Solar with a residental fridge

[prepilot_3ck]

All,

I have a question about solar panels for my new (to me) RV. I have a 2016 Thor Outlaw Gas Class-a. I have three main concerns regarding power when not plugged in and not running the generator (which I would like to minimize). Solar seems like the answer but I'm not sure how much to get or what to look for. For the record we live in Vegas and MOST of our camping will be done in the desert where we get 364 1/2 days of unobstructed, direct, blazing hot, relentless, oppressive, and power generating sunlight.

I have a 6V (4 battery) house system. Each 6V battery is marked as 20 Amp Hours. So, 20 AH/6V pair (no current change in series = 12V@20AH), in parallel with a 2nd 6V pair doubling the capacity bringing me up to 40AH @ 12V of battery life. If I can Apollo 13 this thing and keep my current draw down around 5A, I should be able to run for 8 hours ,assuming ideal conditions, before having to plug-in or run the generator. Whew.. ok.


Here's how the three concerns break down.

1.) My main concern is my residential fridge. I have one. Love the size and the look, but don't love the power requirement. I see myself doing a fair amount of dry camping/boondocking (that's what the kids are calling it right?) and I'd like to be able to use the fridge (along with lights, water pump, maybe the radio, charge phones/computers)without concern.

2.) Modern rigs are wonky with low batteries. Even in my old 2000 RV when the batteries were low, the craziest stuff would happen. Things would chirp, the generator wouldn't start, slides acted funny, I'd get weird dash lights, my transmission would go into protection mode and not shift, etc. In a modern coach, with all it's high-tech gizmos and do-dads, I can only expect things to be worse.

3.) Storage. Being in our early 40's we have a LOOOOOOOOOOONG way to go before we can make RVing a long term thing. So, for 4-5 days a week (or longer) our RV will be sitting in a storage lot - with direct sun. We have a battery shut off that seems to work at this point but I'm sure we're still drawing power at some rate. I'd like enough solar to keep everything topped off while in storage so the coach just springs to life when we are ready to go.

SO! We'd like enough juice to keep the fridge running all day/night while we're camping, and keep everything charged in storage. Some simple-ish, math would suggest I just need to be able to provide more juice in, than I'm pulling out. Which means a single 80W panel (80/12 = 6.6A.) probably won't cut it especially when taking into account loss in the charge controller and conversion, and wires, regulators etc.

My plan is to drop a current meter in series with the battery and fire up the things we want to run while dry camping. Make a note of the draw, and then plan on getting enough solar to exceed that by 50% or whatever is economical.

Has anyone done this exercise or is there an easier way to figure this out? Is 200W enough (16A)?

Thanks,
Brian

[theoldwizard1]

prepilot_3ck wrote:
Each 6V battery is marked as 20 Amp Hours.

What you are looking at is the Amp Hour discharge rate ! Most GC2 batteries are about 220Ah @ a discharge rate of 20A.

[Lwiddis]

Such as “Which means a single 80W panel (80/12 = 6.6A).” Try 4.5 AHs at high noon on a cool day with the sun directly overhead.

[Lwiddis]

I’m not getting the feeling you have the basics of RV electricity or RV solar. You start with an energy survey then plan the solar system around your anticipated use times at least 1.5.

[time2roll]

4x GC2 is about minimum. You could go 8x if needed. Plenty of posts from users with 500 watts solar and still need to run the generator. So 600 to 800+ watts solar would not be too much.

Hopefully you have an inverter/charger that can push 100+ amps into the battery when the generator does run.

If you really want to go big on this consider lithium batteries.

www.solarblvd 255w panel $140
Plan to pick these up or shipping will kill you. Norco, CA. Or local supplier should have similar.

[Ivylog]

I know it’s a dry heat but what do you do for AC? Swamp cooler? 600W plus a $150 controller plus 2 more batteries...$1000.
*OH, I see your AC post. Get some water misters and mist your roof and the side that’s in the sun. Until then spray the rig down and see how much you can drop the temp.

[KD4UPL]

If your batteries really say 20 Ah then you have some unbelievably small odd-ball batteries. Most 6v RV batteries are at least 220 AH.
Solar panels are basically a commodity, shopping should be done on a watts/dollar basis. The larger the panel the better the price. Most larger panels are selling for well under $1/watt. When you start buying little 80 or 100 watt panels you will often pay $1 to $2 per watt. You could probably get a 300 watt panel for $200 or less. I just bought 30 290 watt panels for a job and they cost me under $150 each but that's a wholesale price.
The charge controller, wiring, mounting hardware, etc. will cost you more than the panel. You might as well put up two or three. I just did an RV recently, I installed 3 290 watt panels. The whole job cost the RV owners about $3,000 for a turn-key installation. The 870 watts of panels only about 1/6 of the cost.

[2oldman]

prepilot_3ck wrote:
Each 6V battery is marked as 20 Amp Hours.

That's *way* too small of batteries. Are you sure you're reading that correctly?

prepilot_3ck wrote:
Is 200W enough (16A)?

You only get 16a for a short time on a very cold day. The easiest math for solar is get as much as you can possibly afford and fit on the roof.

[Acampingwewillg]

Yep, $400.00 for 100 watts would be expensive! I suggest another location to shop solar. Solar Blvd is your friend at about 100.00 +/- bucks per 150 watt panel. I've been looking for years to address the same issue you are(residential fridge). OH except, my MH is not new...lol

[prepilot_3ck]

Trackrig wrote:
Quit worrying about it - panels are cheap, put 600W worth up there or more if you have room. Do it once and be done with it. Then be happy.

Bill

LOL!! You're probably right. $400/100W isn't exactly cheap in my world, but point well taken.

Brian

[Trackrig]

Quit worrying about it - panels are cheap, put 600W worth up there or more if you have room. Do it once and be done with it. Then be happy.

Bill