How to Compare Battery Systems
A comprehensive guide to evaluating batteries beyond price and capacity
1. Manufacturer Tenure in Australia
Most Important Factor. How long has the manufacturer been selling in Australia? This determines warranty reliability and support availability.
2. Usable Capacity vs Rated Capacity
Don't be fooled by headline numbers. A "13.5 kWh" battery may only have 12 kWh usable.
Example:
- • Battery A: 13.5 kWh rated, 12.2 kWh usable (90%)
- • Battery B: 15.0 kWh rated, 12.0 kWh usable (80%)
- → Battery A gives you MORE usable energy
3. Warranty Terms (Not Just Length)
A 10-year warranty means nothing if the company isn't here in 10 years. Check the fine print.
Key Questions:
- • Is warranty backed by Australian entity or overseas parent?
- • Does warranty cover labor or parts only?
- • What's the degradation threshold? (70%? 80%?)
- • Are there cycle limits? (e.g., 4,000 cycles in 10 years)
4. Total Cost of Ownership
Cheapest upfront ≠ best value. Factor in warranty costs, efficiency losses, and replacement risk.
10-Year Cost Example:
Budget Battery (New Brand)
- • Lower initial purchase price
- • Estimated service calls: +25% of purchase
- • Early replacement risk (year 7): +100%
- = 225% of initial investment
Premium Battery (Established Brand)
- • Higher initial purchase price
- • Service calls: Covered under warranty
- • Replacement: Not needed in 10 years
- = 100% of initial investment
5. Chemistry: LFP vs NMC
Battery chemistry affects lifespan, safety, and performance.
LFP (Lithium Iron Phosphate)
- • Longer lifespan (6,000-10,000 cycles)
- • Safer chemistry
- • Better in hot climates (Perth!)
- • Slightly lower energy density
NMC (Nickel Manganese Cobalt)
- • Higher energy density
- • Shorter lifespan (3,000-5,000 cycles)
- • More temperature sensitive
- • Common in Tesla systems
6. Local Support Network
Does the manufacturer have Australian offices, service partners, and parts inventory?
Check for:
- • Australian head office location
- • Number of certified installers in WA
- • Parts warehouse in Australia (not just shipping from overseas)
- • Local customer support phone number
7. Inverter Compatibility
AC-coupled or DC-coupled? This affects installation cost and system flexibility.
AC-Coupled (easier retrofit): Works with existing solar. More expensive but flexible.
DC-Coupled (more efficient): Requires hybrid inverter. Better for new installs.
Compare Batteries with These Factors Built-In
Our comparison tools automatically factor in manufacturer tenure, warranty quality, and total cost of ownership - not just headline specs.