Submariner
Channel Surfing
- Joined
- Feb 2, 2020
- Messages
- 1,599
- Location
- Everett, WA
- Website
- www.letsgochannelsurfing.com
- Fluid Motion Model
- R-27 (Outboard)
- Hull Identification Number
- FMLT2702C021
- Non-Fluid Motion Model
- https://tinyurl.com/yrv84xdm
- Vessel Name
- Channel Surfing
- MMSI Number
- 368187810
The boat came with a 6 gallon ISOTemp electric hot water heater (750 watt).
I connected a temperature sensor to my Victron CerboGX, and attached the temp sensor to the hot side of the hot water heater. This tracks the temperature of hot water over time.
What can I conclude from this information?
It takes exactly 2 hours to heat from cold to hot.
To run it off the inverter would require 1,500 watt-hours, or 125amp-hours from the house bank to heat it fully hot.
It's not necessary to heat the tank to fully hot to actually have usable hot water. I usually run the hot water heat off my inverter (since I have LiFePo4) for 30-45 minutes to get enough hot water to take 3 showers onboard.
I'd say that the hot water lasts about 12-16 hours based on the data graphs I have and through personal experience on the boat using hot water.
The hot water heater doesn't have an adjustable thermostat. Instead, it has a "thermo-static mixing valve". This is the knob on the tank that says "Temp" and you adjust it clockwise or counterclockwise. This mixes cold water with hot on the output of the tank. It's meant to avoid scalding. The temp can be set between 100 and 150 degrees F. Note, this is because the actual thermostat is fixed, set to 167 degrees. Normal household hot water heaters are set between 120 and 140 degrees. By heating water to 167 degrees then mixing it with cold water to get the temp down so it's not scalding is a way to get 10 gallons of hot water from a 6 gallon tank. (as an example. I haven't done the math to know how many extra gallons of hot water we get, but just know, it's more than 6). To take a shower, generally speaking, the water temp is 98-105 degrees.
I connected a temperature sensor to my Victron CerboGX, and attached the temp sensor to the hot side of the hot water heater. This tracks the temperature of hot water over time.
What can I conclude from this information?
It takes exactly 2 hours to heat from cold to hot.
To run it off the inverter would require 1,500 watt-hours, or 125amp-hours from the house bank to heat it fully hot.
It's not necessary to heat the tank to fully hot to actually have usable hot water. I usually run the hot water heat off my inverter (since I have LiFePo4) for 30-45 minutes to get enough hot water to take 3 showers onboard.
I'd say that the hot water lasts about 12-16 hours based on the data graphs I have and through personal experience on the boat using hot water.
The hot water heater doesn't have an adjustable thermostat. Instead, it has a "thermo-static mixing valve". This is the knob on the tank that says "Temp" and you adjust it clockwise or counterclockwise. This mixes cold water with hot on the output of the tank. It's meant to avoid scalding. The temp can be set between 100 and 150 degrees F. Note, this is because the actual thermostat is fixed, set to 167 degrees. Normal household hot water heaters are set between 120 and 140 degrees. By heating water to 167 degrees then mixing it with cold water to get the temp down so it's not scalding is a way to get 10 gallons of hot water from a 6 gallon tank. (as an example. I haven't done the math to know how many extra gallons of hot water we get, but just know, it's more than 6). To take a shower, generally speaking, the water temp is 98-105 degrees.