The Flexcharge Night Watchman dusk-to-dawn controller is designed to be mounted outside in a marine salt air environment. It is completely waterproof, and very small (1" x 1" x 1") for mounting in an inconspicuous location.
Because power consumption is always a concern on battery powered systems (sail boats, PV systems, RVs, etc.) the Night Watchman is designed to use an extremely small amount of power in standby mode (only 0.00015A or 0.15mA), yet it is capable of supplying up to 10A of load current.
The Night Watchman will turn 12V incandescent, fluorescent, or LED lights ON in the evening within a half hour of sunset, and OFF in the morning within a half hour of sun rise.
The Night Watchman’s circuitry is designed to prevent flickering therefore it can be used to control 12V fluorescent lamps. 1-year warranty.
Quick guide for selecting the right charge controller
Each time you charge deep cycle batteries with solar panels, it's necessary to use a charge controller in the circuit to protect the battery from over charging, and in some instances from over discharging. The only exception is when using solar panels smaller than 5W. Choosing the most suitable charge controller is simple and only requires two steps:
Step 1 - Voltage selection
Select a charge controller that is compatible with the system voltage. The standard configurations are 12, 24, and 48 volts. If you are wiring your batteries for 24 volts you need a charge controller that is rated at 24 volts.
Some controllers are voltage specific, meaning that the voltage cannot be changed or substituted. Other more sophisticated controllers include a voltage auto-detect feature, which allows it to be used with different voltage settings.
Step 2 - Current capacity
Select a charge controller that can handle the maximum output current of the solar panel (or solar array). The maximum possible current that a PV panel can generate is the “short circuit current,” indicated as Isc in the panel’s label or specs sheet.
It’s recommended to include a safety factor for isolated events as well. For example, a solar panel with a Isc of 7.89 amp could potentially produce an extra 25% on a sunny day with very clear snow pack. (additional light reflected off the snow). This results in a possible maximum of 9.86 amp (7.89 x 1.25 = 9.86 amp). In this case, a 10 amp charge controller would be recommended.
Below you will find a quick guide to choosing the proper charge controller for several popular solar panel sizes.
12V olar panels 5W - 45W
Phocos CM 04 Charge Controller 4A, 12V
12V solar panels up to 70W
Flexcharge PV7D Charge Controller 7A - 12V