Question 1

How many kWh battery do I need to run 1.5T AC overnight for 8 hours?

Accepted Answer

A 1.5T 5-star inverter AC draws ~1.15 kW on average. For 8 hours, you need 9.2 kWh of usable energy. With LiFePO4 (80% DoD), install 11.5 kWh. With lead acid (50% DoD), install 18.4 kWh. A 10 kWh LiFePO4 pack is the most practical choice for one 1.5T overnight.

Question 2

Can a solar system charge the battery and run AC simultaneously?

Accepted Answer

Yes, with a hybrid solar inverter (like Growatt, Solis, Deye). During daytime, solar charges the battery AND runs AC directly. At night, the battery powers AC. A 3–5 kW solar + 10 kWh battery is the standard setup for 1–2 ACs in Indian power-cut areas.

Question 3

What is DoD (Depth of Discharge) and why does it matter?

Accepted Answer

DoD is the percentage of battery capacity you can safely use. LiFePO4 allows 80% DoD — so a 10 kWh battery gives 8 kWh usable. Lead acid allows only 50% — same 10 kWh gives only 5 kWh usable. Exceeding DoD drastically shortens battery life.

Question 4

How long does a battery last for daily AC backup use?

Accepted Answer

LiFePO4 lasts 3000–5000 cycles at 80% DoD, roughly 8–13 years at one cycle/day. Lead acid lasts 500–800 cycles at 50% DoD, roughly 1.5–2.5 years with daily use. For areas with daily power cuts, LiFePO4 is far more economical over 10 years.

Question 5

Is a 5 kWh battery enough for 1 AC overnight?

Accepted Answer

Depends on tonnage and hours. A 5 kWh LiFePO4 (4 kWh usable) runs a 1T 5-star inverter AC (~850W) for ~4.7 hours. For 8 hours, you need at least 8 kWh usable — so 10 kWh LiFePO4 or 16 kWh lead acid. Use our calculator above for your exact AC.

Question 6

What inverter do I need to run an AC from battery?

Accepted Answer

You need a pure sine wave solar inverter with battery support. For 1–2 ACs up to 3 kW total load, a 5 kVA hybrid inverter (like Growatt 5000-ES or Deye 5kW) is standard. Make sure the inverter supports your battery voltage (48V is most common for 5–15 kWh systems).

Question 7

Does adding more ACs linearly reduce backup time?

Accepted Answer

Yes, exactly. If 1 AC gives 8 hours, 2 identical ACs give 4 hours from the same battery. Battery capacity needed scales proportionally with load. Running multiple ACs overnight requires significantly larger battery banks — our calculator shows the exact math.

Question 8

What about PM Surya Ghar subsidy for battery systems?

Accepted Answer

PM Surya Ghar subsidy (up to ₹78,000) applies to grid-tied solar systems without batteries. Off-grid and hybrid systems with batteries may qualify for partial benefits depending on state government schemes. Check your state DISCOM for battery-inclusive subsidy eligibility.

AC Setup	Total Load	LiFePO4 Need (80% DoD)	Lead Acid Need (50% DoD)	5kWh Battery	10kWh Battery	Scenario
0.75T 5★ Inverter, 1 AC	650W	6.5 kWh	10.4 kWh	6.2 hrs	12.0 hrs	Small Room
1T 5★ Inverter, 1 AC	850W	8.5 kWh	13.6 kWh	4.7 hrs	9.4 hrs	Bedroom
1.5T 5★ Inverter, 1 AC	1150W	11.5 kWh	18.4 kWh	3.5 hrs	7.0 hrs	Most Popular
1.5T 3★ Inverter, 1 AC	1400W	14.0 kWh	22.4 kWh	2.9 hrs	5.7 hrs	Common
2T 5★ Inverter, 1 AC	1550W	15.5 kWh	24.8 kWh	2.6 hrs	5.2 hrs	Living Room
1.5T 5★, 2 ACs	2300W	23.0 kWh	36.8 kWh	1.7 hrs	3.5 hrs	2-Room Home
1.5T 5★, 3 ACs	3450W	34.5 kWh	55.2 kWh	1.2 hrs	2.3 hrs	Large Home
1T + 1.5T 5★ Mix, 2 ACs	2000W	20.0 kWh	32.0 kWh	2.0 hrs	4.0 hrs	Typical Home

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