Single 40 gallon traditional water heater

waddler

I have an off grid hunting camp with full sun in Arkansas, It is used 6 weeks per year. It is trailer with electric wiring system with a traditional 40 gallon electric water heater. I would like to run this heater with solar. What and how can I do this?

Photowhit

Not very easy and certainly not going to be able to use it like you would in a home.
So I guess it has 'county water' so no electric for a well?

I live with a 30 gallon traditional water heater, and heat as an 'opportunity load', Water heating is the 3rd highest energy user in an all electric homes after heating and cooling.

I use a traditional 240volt 3600watt heating element, but run it on 120 volt inverter which reduces it's wattage to 900watts. I could likely run this on some where around a 1500-1800 watt array. It takes about 6 hours to raise the water temps to the lower setting on the heater and that is with a full tank that has acclimatized to the home temperature. In rush water this time of year is around 50 degrees and would take even longer to heat.

There would be no quick recovery at this low heating rate.

The good news is that it is resistance heating, so wouldn't require a pure sine wave inverter.

Jarhead

Try small diy water heater tank with smaller submersible heater 12vdc or 120 from the inverter. Also look into water heater panels on roof to pre heat. Diy black tanks should provide warm solar water heaters? Warm water won't take as much to heat

waddler

County water. 3 baths /day. Last year used 10 days. Direct sun all day with southern exposure. (8-9 hours)  What size solar panel do I need? Is a battery bank needed?  Can I route the power to the wh  thru my existing electric panel?   I am totally ignorant about this,  Any and all advice is appreciated.

NANOcontrol

I think a 40 gallon tank is ideal because water easily stratifies.  I have a 40 gallon in my garage just to heat water for the laundry.  This is separate from the 13 gallon I have for the house which has a dishwasher.

The 40 gallon easily heats the upper 10-15 gallons with 1 to 2.5KWH a day with diversion from my 60V array. On good days the lower section gets pre heated for the next day.  This tank is the last place I dump my excess energy and I do laundry about every other day.  Hot water is supplied to cold inlet so all cycles use hot water.  Nice to have things come out steaming to put on the line.

Frankly almost everyone in solar is heating water wrong with diversion schemes which are hokum.  I use the DC from the solar array and pulse the water heating element long enough to drop panel voltage to power point.  I get all the hot water I need with existing panels.  No need for batteries, bigger charge controller or inverter.

You are asking for a lot with three showers a day with a minimal use system.  I use a rule of thumb of 1KWH for 6 gallons raising 60F.  That should be good enough for one shower.  Make it 4KWH for good measure, then use  http://www.solarelectricityhandbook.com/solar-irradiance.html to get solar hours for your location and month.

706jim

I replaced the heater element in my boats water heater from 1400 watts at 120 volts to a 3000 watt 240 volt element giving me about 750 watts at 120 volts. I heat this at anchor with a Honda EU1000 generator. It takes about an hour to heat the 6 gallons of water in the heater. For your application you could consider a much smaller heater (15 gallons perhaps?) that would heat up faster with limited solar power. You can easily shower with about 5 gallons or less of hot water.