18V Monocrystalline Solar Panel 310x120 mm White Back
Custom monocrystalline photovoltaic module made for MR WATT, with a declared nominal voltage of 18 V, 310x120 mm size and an actual panel thickness of about 5 mm. It has tempered glass, a white back and a simple rear junction box that is not rated IP65.
This is remaining stock from an earlier MR WATT production run, offered in the Outlet at cost price. There is no rear technical label and Pmax, Vmp, Imp, Voc and Isc are unavailable, so these values must be checked before connecting batteries, controllers or loads.
The MW_31018 is a custom 18 V monocrystalline photovoltaic module manufactured to MR WATT specifications in a narrow 310x120 mm format. It was developed for small DC projects, prototypes, monitoring systems, model making and educational applications where compact dimensions, front glass and a white backing are useful.
The product comes from an earlier custom MR WATT production run and is offered in the Outlet at cost price while stocks last. It is not a standard catalogue module with a public datasheet: there is no technical rating label on the rear and some electrical values required for system sizing are unavailable.
What to know before ordering
- The declared commercial nominal voltage is 18 V, but the output is not regulated.
- The module measures 310x120 mm and the actual panel thickness is about 5 mm.
- The 3 cm depth stored in the PrestaShop logistics data refers to the packaging, not the panel thickness.
- The rear junction box is a simple j-box and is not rated IP65.
- There is no rear label showing Pmax, Vmp, Imp, Voc and Isc.
- For outdoor use, the module must be installed in a protected position away from permanent direct exposure to water and standing moisture.
Confirmed MW_31018 specifications
| MR WATT reference | MW_31018 |
| Origin | Custom production made for MR WATT |
| Cell technology | Monocrystalline |
| Declared nominal voltage | 18 V |
| Panel dimensions | 310x120 mm |
| Actual panel thickness | About 5 mm |
| Catalogue shipping dimensions | 310x120x30 mm, including packaging |
| Catalogue weight | About 0.37 kg |
| Front protection | Tempered glass |
| Backing | White |
| Connection | Simple rear junction box |
| Junction-box rating | Not IP65 |
| Rear technical label | Not present |
| Pmax, Vmp, Imp, Voc and Isc | Unavailable for this earlier production run |
Why no wattage is stated
The 18 V description alone does not determine module power. A wattage value requires at least the maximum-power voltage and current or a controlled current-voltage curve measurement. Without the original label and datasheet, assigning a Pmax value by comparing the panel with visually similar products would be misleading.
Voltage also changes with sunlight, temperature and connected load. Open-circuit voltage can be higher than the nominal figure, while operating voltage depends on the connected electronics. The panel must not be treated as a regulated 18 V power supply.
Recommended applications
- Electronic prototypes and laboratory testing.
- Low-consumption sensors and environmental monitoring systems.
- Educational demonstrations of the photovoltaic effect.
- Model making, robotics and maker projects.
- Small lamps or DC systems with a dedicated battery and controller.
- Protected experimental installations where the electrical parameters are measured before use.
Compatibility with a device cannot be determined from nominal voltage alone. The real available current, load consumption, battery requirements and converter or controller limits must also be known.
How to connect it correctly
| Application | Required component |
| Nominal 12 V battery | Compatible charge controller sized after checking Voc, Vmp and current |
| USB output or power bank | DC-DC converter or USB regulator with a suitable input range |
| Sensor or fixed-voltage electronics | Voltage regulator and, where continuity is required, a dedicated storage device |
| Several panels in series or parallel | Prior Voc and Isc measurement, polarity check and controller-limit verification |
Do not connect the panel directly to a battery or sensitive electronic device. Because the complete module data is unavailable, final integration should be preceded by electrical measurements using suitable instruments and test loads.
Installation and junction-box protection
The tempered glass protects the cells, but the simple rear junction box is not IP65. The module must therefore not be marketed or treated as a permanently weatherproof outdoor panel.
- Install it where it is protected from driving rain, splashes and standing water.
- Protect cable exits and connections with a solution suitable for the real environment.
- Do not bend the glass or clamp the module at points that create mechanical stress.
- Observe polarity and include the protection devices required by the circuit.
- Allow rear ventilation and avoid persistent partial shading.
- Check the mounting before mobile or vibration-prone applications.
Why it is in the MR WATT Outlet
This module is remaining stock from an earlier custom production commissioned by MR WATT. It is being sold at cost price while supplies last. Its Outlet placement is therefore linked to clearing a previous production run, not to the availability of a current manufacturing cycle or an updated datasheet.
Before ordering, confirm that the format, white backing, simple j-box and lack of complete electrical data are suitable for the intended project.
Frequently asked questions
How many watts does the MW_31018 produce?
Nominal power is unavailable because this earlier production has no rear rating label and no recoverable datasheet. Power must be determined by measurement and cannot be derived from the 18 V description alone.
Is the panel 3 cm thick?
No. The panel itself is about 5 mm thick. The 3 cm value in the catalogue is the packaging depth used for shipping.
Is the junction box waterproof and rated IP65?
No. It is a simple junction box without an IP65 rating. Outdoor use requires protection from water, splashes and standing moisture, together with suitable cable and mounting protection.
Can it charge a 12 V battery?
It can only be assessed after measuring Voc, Vmp and current. A charge controller compatible with the battery chemistry and the panel's real electrical values is still required.
Why is this product sold in the Outlet?
It is remaining stock from a custom production made for MR WATT and is offered at cost price while stocks last.