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Small Cabin Forum / Off-Grid Living / Help me set this up......rain barrel, solar pump, battery, on-demand propane hot water, shower
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rugercpl
Member
# Posted: 29 Jul 2012 22:19 - Edited by: rugercpl
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Ive seen the Rule Rainperfect solar system....mixed reviews and i want something more sturdy.

I have two rain barrels, one for the kitchen and one for the bathroom. I want to rig up for each a separate solar panel, a pump, a battery, a propane tank, and an on-demand hot water heater. Everything will stay in place and inline, (no connecting or disconnecting the pump)

What size battery, solar panel, pump, charge controller, and misc. is needed? Can I use an electric on demand hot water heater with one or two batteries and one solar panel? They will be used once a day, and no more than twice a week.

Winter time will be a different topic

Just
Member
# Posted: 29 Jul 2012 22:42
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it goes-- rain barrel-to pump -to tee spliting to two water lines one cold only and one going to the water heater then to the hot water taps in the cabin ,,,thats it,,, one flow jet pump one rain water supply no pressure tank. thats all you need.

rugercpl
Member
# Posted: 29 Jul 2012 22:48
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Need help with the solar power setup plz

MtnDon
Member
# Posted: 30 Jul 2012 00:19 - Edited by: MtnDon
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Quoting: rugercpl
Can I use an electric on demand hot water heater with one or two batteries and one solar panel?


The short answer is, No, not with just a couple of batteries. Electric on demand water heaters consume electricity in large amounts and very quickly. One or two batteries with an inverter could not supply much heat. These heaters are either 120 VAC for the smallest and 240 VAC for larger.

An example of a small electric on demand heater would be the Stebel-Eltron Mini 6. It can do 1 GPM producing an output water temperature of 105 F if the incoming water is at 70 F. Not very high performance and it is 240 VAC with a draw of 30 amperes. Very high electrical use. True it's only on for brief periods unless one takes long showers. But that is a very high demand on a small set of batteries.

A propane fueled water heater can work. Some have no need for electrical power at all (see Bosch), some small units use dry cell batteries to spark the igniter for the propane. Be aware that exterior mounted on demand heaters need freeze protection which in many makes is provided by a built in 120 VAC heater designed to come on when the temperature drops low enough. Not a good thing for an off grid situation.

If electric water heaters worked well off grid you would see many of them in use. I can't think of any I've ever seen off grid.

When looking at on demand heaters look at the degrees of temperature rise for the different flow rates. There are low flow shower heads that use as little as 1.0 but most are 1.4 to 1.5. Many need 40 PSI to work satisfactorily.

rugercpl
Member
# Posted: 30 Jul 2012 09:51
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Very helpful thx....I'm actually relieved that I can cross something off my list as a possibility because it seems like I have too many.

The propane heaters.....do you know how to effectively drain them enough so if they are in freezing temps they won't get damaged? There will be freezing temps inside the cabin over the winter. Must they have forced air pushed through them? If so I wonder what psi.

GomerPile
Member
# Posted: 30 Jul 2012 09:57 - Edited by: GomerPile
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This would require 600 amps @ 12 volts not counting inverter losses (half that on a 24V system). I was an electrical engineer in another life and can tell you that electrical on demand hot water is not practical for off-grid use. Solar, LPG, geothermal, or cold showers are your only real options.

Quoting: MtnDon
An example of a small electric on demand heater would be the Stebel-Eltron Mini 6. It can do 1 GPM producing an output water temperature of 105 F if the incoming water is at 70 F. Not very high performance and it is 240 VAC with a draw of 30 amperes. Very high electrical use. True it's only on for brief periods unless one takes long showers. But that is a very high demand on a small set of batteries.


skootamattaschmidty
Member
# Posted: 28 Aug 2012 22:11
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The eccotemp hot water on demand has a drain plug to allow all water to drain out for freeze protection. I have used mine for 2 years now and no problems in the winter. I disconnect my hot and cold water lines and siphon them out. No problems so far.

rayyy
Member
# Posted: 3 Sep 2012 17:58
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How'd yah ever make out there,Ruger?Did you get your hot water supply going?Charging the battery to run your water pump can be done by,solar,wind or generator or a combanation of all three.You can also use the battery power for lighting and other small load things.I use mine to charge my cell phone and power up the controls on my propane frig as well as all my lighting.

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