How To Choose A Solar Battery
The factors that matter most when choosing a home battery — usable capacity, power, backup, phase, chemistry, warranty and VPP readiness — explained in plain English.
Choosing a home battery is about matching the system to how your household actually uses energy. Here are the factors that matter most, and what each one means for you.
1. Usable capacity (kWh)
Capacity is how much energy the battery stores. Always compare on usable capacity, not the nameplate figure — the usable figure is what you can actually draw after the depth-of-discharge limit. As a starting point, size the battery to cover your evening and overnight use, which is when stored solar is most valuable.
2. Power output (kW)
Power is how much the battery can deliver at any instant. A higher kW rating lets you run more appliances at once from the battery — important for larger or all-electric homes.
3. Single-phase or three-phase
The battery must match your supply. Most homes are single-phase; larger or all-electric homes are often three-phase and need a three-phase system to back up across all phases.
4. Backup capability
If outages matter to you, check whether the system offers whole-home backup or just a few essential circuits, and how fast it switches over (the best systems change over in a few milliseconds, so sensitive devices keep running).
5. Battery chemistry and safety
Most quality home batteries use LFP (lithium iron phosphate) chemistry, prized for thermal stability, safety and long cycle life. Look for relevant safety certifications and an outdoor (IP65/IP66) rating if it will be installed outside.
6. Warranty
A meaningful battery warranty specifies a term in years, an energy throughput limit, and a guaranteed retained capacity at the end of the term (commonly around 70%). Compare all three, not just the headline years.
7. VPP readiness
A Virtual Power Plant (VPP) lets you earn by sharing stored energy back to the grid at peak times — and some rebates require it. Check whether the battery is VPP-ready.
Compare systems
Sunbridge installs CEC-approved batteries from GoodWe, EcoFlow, Bluetti, ESY SUNHOME and Sigenergy. Browse all home battery systems, and we will analyse your bills and usage to recommend the right one.