Storage addition to existing PV

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tomt_techman
Posts: 2
Joined: Sun Jul 07, 2024 9:32 am

Storage addition to existing PV

#1

Post by tomt_techman »

Hi all,

Newbie here, great forum. I'm looking to add storage install of modest (15-20kWh) storage to my system. House is all electric including a 5kW ASHP and small EV.
I currently have 7.2kWp on a 5kW Solax inverter, has been running happily for 3+ years (5kW G99 DNO approved).
I've had modest success (more so last year) running on Octopus Flux in the summer months; I have so much excess solar that I can make a reasonable credit on sunny days, especially as my array faces west hence I'm at peak export 4-7pm. October to April I'm on Go as you would expect. I'd like to reserve the ability to supercharge my export in summer and add force discharge from the batteries if certain conditions allow. However in theory I'd need to revisit my DNO to up this from the current 5kW.
So, I'm looking at ideally an AC coupled solution, with HA integration capability. UPS circuit would be nice to have. I have pondered the idea of swapping my Solax out for a hybrid inverter that can do everything, but I like the monitoring capbabilites that AC coupled gives, albeit taking the hit on conversion losses (I'm an avid OpenEnergyMonitor user so I have CT clamps everywhere).
I was taken by Polar ESS prices but the software is all closed shop so its a dead end I think.
I was going to push the button on some Pylontechs, but then a serendipitous hunt earlier led me to Fogstar's self build battery kits. I'm thinking of one of those with a Victron Multiplus 5k, could give me all I need? I would describe my DIY and electrical skills as highly competent amateur.

Any thoughts welcome!

Thanks,
Tom
AGT
Posts: 785
Joined: Sat Jan 29, 2022 11:26 am

Re: Storage addition to existing PV

#2

Post by AGT »

Welcome!

A few good threads on battery building, I have no info on home automation /etc that’s something I have no skills in.

im looking at fogstar myself due to adverse in risk from buying from China( good supplier on this site if that’s a route you want to go down) but thinking about a ready build solution just to ensure my family can understand the technology and not be scared of a bank of batteries, bus bars, balancing wires if anything goes wrong and I’m not about and any spark visiting takes a look and walks away but with a out the box solution results may be more favourable to get someone to look in the event of an issue.

Good luck with what you decide

I may just go with the single fogstar 14kW unit
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nowty
Posts: 5333
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Storage addition to existing PV

#3

Post by nowty »

If you do go for the storage and as you already have an EV, the Intelligent Octopus Go tariff might suit you all year round.

7p import on cheap rate and fixed 15p export.
16.9kW PV > 104MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 21MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 500 m3
tomt_techman
Posts: 2
Joined: Sun Jul 07, 2024 9:32 am

Re: Storage addition to existing PV

#4

Post by tomt_techman »

You're right, that's almost certainly what I'll do. I'm now coming down strongly on the side of Multiplus II GX with a Seplos Mason 15.4 battery.
sharpener
Posts: 373
Joined: Fri May 20, 2022 10:42 am

Re: Storage addition to existing PV

#5

Post by sharpener »

tomt_techman wrote: Wed Jul 10, 2024 3:48 pm I'm now coming down strongly on the side of Multiplus II GX with a Seplos Mason 15.4 battery.
No experience of the Seplos batteries but the 5kVA Multi II GX has suited me well and there is a good forum for support, with lots of ppl doing various integrations and writing their own code using NodeRed.

Be warned, even with the retrofit kit the fan noise is significant. Don't know what newly manufactured ones are like.
16 x 230W Upsolar panels in S Devon on 4kW Steca, 3.9 MWh FITs/yr
8 x 405W Longi panels on 250/60 MPPT, 3.3 MWh/yr
Victron MultiPlus II-GX 48/5000/70-50
3 x Pylontec 3.55 kWh Force-L2
zappi 7kW EV charger
Villavent whole-house MVHR
5000l rainwater system
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