12V battery charger for solar powered data loggers

The ML-COVER-SLA is a power provision cover fitting our ML-417 off-grid LTE-m & NB-IoT data logger to power it from a 12V battery and to charge the battery from an external solar panel.

We designed our remote data loggers to be cost effective and low power, but as they are feature rich and practical in use as well, we see a growth in deployment of more power demanding monitoring applications. Think of applications with power hungry sensors or sensors that need to be powered continuously. In such applications a bigger battery (than just one 26650 or a few 18650 cells) is inevitable. f the total current drawn by your connected sensors surpasses the limit of the data logger’s power switch, you can leverage an on-board relay to power the sensors directly from the 12V battery

For more detailed info, please consult the power board manual.

Please use our on-line Data logger power consumption calculator to estimate the battery life of your application.



  • Charge controller
    • Battery over charge protection (auto switch-of above 14.4V)
    • Battery low voltage protection (auto switch-off/on outputs at 11V)
    • Charge current: 1.6A maximum
  • Solar input (X1)
    • Nominal voltage: 12V
    • Open circuit voltage: 21V recommended, 30V maximum
  • Battery input (X2)
    • Voltage: 12V nominal
    • Supported chemistry: SLA (Sealed Lead Acid) or LiFePO4
    • Capacity: 2.7Ah minimum, no maximum
  • Outputs (X3 & X4):
    • Regulated 3.6V (max 2A) to power the data logger (X3)
    • Unregulated 12V (max 4A) to continuously power external devices 1)2)
    • Unregulated 12V (max 4A) switched output relay to be activated from the logger 12V power switch
    • Battery voltage monitoring 3)
  • Enclosure part
    • IP68 (30min@2m) waterproof enclosure.
    • UV stabilized polycarbonate.
    • 130x120x40mm, 185g.
    • Silicone gasket
    • 4x stainless steel (A2/W4/304) M4 bolt (25mm)

1) Sensors that only require power during sampling should be powered from the 12V power switch of the ML-417.

2) Sensors that require continuous power could be connected to the terminals of a 12V battery directly as well, but its better to connect them to the outputs of the charger board as they will be switched of in case of a depleted battery to avoid damaging the battery.

3) The battery voltage monitoring pin reflects the battery voltage divided by 2 to be able to connect it to a 10V analog input of an ML-417 (Don’t forget to multiply the measured value by 2 again).

Tip) Small capacity 12V batteries like the Pbq 2.9Ah could fit into an empty ML-417 enclosure (ML-BOX + ML-COVER), if their dimensions stay within 92x74x64, 112x74x64 or 92x98x64 mm.

Discover the possibilities

Want to know more about what YDOC can do to help you with your quest for the right data logger? Do not hesitate to get in contact.