newbie looking to expand battery capacity

[SteveKnight]

Hi all,

I'm an absolute novice when it come to this but 2 years ago I had 10solar panels a fox ess inverter and 2 HV2600 2.6kw batteries.

We are getting our ASHP installed next month and I'm looking to increase the battery capacity so we can store more power overnight in the cheap charging period. (Using octopus flux). I have been quoted £2400 to install 2 more batteries from the company that installed my original system but have seen on the eco supermarket that batteries are only about £700 so I could be in line to save £1000 by installing myself.

I suppose what I'm looking for is guidance on how I identify which exact battery, versions and so on, I will need to buy and and advice on how to actually install them myself? (Don't want to get electrocuted in the loft) .

Thanks very much and sorry if this has been explained before I've had a browse through and can't find an answer in the most simple layman's terms that I'm after.

Steve

[Dave Foster]

Hi Steve,

If your HV2600 batteries are 2 years old it is very likely they are V1 batteries - you would normally expect to see a white sticker on the front saying Ver:C or Ver:D

If they are V1 batteries they are rare as hens teeth to find them (you might find them on eBay), but there is a V2 HV2600 battery available which is what you are seeing on-line however they need the V1 BMS unit replacing for a V2 BMS to work with your V1 batteries so that will have to be priced in (~£200).

When you mix the V1 & V2 battery types as your V1’s are 2 years old because of ageing they may limit the pack and the amount of power the new batteries can provide to perhaps 90% of what you would expect if all were new.

[Will]

In addition to Dave's correct and accurate advice I wanted to give a fresh idea.

As you only have 2 x HV2600 and they're rare and easy to sell, why not sell them and install a brand new stack of ECS cubes? Keep the same inverter and all the wiring, just replace the batteries.
ECS cubes start at 6kWH and scale to over 41kWH.

[SteveKnight]

Thanks very much for the detailed information.

I've just had a reply from Ollie at eco supermarket, I sent a screenshot of my batteries from the app and he said they are version 2 so should be good to add 2 additional ones on. I must have been fairly lucky maybe one of the early people to get the version 2's?

The ECS cube things look good but I think on account of getting lucky (I will double check when I get home to see what sticker they have, what sticker indicates a version 2) I will just add more of these HV2600.

I have seen some videos on YouTube, is it really as simple as just adding them to the stack and connecting the 4 cables, earth data and the red and black ones?

Thanks again for all the information.

[Will]

Correct, discharge to 50%, isolate battery stack and inverter and turn it all off.
Remove data and earth from BMS. Unplug the HV leads from the first battery, lift off the bms and place to the side.
Carefully add the batteries, make sure you don't accidently short circuit the batteries. Always make sure the final connections go to the bms again not to the top battery as you'll short them out and blow fuses.
Increment the BMS dip switch one click/number for each extra battery. Note that the number is 2 less than the real battery count.
Turn it all on and try to do some full cycle charges and discharges allowing anything from days to weeks for it to all balance.