Solar Hot Water

[ausnp84]

Hey guys,

Got a question about wiring in a 12v water heating element to our battery bank.

We’re running 700w of solar into our 520ah 12v battery bank and the plan is to power the heating element via a VSR to make use of all the excess power. As the battery bank is split over four 130ah batteries, do I connect the positive for the VSR (and subsequently the positive to the water heating element) to the first or last positive post in the battery bank?

Second, there’s a negative that runs from the water heating element ground to the common ground. Could that common ground be the last negative battery post, thus linking it all together?

Appreciate any advice.

N

[smac999]

why are you going through a VSR? you really want something that will only power the water once the bank is full or near full. more like a SOC relay from a victron battery montor or something.

the VSR will open as soon as the bank starts charging. even if the batteries are still low. (I'm also not sure the vsr will even work like this. the ACR version will not, it needs to see voltage on both sides as a safty funtion before closing)

[ausnp84]

Originally Posted by smac999

why are you going through a VSR? you really want something that will only power the water once the bank is full or near full. more like a SOC relay from a victron battery montor or something.

the VSR will open as soon as the bank starts charging. even if the batteries are still low. (I'm also not sure the vsr will even work like this. the ACR version will not, it needs to see voltage on both sides as a safty funtion before closing)

Thanks.. I was basing it off how I setup the campervan (VSR shuffling excess power to the leisure batteries) but if a VSR won’t push excess power to a water heater element, it’s back to the drawing board! Might have a look at the Green Yachting hot water setup in that case.

N