Given solar (more or less every day) which makes more sense?
Packing the power into a LiFePo4
bank, turning on a hot water electric
element when you need hot water, or heating water every day even if you don't necessarily need it and trying to keep hot water in a tank with aerogel or other insulation
Basically, all I'm saying is which has less loss, the LiFePo4
bank or your hot water tank insulation
I've had both systems, one each on two boats.
I prefer solar electric
and LiFePo4 with electric tank heating because we don't have to worry about freezing lines, periodically burping the high spot on the water loop, recirculating pump annual replacements
etc. Just throw a switch for 20 minutes and we have hot water.
Summertime, when we use the boat the most, we always have enough solar (320 watts) to have all the juice we need AND hot water for all our needs including making water and showers.