Views on battery quote please

QrizB

2nd_time_buyer said:

My hunch is that a lot of the benefit from having a battery is being able to deliver required power throughout the day.

Thaat's what I'm banking on, and seem to be seeing ('tho it's early days yet).

Solarchaser

The home battery is an individual choice. 
You have to work out what you want and how much you are prepared to pay for it.
Me personally,  I wanted to buy the least amount of peak electricity,  knowing the cheaper periods were likely to be greener and hoping to run the house on 99% battery.
The roi wasn't really a factor for me hence having 20kwh useable battery.

But for most it's about roi, and for decent roi on a battery it has to cycle every day, whether that's through free solar, or cheap rate electricity. 

You pay your money, you make your choice.

Dobbo123

I've got a similar quote for Pylon batteries to add to solar panels. I generate 3600 kw of electricity from the solar panels each year. I'm home most of the time during the day so can use a lot of this. My usage from the grid is about 15kw a day (high users as quite a few teenagers still at home). We've been quoted £3,200 for two batteries, 4.8kw lithium iron phosphate. I was told the warranty would be invalidated if I top up the batteries at night with cheaper rate electricity as well as charging them during the day from solar panels. I've also read batteries have a high CO2 footprint in their own right so not necessarily as environmentally friendly as they appear. I think I'm over analysing the whole thing but silly to install them if they aren't really going to be better for the environment or my purse. Are there any high electricity users out there who have had similar sized batteries installed on a 4kw solar panel system? Can anyone recommend an online calculator to work out if they are a good idea or not? 

QrizB

Welcome to the forum! This would be better in its own thread but I'm sure we can answer it here.

Dobbo123 said:

We've been quoted £3,200 for two batteries, 4.8kw lithium iron phosphate.

I'm assuming that's £3200 for 2 x 2.4kWh (4.8kWh total). Not terrible; there's about £2300-worth of hardware (link) plus fitting, registration etc.  Here is a similar system for £3400 fitted (link).

I was told the warranty would be invalidated if I top up the batteries at night with cheaper rate electricity as well as charging them during the day from solar panels.

That seems unlikely. Two cycles a day will reduce the lifetime but will also reduce the payback time and should be within the capability of the batteries.

Are there any high electricity users out there who have had similar sized batteries installed on a 4kw solar panel system?

There are lots of Pylontech users here (not me, alas) and they will be happy to tell you how they are getting on.

Can anyone recommend an online calculator to work out if they are a good idea or not? 

At the moment you're potentially saving 15p/kWh/cycle if you can charge them from solar (where you'd otherwise get a 5p SEG), 10p/kWh/cycle if you're charging overnight from Octopus Go. Say 1600kWh total cycled per year and best case you're saving £240/year so payback will take 13 years.

arty688

At the moment you're potentially saving 15p/kWh/cycle if you can charge them from solar (where you'd otherwise get a 5p SEG), 10p/kWh/cycle if you're charging overnight from Octopus Go. Say 1600kWh total cycled per year and best case you're saving £240/year so payback will take 13 years.

Although if you switch to Go now it would be more like 25p and 22p

based on using using using 4KWh of overnight per day and 1000Kwh that would have been exported.

so saving overnight 1500KWh = £330
savings on solar 1000KWh = £250

So total £580 payback - 5.5 years

I don't agree with these figures as its more complicated than that.

QrizB

arty688 said:

I don't agree with these figures as its more complicated than that.

I can agree with that