Making the best of a bad solar PV installation

[ticktockhouse]

I'm after some practical, expert advice on changing a solar PV system.

I've got a 4 kW system which I probably paid too much for in 2016-ish when FiTs were still a thing and which is annoyingly inefficient, mainly due to the Growatt SP2000 battery which only kicks in after dark, when the panels are no longer producing.

Our usage pattern tends to be 3-4 kWh in the evening. In the summer, the battery, which has grabbed the power during the day, holds onto it through that usage peak in the evening and only starts discharging about 9pm, when the house is only drawing around 300-500 W. We've also got Economy 7, so it's doubly useless at that time.

I haven't had much luck getting in touch with Growatt, so I would like to try and sell this to someone who might get a bit more use out of it, and try and knock the price off a new, more useful one. Something with a bigger capacity and that could be used to "top-up" the solar when needed during the day or be used at night etc. Basically, it should knock a bigger chunk of our electricity bill. Any advice on ebaying, etc.? I don't think I'd miss it much if I got rid of it before this winter - it doesn't help much then...

We're also looking at a Sunamp heat battery to replace our gas boiler and I'm planning to try and use Octopus Agile to charge that when the electricity price goes negative (as well as obviously off the panels and/or Economy 7). This should be happening a bit sooner, with any luck..