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Home battery, EV and solar considerations (Fogstar/Sunsynk/Zaptec Go2/Polestar 4)

Energy Storage

Last Post by Sheriff Fatman 3 weeks ago

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webcmg

(@webcmg)

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Joined: 4 years ago

Posts: 114

Topic starter 21/03/2026 9:17 am [#2900]

Hi all - It would be great to get your views and advice on my fully electric home setup (inc 12kw ASHP) and future proofing for V2G and V2H.

I have a solar installation pending installation: 19xAiko 475w panels (9kw), 32kw Fogstar battery, 10-12kw Sunsynk inverter. G99 came back ok with an 8kw export cap.I will also be taking delivery of a Polestar 4 next week which has a 100kwh battery and is V2G/V2H ready, but not yet enabled. I have selected the Zaptec Go 2 home EV charger because they partner with Polestar and it is V2G/V2H 'ready'.

Whilst the 32kwh Fogstar battery will cover 90% of our home energy usage, it would be good to enable the car battery to be used to power the home if the battery is depleted (i.e. on the coldest days when the ASHP usage is very high). I'd also want to benefit from any grid load balancing schemes and allow my car battery to discharge to the grid to increase export payments when available. What is the best way for this to be configured to enable this approach when V2G/V2H is enabled?

I'd also value thoughts on the best tariffs for this setup (Octopus Intelligent Go?)

Any thoughts and advice welcome.

Thanks

This topic was modified 1 month ago by webcmg

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Sheriff Fatman

(@sheriff-fatman)

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Joined: 1 year ago

Posts: 222

22/03/2026 3:56 pm

Posted by: @webcmg

↑

Hi all - It would be great to get your views and advice on my fully electric home setup (inc 12kw ASHP) and future proofing for V2G and V2H.

I have a solar installation pending installation: 19xAiko 475w panels (9kw), 32kw Fogstar battery, 10-12kw Sunsynk inverter. G99 came back ok with an 8kw export cap.I will also be taking delivery of a Polestar 4 next week which has a 100kwh battery and is V2G/V2H ready, but not yet enabled. I have selected the Zaptec Go 2 home EV charger because they partner with Polestar and it is V2G/V2H 'ready'.

Whilst the 32kwh Fogstar battery will cover 90% of our home energy usage, it would be good to enable the car battery to be used to power the home if the battery is depleted (i.e. on the coldest days when the ASHP usage is very high). I'd also want to benefit from any grid load balancing schemes and allow my car battery to discharge to the grid to increase export payments when available. What is the best way for this to be configured to enable this approach when V2G/V2H is enabled?

I'd also value thoughts on the best tariffs for this setup (Octopus Intelligent Go?)

Any thoughts and advice welcome.

Thanks

The immediate point that sprang to mind reading your setup is whether either the charger (which isn't a brand I'm familiar with) or the vehicle itself is compatible with Intelligent Go, as it's a requirement to have one of these to be able to switch onto it. I agree that it's likely to be the best tariff for your setup, so compatibility with it would be an essential factor to consider.

As for the V2G/V2H plans, I suspect that we're still some way away from these becoming a reality for use in the way that you envisage. Short-term, given the price of the Fogstar batteries, it would be relatively cheap to increase the capacity of these further to cover any excessive heat pump usage, depending on your views as to how quickly the V2G capability will take to become usable reality.

130m2 4 bed detached house in West Yorkshire
10kW Mitsubishi Ecodan R290 Heat Pump - Installed June 2025
6.3kWp PV, 5kW Sunsynk Inverter, 3 x 5.3kWh Sunsynk Batteries
MyEnergi Zappi Charger for 1 EV (Ioniq5) and 1 PHEV (Outlander)
User of Havenwise (Full control Jun-Dec 2025, DHW only from early Dec)
Subscriber to MelPump App data via CN105 Dongle Kit

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webcmg

(@webcmg)

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Topic starter 22/03/2026 9:53 pm

@sheriff-fatman thanks for the comments, I checked the link below and it suggests the car is compatible with Octopus Intelligent Go, but not the charger (the Zaptec Go isn't and the Zaptec Go 2 is not listed yet). I assume this will still be OK on this basis?

I appreciate V2G might not arrive soon, but I thought it best to future proof as far as possible?

https://octopus.energy/smart/intelligent-octopus-go/

This post was modified 1 month ago 2 times by webcmg

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Sheriff Fatman

(@sheriff-fatman)

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Posts: 222

22/03/2026 9:54 pm

Posted by: @webcmg

↑

@sheriff-fatman thanks for the comments, I checked here ( https://octopus.energy/smart/intelligent-octopus-go/) and it suggests the car is compatible with Octopus Intelligent Go, but not the charger (the Zaptec Go isn't and the Zaptec Go 2 is not listed yet). I assume this will still be OK on this basis?

Yes, a compatible car will be fine to qualify for the tariff. The basic requirement is that you do a form of smart charging from it at least once every 30 days, or something like that.

This post was modified 1 month ago 2 times by Sheriff Fatman

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webcmg

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Posts: 114

Topic starter 03/04/2026 7:38 am

Thanks, I've gone for the Andersen Quartz rather than Zaptec to be on the safe side with the charger compatibility. It's so difficult to know what tariff to go for with the EV and high usage Heat Pump...

This post was modified 3 weeks ago 2 times by webcmg

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Sheriff Fatman

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Posts: 222

03/04/2026 11:04 am

Posted by: @webcmg

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Thanks, I've gone for the Andersen Quartz rather than Zaptec to be on the safe side with the charger compatibility. It's so difficult to know what tariff to go for with the EV and high usage Heat Pump...

I doubt you'll find anything better than Intelligent Octopus Go in terms of minimising overall costs. During this winter, my highest heat pump usage was in January, during which the overnight stored battery charge (15kWh) was depleted by around midday. My peak blended tariff rate per the Octopus bill was 12.47p/kWh for that month, so the increase from the base 7p/kWh rate at the time was less than I expected.

You'll be starting with more than double the battery storage, so should be able to achieve a smaller increment than this. The rates have changed from 1st April, but the principle will be the same. By fortunate timing of when my fixed rate renewal window opened I've got 22 days in April with an off-peak rate of 3.5p/kWh followed by 12 months at 4p/kWh. None of the other tariff structures I've seen (Flux, Cosy, etc) have ever looked like being competitive with IOG for me.