Once you have reached your 3.6kw export limit, can you then use the excess to top up a battery?

MancMan123

Afternoon all.
Well obtaining quotes for a solar installation is proving more difficult than I first thought 

As mentioned in one of my first posts I have been given a quote to have 5.6kwp installed on my south facing roof

Assuming that next summer will have a few abnormal blue sky days (currently grey and overcast now in Manchester) i think the hassle of applying for DNO might not be worth it .............. but instead of the excess kwh being wasted would it be possible for this to go and top up the battery/run appliances with?
Or is it a case you get your inverter say 5kw, but throttled back to 3.6 so no DNO approval is needed, and that is all you have  ...... you can either send it to the grid or you can use it yourself.

I hope that question makes sense

Thank you

Reed_Richards

If the battery is on the DC side of your inverter then your solar power will supply your house, any excess will charge your battery and any remaining can be exported.  Your battery may well have a maximum charging power/current so some export could occur before your battery is fully charged.

MancMan123

Superb

thanks for the quick response

Ectophile

My inverter charges the battery first.

Imagine it's a slightly sunny day, and the panels are generating 3kW all day.  With your approach, it would all be exported, and your battery would still be flat when the sun goes down.  So you end up buying electricity from the grid all evening.

It's likely to work out more financially effective to make sure the battery is fully charged, then export what's left, capped to 3.6kW.

Alnat1

I sometimes delay charging the battery until a bit later in the day if I know it's going to be a good day with plenty of sun.

I'll start charging when I see generation is getting up near the cap. As the cap only limits what comes out on the load/grid side, this allows higher generation as the battery fills.