I have a 4KW solar panel, and would like to control the charger for my electric car automatically, so that it switches on when the output from the panel is high enough to power it. It draws about 2.5 KW, reducing as the car charges up. I also have an electric drainage pump, which I would like to switch on instead once the car is fully charged.

I am already purchasing an Immersun immersion heater controller, which diverts all excess power to my immersion heater, which will take care of smaller amounts of excess power.

I have a low power Linux computer which is on all the time, and I'm a computer programmer, so I thought it would be nice to buy a couple of mains switches which could be turned on and off by the computer, and would also report back to the computer the amount of current drawn.

I was considering Watts InPlug, but I now understand they can only be controlled by a smartphone app supplied by the company, and the protocols are proprietary.

Can anyone recommend what devices to get? Bear in mind the budget is low, as spending more than 100 on the 2 switches and any extra control gear would make the payback time ridiculously long.

Thanks in advance,
Nikki Locke