Need help setting up solar electric system on our converted bus/motor home

TellGRBill · September 2023

DROK 200123 Digital Multimeter AC 80-260V 100A Voltage Amperage Power Energy Meter AC Volt Amp Tester Voltmeter Ammeter Watt Meter

With the CT around the 120 volt power wire coming off the inverter

Looking at this image I think I can see Wh in the energy corner.

The meter, and numbers are so small that I probably missed the h

BB. · September 2023

Yes, that is Watt*Hour = Energy in the corner (Wh).

Guessing that the Voltage, Current, and Power are "instantaneous" readings (updated once a second or whatever).

The Energy is cumulative between resets. If you had a refrigerator running as:

120 Watts average
50% duty cycle (motor on 50% of the time)
And 24 hour period

120 Watts * 0.50 duty cycle * 24 hours = 1,440 Watt*Hours (Wh) per day (average)

Note that a typical frost free Energy Star refrigerator may have door heaters (to keep the door/gaskets from sweating in humid weather). And there is an approximately 300-600 Watt Calrod heater inside below the evaporator to defrost it once or twice a day (yes, I had a freezer apart as it got iced up and the defrost heater tripped and there is a dimly glowing red heating element inside the freezer to de-ice the evaporator). So you can see a few minutes (or longer) of 300-600 Watts on your meter as the fridge defrosts.

Don't disconnect the defrost heater... We had a member here that did the test. Yes, saved energy in the first 24 hours, but after that, the increasing frost/ice on the evaporator blocked airflow and ended up consuming more energy (compressor motor running more) to make up for the decrease in air circulation.

-Bill

706jim · September 2023

Agree: Keep the defroster. (Former propane fridge owner)....

TellGRBill · September 2023

Thanks Bill,

Our refrigerator was built to be a freezer but I put a universal refrigerator thermostat on it. It has a back wall and behind it are the evaporator coils and a fan blowing across the coils. There must not be a defroster because, if we don't turn it off regularly, the coils and back wall build up frost. The bus/motor home at our farm is used like a cottage so we can turn off the thermostat at night, and on again in the morning. Thus we save electricity use`with the door closed, compressor not running, and the freezer quality insulation. The box and contents stay cold, and the frost doesn't build up. The water from turn off defrosting goes down a tube into the ground under the bus.

Ralph Day · October 2023

I always used to shut down the freezer to defrost, not anymore. Get a good (or cheapo) ice scraper like you'd use on your car or truck (depending in your location) and use that. A little muscle and you can defrost in 5 minutes.
Pull out everything, put into boxes or laundry baskets, chip off ( but don't hammer it off or damage the inside liner) the frost, scoop it out with a dustpan and fill it up again. Done if 5 minutes.

TellGRBill · October 2023

That is a dangerous practice. My brother-in-law rushed his defrost by chipping the ice and had to buy a new refrigerator because he poked a hole in the evaporator freezer liner. If you add to your advice:" let the frost soften before scraping" you would have good advice for defrosting. Hot water or hair dryer speeds it up too.

Our upright freezer has the evaporator behind a wall and a circulating fan blowing the air across it into the food compartment.so we have to just let it melt.

TellGRBill · August 21

Message for Bill the person that patiently advised me while I built our Solar electric system:

This is the second summer with our solar system and we are happy with what we have assembled to be used now and in an emergency if the "grid" goes down. We just connected the last four batteries to our second battery bank, designed to be used at the farm house if needed.

We have two solar arrays, both with four 175 watt 12volt solar panels on two converted boat trailers, two 60amp controllers and a spare 3000watt inverter, two battery banks of ten each (total of 20) 12volt 90AH automotive batteries, one mounted in a heavy duty wagon that can be moved from the bus to the farm house.

We are able to live in our converted bus "off the grid" most of the time using all the normal appliances that we used "on grid". We use the radio, computer, old upright freezer converted to refrigerator temps, microwave, large fan, and all the 12volt lights, and water pump. we are using all the solar equipment that can be divided to provide power to both our farm house and our converted bus if needed::We carefully watch the voltage level, and turn off the refrigerator compressor when the sun goes down, until morning.

Our bus/motor home has a gasoline 7000 watt generator that we added a Propane conversion kit to allow us to use propane as well as gasoline to run the generator. The propane kit was fairly easy to mount in the bus generator compartment and add to the gasoline generator.

Thanks for all your patient advice Bill

BB. · August 21

Very happy to read that you are doing well with your second summer of off the grid in your converted bus Bill.

Once you get the details worked out--Solar can be pretty reliable energy source.

Take care,
-Bill

TellGRBill · September 14

I have found a way of manually having our arrays track the sun ( realigning our solar arrays toward the sun ) when we need to increase our power generation.

Our arrays are mounted on boat trailers that we can now easily turn. The last photo shows the lead wire from the array, going to the buried 10 gauge cable. The exposed cable is run through a heavy garden hose to protect the cable.

Need help setting up solar electric system on our converted bus/motor home

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