- Solar Lantern Definition: A solar lantern is a portable solar electric system used for temporary lighting both indoors and outdoors.
- Main Components: It includes an electric lamp, a battery, and an electronic control circuit, with the solar PV module connected separately.
- Functionality: The solar PV module charges the battery, which powers the lamp, providing efficient lighting.
- Different Models: Solar lanterns come in various configurations based on lamp type, battery capacity, and PV module rating.
- LED Benefits: LED-based solar lanterns are energy-efficient, consuming less power and requiring smaller batteries.
A solar lantern is a portable stand-alone solar electric system that stores daytime solar energy for later lighting. Depending on the design, the solar PV module can be separate or built into the product. The main components are an electric lamp, a rechargeable battery, a charge controller and a lamp driver. When separate, the solar PV module connects through a dedicated charging input rather than directly to exposed battery terminals. The enclosure supports portable indoor or outdoor use within the product’s stated ingress-protection rating. Historical products used a compact fluorescent lamp (CFL), while modern products generally use an LED lamp. Controls and indicators can show charging, low-battery or operating status.
For charging, place the solar PV module in unobstructed sunlight and connect it as the product instructions specify. Battery voltage, capacity, lamp power and the rating of the solar PV module vary by model. They must be matched through the controller to the required runtime and local solar resource.
The following table records four historical CFL solar-lantern configurations from an Indian government programme. These are legacy programme ranges, not universal specifications for current products.
| Model | Lamp (CFL) | Battery | PV Module |
| I-A | 5 W | 12 V, 7 Ah at 20oC | 8 to 9.9 Watts (Peak) |
| I-B | 5 W | 12 V, 7 Ah at 20oC | 10 to 11.9 Watts (Peak) |
| II-A | 7 W | 12 V, 7 Ah at 20oC | 10 to 11.9 Watts (Peak) |
| II-B | 7 W | 12 V, 7 Ah at 20oC | 12 to 14 Watts (Peak) |
Light output is product-specific and should be stated in lumens with its test conditions. The original blanket value of 230 ± 5% lumens for every 7 W CFL was not supported by the programme configurations and should not be used as a universal rating.
Components of a Solar Lantern
Solar Module or PV Module
The rating of the solar PV module is expressed in watts peak (Wp) under specified test conditions. It must provide enough daily energy to replace the lantern’s expected use while accounting for controller, battery and temperature losses. Place the solar PV module where it receives direct sunlight without shade and orient it according to the product instructions. Portable modules should be secured against damage and weather exposure.
Battery
Historical CFL lanterns commonly used a sealed lead acid battery rated at 12 V and 7 Ah. Current lanterns may use sealed lead-acid, lithium-ion or other rechargeable chemistries. The controller and charger must be designed for the installed battery type, voltage and capacity.
Inverter
A CFL lantern uses an electronic ballast or inverter to convert battery DC into the waveform needed by the lamp. An LED lantern instead uses a current-regulated LED driver. Conversion efficiency, standby loss and low-voltage behaviour should be checked in the product test data.
Protection and Indication System
The control circuit should protect the battery from overcharge and excessive discharge. An electrical fuse or electronic current protection can limit damage from a short circuit. Status Light Emitting Diodes (LEDs) may indicate charging, full charge, low battery or fault conditions. Their exact meaning must match the product instructions.
LED Based Solar Lantern
An LED is well suited to a portable solar lantern because it can produce useful light with less electrical energy than a CFL and can be driven directly from a regulated DC circuit. Lower energy use can reduce the required PV-module and battery capacity for the same tested runtime. White-light colour temperature, colour rendering, beam distribution and glare also affect whether the lantern is suitable for its intended task. No single module rating, battery capacity or LED package is correct for every product. For example, a historical design might use a 12 V, 2.3 Ah battery rated at 20 oC, while a modern design can use a different voltage and chemistry. Buyers should compare tested lumens, runtime, charge time, battery durability, warranty and safety information.
