Daddy Tanuki
Emperor Of Solar
so I whimped out and went the AC route. i have a 1700 liter tank (purchased) on standby (insulated) and a 5kw signeer inverter I bought last year on a whim. with 70kWh of storage the plan is to use a timer to turn on the elements from 1000-1800 dependent upon the battery voltage. will take some tinkering and adjustment to find the correct balance. if i did not have the inverter already sitting on a shelf doing nothing I would have tried some of these other setups. but the signeer is large enough that it can run a 4500 watt immersion heater, or two 2500 watt units with all of the local controls that come with a water heater.. yes I am like a golden retriever... Squirrel! but it seems to me that @SeaGal is on too something here. ac controls are common place and easy. a cheap inverter like the 5kw signeer is a shoe in for water heating. its cheap, has TOU protocols and all you need after that is a relay that measures battery voltage. do not turn on if below xxx and you are set. still sussing this out, but I have a set of elements inbound (actually several different ones for testing) along with bulkhead fittings that match the elements thread in size. I have 8 months from today to figure this out.. wish me luck.