RV Power

ronc89021

Hi guys,
I'm back with all new questions...
My wife wants me to buy an RV for extended camping trips instead of staying in motels...(not sure if I should be happy or sad about that) anyway, I'm thinking of an average 24-26' bumper pull trailer with maybe keeping the frig cool and maybe running the microwave for a few minutes a day plus 4-5 hours of lights in the evenings, oh and powering my laptop for 3-4 hrs a day also... Any idea what size system I might need to buy and install for such loads???
Any insite would be great!

BB.

Re: RV Power

The refigerator will probably be a large part of your electrical loads... Do you have a brand/model/voltage range/energy usage you would like install?

Depending on what you choose, it could run from 0.5 to 1.5 kWH (more or less) per day...

For example, say you want 2kW hours per day of electricity and are mostly in the South West... Assuming a flat mount (no tilt/racks) and good weather, say 4 hours of sun per day, and end to end efficiency of 0.52 for solar PV to AC power:

• 2,000 WH * 1/0.52 system efficiency * 1/4 hours of sun = 962 Watts of solar panel

So, how does 1,000 watt of solar panel look for your project?

-Bill

SirSparks

Re: RV Power

I would agree with BIll I have a 1,000 watt RV system and today a particularly sunny day I have 2.9Kw at 3.45PM.

ronc89021

Re: RV Power

Ya, not sure of spacific load requirments because I haven't bought a trailer yet.
I had assumed that most trailer frig/freezer combo units are standard...maybe that's not true.
I do live in the south west and we would spend most of our time in the intermountain west or north west now and again.
If I would need about 1000watts of panels, what system would I need to install to handle that much input?

SirSparks

Re: RV Power

When I was rsearching my fridge I found that nearly all reasonable priceed ones consume about 365 KWhr a year so 1 Kwhr a day/it didn't really matter if it was 3 Cubic ft or 18 Cuibic ft. So I recommend checking out the Yellow Effciency Label.

I think it best more experienced members suggest which system you might choose to use. Although personally I am very pleased with my decision to purchase an Outback charge controller despite the high $ cost.

If you think you might need AC or heat then treat Insulation of your purchased trailer as a primary !

techntrek

Re: RV Power

The #1 rule for RVs and fridges off-grid is to use the propane mode and forget the 12 volt mode. The size fridge that comes in a 24 foot trailer will last around 3+ weeks on one 20 pound propane bottle. If you look inside you'll see it has a very small flame, RV fridges truly sip the LPG (RV furnaces on the other hand are propane and battery hogs... look at using a catalytic heater instead). While older RV fridges didn't use any amps while running in propane mode, newer fridges all have computer control boards and so they do need a 12 volt supply. They don't use much, but they do use some.

Next step is to convert the lights to LED lights. At that point 2-3 PV panels and 2 deep cycle batteries will be enough to hold the fridge (in propane mode), run the LED lights, and charge your laptop (best to do that in the middle of the day when the sun is on the PV panels).

Your microwave is in another league. Just 10 minutes of use per day will take 25 amps out of the battery. Figure on adding another panel and a 3rd battery. Partly to handle the high amperage draw so you don't get a large voltage drop.

Get a 2000 watt inverter to run the microwave, and a 200 watt inverter for your laptop. Even better, get a car-charge adapter for your laptop and forget the small inverter. You'll be tempted to get a modified sine wave inverter for the microwave but be warned that it will take far longer for your food to cook so you'll end up using more amps. It will run most efficiently with a pure sine wave inverter. Not cheap, but necessary.

icarus

Re: RV Power

In addition to the fridge loads, ( go with LP) A/C is a huge load, and makes solar counter productive. If you need a/c you want shade,, ergo, no solar.

All calcs and all hardware remerge from the loads. Figure out the loads, and you can design a system. You also have to figure in how much charge you get from the two vehicle pe day. A small Honda eu genny might be the cheapest/best alternative.

Tony

ronc89021

Re: RV Power

Thanks guys! ...once again, plenty to think about. I will find the RV first then start doing the figuring. but before I buy anything, I will be back to ask more questions.