Solar Project

Researching and eventually putting together a solar electric system for truck camping this summer.

MPPT controller

Still chewing over upgrading to an MPPT solar controller for my truck. With winter coming and the solar angle declining, an MPPT controller might charge my batteries much quicker than a PWM controller, especially with the sub ideal conditions in the woods.

Low Voltage Disconnect Relay - Solar Controller

MPPT is great as it can buck or boost voltage from the solar panel appropriately to maximize charging speed. In contrast, the Renology PWM controller like I have now works but it’s often either using PWM to reduce voltage (wasting the excess power from the panel) or the panel isn’t producing enough voltage to properly charge the battery in less than ideal conditions. Bucking or boosting the voltage one can trade amperage for voltage and vice versa for the ideal charging voltage and best ratio of resistance for maximum panel efficiency.

100 Watt Panel

I am looking primarily at the Renology 20 Amp MPPT controller, which I’ve seen online for under $100. I would have to rewire a few things to make it work, including mounting it where the large inverter is now and moving that back to the shelf in the cap. No decisions have been made but I’m continuing to think about my options.

The 750 watt hour plus weekend

Over a three day period, I generated and consumed over 750 watt hours of power using the solar panel on my truck. It’s been a hot and buggy weekend so many nights I was up late burning the lights into the wee hours of the day and running the fan to keep cool. But during that 72 hour period at camp I was able to keep my truck turned off and everything fully charged without problems entirely on solar. While my system is too small for powering a house or cabin it works great for camp power, and had no problems when it was relatively cloudy on Saturday.

100 Watt Panel