Guide · Understanding the sizing
Running an air conditioner all night on solar in Togo: what it really takes.
Published 4 September 2026 · 6-minute read
The question we're asked most often
"Will the air conditioner make it through the night?" That's the only question that matters, and a lot of systems sold in Lomé answer it poorly. We see 3 kWp systems marketed as a "family villa" solution that can handle two air conditioners, not five. The problem isn't sunshine — there's plenty of that — it's what you store for the night, and what you ask of it.
This guide gives the figures we use to size our kits. They apply to Lomé's climate and are deliberately conservative.
What an air conditioner really consumes
The power rating on the nameplate isn't the actual consumption. An inverter split unit modulates its compressor: once the room has cooled down, it slows down instead of stopping and restarting. Here's what we use:
| Air conditioner | Average power while running | Typical use | Energy |
|---|---|---|---|
| 9,000 BTU (1 HP), bedroom | ≈ 800 W | 8 h per night, compressor at 55% | ≈ 3.5 kWh per night |
| 12,000 BTU (1.5 HP), living room | ≈ 1,150 W | 5 h per day, compressor at 60% | ≈ 3.5 kWh per day |
The number to remember: roughly 3.5 kWh per night per bedroom air conditioner. Add the refrigerator, lighting, television and fans, and you get the lower limit of our Studio · 1 bedroom kit, 4 kWh per day. That's why our kits are chosen by counting air conditioners, as explained in the guide which kit fits your home.
A non-inverter air conditioner, with an on/off compressor, uses more energy for the same comfort and causes a current spike every time it restarts. On a solar system, an inverter unit isn't optional.
The battery decides everything
In an air-conditioned home, roughly 70% of consumption falls at night, when the panels are no longer producing. The battery isn't an accessory, then: it's the heart of the kit, and it's the most expensive component.
A lithium iron phosphate (LiFePO4) battery can be used down to 90% of its capacity without damage. What a kit can cover per day is therefore its battery capacity multiplied by 0.9, divided by 0.7. For a 5.12 kWh battery, that comes to 6.5 kWh per day, the upper limit of the Studio · 1 bedroom kit. The same calculation sets the limits for the whole range:
| LiFePO4 battery | Kit upper limit | Air conditioners covered |
|---|---|---|
| 5.12 kWh | 6.5 kWh/day | 1 |
| 10.24 kWh | 13 kWh/day | 2 |
| 15.36 kWh | 20 kWh/day | 3 to 4 |
| 20.48 kWh | 26 kWh/day | 5 to 6 |
| 30.72 kWh | 40 kWh/day | 7 to 9 |
Why not a lead-acid battery?
Because it can only be discharged to 50% without damage, it has a service life two to three times shorter in hot weather, and for the same usable capacity it ends up costing more. A LiFePO4 battery lasts several thousand cycles, emits nothing, and withstands the heat of a technical room in Lomé. Our batteries are certified to IEC 62619 and UN38.3.
Panels: recharging for the next night
In Lomé, a 550 Wp panel produces on average 1.73 kWh per day once you account for actual sunshine — about 4.2 peak-sun hours — and system efficiency of around 75%. Four panels therefore produce 6.9 kWh per day, enough to fill a 5.12 kWh battery and power the house during the day at the same time. Every kit is calculated this way: the panel array recharges the kit's upper limit within the day, rainy season included, thanks to the built-in margin.
The panels are 550 Wp modules certified to IEC 61215 and IEC 61730, mounted on sheet-metal or concrete slab roofs with the appropriate fixings.
Compressor start-up, and why 48 V
The classic objection to solar and air conditioning is the inrush current at compressor start-up, which can trip a small inverter. That objection holds for air conditioners with an on/off compressor. With a DC inverter split unit, the compressor ramps up gradually: no spike at start-up.
Even so, we removed the small 24 V inverters from our range. All our kits use a 48 V hybrid inverter of at least 6 kW, even for a single air conditioner. The extra cost is small and it buys two things: margin for the air conditioner you'll add later without telling us, and room to grow. On 48 V, a battery of the same model can be added within the year without changing the inverter.
The four mistakes we see in Lomé
- Undersizing the battery by counting daytime consumption. Night-time accounts for 70% of the bill.
- Installing non-inverter air conditioners on solar, then finding that the inverter trips on every restart.
- Choosing lead-acid to save on the purchase price, then replacing the whole battery bank after two years.
- Planning for "one air conditioner for the house" when at an average of 38°C you need one per bedroom. The kit should be chosen based on the actual number of air conditioners, not a wish.
Frequently asked questions
- How much does a 9,000 BTU air conditioner consume per night?
- About 800 W while running, and roughly 3.5 kWh over an 8-hour night with an inverter compressor working 55% of the time.
- What size battery is needed to run an air conditioner all night?
- A 5.12 kWh LiFePO4 battery at 48 V per bedroom air conditioner, covering the rest of the house too. Two air conditioners: 10.24 kWh. Three or four: 15.36 kWh.
- Can the inverter handle the compressor start-up surge?
- With a DC inverter split unit, there's no start-up spike. Our kits use a 6 kW, 48 V hybrid inverter regardless, with margin to spare.