Retrofitting a battery to a solar FIT installation...

We recently had some solar panels fitted (~6.1kW installation, but limited to export at 4kW) and signed up to the FIT tariff just before it ceased to be.
We’re now realising that we have excess capacity in the day which we could use to get us through the peak 4-7pm period (and possibly overnight too, depending on the day).

I know that when we filled in the FIT form, we declared that we did not have battery storage - if we were to retrofit a battery now (on the DC side ~ 9.5kWh) does anyone know whether that will affect our eligibility for FIT payments etc?

Mostly just toying with the idea at the moment - losing FIT payments would be a dealbreaker though.

Re: Economics For us we know it doesn’t entirely make financial sense (i.e. repayment period > battery lifespan, unless elec prices jump), but it feels like the right thing to do, environment-wise, as it’ll get us very close to carbon-zero through the summer.

Hi, I have fitted a sofar inverter and 4.8kWh pylontech batteries. They are really good as they store excess energy during the day and then I use the energy in the evening. FiT is unaffected as the install is on the AC side. I wouldn’t fit a storage system on the DC side as that would affect your generated electricity and due to inefficiencies it would be cost prohibitive in my opinion.

The operation of the batteries discharging and charging is seamless; when the batteries are exhausted I just buy my energy from Bulb as normal. I would like to use this set-up in tandem with the Bulb smart tariff so that I don’t buy any energy during the peak periods (if I can get on it!).

Economics of batteries make more sense than you might think as the government are looking at something called Smart Export Guarantee (SEG) where we, as consumers, will be able to sell energy back at higher prices during peak times. Great for people with batteries or if your panels produce surplus energy in the late afternoon/early evening (peak).