Solar only vs solar plus grid

Hi Guys,

Just in the process of getting my new model 3. As I am going through the reading material I have couple of questions I hope you can answer.

This is my set up:

  1. Tesla model 3 highland

  2. 6.6 kw solar system

  3. Fronius inverter

  4. Fronius smart meter

  5. Tesla UMC connector to a single phase 32a socket.

  6. I would like to set up my solar charging to solar only, but I am worried about the early contactor wear… I understand the steps Charge hq has put in place to prevent this, is this something I should be worried about?

  7. With the solar plus grid option, can you please describe how Charge HQ knows when is the solar production window? If I get a cloudy day and the solar production is below the 1.2 kW all day, does it mean I’ll be constantly pulling from the grid?

Hope this makes sense.


Your equipment should all work well with Charge HQ.

Re contactor wear, we think the mechanisms we have in place are ok but you really have to make a decision. It’s worth noting that Tesla’s own Charge on Solar product works in a very similar way, with the same pattern of starting and stopping charging.

Re solar plus grid, when solar generation is > 200 W, solar charging will start and continue until it drops below this level. You can tweak this by setting the Min Solar Generation or Min Excess Solar values.

By default, if solar production is below 1.2 kW on Solar + Grid mode, the EV will charge all day. You will automatically make use of what ever excess solar exists.

Thank you Andrew for your prompt response and all the info. I feel like i can make a more educated decision!