Extra batteries & future system expansion

[richbee]

I'm enjoying my Solar PV + battery system after the initial pain getting the installation sorted out - especially now that spring is on the horizon.

Looking ahead, I wish I had a bit more battery storage capacity (and max power output from the battery - current max 50A) - Currently I have 1x 5kWh Sunsynk CATL battery, matched with the Sunsynk 3.6kW hybrid inverter & 5.6kWp of east/west panels, up in (sunny!) Northumberland.

I could buy an extra Sunsynk 5kWh battery, but apparently has to be the CATL variety, not the BYD variety which are cheaper - and they are currently ~£2400 each!
A 5kWh Pylontech is around £1600 currently, but not so easy to attach to my system (and does it have built in BMS?).

My question is:

Looking forwards to the future, where I could see an EV at some point, and also maybe GSHP/ASHP and a few more PV panels to boost capacity, what is the best future proof way to increase battery capacity in the short term, without making expense or problems for the longer term?

1. Bite the bullet and just buy another Sunsynk battery - I know the system would work well, then deal with the other future upgrades as they arise
2. Fit an AC coupled inverter and a couple of Pylontechs as a separate battery system - does that just complicate the charging / discharging as the 2 inverters would have to talk to each other, or just rely on CT coils & time slot programming?
3. Sell the current battery and buy a couple of pylontechs (I'm not wanting to go down the self build battery stack as some of you guys have done)
4. Thinking about the possible future Pv panels, buy another hybrid inverter + pylontechs to future proof to some degree - with the same question about working together as no. 2.

thanks in advance

[marshman]

As far as I know unlike a lot of other hybrid inverters such as Solis or Sofar, the Sunsynk Hybrid inverters can be "paralleled up". They are linked by a "coms" cable so will work "nicely" together. So adding another Sunsynk together with "cheaper" easier to source batteries, like the Pylontechs could be a way to go especially if you are looking to add more PV. BUT you will have to notify/negotiate with the DNO as you will be adding another grid connected generator, even though it will likely be set to zero export.

[nowty]

The sunsync battery is a 16 cell battery with capacity of 5.12kWh vs the Pylontech 15 cell battery with a capacity of 4.8kWh so your not quite comparing like with like.

From ITS the sunsync is £2290 vs the Pylontech at £1608.

Sunsync £447 per kWh vs Pylontech at £335 per kWh.

Yes the Pylontech is cheaper but considering you already have your setup, I'd bite the bullet and buy the Sunsync. Or at least await the prices to equalise a bit if money is tight.

I note you don't want to build your own.

https://www.itstechnologies.shop/produc ... UMQAvD_BwE

https://www.itstechnologies.shop/collec ... ry-storage

[richbee]

Thanks guys,
Simple is best!
I might keep an eye & see if prices soften a bit for the Sunsynk batteries - maybe when electricity prices start falling later in the year??

[richbee]

Has anyone used these people https://www.dsws.shop/product-page/suns ... fp-5-12kwh for solar stuff?
They are currently ~£200 cheaper than ITS for the battery - and both charge ~£80 for delivery

[Tinbum]

I'd be very cautious using that site.

The company number is a legitimate company but the web shop seems badly set up and I can't find an address, email or telephone number on the site.

note companies house says;

Nature of business (SIC)

42120 - Construction of railways and underground railways
96090 - Other service activities not elsewhere classified

web site says ©2022 by DSWS SOLAR yet company number is DSWS SUPPORT SERVICES LTD

it also says;

OPENING HOURS
Come Visit
Mon - Fri: 9am - 6pm
Sat: 10am - 2pm
Sun: Closed

yet no address and map directions only links to Crawly

I would ring up DSWS SUPPORT SERVICES LTD directly if you can find a number.

[Joeboy]

24th Oct 22 was their first FB shop picture and they have 1 follower. That's a bit close to the edge for me. I like a company to still be trading if I contact them in 6 months.

Then again, maybe a small mob with low overhead?I remain unconvinced for a sizeable purchase.

[nowty]

This is their registered company address in Crawley,

< Image deleted as requested >

[Yuff]

Is there a general rule of thumb in terms of battery capacity against general use.
Ie if in December/January you use roughly 100kWh a day, average, what would the ideal battery capacity be as a percentage of use?

[richbee]

Thanks guys - I'm very impressed - like having a team of private investigators
They do sound a little on the 'inexperienced' side, giving them the benefit of the doubt!