Where to place a solar light and how to assess its run time
The best position for a solar light needs to meet two needs: delivering light where you use it and allowing the panel to receive enough sunlight. Before choosing by shape or lumens, observe the location during the day. A spot that seems perfect at dusk may be in the shade during charging hours.
Run time depends on the whole system and how it is used. To compare it, gather information about the panel, battery, operating modes and the manufacturer's test conditions. A capacity figure on its own cannot guarantee how long it will provide light each night.
Start with a simple map of sunlight and shade
Choose two or three possible positions and note what happens in the morning, at midday and in the afternoon. Look for shade from eaves, balconies, trees, walls and nearby buildings. Photograph the location from a fixed point so you can compare without relying only on memory.
The solar radiation received varies with location, time of day, season and surroundings, as explained by the US Department of Energy. Observing a spot in summer is not enough to establish how it will perform in winter. If you have only seen the space on one day, mention that limitation when seeking advice.
Assess orientation alongside the actual shade
A favourable orientation can be undermined by a nearby obstruction. Check the model's guidance on tilt and orientation, and whether the panel can be adjusted. In the installation instructions for its XSolar SOL-O STEINEL warns about shaded positions, locations behind glass or under structures that restrict solar collection. Its recommendations apply to that product family; they do not establish a universal configuration for all solar lights.
Integrated or separate panel: how it affects positioning
| Aspect | Integrated panel | Separate panel, if supported by the model |
|---|---|---|
| Position | Lighting and solar collection share one location | Allows different positions to be chosen |
| Shade | Check the shade falling on the whole unit | Pay particular attention to the panel's location |
| Installation | Check the unit's orientation and fixing | Check the cable, its route, connectors and fixings |
| Maintenance | Panel access from the same location | Access to both components |
Do not assume that a panel can be separated because it looks distinct in a photograph. Confirm the design, included accessories and permitted cable length. Avoid improvised extension leads or connectors. If the product houses everything in one unit, changing the light's direction may also change the panel's orientation.
The information you need to assess run time
The panel collects energy, the battery stores it and the light fitting consumes it. The DOE explains that solar production varies with conditions and that storage involves losses. You therefore need to consider the energy collected, the usable energy and the demand of the selected mode.
- Panel: declared power and conditions, permitted orientation and charging recommendations.
- Battery: capacity, voltage, technology and documented replacement options.
- Consumption: power or behaviour in each mode, including reduced levels where available.
- Intended use: continuous or sensor-triggered lighting, activation frequency and the duration of each cycle.
- Testing: initial charge, mode, temperature and circumstances associated with the advertised run time.
Milliamp-hours, or mAh, describe electrical charge capacity. To compare energy, you also need the voltage; even with both figures, not all the nominal energy is available for the light to use. Ask for a documented run time for the mode you will use, without converting mAh directly into hours.
Compare the operating behaviour you need
A light that activates when someone passes and one that stays on have different demands. Before choosing, write down how you will use the patio or terrace. Also ask whether the unit reduces brightness when the battery is low and whether the published light output is a momentary maximum or a sustained level.
The run time observed needs to be compared with a specific requirement. If you need continuous lighting for an essential period, consider a solution whose power supply and operation can demonstrably cover it. Having a solar panel does not, by itself, establish that it can do so.
Practical example: lighting a door beneath a porch
The door is sheltered by an overhang and only receives sunlight in the late afternoon. Before fixing a wall light in place, check whether the panel would sit beneath the same overhang. If solar collection is insufficient, consider another position or a model with a separate panel where it is expressly designed for this.
Carry out a test following the manual, with the specified initial charge and the mode you will actually use. Record the weather, position and behaviour at dusk. One satisfactory night helps you assess those circumstances; it does not represent the whole year. Avoid drilling permanent fixing holes until you have resolved the position and its conditions.
What to ask when comparing two solar models
Ask for documented run time in the mode you will use: continuous lighting, motion detection or reduced output. Check the charging and test conditions and compare them with your intended location. Lumens, mAh and the presence of a solar panel cannot individually guarantee the hours of illumination.
Also check the outdoor installation and maintenance requirements. A declared IP rating does not, on its own, tell you all the acceptable weather conditions, battery durability or permitted exposure of the whole unit.
Checklist before choosing the position
- Sunlight and shade observed at different times.
- Panel position and tilt checked against the manual.
- Operating mode matched to the planned activity.
- Sufficient information about the battery and stated run time.
- Fixing, cleaning access and maintenance planned.
Observation log for comparing two positions
Copy one sheet for each position and each test night. Record actual observations; enter ‘unknown’ if you cannot confirm the initial charge.
- Date, position and reference photograph: __________
- Observed hours of sunlight and shade on the panel: __________
- Weather and any obstructions present: __________
- Selected operating mode: __________
- Initial charge or charging procedure followed: __________
- Switch-on time and end of observation: __________
- Observed changes in brightness or switch-offs: __________
- Approximate number of activations, if sensor-operated: __________
Compare records with similar modes and conditions. One favourable night does not establish winter run time or allow the result to be applied to other models.
Frequently asked questions
Does a higher mAh rating mean more hours?
It does not let you compare run times without knowing the voltage, consumption, mode and usable energy.
Can I install the panel behind a window?
Do not assume so. Check the manual; the glass and the position may limit the expected solar collection.
To assess where the light will reach, see the guide to beam angle. To consider maintenance, see integrated LEDs and replaceable bulbs. You will find more information in the lighting guides index.