Does anyone know of a good independent battery storage review and comparison source?

 

Looking for

1. something to install before panels (retrofit something later, money flow),

2. charge at low rates, use during high rates,

3. flexible control (doesn't necessarily have to be simple to use although that's a bonus)

4. Modular so can add storage if required at a later date

5. Preferably not Chinese origin, or US come to think of it ( to be more specific, I dont want any data going their way, so if contains components I'll suck it up)

6. Whole house automatic backup in event of power failure

Edited November 1, 2025Nov 1 by BotusBuild
Clarified point 5

Also very interested in this! 

 

For what it's worth, the Chinese generally make the best and cheapest batteries. They're several years ahead of the West, and even batteries made outside of China... Everything comes from them anyway. 

Clarified OP

GivEnergy AIO. This is AC coupled and in a power cut just continues as if there hasn't been a power cut up to 6kW continuous and I think 7+kW transient. 13.4kW usable power, so really a 15-16kW when comparing.

 

Use mine with Cosy. Morning slot charge to 100%, afternoon slot have set 3 charge slots to make most of any solar and night slot charge again to 100%. All done via GivEnergy app. You can either set your own slots to charge or it has full integration with Octopus, just add your API and the control does the rest.

 

Charge rate is 6kW which is needed after heavy use for the night slot to charge to 100%.

 

My max cost for electricity is Cosy cheapest slots all year round.

The Sigenergy system ticks every box apart from it’s Chinese. 
 

These guys are Austrian 

 

https://www.fronius.com/en-gb/uk/solar-energy/about-us

39 minutes ago, Kelvin said:

The Sigenergy system ticks every box apart from it’s Chinese. 

 

A big negative with them as far as I'm concerned is that they explicitly tell you that if their system can't call-home via the internet it may disable function after a period of time (30 or 90 days). That's unacceptable to me under any circumstance for something you expect to last 10+ years. Who knows if they will still be around then and if not you have a very expensive and heavy paperweight. Cloud connection should be for additional quality of life features. Basic function should always be there and locally manageable.

Im also interested in this thread as Im having (yet) another try at making the battery business case work (so far I haven't been able to).  I have 4kW peak PV, a heat pump and an EV and currently get paid 16.5p for export and pay 7p (midnight-7am) or 26p (7am-midnight) for import.  With the optimisation possible in the absence of a battery, that makes quite a challenge for the battery business case, although its close.

 

Judging by the price on the Midsummer site, Givenergy AIO hardware alone looks expensive compared to quotes I am currently receiving for fully installed systems; Is it worth the extra or are there deep discounts available?

Edited November 1, 2025Nov 1 by JamesPa

11 minutes ago, -rick- said:

 

A big negative with them as far as I'm concerned is that they explicitly tell you that if their system can't call-home via the internet it may disable function after a period of time (30 or 90 days). That's unacceptable to me under any circumstance for something you expect to last 10+ years. Who knows if they will still be around then and if not you have a very expensive and heavy paperweight. Cloud connection should be for additional quality of life features. Basic function should always be there and locally manageable.

You need to update your information on that. Sigenergy have published clarification on what happens after 90 days on no internet connection. 

13 minutes ago, JamesPa said:

Judging by the price on the Midsummer site, Givenergy AIO hardware alone looks expensive

It isn't the cheapest - but for it ticked lots of boxes other system just didn't do when I installed. Main thing is invisible change over in a power cut and the PV string inverters just continuing in a power cut, just as they did with mains available.

3 minutes ago, Kelvin said:

You need to update your information on that. Sigenergy have published clarification on what happens after 90 days on no internet connection. 

And it is?

6 minutes ago, JohnMo said:

And it is?

Was just looking for the pdf. 
 

It enters a safe operating mode so it still works just at a reduced capacity. If they ceased trading then you have different problems just like many of the other systems. 
 

https://www.sigenergy.com/uploads/en_download/1757241630757894.pdf

Edited November 1, 2025Nov 1 by Kelvin

13 minutes ago, Kelvin said:

You need to update your information on that. Sigenergy have published clarification on what happens after 90 days on no internet connection. 

 

Now updated my knowledge: https://www.sigenergy.com/en/support/files/2213

 

It's still reduced functionality 'for your safety'. Struggling to find the reasons for most of the restrictions, most of the justifications I can think of are to limit warranty claims for more extreme cases.

 

Edit to add: other systems don't have such artificial limitations. They claim they may add more functionality in future, but equally they could take stuff away in future if you are limited in what you can do without their involvement.

Edited November 1, 2025Nov 1 by -rick-

It might well be aimed at folk running completely off grid systems with no internet connectivity which means Sigenergy can’t keep the firmware up to date. There’s no way to do it manually. It has MODBUS built in so you can access it and monitor it via Home Assistant. You can also control it but I’ve not tried that so don’t know how comprehensive the control is.  
 

However, the basic function is still there and locally manageable which you highlighted as an issue. The only system access functionality you lose is the AI control.
 

Many  of the current systems rely on some sort of cloud service to manage them. But there are more DiY routes where you aren’t tied the manufacturer. 
 

A slightly more likely scenario is the system is tied to the installer regards some of the configuration options including upgrading it as you can’t do it yourself. If they go bust you have to get Sigenergy to transfer installer control to another company. I don’t know how much of an issue that might be. This is also the case with some other systems though. 
 

 

 

Edited November 1, 2025Nov 1 by Kelvin

47 minutes ago, JamesPa said:

Im also interested in this thread as Im having (yet) another try at making the battery business case work (so far I haven't been able to).  I have 4kW peak PV, a heat pump and an EV and currently get paid 16.5p for export and pay 7p (midnight-7am) or 26p (7am-midnight) for import.  With the optimisation possible in the absence of a battery, that makes quite a challenge for the battery business case, although its close.

 

Judging by the price on the Midsummer site, Givenergy AIO hardware alone looks expensive compared to quotes I am currently receiving for fully installed systems; Is it worth the extra or are there deep discounts available?

You’d need to get installation quotes I think rather than the published online prices as there is some discounting going on going through installers. Certainly in my case the hardware costs from the installers were a bit less than any of the online prices I could find. The problem I had with GivEnergy was I couldn’t get any local installers to quote as they have all dropped it. When I contacted GivEnergy to suggest an installer the nearest one they suggested was Manchester (we’re in Perthshire) so I gave up on them as an option. 

Getting back to the question. There are a huge number of options in the market so finding somewhere that does a broad comparison isn’t straightforward. Some of the installer companies do fairly comprehensive reviews but they tend to focus on the same few brands which is mostly what they sell. These guys are quite active with videos and comparisons for example: 

 

https://www.spiritenergy.co.uk/kb-batteries-residential-solar-energy-storage-overview

 

If you’re not going down the self install route then the first bit of investigation is find installation companies that are relatively close to you and what their feedback is. Narrow that down and that will also narrow down the hardware they are familiar with and will install. This really limited me to Tesla, Fox, SolarEdge and SigEnergy. There were  others that did Duracell and the like but I ruled those out. 

Edited November 1, 2025Nov 1 by Kelvin

15 hours ago, Kelvin said:

These guys are Austrian 

 

https://www.fronius.com/en-gb/uk/solar-energy/about-us

Come across these guys before. Been around a long time, and they make good kit. Locals installer available (Cornwall) so will be in touch with them.

On 01/11/2025 at 21:06, JamesPa said:

I have 4kW peak PV, a heat pump and an EV and currently get paid 16.5p for export and pay 7p (midnight-7am) or 26p (7am-midnight) for import. 

Care to share who your eleccy supplier is?? Those rates look better in all respects than the Octopus Go rates were on!

I am just installing a pretty big system using Victron inverters etc. from EnergyMonkey

7 hours ago, Dillsue said:

Care to share who your eleccy supplier is?? Those rates look better in all respects than the Octopus Go rates were on!

Eon next drive, but locked in Dec 2024 for 12 months so soon to be re-contracted.  There current offer is not as good, but still better than octopus.

Ta. Will have a look

GivEnergy has gone into administration unfortunately. Not clear what this means for customers. 

37 minutes ago, Kelvin said:

GivEnergy has gone into administration unfortunately. Not clear what this means for customers. 

Had an email the other day saying cloud services were now going to charge via a monthly subscription. Sort of raised a warning bell. Will do things other ways, locally via home assistant and or Monitor for GivEnergy Inverter.

59 minutes ago, JohnMo said:

Had an email the other day saying cloud services were now going to charge via a monthly subscription. Sort of raised a warning bell. Will do things other ways, locally via home assistant and or Monitor for GivEnergy Inverter.

I wondered about that too. The software side of it is a separate company apparently. Unclear how that survives if not enough people take up their subscription service. The good thing is it’s completely controllable locally with no phone home requirement. How you get spare parts remains to be seen. Bit of a nightmare for the installers as the responsibility rests with them for the first two years. 

1 hour ago, JohnMo said:

Had an email the other day saying cloud services were now going to charge via a monthly subscription.

 

Does all the normal stuff work without the cloud? Full ability to change configs, etc?

 

This situation is why I'm very dubious of SigEnergy. They seem to be market leading technology wise but they are very cloud dependant and I don't want to put money into a system that could go away/start costing more than expected/lose features.

Bugger. Fingers crossed everything keeps working locally. I can live without the cloud access.