Quick Picks for Inverter-Type 2HP AC

Runtime depends on the battery bank, not just the inverter. Every row below carries the matching battery and runtime guidance, calculated using 80 percent depth of discharge for GEL batteries and 85 percent inverter efficiency, the values that match real Nigerian operating conditions.

If you have been searching for the right inverter to back up your 2HP AC, you have probably already noticed that most generic answers do not help. “Use a 5kVA” or “you need 7.5kVA” does not survive contact with a real Nigerian buyer, because the answer depends on whether your AC has a variable-speed compressor or a fixed-speed one. Get this wrong and the inverter trips on every startup attempt. This guide gives you the honest sizing, the right battery bank, the realistic runtime, and the petrol cost the inverter will spare you. If you want the formula yourself, our battery runtime calculator walks through every step.

“Inverter AC” vs. Running AC on an Inverter: The Key Confusion

If you own an LG, Hisense, or Samsung AC with the word “inverter” on the unit, you may have assumed it already handles battery backup. It does not. This is the single most expensive misunderstanding in the Nigerian power market, and it causes people to buy undersized inverters that trip immediately.

• What “inverter AC” does NOT mean: It does not mean the AC runs on battery backup when NEPA takes light. The label refers only to how the internal compressor motor works, not to backup power.
• What “inverter AC” actually means: An inverter-type AC has a variable-frequency drive (VFD) that speeds the compressor up or down based on how cool the room is. It uses less electricity and starts up gently, which is the key advantage for backup power.
• Why this matters for sizing: An inverter-type AC requires a much smaller and cheaper backup inverter because its startup surge is 70 to 80 percent lower than a standard fixed-speed AC.

To run any air conditioner during a NEPA outage, you need a separate battery inverter system regardless of what type of AC you have. Your “LG Inverter AC” label describes the compressor technology; your Mercury battery inverter is what keeps the AC running during NEPA outages. You need both, and they work together, but one does not replace the other. If you are new to all of this, our inverter buying guide for Nigeria walks through the categories from the start.

What Does 2HP Actually Mean for Nigerian AC Buyers?

Horsepower is a legacy label from when compressors were described by the motor shaft power they produced. In the Nigerian retail market, “2HP” maps loosely to 1.5 tons in the international BTU system, which means approximately 18,000 BTU of cooling capacity. Some sellers label the same unit as “2HP” or “1.5-ton” interchangeably.

The practical implication: a 2HP AC is one of the most common sizes in Nigerian master bedrooms and smaller offices. It draws meaningfully more power than a 1.5HP unit, which means inverter sizing cannot be copied directly from the 1.5HP inverter sizing guide you may have already read.

2HP AC Power Requirements: The Numbers That Determine Your Inverter Size

The startup surge is what kills undersized inverters. AC compressors do not start gently, they draw a large spike of current in the first second of operation as the motor overcomes static friction and pressurises the refrigerant circuit. Your inverter must survive this spike, not just the steady running load.

Inverter-Type (Variable-Speed) 2HP AC

Standard (Fixed-Speed) 2HP AC

• Why modified sine wave destroys ACs: Every air conditioner, inverter-type or standard, requires pure sine wave power. Modified sine wave produces a stepped waveform that causes the compressor motor to draw excess current, build up heat, and fail prematurely.
• On inverter-type ACs: The variable-frequency drive control board is particularly vulnerable. It can fail within weeks on modified sine wave, and the failure pattern is often enough for manufacturers or installers to reject the warranty claim.
• On standard ACs: The compressor motor overheats, draws excessive current, and the lifespan is dramatically shortened. Repair cost typically exceeds the price gap between modified and pure sine wave inverters.

Mercury Inverter Recommendations for Inverter-Type 2HP AC

Three Mercury systems sensibly back up an inverter-type 2HP AC. The right one depends on how long you need the AC to run during a NEPA outage, and whether you want to add solar panels later. Remember: the inverter handles the surge, but runtime is determined by the battery bank, not the inverter capacity. We do not list a smaller Mercury inverter for 2HP AC use because 3kVA-class units (typically 1,900W continuous) leave no headroom for AC peak load plus household lights and fans.

• Minimum sensible buy, recommended for most homes: Mercury 3.5kVA Hybrid MPPT at ₦335,000. 24V platform, pure sine wave, built-in MPPT charge controller. Pair with 2 GEL batteries for about 3 hours of AC, or 4 batteries for about 6.5 hours. For meaningful daytime AC offset, pair with 4 × 450W panels; smaller arrays help but only the 1.8kW configuration gives comfortable headroom after heat, dust, cable, and MPPT losses.
• Long outages or managed multi-AC setups: Mercury 5.5kVA Hybrid 48V. 48V platform, larger surge ceiling, lower DC current. Pair with 4 GEL batteries (about 6.5 hours at AC cruise) or 8 batteries for overnight runtime. Solar-ready. For two 2HP inverter-type ACs running together, confirm the AC models and combined load profile before purchase, two ACs at full blast can pull 3,000 to 3,600W before other loads.
• Overnight cruise, low-maintenance: Mercury 5kVA + 10kWh Lithium. LiFePO4 chemistry runs at 95 percent depth of discharge with a 5-year warranty and no water top-up. About 8 hours at AC cruise on the battery alone, and may stretch longer if the inverter-type AC throttles down after the room is cool. Pair with panels for true all-night coverage on long outages.

For lithium versus lead-acid trade-offs across Mercury chargers and inverters, see our guide on which battery is best for an inverter, and the practical wiring steps in how to connect an inverter to a battery.

Battery Sizing and Runtime for 2HP AC in Nigeria

An inverter-type 2HP AC running at cruise draws approximately 900 to 1,100 watts. That is the figure to use for battery calculations. We size every Mercury system at 80 percent depth of discharge for GEL or AGM batteries, and 95 percent for LiFePO4 lithium. Nigerian operating reality, poor grid and heavy daily cycling, makes the textbook 50 percent DoD figure overly conservative for sizing decisions, and underrates the actual runtime our customers get. Inverter efficiency is taken at 85 percent.

• Runtime formula: Backup Hours = (Voltage × Amp-hours × DoD × Efficiency) / Load Watts
• Example A, Mercury 3.5kVA (24V) with 2 × 12V/200Ah in series (24V/200Ah): (24 × 200 × 0.80 × 0.85) / 1,000 = 3.26 hours of AC cruise
• Example B, Mercury 3.5kVA (24V) with 4 × 200Ah (2S2P = 24V/400Ah): (24 × 400 × 0.80 × 0.85) / 1,000 = 6.5 hours of AC cruise
• Example C, Mercury 5.5kVA (48V) with 4 × 200Ah in series (48V/200Ah): (48 × 200 × 0.80 × 0.85) / 1,000 = 6.5 hours of AC cruise
• Battery wiring rule: Two 12V/200Ah batteries in series give 24V/200Ah, not 24V/400Ah. Voltage doubles, amp-hours stay the same. To double the amp-hours you need a second parallel string of the same series pair. For a Mercury 5.5kVA at 48V, the minimum string is 4 batteries in series, not 2.

12V is not viable for any AC load. A 2HP inverter-type AC at 1,000W on a 12V system demands over 83 amps of continuous current. At that draw, 12V cables and battery terminals generate dangerous heat and the voltage sags badly, which triggers inverter shutdown. Always use 24V minimum. For a Mercury 5.5kVA the platform is 48V, which is the correct voltage for any AC backup system that runs more than 4 hours.

Solar Panels: Offsetting the AC Load During the Day

If your NEPA outages extend through daylight hours, a hybrid MPPT inverter allows solar panels to run the AC directly from the sun while topping up your batteries. The serious recommendation for a 2HP inverter-type AC is 4 × 450W panels (1.8kW array). Smaller arrays can help, but after panel-temperature derating on a hot Nigerian roof, dust and soiling, cable losses, MPPT efficiency, and cloud movement, a 1.2kW array (4 × 300W) typically delivers 750 to 900W of usable output at peak, not the rated 1.2kW. That leaves no comfortable margin against a 1,000W AC cruise. The 1.8kW array gives roughly 1,200 to 1,400W effective at peak, enough to carry the AC plus a few lights and still trickle charge the batteries.

The Mercury 3.5kVA Hybrid MPPT supports up to 2kW of solar input, which fits the 4 × 450W setup neatly. For roof angle, cable, and shading considerations, see our guide on connecting solar panels to your battery bank, and the differences between monocrystalline and polycrystalline panels.

Realistic daily yield, after all losses: 4 × 450W produces roughly 6 to 8 kWh on a clear Nigerian day. A 1,000W AC running for 6 daylight hours consumes about 6 kWh, so the 1.8kW configuration covers the daytime AC and still has spare capacity for battery top-up. If you only have roof space for 4 × 300W (1.2kW), expect meaningful but not full offset, the panels lighten the battery drain rather than carry the AC outright.

The Standard 2HP AC Reality Check

If you currently own a standard fixed-speed 2HP AC and want inverter backup, here is the honest math before you spend money on the wrong solution. The startup surge from a fixed-speed compressor is roughly 4,200 to 6,000 watts, which is what makes it so expensive to back up.

The correct path for anyone with a standard 2HP AC who wants inverter backup is to replace the AC with an inverter-type model first. The compressor upgrade reduces your inverter requirement from “no sensible option” to “Mercury 3.5kVA”, cuts your battery requirement in half, and extends battery lifespan because the load is steadier and lower. There is no shortcut here, an oversized inverter is not the answer.

Generator vs. Inverter for 2HP AC: True Cost Comparison

The reason inverters win over generators for AC backup is petrol. As of early May 2026, market reports put NNPC petrol in Lagos around ₦1,320 per litre, with NNPC raising prices from ₦1,230 to ₦1,320 on 30 April 2026 in response to global crude pressure. Fuel prices now move quickly, so the exact pump price may differ by location and week, but the direction is clear: every extra hour on generator is becoming more expensive.

At ₦1,320 per litre, a small generator burning 1.5 to 2 litres per hour costs roughly ₦1,980 to ₦2,640 per hour in petrol alone. A full 10-hour outage costs ₦19,800 to ₦26,400. If you run that generator only 1 hour per day on average, annual petrol is about ₦720,000 to ₦960,000. If you run it 5 hours per day (a realistic Nigerian evening pattern), annual petrol crosses ₦3.6 million. At 10 hours per day, annual petrol crosses ₦7 million. Servicing, oil changes, noise, fumes, and fuel queues are on top.

The inverter system pays back inside 12 months for a household running the generator even 3 to 4 hours per day, and the gap widens every month after that. The inverter still needs to be charged from NEPA, solar, or another energy source, but it removes the daily petrol burn that makes generator backup so expensive. Add 4 × 450W panels (approximately ₦360,000 to ₦420,000 installed) and the electricity charging cost drops close to zero, accelerating the break-even further. For the full breakdown across home sizes, see our generator running cost guide for Nigeria.