Solar Off Grid.  PV Solar Matched to Heating Element .

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Davo99
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Joined: 03/06/2019
Location: Australia
Posts: 1584
Posted: 09:42am 13 May 2023      

  Confused said  AH Davo99, thanks very much.   Any chance of a close up photo of the units in your system. My son has experience in TVs and Computers and will understand the makeup of your system far better than i do. Do you foresee any problems or the need to test for a bit longer. Again thanks very much to you, KeepIS, Phil, Roger and Murph. for the detailed replies.


What units are  your referring to specifically?
The control board or??

The panels are connected direct to the caps and they are in circuit all the time.
There is a mosfet ( or 2) connected between the cap bank and the load.
The timer board or Arduino merely switches/ pulses the mosfet to connect the cap and the load.

I forgot to mention the Thermo side as Murph mentions.
That has a 2A plug pack connected to the solar  which drives a 500A, 500V DC relay.
The water heater thermo controls the relay so it is only switching the 15V side not the solar input itself.  Be better to use mosfets for that but I bought the relays so I put them to use.

I have been meaning to test the pulse side for a while because due to the cycling of the power from the caps to the element, I don't see why the thermostat can't run the load as normal? The frequency should I believe make the DC act like AC and extinguish the arcing.

I am running the DC at the same frequency mainly as the mains so at worst, I am thinking I may only have to bump up the discharge side which shouldn't be a problem although may need more caps depending on the amount of panels I am taking power from.
To straight drive a load off panels, wouldn't have to worry about the caps of course.  

I have been meaning to set up a driver unit like this to test because if it works as I think it will, then I can simply plug in my kettle or space heater and run them unmodified and use the inbuilt thermostats on them or anything else which will be very handy.