New member SMA 5kw in France

Julian Divett · Apr 6, 2023

Hi, I self installed 2 arrays in my home in the south of France. A total of 5.3kw with a SMA 5 tripower inverter (3 phase).
My house is all electric with Aircon and Swimming pool in the summer and a heat pump for the underfloor heating in the winter. I have a separate solar system for hot water. I also run an electric car. I do not have a resell contract for feed in, the rates are super low and you have to jump through major planning hoops with a local mayor who has shown zero interest in solar.

I try as far as possible to maximize energy usage during the sunny hours but I'm definitely throwing away several kw of energy each day. Annoyingly the inverter does not have a storage function so I'm looking at a separate inverter and battery solution. At the moment this doesn't seem to add up financially. We pay around 12p kWh off peak and 18p peak. In the future i will get a second electric car and I would be tempted by v2h.

binky · Apr 6, 2023

Have a look at the build your own batter to threads on here. The cost savings make batteries far more viable.

Julian Divett · Apr 6, 2023

binky said:
Have a look at the build your own batter to threads on here. The cost savings make batteries far more viable.

Yes I did watch a few YouTube videos a while back about this. One other issue is 3 phase, I will somehow need to balance the excess.

binky · Apr 6, 2023

Julian Divett said:
Yes I did watch a few YouTube videos a while back about this. One other issue is 3 phase, I will somehow need to balance the excess.

3 phase inverter, although 5kw units are in short supply.

michael8554 · Apr 7, 2023

The existing swimming pool heating could be supplemented by the excess ?

arwooldridge · Apr 7, 2023

michael8554 said:
The existing swimming pool heating could be supplemented by the excess ?

Exactly. The swimming pool is almost an infinite sink for heat compared to 5kw. Use a solar diverter. I designed and manufacture the SolaControla solar PV diverter, and have made bespoke 3 phase versions up to 50kw special order. But you could use 3 separate single phase alternative brands .

arwooldridge · Apr 7, 2023

Having said that 5kw is not going to heat the pool very much, a more efficient way would be to divert the underfloor heating water from the heat pump system in the summer to a heat exchanger in the pool. That way you get three to four times the amount of heat out. Probably more complicated than you want though especially as the HP cycles on/off so you would probably need batteries too!