Solar Flood Lights: Buyer's Guide to Specs and Sizing

A solar flood light that lights a whole yard in July and is dark by 9 pm in December was sized for the wrong month.

This guide starts with the five parts of a solar flood light and how to read its spec sheet, then matches lumen tiers to a driveway, a yard or barn, and a parking area. It compares an integrated panel with a separate panel on its own bracket, shows how to size panel and battery for the worst month of the year, and ends with the seven items a buyer writes into a bulk or OEM specification. Property managers, farms and resellers planning a volume order can send a bulk or wholesale lighting enquiry once those items are filled in.

What is a solar flood light, and what does each part do?

A solar flood light is a wide-beam LED light that charges a battery from a solar panel by day and runs from that battery at night. It needs no mains wiring, so it can go up on a wall, pole or gate where an AC cable run would cost more than the light itself. Five parts do the work, and each one maps to a line on the spec sheet.

• Solar panel. The panel converts daylight into DC power and sends it to the battery. Its watt rating sets how much energy comes back in each day.
• Charge controller. The controller stops the battery from over-charging in strong sun and from deep discharge on long nights. It protects battery life at both ends of the cycle.
• Lithium battery. The battery stores the energy for the night, rated in watt-hours. Lithium iron phosphate is the typical chemistry on commercial units.
• LED head. The LED head turns stored energy into light, measured in lumens. An LED driver between the battery and the head holds the current steady as the battery voltage falls through the night.
• Sensors. A PIR sensor picks up motion from body heat, and a photocell tells dusk from day. Together they set when the light switches on and at what level.

The panel refills, the battery is the tank and the LED head is the engine. A brighter head empties the same tank faster, and an undersized panel may not refill it before the next evening. The guide on why the battery, not the panel, runs the light after dark covers what happens between sunset and sunrise.

The sensor setting changes the nightly energy use more than most first-time buyers expect. A motion-only light draws from the battery only when the PIR sees movement, while a dusk-to-dawn light draws all night, even when dimmed.

How do you read a solar flood light spec sheet?

A solar flood light spec sheet is read through four numbers: lumens for brightness, battery watt-hours (Wh) for runtime, panel watts (W) for recharge, and the IP rating for the site. The "LED watts" figure printed on many sheets is a power draw, not a brightness figure.

Lumens, not LED watts

According to ENERGY STAR (2026), brightness is measured in lumens, not watts, and a 100 W incandescent bulb equals a minimum of 1,600 lumens. For a first-time buyer, a 1,600 lm flood head puts out about the light of one old 100 W bulb, spread across a wide beam.

Battery watt-hours

Battery capacity is only comparable in watt-hours. Many sheets quote mAh instead, so convert it: amp-hours × cell voltage = Wh. An illustrative 20,000 mAh pack at 3.2 V holds 20 Ah × 3.2 V = 64 Wh, which shows how a large mAh number at 3.2 V is a small Wh number.

Lithium iron phosphate is the typical chemistry on commercial units. A sheet with no voltage leaves the mAh figure uncheckable.

Panel wattage and the honesty check

Panel watts are rated under standard lab conditions, so the daily harvest on a real wall or pole is lower.

Integrated LED flood heads on commercial spec sheets typically quote around 100 to 150 lm per LED watt, so divide the lumen claim by that figure to estimate the draw. An illustrative 10,000 lm claim at 100 lm per watt draws about 100 W, and ten hours at full output would need around 1,000 Wh, far beyond a typical integrated battery.

A lumen figure far above what the panel and battery could feed is the inflated-spec tell.

IP rating

The two digits of an IP rating grade protection against dust and against water, so ask the supplier for its test report on the finished light. IP65 is typical for exposed walls, and IP66 or IP67 is typical for coastal, irrigated or wash-down sites.

Sensor modes and mounting

• PIR motion mode: the light stays off or very dim until the passive infrared (PIR) sensor detects movement.
• Dusk-to-dawn mode, dimmed with motion boost: a photocell switches the light on at low output at dusk, and motion raises it to full brightness.
• Timer: the light runs for a set number of hours after dusk, then switches off. Signs typically use this mode.

Motion detection works best at a typical mounting height of 2.5 to 4 m. The charge controller line names PWM or MPPT, and the choice changes how much of the panel's rated output reaches the battery, as explained in MPPT versus PWM controllers on small panels.

Specs to compare before you order: which tier fits which job?

A solar flood light should be chosen by the lumen tier its job needs, and the panel W and battery Wh on its spec sheet should sit in the same typical range as that tier. Lumens without the energy behind them only last a few hours, and a sheet that lists a high lumen figure next to a small panel and battery shows the typical inflated-spec tell.

The table below compares three typical tiers by job, lumens, panel W, battery Wh, IP rating, sensor mode and mounting layout.

Specs to compare before you order (typical ranges, not test results)

Lumen tier (typical)	Job	Panel W (typical)	Battery Wh (typical)	IP (typical)	Sensor mode	Mounting
1,000-2,000 lm	Entry, driveway, sign	10-25 W	30-80 Wh	IP65	Motion only, or timer for signs	Wall at 2.5-4 m, integrated panel
3,000-5,000 lm	Yard, barn, loading area	30-60 W	100-250 Wh	IP65 to IP66	Dusk-to-dawn dimmed with motion boost	Wall or pole, integrated or separate panel
8,000 lm and up	Parking, perimeter	80-150 W	300-600 Wh	IP66	Dusk-to-dawn	Pole, separate panel on its own bracket

Send LinkSolar the job, the site and the worst month from the bulk specification list further down this guide, and LinkSolar confirms that the panel and battery side of your chosen tier fits the job; for the entry tier, a quick cross-check is this guide to small solar panel sizes and what they power.

Read each row from left to right: start with the job, then check that the panel W and battery Wh on the supplier's sheet land inside that row's range. A light that claims the lumens of one row but carries the panel and battery of the row above will run bright for a short time, then dim or cut out well before dawn in the shortest-day months. These ranges are typical of commercial spec sheets rather than LinkSolar data, so confirm each figure against the supplier's test report on the finished light, and treat a coastal, irrigated or wash-down site as an IP66 or IP67 job whatever the tier.

Integrated or separate panel: which layout suits the site?

An integrated solar flood light is the simplest choice where the light itself sits in full sun, while a separate panel on its own bracket is the better choice wherever the light has to hang under eaves, in a barn doorway or in shade.

An integrated solar flood light puts the panel, battery and LED head in one housing. That means one bracket and no external cable, but the panel faces wherever the light is aimed, and its area is capped by the size of the housing.

A split solar flood light joins the LED head to a remote panel with a cable. The head is mounted where the light is needed and the panel is mounted where the sun reaches it. Larger, brighter heads typically move to this build because the panel they need no longer fits on the housing.

Choose a separate panel when any of these apply at the mounting point:

• The light mounts under eaves, a porch roof or a barn overhang.
• The wall faces away from the midday sun.
• Trees shade the spot for part of the day. Under canopy a panel sees only a few usable sun hours compared with an open site, and controller and charge losses take a further share of what it does collect.
• Gates and fence lines cast moving shade across the lower part of the site.

On remote sites, where the panel sits usually matters more than how large it is. Farms, yards and construction sites where AC runs are impractical are the same places that need solar power for cameras and gates on remote sites, and the same rule holds: lift the module above fence lines and gates so moving shade never crosses it.

Use pole mounts that lift a separate panel above shade when no wall or roof edge gets clear sun. Keep the DC cable run short, and add a drip loop where the cable enters the light's gland.

For a compact integrated example in open sun, see a small panel running a dusk-to-dawn light on a boat. Product builders fitting a panel into their own light can specify small custom panels for integrated light housings, which LinkSolar sources to a set outline and shape, target Vmp and Imp, lamination and connector leads.

Why does the panel decide whether a solar flood light works in winter?

A solar flood light's battery sets how long one night lasts, but its panel sets whether that battery is full again by the next evening. The worst month of the year gives the panel the fewest peak sun hours to refill it, so a light sized on a July day runs short in December.

According to PVEducation, peak sun hours equal the average daily insolation in kWh/m² per day, because peak solar radiation is 1 kW/m². Size against the worst-month figure for the site rather than the yearly average.

The worst-month sizing method used for off-grid security cameras carries over to lighting:

1. Add up the light's watt-hours per night, including sensor standby.
2. Divide that figure by the worst-month peak sun hours to get panel watts.
3. Add 20 to 30 % for controller, wiring and temperature losses.
4. Size the battery for the days of autonomy the job needs: 1 to 2 days in milder climates, 3 to 5 or more where security lighting must stay on through storms.

As an illustrative example with round numbers, a yard light using around 80 Wh a night at a site with 2 peak sun hours in December needs 40 W of panel, or around 50 W once losses are added. Three days of autonomy puts the battery at around 240 Wh. The same light in a July with 5 peak sun hours needs only about 20 W, which is why a unit tested in summer can go dark by winter.

Buyers who want every step can follow the full load-to-panel sizing method for LED systems.

Cold shrinks the battery in the same months the sun is weakest. Lead-acid gives up a large share of its capacity below freezing, while lithium iron phosphate (LiFePO4) typically keeps most of its capacity well below zero, so buyers in northern states should specify lithium. The details are in this guide on how cold weather cuts usable battery capacity.

Set the panel tilt angle at 30 to 45° to improve winter harvest and shed rain and snow. A low-voltage disconnect (LVD) switches the light off before the battery drains into a brownout, and a charge controller with low quiescent current keeps more stored energy for the night.

When a light's own panel is too small for a northern winter, the fix is a panel sized and shaped for that housing or bracket. LinkSolar sources custom solar panels built to a lighting product's outline and voltage at 3 V to 48 V, including mini formats of 0.1 W to 25 W laminated in PET, ETFE or fiberglass. For prototyping a light, LinkSolar's catalog also lists 4 W, 8 W and 12 W small panels with selectable 5, 6, 9 or 12 V DC output and support for up to six 18650 cells, plus a 25 W version with a built-in MPPT controller in an IP66 enclosure.

How do you specify solar flood lights for a bulk or OEM order?

A bulk or OEM order for solar flood lights is specified by writing each job down as numbers a supplier can test against, then asking for the test report on the finished light before volume. The seven items below turn the tiers, layouts and winter sizing from the sections above into a bulk order specification a supplier can quote from.

1. Set the lumens per zone. List each area to light with its size and mounting height, and give it a lumen tier, for example around 1,000 to 2,000 lm for an entrance or 3,000 to 5,000 lm for a yard.
2. State the runtime and autonomy. Give the on-hours per night and the number of sunless days the light must ride through, typically 1 to 2 days in milder climates and 3 to 5 or more where security has to stay up through storms.
3. Name the worst month. Give the site latitude or nearest city and the month with the fewest peak sun hours, so the supplier sizes the panel for that month.
4. Fix the panel W and battery Wh. Ask for both figures in writing, with lithium iron phosphate as the battery chemistry for sites that freeze.
5. Specify the IP rating and mounting. Typical choices are IP65 for exposed walls and IP66 or IP67 for coastal or wash-down sites, plus wall or pole mount, integrated or separate panel, and the cable length between panel and light.
6. Choose the sensor mode. Pick motion only, dusk-to-dawn dimmed with a motion boost, or a timer that runs a set number of hours after dusk.
7. Send the list with OEM branding and quantity. Add logo, label text, packaging and quantity by batch, and ask for the finished light's test report before the volume order.

LinkSolar is a sourcing partner on the China side with direct factory-side QA, not a factory owner, and it covers the panel side of a lighting order. From the list, LinkSolar returns a buildable panel specification (cell layout, target Vmp and Imp, lamination, connector) with a price at your quantity, then runs one pre-shipment inspection with photo and video evidence. Panels for integrated housings follow the same custom mini panel specification route, covering outline, target voltage, connector and logo.

Send the seven items and LinkSolar confirms the panel and battery side fits the job before you order.

FAQ: solar flood lights

How many lumens does a solar flood light need for a driveway?

A solar flood light for a typical residential driveway needs around 1,000 to 2,000 lumens. Long or curved drives usually move up to the 3,000 to 5,000 lumen yard tier. Either way, check that the battery watt-hours can feed those lumens for the hours the light stays on.

Do solar flood lights work in winter?

Solar flood lights work in winter when the panel is sized for the month with the fewest peak sun hours and the battery is lithium iron phosphate, which typically keeps far more of its capacity in the cold than lead-acid. A panel sized for summer leaves the battery part-empty, so the light shuts off early in midwinter. A steeper tilt and a spot clear of snow and shade help it refill each day.

How long do solar flood light batteries last?

The service life of a solar flood light battery depends on its chemistry, how deeply it is discharged each night and how hot the housing gets in summer. Lithium iron phosphate is the typical chemistry on commercial units because it handles outdoor temperature swings well. Ask the supplier for cycle-life data at a stated depth of discharge.

Can I buy solar flood lights in bulk with a custom panel?

Solar flood lights can be bought in bulk with a custom panel through a sourcing partner that specifies the panel to the light's outline, voltage and site. Send the job, lumen tier, sensor mode, site and worst month, autonomy days, battery chemistry and Wh, panel layout, IP rating and branding. LinkSolar returns a buildable panel specification, then checks the order with one pre-shipment inspection backed by photo and video evidence.

Next step

A solar flood light order comes down to three numbers: lumens for the job, watt-hours for the night and panel watts for the worst month. To request a quote for panels on a lighting order, send LinkSolar the light's outline, target voltage and the site's worst month. LinkSolar confirms the panel and battery side fits the job before you commit to volume.