Graphite Dave
Dave Orton
In the sold Sprinter I had a 5 gallon SS beer keg with a 450 watt heating element to provide warm water for a shower. Have made some improvements for the Transit build. To eliminate the space required for the beer keg I had a custom 14 ga. SS tank built to also be the support pedestal for the portapotti and located the tank/potapotti in the shower enclosure. That used wasted space. The 120 volt AC heating element was changed from 450 watts to 625 watts. The Sprinter used a "6 gallon" propane to electric conversion kit. The Transit kit is the "10 gallon" kit. The tank is a non pressure tank with holes for filling and for the pump on the top of the tank. Pump is a 12 volt DC submersible centrifugal pump. Pump discharges into a garden hose with a on/off nozzle. I do not need hot water at the sink. This design does not have any plumbing or hot/cold water mixing. All the water in the tank is at the correct temperature. Tank is not insulated so warm water is not stored.
At start:
5 gallons of water.
Air temperature = 74 degrees.
Water temperature in tank = 74 degrees.
Single 255 amp-hr battery at 100% SOC.
Weather was clear with full sun.
Single 300 watt solar panel with MPPT controller.
No other electrical running.
Thermostat to control the heating element.
Indicator light to show when power applied to heating element.
Tested the system today with these results:
9:55 AM start with 5 gallons of water at 74 degrees.
10:38 AM power off to heating element. Water temperature 97 degrees and SOC at 92%.
2:30 PM the house battery SOC was back to 100%. Used 20.4 amp-hrs of the house battery.
The test result shows the house battery/inverter can be used to heat shower water on a clear day. On no sun days the 120 volt AC power from the vehicle powered inverter would be used with the engine running or shore power if that is available.
For one person shower less water could be put in the tank to reduce the heating time. A 12 volt DC heating element could be used instead of the 120 volt AC unit I use.
At start:
5 gallons of water.
Air temperature = 74 degrees.
Water temperature in tank = 74 degrees.
Single 255 amp-hr battery at 100% SOC.
Weather was clear with full sun.
Single 300 watt solar panel with MPPT controller.
No other electrical running.
Thermostat to control the heating element.
Indicator light to show when power applied to heating element.
Tested the system today with these results:
9:55 AM start with 5 gallons of water at 74 degrees.
10:38 AM power off to heating element. Water temperature 97 degrees and SOC at 92%.
2:30 PM the house battery SOC was back to 100%. Used 20.4 amp-hrs of the house battery.
The test result shows the house battery/inverter can be used to heat shower water on a clear day. On no sun days the 120 volt AC power from the vehicle powered inverter would be used with the engine running or shore power if that is available.
For one person shower less water could be put in the tank to reduce the heating time. A 12 volt DC heating element could be used instead of the 120 volt AC unit I use.
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