20 minutes to warm everything.

[Rd1]

your coach in "general" may handle light freezing temps for short periods of time. However,the hydronic heating system can be very susceptible to freezing temps. If there is any water inside the heat exchanger, it is very likely the heat exchanger will be compromised.


If you have the oasis unit in your coach, the heat exchanger is located in the heat distribution box. usually located in the compartment behind the oasis unit. In the pic, the heat exchanger is the brass looking item (on the left side) and is about the size of a brick.


That small "brick" box, has one compartment for the engine coolant, a second one for the oasis fluid, and the third is for fresh water. in that small space, any water could easily freeze and damage the unit.



It may be safest, to make sure there is no water inside the exchanger, or the compartment is plenty warm.