Solar Batteries in Singapore: When They Make Sense (Backup) vs When They Don't (ROI)

Why Batteries Often Don't Improve ROI

No time-of-use tariffs: Singapore has flat residential tariffs. Cost vs benefit: 10–14 kWh battery costs S$15,000–S$25,000 but delivers only S$330–S$580/yr benefit. Payback: 26–75 years.

When Batteries DO Make Sense

Backup power: Critical loads during outages — lights, fans, fridge, Wi-Fi. EV charging: Store solar by day, charge EV at night. Future tariffs: EMA has signalled interest in time-differentiated pricing.

Specs to Look For

Usable capacity: 5–13 kWh for most homes. Round-trip efficiency: Tesla Powerwall 3 achieves ~97.5%. Cycle warranty: 4,000–6,000+ cycles at 70% retention.