I wanted my solar battery installation to give me some protection against rising electricity prices. I also wanted to use greener energy and have a battery that could help keep the house going through power cuts.
The payback will take a considerable time. I knew that before committing to the installation. Peace of mind was a big part of the decision, alongside the financial calculation.
I chose Sigenergy SigenStor, with 15 panels, around 45 kWh of battery storage and a 10 kW inverter. Planning my solar battery installation meant looking at the roof, backup power, outdoor installation and how much control I could have over the system.
If you’re starting your own research, this video gives some context for how solar can reduce your bills. Your own figures will depend on the roof, electricity use, battery and tariff.
Five panels south, ten north
My south-facing roof only had room for five panels, so I filled the available north-facing roof with another ten.
North-facing panels will generally produce less than equivalent south-facing panels. Roof pitch, shading and the season affect the difference, so I wanted realistic expectations about what each roof face would contribute.
The installation cost helped shape that decision. Panels themselves were relatively inexpensive, at under £150 each. Scaffolding and getting people onto the roof accounted for a substantial part of the cost.
Once you’re paying for that access, fitting additional panels becomes a different calculation. Returning later means paying for scaffolding and labour again.
Ask for generation estimates for each roof face separately. Then compare the extra output with the extra cost of fitting the panels while everyone is already there.
Shading, microinverters and optimisers
Panel choice deserves more attention than just comparing wattage.
AIKO’s ABC panels are one example worth looking at where some partial shading is unavoidable. AIKO describes cell-level shade management that allows current to pass through a shaded cell while more of the remaining panel continues generating. It calls this Partial Shading Optimisation. “Cell-level isolation” is a useful shorthand, but there isn’t a separate electronic optimiser attached to every cell. AIKO’s explanation of its shade management
That can reduce the case for adding separate optimisers purely to handle small patches of shade. It doesn’t make the panel immune to shading, and the benefit depends on the exact panel model and shadow pattern.
This panel comparison is worth watching alongside the specifications. I’ve linked it from 4 minutes 47 seconds, the point I wanted to highlight.
There are two other approaches you’ll encounter:
- Microinverters convert DC electricity to AC at each panel, allowing panels to operate independently. They change the system architecture, including how batteries connect. Enphase’s microinverter explanation
- Optimisers manage individual panels’ DC output while retaining a central inverter. They can reduce losses caused by differences between panels, including shading. Tigo’s explanation of optimisation
If trees, chimneys or neighbouring buildings cast substantial moving shadows across the array, these options deserve a proper comparison. They can also offer benefits such as panel-level monitoring, depending on the system.
My advice is to ask the installer to show the expected annual generation with and without the extra equipment. Shade-tolerant panels may be enough for modest shading. More complicated roofs may justify additional hardware, but nothing generates electricity from sunlight that never reaches the panel.
This video looks at the question I’d put to an installer: does your roof actually justify optimisers or microinverters? Ask for the expected benefit on your installation, rather than treating them as an automatic upgrade.
Power Backup close to a UPS
I wanted backup as close as possible to UPS-style behaviour.
A UPS, or uninterruptible power supply, is intended to keep connected equipment running when the mains fails. An EPS, or emergency power supply, can involve an interruption before backup takes over. I wanted to know what those descriptions meant in practice.
How quickly does it switch? Which circuits remain powered? How much can you run?
Sigenergy advertises zero-millisecond load-side disruption when SigenStor is used with the appropriate Energy Gateway. That helped put it on my shortlist. It depends on the complete backup arrangement and installation, rather than simply having a battery. Sigenergy Energy Gateway
You also need to leave energy in the battery. I want to export when prices are attractive while keeping a reserve for power cuts.
Planning an outdoor solar battery installation
I didn’t want the equipment taking up space in the house or garage. Weather protection and winter operation were essential.
SigenStor combines a hybrid inverter with modular, stackable batteries. Sigenergy specifies IP66 protection: a dust-tight enclosure protected against powerful water jets. The equipment still needs a suitable location and installation that follows the manufacturer’s requirements. SigenStor specifications
The batteries also have heating provision. Cold batteries can have charging restrictions, so being able to warm them mattered for an outdoor installation. Heating uses electricity, which needs to appear in the running costs. SigenStor user manual
If you’re comparing battery systems, this video puts Sigenergy alongside Tesla Powerwall 3. For me, outdoor installation, battery heating, backup capability and control were the requirements that shaped the choice.
Sizing my solar battery installation
I chose around 45 kWh because I wanted to import cheap electricity, hold it, and either use it in the house or sell it when export prices were high.
The 10 kW inverter supports that plan. Charging 45 kWh at a steady 10 kW takes 4½ hours on paper. Losses, household demand, temperature and charging limits affect the actual time, but my aim was to charge in just under five hours.
Export power matters too. A high price might only last for a short window, so I wanted to export quickly, within the approved limit for my connection.
Time-of-use and dynamic pricing
Time-of-use tariffs charge different prices depending on when you use electricity. A scheduled tariff might give you a cheaper overnight window and a higher daytime rate. A battery lets you buy during that cheaper window and use the stored electricity later.
Dynamic pricing is a form of time-of-use pricing where the rates themselves change. Octopus Agile, for example, has a different import price every half-hour, linked to wholesale prices. The cheap periods can move around from day to day. Octopus Agile explained
Export can work in the same way. Agile Outgoing pays half-hourly prices, while other tariffs pay a flat rate or use scheduled peak periods. Octopus export tariffs
My view is that dynamic pricing will become more important as export rates come under pressure. It won’t automatically pay more: the useful figure is what you earn across the energy you actually export, after allowing for charging costs and losses.
Home Assistant, Predbat and the car
Home Assistant control was a key requirement for my solar battery installation. I wanted to decide when to charge and export, with the battery working alongside the other equipment in the house.
Predbat uses electricity prices, solar forecasts and predicted household demand to plan battery charging and discharging. It has documented Sigenergy support, although the integration and configuration need setting up properly. Predbat documentation
Home Assistant also lets me control my Hypervolt charger. I don’t want the car draining the battery I’m keeping for the house.
“Solar charging” needs care with a hybrid inverter. The panels and battery connect on the DC side, while a normal AC current transformer, or CT clamp, sees their combined output. It can’t distinguish solar generation from battery discharge.
Hypervolt confirms that limitation and says a second CT should not be fitted for that purpose with a hybrid inverter. It also documents battery protection for the Home 3 Pro, so the options depend on your charger model and configuration. Hypervolt’s hybrid inverter guidance
For my setup, Home Assistant gives me the information and control to coordinate charging.
I’ve also written about using smart plugs to reduce energy consumption, including what happened when the plugs stopped switching reliably. Automation still depends on the equipment doing what you expect.
Warranty cover for a solar battery installation
My batteries have a ten-year warranty and the Gateway has five years.
The BAT 10.0 also has a performance warranty. Sigenergy’s European document specifies at least 60% retained usable energy for ten years or until the stated throughput limit is reached, whichever comes first.
It lists 8.76 kWh usable energy and 30.66 MWh warranted throughput per BAT 10.0 module. Those are the warranty’s figures; the model name doesn’t mean 10 kWh of usable storage.
Internet connectivity is a condition too. The document says more than one year of cumulative disconnection reduces cover to five years. Covered repair labour is included, but on-site travel and accommodation are excluded unless agreed otherwise. Sigenergy European warranty, May 2025
If you plan to cycle the batteries regularly, read the throughput terms. Check the panel product and output warranties, inverter cover and installer’s workmanship warranty too.
Practical tips for a solar battery installation
- Specify Ethernet. Include a wired network connection in the installation plan, especially for outdoor equipment controlled through Home Assistant.
- Get a shading assessment. Ask about winter shadows, trees and the exact panel model’s shade handling. Request figures to justify optimisers or microinverters.
- Check usable storage and charging power. Battery capacity, inverter power and the approved export limit are different figures. Ask how much energy you can actually move during your tariff’s cheap or expensive windows.
- Agree the backup arrangement. Get the protected circuits, power limits and reserve settings documented, and ask for a demonstrated changeover test.
- Confirm automation access. Have the installer enable and demonstrate the controls your Home Assistant integration needs before handover.
- Plan the paperwork. Ask who submits the connection and export documents, what you’ll receive, and what remains outstanding.
- Measure the overheads. Keep your pre-installation consumption figures and compare them with consistent measurements afterwards.
That last point is still live for me. My overall energy use appears around 20% higher than before. I’m challenging it with the installers because it seems high.
Conversion losses, running the equipment and battery heating consume energy. I want to understand their contribution and whether the measurements are comparable. Allow headroom in your budget, but don’t assume 20% is normal for every installation.
This is another useful video to watch before agreeing an installation. Use it to build your list of questions, then get the answers for the equipment and design you’re being quoted.
Channels that helped me
YouTube helped me understand the options and work out what to ask. These are some of the channels I found useful:
I’d use them to inform your questions, then get answers for your own roof, usage and installation.
Where I am now
I’m waiting for Octopus Energy to process my export paperwork before I can start trading. I also want an explanation for the extra consumption.
Higher electricity prices could shorten the payback, although tariffs, generation, losses and battery use will all affect it. I went into this knowing it was a long-term purchase.
Generating some of my own electricity, choosing when to buy it and having backup for power cuts all have value to me. The peace of mind is a big part of why I installed the system.
Tell me what you think in the comments below or on X @timdixon82
