Fitting a retrospective solar battery advice needed.

teachergirl

Hello everyone
I have had lots of help from the forums before and so hoping for some advice again

I have a 4.7kW solar panel system fitted 15 years ago this October. It seems to be working well and I have the top level of FIT. 
My local council have offered a solar together scheme . The company they have chosen is Sustain energy. They have offered me a 4.7kW battery for £2772 .  I  have established that this is not one that would work in a power cut and will have to pay between £500-£1000 extra to have this fitted , depending on the survey.

So my questions are? Is the right size battery?  (I live alone if that makes any difference) Is it a good price?

I have phoned my FIT provider and from what I understand I have to fill in a battery declaration form. I think my generation payment will stay the same but my export payment (the much smaller payment) will go down. Is this correct?

I really don't know if I am asking the right questions ,so what do people think?
Thanks in advance.

gefnew

https://forums.moneysavingexpert.com/categories/green-ethical-moneysaving
You may be better posting in the above forum lots of good advice here.

QrizB

teachergirl said:

I have a 4.7kW solar panel system fitted 15 years ago this October. It seems to be working well and I have the top level of FIT. 

That was a big system for 2010! On the plus side it's surely paid for itself and then some by now.

My local council have offered a solar together scheme . The company they have chosen is Sustain energy. They have offered me a 4.7kW battery for £2772 .  I  have established that this is not one that would work in a power cut and will have to pay between £500-£1000 extra to have this fitted , depending on the survey.
So my questions are? Is the right size battery?  (I live alone if that makes any difference) Is it a good price?

That seems a little bit expensive. What make/model have they quoted for?

Just as an example, there's a 5.1kWh Fox ESS system for £2016 here:

https://theecosupermarket.co.uk/product/fox-ess-ep5-ac-battery-bundle/

As for "is it the right size?", if you use less than 5kWh of electricity a day from March to October I'd expect you to be very nearly grid-independent for that period once you've got a 5kWh battery.

I have phoned my FIT provider and from what I understand I have to fill in a battery declaration form. I think my generation payment will stay the same but my export payment (the much smaller payment) will go down. Is this correct?

Correct, your generation payment won't change. Your export payment might fall, but only if you're on metered export; deemed export shouldn't be affected.

And I agree with the pregious reply, this sort of thing gets discussed more often on the "Green & Ethical" forum.

mmmmikey

Hi - these are just my opinons....

1. Although the ability to work in a power cut sounds like a good thing, in practice it can be of quite limited value as often the battery will only supply power to a specific socket connected to very close to the battery. You could use an extension lead, but (with my battery at least) it's not as easy as the battery keeping everything going in a powercut. So nice to have, but I'm not sure I'd spend that amount extra myself. Having said that, it may be they're offering something a bit more sophisticated, so might be worth asking if the battery supplies the whole house in a powercut (subject to the limit of the load it can handle) or if it's like mine and just supplies a socket by the battery.

2. 4.7kWh is probably the minimum I'd go for - it's worth asking if this is the maximum theoretical capacity of the battery, or the usable capacity. I upgraded from a 4kWh battery to a 6kWh battery and found it to be very worthwhile in terms of battery life. It sounds like a 50% upgrade, but in practice it's a bit more than that because you can lose 1kWh or so of capacity per day in standby mode and other losses, so going from 4kWh to 6kWh is more like going from 3kWh to 5kWh if that makes sense. So (again just my view) I think it would be worth asking how much extra a slightly bigger battery would cost.

3. The price sounds good to me, but in truth I may be a bit out of date as I bought mine a few years ago and prices have come down. Maybe someone else could answer this.

4. It's worth knowing if you can charge the battery up from the grid using cheap overnight electricity to use during the day, and/or force the battery to discharge at certain times. That way, you can get good use from it all year round, nit just in the summer when the sun is shining and the solar panels are going full tilt.

Hope this helps....

teachergirl

mmmmikey thank you...I did not know that it might only supply one socket ...definitely gives me some more questions to ask and I will ask about a bigger one

teachergirl

QrizB yes it has paid for itself ...it was a risk at the time as the panels were expensive but possible one of my only ever good financial decisions .
As of yet I don't know the make and model but will definitely look so I have something to compare it with

teachergirl

gefnew thank you...how do I change which forum I have posted it in?