Choosing a Solar Controller - MPPT or PWM

solar-controllers-640x418Standard solar panels produce much higher voltages than are safe to feed directly to a battery, so a solar controller or regulator must be connected between them.

Two types of controllers are available; PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking).

PWM Controllers - When charging, these controllers feed the power from the panel straight through to the battery until
the battery voltage reaches a predetermined Acceptance level. It will then keep the voltage at that level by pulsing
the panel voltage on and off to keep the battery voltage constant.

During the Bulk stage of charging, the amperage delivered to the battery is slightly less than the amps from the panel due to losses in the electronics.

MPPT Controllers - These controllers take the best mix of amps and volts from the panel to give the maximum power.
They then track this Maximum Power Point as conditions change to ensure the highest power is extracted from the panel
at all times.

The DC panel output is then inverted into very high frequency AC and then converted back down to DC to feed to the battery. The result of that inversion/conversion process is that more amps can be delivered to the battery than were produced from the panel, resulting in reduced charging times.

That is a significant advantage over PWM controllers, and more than justifies the higher cost of the MPPT models.

Electrical testing on Frigoboat 12/24v systems

voltmeterWe handle many calls for troubleshooting help, and the vast majority end up being electric problems, mostly with the boat’s power supply to the Frigoboat unit. While the voltmeter on the distribution panel might show more than adequate power, it is what comes out of the end of the two wires at the Frigoboat unit that counts, and there is a lot of potential in the wiring for gremlins to creep in and spoil the party.

Power supply testing on Danfoss DC powered refrigeration systems

To properly test the power supply to a Danfoss powered 12v or 24v system, the following testing procedure must be carried out. This will establish whether the power supply feeding the system is free of bad, loose and/or high-resistance connections. Reading the voltage on the panel or at the batteries is meaningless,

Read more: Electrical testing on Frigoboat 12/24v systems
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