diy solar

diy solar

Off grid camper idea in southern utah help!!

kyleswenson72

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Nov 7, 2020
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I have 20 acres in southern Utah and need some help starting off with what I want to do. We have a 38 ft park model camper that we hook up to shore power at 220 volt or we put a converter on the cord for 120 volt. The 120 volt doesn't work great when we run our campers a/c unit. I can always get a more efficient one too. I want to run solar and tie it into my circuit breaker if that is possible. Id like to have the option with shore power as well. How much solar should I need and how hard is it to run the solar to the breaker? thanks!
 
I dont understand why you need a converter. You should be able to pull 120v off the 220v if you run it into a standard electrical panel.

As for your solar request. Your going to need to specify what kind of budget you have in mind and what your power requirements are.
 
What I was meaning is that when I hook up the camper to a campground that doesn't offer 220 volt I have a converter to hook up into 120 volt. maybe this is irrelevant to what I am trying to do with solar. I figure I will need to have an inverter that I plug in that 120 converter into unless there is a 220 volt inverter and I can plug in the power too. Is that the way to do it or is there a better route to take? I would like an easy to install system with plug and play connections so I can add panels and battery's if need be.
 
You can get a 120/240V inverter or 120V only.
The key questions are:
What are the wattage (or amps & volts) rating of your appliances?
How many kWh do you consume per day?
How many kWh per night?
How much space do you have for PV panels?
How deep are your pockets?
 
240 volt is what I was meaning to say. sorry im a newbie.
Im not sure how to add up the kilowatt hours per day but could I go with the average being at 20 kwh?
  • I have a fridge that I can get a more efficient one.
  • A microwave that ill need a more efficient one as well.
  • Toaster
  • tv
  • computer
  • lights that will be LED
  • Hot water heater, oven, stove, and heater are all propane.
More than enough space for panels. either going to build a panel holder outside or going to fit them on top of my 38ft camper. This camper will be on my land for 3 years as im going to school.
willing to spend some good money on this setup to do it right the first time haha
 
You can look up energy labels.
Modern full-size fridge is 1500 Wh/day.
Microwave efficiency doesn't matter (few minutes a day), but power draw is about 1.5x it's cooking power, maybe 1500W for 900W cooking.

Induction motors need 5x current to start. Fridge label includes defroster element, probably runs on 200 to 400W, starting needs 2000W for a second.
Your AC having trouble with 120V 15V from utility is an indication it needs more. Look at the label.

Other than A/C, a 2000W sine wave unit might run things. A heavy, transformer based inverter (low frequency) of 3000W with 6000W surge, or larger would be better. Inverters can be $500 to $5000, differences in performance and quality.

In the summer, if your panels are tilted, can get 5 hours or so effective full sun per day (search on line for your location.) So 20,000 Wh would be 4000W x 5 hours. Panels put out less than rating and electronics less than 100% efficient, so 5000W of panels might do it, if you have room to fit them. I can buy 5000W of panels for about $1500 on the used market.

Need a charge controller, unless built in to inverter. They run $200 to $1000.

Batteries can get very expensive, or DIY can be cheaper but you can screw up and wreck them.
Having batteries for 3 days without sunshine would be excessive $$, get a small generator to help.
A 20kWh battery might cost $5000, more or less (some name-brand lithium cost much more.)
If you only have enough battery for one night, cost gets closer to $1000.

Your power consumption figure of 20 kWh/day is probably higher than a modest home. A/C can be a big consumer in some locations. You may be able to reduce consumption considerably and have a smaller system.
 
RV shore plugs are two types...
30A 120v, or 50A 240V

the 120V is capable of supporting 3000 W...

the 240V is capable of supporting 12000W

so, it is easy to see why 1/4 the wattage won’t support your loads.

Your daily consumption likely won’t need 12KW, but only a real load assessment will tell you what your needs are.

you probably could survive with a 6000W split phase inverter with. LF transformer. That could spike up to 18KW...
 
Im coming up with an idea that I might buy a 5th wheel travel trailer and sell my park model type. This might be easier to run solar and most of the 5th wheels have propane that runs the fridge and most appliances. also non solar related I need a grey water storage and a gravity fed water holding tank. What do you all think? will a 5th wheel camper be a better route? I found one with 2 6 volt battery's and a panel already.
 
Rooftop A/C is still an energy hog, and compact split-units are more efficient, also some are inverter drive and draw little start-up surge (all hearsay to me).
Propane will power a fridge, but then you need refills. A compressor type fridge can run off a reasonable amount of PV.
RV is parked in the sun for PV, would rather it was in the shade to reduce A/C load. Best setup is ground-mount for PV (which can then be arbitrarily large), and RV in a shady location.

I'm not sure park model vs. 5th wheel makes that much difference in energy consumption. Differences in standard configuration and towability, of course. What I did with a small trailer was ignore the propane/electric fridge and use a dorm fridge. You could put a small fridge inside and a full size outside. One with generator lets you start before PV, add later, don't need as much PV or battery.

If you're not trying to be mobile, you can go with heavy stuff. You could use lithium batteries if price/performance looks good. You can get FLA forklift battery for economical capacity and lifespan. You can get AGM for maintenance-free. For my grid-backup I have small AGM bank on Sunny Island and large PV array on Sunny Boy. Battery sized for the night, PV sized for inefficient older household appliances. Will your site be left unattended, subject to theft? For $20k you could have 12kW of battery inverter, 24kW of PV inverter, 30kW of PV panels, 10kWh of AGM battery. (plus cost of mounting hardware and electrical hookup.) That would supply 500W average at night with reasonable battery life, kick over and run rooftop A/C and anything else during the day. Could get by with half the PV and have larger battery if desired.

Or you can have much cheaper smaller PV system of other brands, if you limit power consumption and get appliances without large starting surge.
 
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