Solar Panel questions

Ectophile

So what if we bought another 1 of these 10kw storage batteries, when one
is fully charged would it then go over to the second and only when
second one is full any extra go back to the grid and we would have more
to use to hopefully cover everything for longer.

With these more complex systems, you need a controller that handles the battery charging when it's sunny, and then using the battery when it's not. The controller may also allow you to charge at night on cheap rate electricity. You'd need to check whether it can handle a second battery. Many can.

I assume you would have to pay the daily standing charge still?

Yes.

So to get this straight any that goes back to the grid it would put us in credit?

You get paid for what you export, and you pay for whatever you import from the grid. The price per unit won't be the same. Overall, the export will lower your bill.

Newbie_John

Electricity isn't that exensive. 10kWh battery stores about £2.50 worth of electricity. Battery of this size let's say costs £5000 - no way to buy enough to collect enough in summer to make it to winter.

Qyburn

Do you know how much electricity you are likely to use? In a sense it's a side issue given you'd be taking in an existing system, not designing one for your own needs. But the relevance is that electricity you use yourself is more valuable (saying 25p or so) that electricity you export (earning say 12 or 13p).

Installed two years ago it won't come under the FIT scheme, so what you need to ensure is you have the correct paperwork to apply for export payments. You will need ..

1. MCS certificate for the installation. We actually had two, one for the inverter and panels and one for the battery. If you're the same, the first is the one you need.
2. Confirmation of connection and export permission from the DNO. If the inverter power is more than 3.6kW, which it should be, then the approval process is G.99 and the document you need is confirmation back from the DNO after commissioning.

If you're not clear on either, or if the seller offers something different, we can advise.

By the way and just as an example we have a 20 panel system with battery, installed end of May 2024. We've not paid anything for electricity since, in fact it makes a return with export credits exceeding bills on a year round basis.

Dogbyte009

"So for what you get paid for export, how do you get it, does it go on your account as credit?"

Assuming you have imports and exports with the same supplier - you can have them with separate ones - then your exports will be credited to your bill.

I have a 10 panel system and a 2Kwh battery, from around May to September I generally earn enough from exports to wipe out the cost of imports and standing charge and make a small profit.