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RVing message boards => Newcomers' Corner => Topic started by: peterpanda on November 05, 2017, 04:47:08 PM

Title: is solar power worth it in this case
Post by: peterpanda on November 05, 2017, 04:47:08 PM
Greetings again,
I actually found a mostly gutted 86 toyota huntsman  ::) rebuilt trans, swapped dually rear.. blahblah rides pretty nice (yeah i drove this one). Not sure if she's 'the one', going to check it out again in a few days.

Anyways, I was hopin' to put a solar power system on whatever RV I end up buyin' bc I'm planning on mostly boondocking. but I'm just not understanding some things about it. or if its even worth it?
I want to run a few items, not sure if possible
- electric fridge (240 volts) nonstop
- vitamix blender (120 V, 50/60 Hz, 11.5 Amps)
- charge phones, laptops
- maybe a slow cooker 700W / 120V~60Hz

i didnt really want to run propane but i will if i need to. thanks for reading  :-[
Title: Re: is solar power worth it in this case
Post by: QZ on November 05, 2017, 05:03:09 PM
We need to talk. :)
Title: Re: is solar power worth it in this case
Post by: SeilerBird on November 05, 2017, 05:07:07 PM
I would not put a lot of money into a Toyota RV. They are dramatically underpowered and very small. You can sink a lot of money into it in a hurry and you won't want to keep it very long. And there is very little roof space for you to put solar panels on. You won't get much power.
Title: Re: is solar power worth it in this case
Post by: Isaac-1 on November 05, 2017, 05:18:36 PM
Without addressing the specific RV, I generally feel propane is the only reasonable option for powering a refrigerator while boondocking in a small to mid size motorhome.  A typical 8 CU Ft 2 door propane refrigerator will consume about 1/4 gallon of propane per day in warm weather, so you can go about 3 months on a typical 25 - 30 gallon propane tank, not accounting for propane used for cooking, hot water, or furnace.  Solar is great for powering the other stuff, I have 400 watts of solar panels on the roof of my 28 ft coach, and I think this is just about the minimum anyone should plan on, 400 watts may sound like a lot, but when you factor in less than optimal mounting angle, cloudy days, etc. the realistic output is much lower.  With 400 watts of solar panels, I get enough power to run my interior LED lights in the evening, power my 28 inch flat panel tv for a couple of hours, run the vent fans as needed, and even provide power for my furnace blower on cold nights.  Sometimes in the mornings I will still have enough power to heat up oatmeal or something else that only takes 1-2 minutes in the microwave using my inverter for power, though the issue there is battery bank size/age more than a solar limit.

If you plan to run a residential refrigerator even a high efficiency model you will likely need something over 1,000 watts of solar panels, and a 1,000 watts worth of panels tend to take up more space than is available on a typical 30 ft long coach once you allow for the space taken up by skylights, vents, air conditioner, etc.

p.s. it should be noted that the control electronics on a propane refrigerator draw 6 to 10 watts constantly while the refrigerator is in operation, to recoup that with solar you will need around a 60 to 80 watt solar panel once you consider mounting angle, charge losses, number of hours a day of sunlight, etc. A 10 watt draw for 24 hours is 240 watt hours per day, an 60 watt solar panel pointing straight up in mid North America latitudes in the middle of the summer on a typical day will generator about the equivalent of 6 hours of peak output, or 6x60 =  360 watt hours, which will be reduced to about 250 watt hours  of power available once it gets into the battery, which is getting very close to our 240 Watt hour on the upper end of the range needed to run a refrigerator on propane.  Better hope for no cloudy days if you only have a 60 watt panel and don't run anything else.

p.p.s. those things like blender and slow cooker draw on average less than you might think, sure it is a 700 watt draw on the slow cooker, worst case, but they typically cycle on and off, putting the average draw at a fraction of that 700 watts.  As to the blender even drawing 1200 watts when running, it is unlikely you will run it for more than 6 minutes per day, which is only 120 watt hours, or about half the daily draw of the control circuit on a propane refrigerator.
Title: Re: is solar power worth it in this case
Post by: ArdraF on November 05, 2017, 06:24:57 PM
Absolutely you will want all the solar power you can get so you can recharge those batteries.  And you should have propane for the refrigerator, heating, cooking and hot water.  I wouldn't want an electric refrigerator unless I had all the proper equipment (pure sine wave inverter and large generator) to run it and that doesn't appear to fit the type of RV you're considering.  You will need a generator for cloudy and sunless days.  You'll probably need to use it in the morning and at night, even with trickle charging the batteries with the solar panels.  I don't usually use the crockpot when boondocking.  Things like lights, the TV, and computer don't take all that much power when boondocking but you do need to learn how to manage the electric expenditure.  Look at the labels on all the appliances you want to run.  I prefer a propane range and oven for cooking.  We also have a convection/microwave but generally need to run the generator if using it for very long.  It can heat a cup of coffee off the inverter, but not much in the way of cooking.  By the way, RVs have 12 volt and 120 volts, not 240 volts which is typical of a household clothes dryer.  I hope you'll ask lots more questions because there's a lot you need to know before purchasing any RV.  We want to help you avoid making some huge mistakes!

ArdraF