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12v solar to heat water Answered

im looking to install a hot water cylinder with a 12v immersion heater powered by solar panels(to add wind later) to my hot tub.

the idea is to either heat the whole thing all the time or to at least reduce my power usage on the heat side of the running cost.

has anyone done anything like this and have any advice?

the basic install idea i have is,

solar panel/s to a controller
controller to a battery
controller to immersion heater

was also thinking of installing a normally open relay onto the stat of the heater so when it is at temp a fan heater would kick in, but that would be a later install if the water heating would work.

any info would be great, if i get enough info i will be doing this and making it into an instructable to further help adopt this to work better.




2 years ago

I'm using PV panels to heat water for the house, its only been on a few weeks, but so far so good. The reason is simple, I had solar water panels and the frost got them and they broke. Also they also didn't work well in the winter. I was able to get 1000 watts of second hand panels for $700 which is cheaper than a replacement solar water panel . I used them for a few weeks without a controller and then bought a mmpt controller to help on cloudy days. After playing with both systems I would never go back to a solar hot water panel.

Have a look here for more info, and I used the controller on their site.



2 years ago

There are reasons why someone invented solar hot water systems ;)
One reason for example is the simple fact that you can heat water by the sun directly better than through generating electricity for a heater.

Ya I know and that is fine for summer but I'm thinking long term and all year round use, hence the need for installing a wind turbine later.

I'm not too interested in what's more Eco as in direct heat or passive, I just want to do it this way so it's a yearly use

Simply check how much energy your heater needs to heat the amount of water by X degrees.
From there you know what size panels, batteries....

I know about the sizing of panels, batts and usage etc..

Just looking to see if anyone else has done this and if so any tips tricks or other ideas they wished they had done

If I had enough room if have thermal as well as pv but I'm not able to


Reply 2 years ago

heating water directly from sun isn't just eco. It's also the best bang for yer buck.


Reply 2 years ago

I want meaning Eco in that sense.

I know it's better but I'm looking for an all year round solution not just when it's sunny enough to hear the panels