Solar flood light wattage explained: why a "300W" solar light isn't 300W
A "300W" solar flood light does not draw 300 watts all night. On most all-in-one solar lights the wattage in the name works as a size or class label, and the amount of light you actually get is limited by the battery and the panel. To compare two solar lights properly, multiply the battery voltage by its amp-hours to get watt-hours, then look at the panel size, the stated run time and the IP rating.
Why the number in the name is not the real power
Take a light sold as 1,000W with a 3.2V 52Ah lithium battery. The battery stores about 3.2 x 52 = 166 watt-hours (Wh). If the LEDs really drew 1,000 watts, that battery would be empty in 166 / 1,000 = 0.17 hours, roughly ten minutes. The manufacturer of that light states 12 to 15 hours of discharge, which means the lamp is running at an average of around 11 to 14 watts across the night.
That is not unusual, and it is not a fault. It is how the solar light market labels its products. The figure on the box often reflects the size of the LED board or the product class rather than the power the LEDs draw from the battery. The useful habit is to ignore the headline wattage when comparing value and read the battery, panel and run-time figures instead.
Battery: the most important number on the sheet
The battery decides how much light the fitting can give between sunset and sunrise. Spec sheets quote it in two ways:
- Amp-hours (Ah) or milliamp-hours (mAh). 18,000mAh is the same as 18Ah.
- Voltage (V). Single lithium iron phosphate (LiFePO4) cells are 3.2V. Packs are built up to 6.4V, 12.8V and so on.
Amp-hours alone can mislead, because a 12.8V 18Ah pack holds four times the energy of a 3.2V 18Ah pack. Always convert to watt-hours: volts x amp-hours = Wh. Some real examples from our range:
| Light (as listed) | Battery | Stored energy | Stated discharge |
|---|---|---|---|
| 300W, 18000mAh | 3.2V 18Ah LiFePO4 | about 58 Wh | 10 to 15 hours |
| 200W YW-200, IP67 | 6.4V 18Ah LiFePO4 | about 115 Wh | 12 to 15 hours |
| 1000W, 52Ah | 3.2V 52Ah LiFePO4 | about 166 Wh | 12 to 15 hours |
| 200W, 30-36 hours | 12.8V 18Ah LiFePO4 | about 230 Wh | 30 to 36 hours |
| 300W, 96Ah | 3.2V 96Ah LiFePO4 | about 307 Wh | 30 to 36 hours |
Notice that a light sold as 200W can hold more energy than one sold as 1,000W. Discharge hours are the manufacturer's figures and assume the battery reached full charge that day.
Chemistry matters too. LiFePO4 is the usual choice for quality solar lights because it handles daily charge and discharge cycles and heat better than older battery types. Check that the sheet names the chemistry, not just "lithium" or "battery".
Panel size: can it refill the battery?
A big battery is only useful if the panel can fill it. As a rough check, a panel produces about its rated watts multiplied by the number of peak sun hours in a day, minus losses. Much of Kenya gets somewhere around 4 to 6 peak sun hours, less in cloudy seasons. So a 6W panel can put back perhaps 15 to 25 Wh on a good day, while a 65W panel can put back well over 200 Wh.
Compare the panel to the battery. The 1000W model above pairs its 166 Wh battery with an 80W panel. The 300W 96Ah model pairs 307 Wh with a 65W panel. If a light has a large battery and a very small panel, expect it to run short after a dull day.
Lumens and efficacy
Brightness is measured in lumens. Many sheets quote an efficacy, such as 160 lumens per watt, which is the light produced per watt actually consumed. Multiply efficacy by the real average power, not the headline wattage. A lamp averaging 14W at 160 lm/W gives roughly 2,200 lumens. Many lights also run brighter early in the evening and dim later, so lumens vary through the night.
IP65 or IP67
The IP rating describes protection against dust and water. Both IP65 and IP67 mean the fitting is dust-tight. IP65 adds protection against water jets, which covers heavy rain. IP67 is tested against temporary immersion, so it gives more margin for a fitting that faces driving rain, hosing or a dusty yard. Die-cast aluminium bodies, such as the 100W IP67 aluminium model, also carry heat away from the LEDs better than plastic.
Sensor, remote and lighting modes
- Dusk to dawn: the light switches on when it gets dark and runs until the battery or the timer says stop.
- PIR motion sensor: the light stays dim or off and brightens when someone approaches. This stretches a small battery much further. The 100W PIR sensor model offers sensor and constant-on modes from a remote.
- Timer and remote: lets you choose brightness and hours without climbing a ladder. The MODI MD-PT77 lists optical, timer, remote and manual switch control plus a battery level display.
What to check on a spec sheet
- Battery voltage and Ah, converted to Wh.
- Battery chemistry (LiFePO4 is preferred).
- Panel watts, compared with the battery size.
- Stated charging and discharging hours, and whether a cloudy-day reserve is quoted.
- Lumens or lm/W, applied to real power.
- IP rating and housing material.
- Control modes: sensor, timer, remote.
- The manufacturer's stated warranty.
If a listing leaves a figure out, ask for the data sheet before you rely on it for a site.
Which size for a gate, a compound or a parking yard
These are practical starting points based on stored energy, not the name on the box:
- Gate, doorway or back door: 20 to 60 Wh is usually enough, especially with a motion sensor. A 50W or 100W PIR model, or the 100W 6,000mAh unit, suits a single entrance.
- Compound perimeter or a house frontage: 100 to 230 Wh per light. The 200W YW-200 or the 200W 30-36 hour model gives a full night with reserve.
- Parking yard, godown yard or construction plot: 160 to 310 Wh per fitting, often several fittings rather than one. The 300W 96Ah model, or the 1000W to 3000W family on poles, are the usual choices. For long access roads, a pole-mounted solar street light usually spreads light more evenly.
Siting matters as much as size. Mount the panel where nothing shades it between mid-morning and mid-afternoon, and wipe off dust in the dry months.
Where to see the range
Browse every model with full specs in our solar flood lights collection. For a site with many lights, send us the layout through our trade and bulk page and we will help you size it, or WhatsApp us with photos of the area.
You can see the lights at our Nairobi trade counter at Royal Business Park, Opposite Complast, Old Mombasa Road, open Monday to Saturday, 8:00 to 17:30. Delivery is KSh 350 flat countrywide, and free on orders over KSh 15,000.
Common questions
Is a 1000W solar flood light brighter than a 300W one?
Not necessarily. Compare stored energy in Wh, panel size and lumens. In our range, a 300W light with a 96Ah battery stores more energy than a 1000W light with a 52Ah battery.
How many hours will a solar flood light run?
Manufacturers quote run times from a full battery, commonly 10 to 15 hours or 30 to 36 hours for larger packs. Real nights depend on how much sun the panel received that day.
What does mAh mean on a solar light?
Milliamp-hours. Divide by 1,000 to get amp-hours, then multiply by battery voltage to get watt-hours. 18,000mAh at 3.2V is about 58 Wh.
Do solar flood lights work during the rainy season?
Yes, but with less charge. Choose a light with a larger battery and panel, or a stated cloudy-day reserve, if the site must stay lit through dull weeks.