top of page


Your guide to Solar Battery Storage

Solar Battery Storage

Solar Star Power is an MCS Approved battery installer, in addition to solar PV accreditation.

Please get in touch for a free survey and discuss options for a solar panel and/or battery: Tesla, Solax, eCactus, GivEnergy installation.


Rebates are now available for Tesla Powerwalls installed between 11 August and 31 December 2023, read more here.

Electricity is stored as DC (Direct Current) and there are two basic methods of converting solar electricity for storage.

The first method is to simply feed DC electricity directly from the solar array into the battery and then use the existing DC – AC solar inverter to convert the solar power for household use as required. This type of inverter is called a Hybrid, the advantage being that it is cheaper to use than a single inverter. The downside is that if you already have a solar system installed the current inverter will require changing. However, if you are having a new solar system fitted or changing an old inverter this makes perfect financial sense.

The second method is an AC side connection which in effect is a complete battery storage system totally separate from the solar array and more expensive because a second inverter is required. If you have a Solar Edge optimized system fitted, then this will require an AC side connection as the Solar Edge inverters cannot be exchanged. Also, if you are contemplating storing electricity from the grid at cheap overnight rates this will also require an AC side connection.

An AC side connected battery will discharge at a higher rate than a DC side battery, plus it

can be charged from the mains using an overnight cheap rate if required.

The next thing to consider is storage capacity and whilst batteries come in many sizes the

average household will require a 6 – 10 kWh (Kilowatt Hour) storage battery. As an example,

the average hot water kettle uses 2kW per hour, so a 6kWh battery would continuously

boil a kettle for 3 hours.


We supply and install a variety of battery types:

The SOLAX 5.8 kWh 

Solax AC side connected (can be retrofitted):

  • 5.8kWh                Discharge rate 3.68kWp                 £4,523.43

  • 5.8kWh                Second unit retro fitted                  £3,202.25

  • 11.6kWh              Discharge rate 5.00kWp                 £7,510.97 (two x 5.8kWh)

  • 17.4kWh              Discharge rate 5.00kWp                 £9,836.05 (three x 5.8kWh)

  • 17.4kWh              Three Phase Sysstem                     £10,959.05 (three x 5.8kWh 3-phase inverter)


The Solax Hybrid DC side connected Tri Power can only be fitted to new installations. 5.8kWh,

with a discharge rate of 5kWp, priced at £5,125.20 fully fitted.

Features: Overnight cheap rate charging capability. Ten-year Solax manufacturers warranty.

GivEnergy Hybrid 8.2kWh

DC side connected (can only be fitted to new installations)

  • 5.2kWh               Discharge rate 3.6kWp                    £3,714.92

  • 9.5kWh               Discharge rate 5.0kWp                    £5,845.70

Features: Overnight cheap rate charging capability. GivEnergy has recently made a major announcement: introducing an industry leading 12-year warranty.

GivEnergy AC side connected All in One Gateway (can be retro-fitted)

  • 13.5kWh            Discharge rate 6.0kWp with back-up gateway      £7,831.39

Features: Automatic back-up in case of grid failure. Overnight cheap rate charging

capability with automatic artificial intelligence. Alternative to Tesla Powewall with a 

12-year warranty.


A manual changeover switch, will provide electricity during a power cut to the

above batteries and is priced at £485.

E Cactus Hybrid DC Side Connected

  • Agave - SH   5.12kWh        Discharge rate 3.68kWp          £3,996.00    

  • Agave - SH  10.24kWh       Discharge rate 5.0kWp            £6,257.25

Features: Overnight cheap rate ccharging capability

Solax 2_edited.jpg

The TESLA Powerwall 

The first battery is priced at £8,272.80 including gateway and installation. 

The Powerwall has the advantage of high-capacity storage (13.4kWh) plus

off grid capability.  Discharge rate is 5kW, 7kW at peak.


Additional Powerwalls are priced at £7,221.60, up to a maximum of six on

a single-phase supply. Purchasing two Tesla Powerwalls at the same time would cost £14,868.00.

Tesla Powerwalls x 3
Tesla Powerwall Storage Batteries

Features: Automatic back-up in case of grid failure. Ten-year warranty from Tesla Motors. Overnight cheap rate charging with automatic artificial intelligence.

Please have a look at our latest Trust Pilot reviews, from our happy customers.

*** Limited time offer from Tesla! ***

If you have your Tesla Powerwall installed between 11 August and 31 December, you can claim £350 back directly from Tesla

There are several other battery packs on the market, and we will be pleased to quote for these however some are composed of batteries and controllers from different suppliers, and this can cause issues with warranty of work. We feel it better to source a complete package from one manufacturer.

Whilst the main usage of a battery would be at night-time when the solar system is not functioning, they can also work during the day to smooth out peak usage or when the sun goes behind a cloud. Once the roll out of smart meters is almost complete the electricity suppliers intend to introduce varied pricing bands throughout the day and again the battery systems will help to smooth the costly peak bands.


"Dear David 

Just a little bit of feedback from the 2 extra Powerwalls that have finally been added to my system. 

As I expected (and was the case with the original install), your team were nothing but courteous, professional and meticulous. I mean, they even vacuumed the area of the garage where they’d been working! 

The Powerwall system is working perfectly. The first “Off Grid” test resulted in circuit breakers tripping and a few shenanigans, but all breakers were swiftly replaced, and everything seems to be working perfectly. 

Top quality service! "


bottom of page