If you’re considering installing solar panels and battery storage at your home, you might feel overwhelmed by all the technical terms and equipment. Inverters, isolators, optimisers, battery sizing, G99 applications… where do you start?
In this beginner’s guide, we’ll walk you through each part of a modern solar PV system in plain English, helping you make smart decisions and avoid costly mistakes when it’s time to invest in renewable energy.
Key Components of a Solar PV System
1. Solar Panels
Mounted on your roof, these are the workhorses of your system, capturing sunlight and generating DC (direct current) electricity. While you won’t see them much after installation, their size, number, and placement are key to system performance.
💡 Tip: Once the scaffolding’s up, add as many panels as your roof (and budget) allows. The extra cost is usually minimal.
2. Inverter
Your home runs on AC (alternating current), so the inverter converts the solar DC electricity into usable AC power. It’s the “brain” of your solar setup and plays a major role in efficiency, smart charging, and grid interaction.
Main types of inverters:
- String Inverter: Basic, no battery storage support.
- Hybrid Inverter: Handles solar & battery charging.
- AC Coupled Inverter: Ideal for retrofitting batteries to existing systems.
- All-in-One Inverter: Combines battery and inverter (e.g. Tesla Powerwall 3).
💡 Ask your installer: Can the inverter charge from cheap night rates?
3. Battery Storage
Store excess energy during the day to use at night, or buy cheap electricity overnight (as low as 7p/kWh) and use it later. Choosing the right battery size is critical.
How to size your battery:
- Find your yearly usage (from your bill).
- Divide by 365 for daily use.
- Aim for a battery size close to your average daily usage.
🔁 Good to know: Some brands (like GivEnergy) offer stackable batteries you can expand later.
4. Isolators & Fuse Boards
Safety first. Isolators allow safe shutdown during maintenance. Fuse boards (existing or additional) protect your system and your home.
5. Optimisers & Monitoring Devices
If your panels face shading from chimneys or trees, optimisers can help by letting shaded panels “turn off” without affecting the rest of the system.
Paired with cloud-connected monitoring tools, you can see exactly how each panel performs and identify issues instantly.
Battery Tech 101: What to Ask
Battery Warranties and Cycles
Some batteries have limits on how often they can be charged and discharged (called “cycles”). For example, a 5,000-cycle limit could be used up in just a few years if you cycle the battery twice daily.
🔍 Look for:
- A long warranty with unlimited cycles, or
- Clear throughput terms like GivEnergy’s 10MWh per kWh capacity.
Depth of Discharge (DOD)
This determines how much of the battery’s capacity is actually usable.
- 100% DOD = full access
- 80% DOD on a 10kWh battery = only 8kWh usable
Location, Location, Location
Where should your battery and inverter go?
- Avoid attics (awkward, hard to access, not ideal for fire safety)
- Ideal locations: garage, exterior wall, or ground-level utility space
- Must be 1 metre away from windows, doors, or escape routes
🔒 Check the IP rating (ingress protection) to ensure it’s weatherproof if mounted outdoors.
G98, G99, G100 – What Do These Mean?
These are grid connection applications based on system size:
| Type | Max Size | Key Info |
|---|---|---|
| G98 | ≤3.68kW | Quick, install-first approach (fit and notify) |
| G99 | >3.68kW–50kW | Requires approval before install |
| G100 | Export-limited | Used when your DNO restricts how much you can export |
📬 Pro tip: You can challenge low export offers from your DNO – ask your installer to push back.
Where Should You Spend Your Money?
- Panels: Add as many as possible within reason – it’s a one-time opportunity once scaffolding is up.
- Inverter: Choose a reliable brand with smart charging features and UK-based support.
- Battery: Start with a smaller unit and expand later if needed.
🚨 Avoid mismatching brands: Mixing inverter and battery manufacturers may invalidate your warranty if things go wrong.
Final Takeaways: What to Ask Your Installer
- Is the inverter compatible with time-of-use tariffs?
- What’s the warranty on the battery (years + cycle count)?
- Can I expand the battery system later?
- Is export limited (G98/G99/G100)?
- Where will the system components be located?
- How much experience do you have with the brands quoted, and do they offer UK-based support?
Ready to Make the Switch?
Solar PV systems are one of the smartest long-term investments UK homeowners can make. With the right setup and guidance, you’ll reduce your bills, increase your independence from the grid, and protect your home against rising energy prices.
Still got questions? Browse our other guides or get in touch for personalised advice.
