Can I get a second battery

I currently have a 9.5kwh battery and a 3Kw inverter, I’m considering getting a second battery, is it possible and is it worth it.

Possible - yep, up to 5 on one inverter.

Worth it - very much down to how you use it.

Would a second battery qualify for 0% VAT? If so, this would make a second battery more affordable obviously.

hazelst3

Yep. Since Feb.

All depends on your personal circumstances and how you will use the battery, so you really need to work it out properly in a spreadsheet. My own calculations of different strategies (charging overnight at cheap rate to avoid day-time import, charging on solar then discharging at Flux peak rate, etc) came up with payback periods of between 5 and 22 years.

Its nice to have more battery capacity but its not great financially.

Bear in mind that your inverter will see all connected batteries as one big battery, so adding a second battery you’re still limited to the same inverter charge/discharge rate. This often becomes the overnight charging constraint.

Martinsmith I have done exactly this.
After a few months I realised that the 9.5 battery wasn't big enough to run the house for the whole day.
I added a second 9.5. I had to pay the VAT, but since Feb it would now be VAT free.
My calculations and current experience is payback in 5-6 years.

My current operation is.
Intelligent Octopus (7.5p 23:30 - 05:30) Fill battery to 100% + fill PHEV & home - not running Washing, drying etc overnight as wife doesn't consider this a safe practice)
Run house & hot water from battery during the day.
If virtually no solar power - battery lasts all day comfortably.
If some solar power and battery is above 75% at 19:30, then export to 23:00 ay 15p Outgoing Octopus
If lots of solar, battery gets back to 100% during the day and solar is exported most of the day plus the evening battery to grid export - all at 15p.

Overall I am pleased with the flexibility the second battery gave me. I am also happy with the return period as I am working the system quite hard.

Above, it was pointed out the both battteries would be on the same 3.0 inverter which has a limit of 3kw charge & discharge.
This means that it takes most of the IOG 23:30 - 05:30 to recharge the two batteries from 20% to 100%

There are quite big losses in the inverter battery system. take 3kkw from the grid/consumer panel, it arrives as 2.6kw at the battery.
Take 3kw from the battery and it arrives as 2.6kw at the consumer panel.
ie you have lost nearly 1kw in the round trip.