UK Hybrid Inverter recommendations for grid charge and home power usage

[kwaichi]

Hi everyone, I'm in the UK. What's the best inverter to buy to charge up a Fogstar Energy 15.5kwh overnight for 6 hours on cheap rate (7.5p per kwh on Octopus Intelligent Go) while I charge up one of my EV cars which draws 30amps. I have 100amp max to use when car stops charging. overnight amp draw from the house is minimal. My electrician is fine to hook up any all in one inverter and as I'm not exporting back to grid and I'd prefer something that can draw 5kw-6kw peak for battery usage. I'm after something that is smart enough to determine how much ampage is left out of my 100amp to take as much electricity as possible from the grid. My DNO is UK power. A bonus is if it is on the G99 list with an export limiter built into the inverter for when I go on holiday to sell back to the grid at 15p per kwh. Any help welcome!

 

[kwaichi]

Also being limited to 100amp is at 240v. Does that mean I can get a battery charger at say 300amp if charging 48v? If so I can increase my battery storage to 31kwh

 

[houseofancients]

Sunsynk/deye ( but I am biast)

 

[kwaichi]

Sunsynk/deye ( but I am biast)

Isn't their max Ac input 25 amps?

 

[houseofancients]

Isn't their max Ac input 25 amps?

Entirely depends on the model.
I run 12k 3 phase sunsynk's, they will take 63a ( @ 3* 230v)

 

[kommando]

Your best bet is to start off with the DNO and see what they would allow max Inverter size which will be based on the loading on the local transformer. Then once you have that figure you can go on the ENA website and list all the G100 inverters of that size and then see which one will charge batteries at the highest amps.

 

[SeaGal]

I have Solis inverters. The S5-EH1P6K-L will charge/discharge at 100A DC = 5kW AC. That is more than sufficient to fully charge my 14.3kWh battery overnight.

I'm after something that is smart enough to determine how much ampage is left out of my 100amp to take as much electricity as possible from the grid.

Rate of charge is configurable manually out-of-the-box. Or automatically/dynamically via RS485 Modbus RTU comms. Having said that, if your EV is only taking 30 or your 100A available via your DNO cutout, that is a non issue, as it will only draw 5kW-ish max.

My DNO is UK power. A bonus is if it is on the G99 list with an export limiter built into the inverter for when I go on holiday to sell back to the grid at 15p per kwh.

Any grid-tied inverter of that size will need to be G99 type tested. The Solis also has G100 compliant export control.

for when I go on holiday to sell back to the grid at 15p per kwh.

Octopus's TOU do not permit the selling back of "brown electricity".

Export Tariffs - Terms & Conditions

octopus.energy

 

[rpdom]

Octopus's TOU do not permit the selling back of "brown electricity".

Export Tariffs - Terms & Conditions

octopus.energy

They don't have any problem with selling back electricity stored from cheap rate overnight though, as long as the batteries are connected to a suitable system such as a hybrid inverter.

 

[kwaichi]

I have Solis inverters. The S5-EH1P6K-L will charge/discharge at 100A DC = 5kW AC. That is more than sufficient to fully charge my 14.3kWh battery overnight.

Thanks! How long does that take? I'm thinking doubling battery capacity to 31kwh

 

[kommando]

Thanks! How long does that take? I'm thinking doubling battery capacity to 31kwh

6 hours at 5kw is 30kwh, well 27 or 28 usable after losses.

 

[kwaichi]

ooh there is a new website for ENA devices

 

[kwaichi]

wow there are loads of major brands there that are not compliant. (inversely loads of small outfits that are compliant)

 

[kommando]

Don't worry about the non compliant, they are just waiting approval or ENA need clarification after getting the paperwork. They may already have approval and the ENA have not updated. Its the ones not listed you ignore, any non-compliant that interest you will need some digging on to see if they are already approved or when they aim to be approved.

 

[SeaGal]

They don't have any problem with selling back electricity stored from cheap rate overnight though, as long as the batteries are connected to a suitable system such as a hybrid inverter.

... but they do specifically refer to Brown energy by saying...

4.5.1 We are not obligated to make Export Tariff payments to you:
(i) for any ‘Brown Export’ – i.e. exported electricity not generated by an eligible generation asset, (including standby generators, batteries and technologies not supported by the Smart Export Guarantee
And later refer to "an eligible generation asset" as being:-

5.3 The generation asset must generate electricity wholly or mainly from one of the following energy sources):
(i) Solar Photovoltaic (PV);
(ii) Hydro;
(iii) Micro-combined heat and power (micro-CHP);
(iv) Wind;
(v) Anaerobic Digestion (AD).

 

[rpdom]

... but they do specifically refer to Brown energy by saying...

4.5.1 We are not obligated to make Export Tariff payments to you:
(i) for any ‘Brown Export’ – i.e. exported electricity not generated by an eligible generation asset, (including standby generators, batteries and technologies not supported by the Smart Export Guarantee
And later refer to "an eligible generation asset" as being:-

5.3 The generation asset must generate electricity wholly or mainly from one of the following energy sources):
(i) Solar Photovoltaic (PV);
(ii) Hydro;
(iii) Micro-combined heat and power (micro-CHP);
(iv) Wind;
(v) Anaerobic Digestion (AD).

I'll go with the "mainly" for a hybrid with PV and batteries.

Although Octopus also have a scheme where they can control your home batteries or possibly EV(?) automatically to charge at low rate and export at peak times. I forget what it's called. Then there's the Saving Sessions where they encourage you to export during extreme peak times and pay a decent amount for it. They get the cost back from National Grid.

 

[SeaGal]

"mainly" sounds vague enough

 

[kwaichi]

Don't worry about the non compliant, they are just waiting approval or ENA need clarification after getting the paperwork. They may already have approval and the ENA have not updated. Its the ones not listed you ignore, any non-compliant that interest you will need some digging on to see if they are already approved or when they aim to be approved.

I was really surprised to see no Victron inverters on the compliant list. I'm looking to install soon so I'm looking at only models which can fast track inform with DNO. My sparky has trade login into connect to commission and sign off (so he says, did one last week blah). I'm now looking at the Solis EH1 6kw and a 30kwh system built by SupersolarUK

 

[kommando]

I looked at Supersolar, some of the cells they use are potential fire hazards, maybe the Hyundai one, too long ago to be sure. I went DIY using LFP cells from Fogstar instead and have no issues.

 

[SeaGal]

Also happy with my DIY cells from Fogstar. But now they also do a pre-built 15.5kWh system if you don't want to DIY.

Fogstar Energy 15.5Kwh 48V Battery

A high-performance 15.5kWh battery designed for UK conditions, featuring intelligent heating, plug-and-play inverter compatibility, an intuitive LCD touchscreen interface, premium Grade A EVE cells, scalable energy storage,

www.fogstar.co.uk

 

[kommando]

My self build was about £900 cheaper than the full build and also meant I could pick a different BMS and I used the JK PB with 2A balancer and also Canbus closed loop to my Sunny Islands. Build time was 8 hours battery 1, 5 hours battery 2. As the cells come 4 to a box they are liftable and come in a normal courier van, the fully assembled battery is a lot heavier but with wheels.

 

[kwaichi]

I looked at Supersolar, some of the cells they use are potential fire hazards, maybe the Hyundai one, too long ago to be sure. I went DIY using LFP cells from Fogstar instead and have no issues.

they want to build with 3x 9kwh LG packs to make up 27kwh.

 

[SeaGal]

I went for self build too - much cheaper, especially in 2022. I like the flexibility of my own control systems too, so personally, would chose DIY over pre-built anytime. But, I have spent a lifetime with electronics and software, so have that advantage

 

[kommando]

Google LG lithium battery recall.

 

[kwaichi]

I looked at Supersolar, some of the cells they use are potential fire hazards, maybe the Hyundai one, too long ago to be sure. I went DIY using LFP cells from Fogstar instead and have no issues.

He is using NMC from LG and I didn't realise it was a whole different chemistry. A bit daft if me but I saw that total lifecycle would be under 4 years for what I'm going to be doing with the system.

 

[kwaichi]

My self build was about £900 cheaper than the full build and also meant I could pick a different BMS and I used the JK PB with 2A balancer and also Canbus closed loop to my Sunny Islands. Build time was 8 hours battery 1, 5 hours battery 2. As the cells come 4 to a box they are liftable and come in a normal courier van, the fully assembled battery is a lot heavier but with wheels.

Did you buy all of the battery equipment from Fogstar or a different source?