What battery size for pre installed solar?

[ade73]

Looking for advice on what sized battery for pre installed solar array.

We have x13 285w panels on the roof with a Zeversolar inverter, installed in 2015. We didn't get a battery at the time as the installers said to wait as these would drop in price as the solar installs did.

Well they never did and we have looked at getting a battery a couple of times since.

Prices seem to be around £4,000 for a 5kw and inverter.

We had a leaflet through the door for switch together (North east Mayor thing for collective prices)

After submitting our details they have got back to us with a quote of £4500 but for a 15.6kw Fox battery and inverter, much bigger then the sizes we were originally looking at.

Last year we used 1,521.9 kwh and Generated 3504.1.

2 Person household, 1 work's from home Mon-Fri and 1 work's alternating days and then lates Mon-Fri site based.

No EV and no interest in one. Regular household appliances, couple of laptops, a work computer, cross trainer and home cinema set up.


Is this this battery overkill or a good idea?

T.I.A

[kambites]

The usual advice is "get a battery big enough to cover your average daytime usage". That way you never have to import from the grid at peak rate.

[Steve H]

Or, get a battery big enough to ensure you have plenty stored when the sun isn’t shining, particularly overnight.

Your usage looks pretty low, very low in fact compared to ours . We have a 30kwh battery setup which works well so I would think 15 would suit pretty well.

I wouldn’t think it’s over the top although again, with such low usage any gains are going to be smaller and any payback will be quite long.

[biggiles]

The battery itself itself isn't all that expensive - so going from 5kwh to 15kwh can be surprisingly cheap. Bear in mind you only use about half the capacity of the battery (for longevity), so if it's only £500 to upgrade to 15kwh I'd think that was good value in itself.