Home Battery Storage From Local Council (Growatt)

[InventEd]

My local council (Horsham West Sussex) has a system of offering (allegedly) discounted home battery storage solutions. I am keen to get this as I have both solar panels and cheap night time electricity (Go). They offer a 12.3Kw system called a Growatt GBLI6532 for £5680. It is 2x 6.5Kw batteries and 1x 3Kw AC Inverter

Anybody advise if this is

a) A reasonable price. Seams a lot less then a Tesla Powerwall
b) Know anything of this manufacturer
c) Experience of these local council schemes

Open to advice on other systems anyone recommends.

 

[Dilly]

Sorry, I know nothing about Growatt but my advice would be to take note of charge/discharge rates.
a single Powerwall will give out about 3kWh depending on the model. This is ok unless you’ve cooking in the evening and put a 3KW kettle on. Then you’re drawing the excess from the grid at peak rate.
Ideally a 5KWh minimum is more useful.
I’d also also ask if further battery packs can be added in the future. You may find as I did, that 12kWh isn’t quite enough

 

[Burley]

Powerwall discharge rate is software restricted to 3.7kW if you have a lower power connection to the grid (i.e. your invertor is also 3.7kW) - it allows for faster processing when you apply to the DNO. It can be unlocked to 5kW constant with a 7kW peak, provided the DNO has approved the higher rate. It does seem odd to me that the Powerwall is seen as a generator when it doesn't send power back to the grid, but there you are..

@InventEd the price you've quoted it very competitive compared to the Powerwall, but it would be worth finding out how controllable the system is. i.e. can you set it up to know when your lower rate is and for it to charge during this period when sunlight levels have been or are forecast to be lower? etc..

 

[ACarneiro]

Powerwall discharge rate is software restricted to 3.7kW if you have a lower power connection to the grid (i.e. your invertor is also 3.7kW) - it allows for faster processing when you apply to the DNO. It can be unlocked to 5kW constant with a 7kW peak, provided the DNO has approved the higher rate. It does seem odd to me that the Powerwall is seen as a generator when it doesn't send power back to the grid, but there you are..

@InventEd the price you've quoted it very competitive compared to the Powerwall, but it would be worth finding out how controllable the system is. i.e. can you set it up to know when your lower rate is and for it to charge during this period when sunlight levels have been or are forecast to be lower? etc..

It does seem a bit silly but then I remember that it CAN be configured to send power back to the grid "à lá Tesla Energy Plan" so maybe that's why the DNOs get upset about it. It does seem like despite all the talk and virtue signalling the DNOs aren't really serious about incentivising micro generation...

 

[InventEd]

Powerwall discharge rate is software restricted to 3.7kW if you have a lower power connection to the grid (i.e. your invertor is also 3.7kW) - it allows for faster processing when you apply to the DNO. It can be unlocked to 5kW constant with a 7kW peak, provided the DNO has approved the higher rate. It does seem odd to me that the Powerwall is seen as a generator when it doesn't send power back to the grid, but there you are..

@InventEd the price you've quoted it very competitive compared to the Powerwall, but it would be worth finding out how controllable the system is. i.e. can you set it up to know when your lower rate is and for it to charge during this period when sunlight levels have been or are forecast to be lower? etc..

Thanks. I will ask as they have not detailed much yet. For example I cant find the loses in the system from charge/discharge.

 

[Dilly]

I guess the other thing worth mentioning is the Powerwall’s ability to operate during a power cut via it’s backup gateway.
In a normal power cut scenario, most batteries will shut down as will any solar panels. With a Powerwall, it all just keeps going.

 

[MrBadger]

You can get ~7kWh (configurable in approx 2.4kWh chunks for around £800) battery storage for ~£3k plus install - all but final electrical connection is a DIY job for many - electrical connection requires DNO approval and some tests from a qualified electrician.

It won’t give you whole house backup but most people don’t have enough power outages to worry too much about. It won’t offset 100% of your electricity needs either but neither will a system costing twice that or more unless you have a second source of renewable energy.

5k for a growatt sounds a lot to me even if it’s 12kWh - ask if you need a battery that big. A much smaller system may still cover a very large proportion of your needs and give a much higher cost/benefit ratio.

I use to keep up with these things years a go but I think it was growatt who were using old battery tech that was causing issues if deep discharged. You would need to check what batteries they use now - I would like to think it’s now lithium in some form.

If you are looking for financial justification, the thing with batteries is that they have a finite useful life which you can work out the lifetime usable kWh. It’s that which governs the potential electricity savings if you want to do any financial calculations - many people assume infinite life of battery which is not the case. You may find that usable battery life may be equates to 30000kWh - quick reality check but if you can save/make 10p per kWh for every one of those units, you are only talking 3k in savings - pre recent electricity price rises but you get the idea. That’s why I configured my system to the size I did - I could have gone much bigger by simply adding more £800 batteries in 2.4kWh chunks but financial payback for my usage patterns was just not there. It also means that I can achieve a large self use ratio for my solar generation for a large proportion of the year.

 

[gangzoom]

5k for a growatt sounds a lot to me even if it’s 12kWh - ask if you need a battery that big. A much smaller system may still cover a very large proportion of your needs and give a much higher cost/benefit ratio.

A PowerWall is pretty much £10K+ installed for same capacity, if its £5K including professional installations its a bargain!

 

[InventEd]

You can get ~7kWh (configurable in approx 2.4kWh chunks for around £800) battery storage for ~£3k plus install - all but final electrical connection is a DIY job for many - electrical connection requires DNO approval and some tests from a qualified electrician.

It won’t give you whole house backup but most people don’t have enough power outages to worry too much about. It won’t offset 100% of your electricity needs either but neither will a system costing twice that or more unless you have a second source of renewable energy.

5k for a growatt sounds a lot to me even if it’s 12kWh - ask if you need a battery that big. A much smaller system may still cover a very large proportion of your needs and give a much higher cost/benefit ratio.

I use to keep up with these things years a go but I think it was growatt who were using old battery tech that was causing issues if deep discharged. You would need to check what batteries they use now - I would like to think it’s now lithium in some form.

If you are looking for financial justification, the thing with batteries is that they have a finite useful life which you can work out the lifetime usable kWh. It’s that which governs the potential electricity savings if you want to do any financial calculations - many people assume infinite life of battery which is not the case. You may find that usable battery life may be equates to 30000kWh - quick reality check but if you can save/make 10p per kWh for every one of those units, you are only talking 3k in savings - pre recent electricity price rises but you get the idea. That’s why I configured my system to the size I did - I could have gone much bigger by simply adding more £800 batteries in 2.4kWh chunks but financial payback for my usage patterns was just not there. It also means that I can achieve a large self use ratio for my solar generation for a large proportion of the year.

Thanks for the advice. I appreciate the economics are hard to justify.

They offer several sizes. 6kw is £3,509. Seamed £2k for double the capacity could be good - but to your point maybe I will never use it if the battery can’t actually sustain the power demands in the evening. Induction job, oven, tv, computers, lights….

 

[kriscii]

Thanks for the advice. I appreciate the economics are hard to justify.

They offer several sizes. 6kw is £3,509. Seamed £2k for double the capacity could be good - but to your point maybe I will never use it if the battery can’t actually sustain the power demands in the evening. Induction job, oven, tv, computers, lights….

If you don't mind spending something up front (~£160) get a emonPi: emonPi Energy Monitor It will give you a great insight into how you use power unlike most smart meters.

It is very easy to install just connect a CT Clamp on the main feed near the meter. You see your usage profile through the day and how much power you might need.

I use about 500-600w constantly 24/7 with peaks of around 2-4kw for cooking etc. I have a single 2.4kWh Pylontech battery which I charge with Solar during the day. It gives ~300w for 3-3.5hrs when "fully charged" that is 90% max charge and discharges to 20% which is the recommendation from the installer.

You get a graph like this the yellow/paler blue is the solar generation which you won't have and the flat pale blue part from about 19:30 is the battery discharging. The big usage peak at 00:30 is the car topping up on the Octopus Go.

Cheers
Chris

 

[Cilonen]

Growatt Battery Storage | Solar Battery Installers | Deege Solar

With a wide range of Inverters and Solar Batteries, you can always rely on Growatt for your Residential and Commercial Solar PV needs.

www.deegesolar.co.uk

https://deegesolar.co.uk/wp-content/uploads/2021/02/Growatt_6.5_Solar_Battery_Storage_And_Controller.pdf

Indicates peak discharge 4.2kW, with 5kW for max 3sec. Up to 8 batteries on a single inverter.

 

[btc1k]

My local council (Horsham West Sussex) has a system of offering (allegedly) discounted home battery storage solutions. I am keen to get this as I have both solar panels and cheap night time electricity (Go). They offer a 12.3Kw system called a Growatt GBLI6532 for £5680. It is 2x 6.5Kw batteries and 1x 3Kw AC Inverter

Anybody advise if this is

a) A reasonable price. Seams a lot less then a Tesla Powerwall
b) Know anything of this manufacturer
c) Experience of these local council schemes

Open to advice on other systems anyone recommends.

Did you end up going for this?

 

[Battpower]

the DNOs aren't really serious about incentivising micro generation.

smaller system may still cover a very large proportion of your needs and give a much higher cost/benefit ratio.

These points match my experience too.

Chasing zero daytime grid consumption is most often pointless other that knowing you can do it.

Putting even a small buffer battery on a PV system can earn its keep quite easily.

 

[kriscii]

I have one battery (2.4kWh) which I charge in the Octopus Go on the overnight rate if you look at the graph you can see the car and the battery charging until about 3am. then at 4.30 the battery starts discharging and covers me until 8.30 ish then the sun came out and covered my most of my usage and charged the batterry with the spare until 17:45 when the sun and latter the battery ran out. I've considered another battery or 2 but I'm looking to move later this year so didn't want the wasted investment or hassle of disconnecting and taking them with me.