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
| Load | Power (W) | Hours (5PM-7AM) | Energy (Wh) |
|---|---|---|---|
| Air conditioning (2 bedrooms) | 1,800 | 10 | 18,000 |
| Refrigerator | 100 | 14 | 1,400 |
| LED lighting | 80 | 6 | 480 |
| TV and entertainment | 150 | 4 | 600 |
| Router and electronics | 50 | 14 | 700 |
| Total | 21,180 Wh (21.2 kWh) |
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:
| Scenario | Target Energy | BOS-G5.1 Units | Total Capacity |
|---|---|---|---|
| A: Self-consumption | 5-10 kWh | 2-3 units | 10.2-15.4 kWh |
| B: Evening coverage | 10-15 kWh | 3-4 units | 15.4-20.5 kWh |
| C: Full overnight | 20-25 kWh | 6-7 units | 30.7-35.8 kWh |
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
| Configuration | Cost (AED) | Annual Savings | Payback Addition |
|---|---|---|---|
| 2x BOS-G5.1 (10.2 kWh) | 8,000-12,000 | 1,500-2,500 | 4-6 years |
| 4x BOS-G5.1 (20.5 kWh) | 16,000-22,000 | 3,000-4,500 | 4-6 years |
| 6x BOS-G5.1 (30.7 kWh) | 24,000-32,000 | 4,500-6,500 | 4-6 years |
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%
Frequently Asked Questions
How much battery storage for a UAE villa?
A typical UAE villa needs 10-15 kWh for evening coverage (5 PM to midnight) or 20-25 kWh for full overnight backup with AC. This equals 3-4 Deye BOS-G5.1 units for evening or 6-7 for full overnight.
Can I add more batteries later?
Yes, Deye BOS-G batteries can be added at any time. Connect in parallel via CAN bus and update the capacity setting. The BMS automatically balances charge across all units.
Is battery storage worth it in the UAE?
Battery storage adds 4-6 years to payback with AED 1,500-6,500 annual savings. Value increases with backup power needs and as time-of-use tariffs expand. Starting small and expanding is a practical approach.
