Solar Battery Sizing Guide — UAE

Adding battery storage to your solar system transforms it from a daytime-only generator into a round-the-clock energy solution. In the UAE, battery sizing balances three goals: maximising solar self-consumption, providing backup during outages, and achieving a reasonable return on investment.

Why Add Battery Storage?

• Self-consumption: Store surplus solar for evening use when electricity is most expensive
• Backup power: Keep critical loads running during grid outages
• Peak shaving: Reduce grid imports during high-tariff hours
• Future-proofing: As time-of-use tariffs expand, stored solar becomes more valuable

Step 1: Evening and Night Consumption

Step 2: Choose Your Storage Goal

Scenario A: Self-Consumption Optimisation (5-10 kWh)

Store surplus for 3-4 hours after sunset. Covers lighting, electronics, partial AC.

Scenario B: Evening Coverage (10-15 kWh)

All evening loads until midnight, then grid takes over.

Scenario C: Full Overnight Backup (20-25 kWh)

Power all nighttime loads from sunset to sunrise.

Step 3: Calculate Usable Capacity

Required nameplate = Target energy / (DoD x Round-trip efficiency x Inverter efficiency)

Example (Scenario B): 12 kWh / (0.80 x 0.95 x 0.96) = 16.4 kWh nameplate

Step 4: Select Battery Configuration

Deye BOS-G5.1 provides 5.12 kWh per unit:

Step 5: Verify Inverter Compatibility

All Deye hybrid inverters (SUN-5K, SUN-8K, SUN-12K) support up to 16 parallel BOS-G batteries (81.9 kWh) via CAN bus with automatic charge management and cell balancing.

Cost and ROI

Pro Tips for UAE

• Start small, expand later: BOS-G batteries can be added to existing systems at any time
• Prioritise AC backup: Air conditioning is 60-70% of consumption — size for that if backup is the goal
• Seasonal variation: Summer AC usage is 2-3x winter — size for average unless backup is critical
• Install indoors: Air-conditioned or ventilated indoor location extends battery life 30-50%