Charge Controllers for RVsThe main function of a solar charge controller is to prevent the solar panels from overcharging batteries. The algorithm or control strategy of a charge controller determines the effectiveness of battery charging and solar panel utilization, and ultimately the ability of the system to meet the load demands.
Additional features such as maximum power point tracking, temperature compensation and equalization can enhance the ability of a charge controller to maintain the health, maximize capacity, and extend the life of batteries.
Two basic methods exist for controlling or regulating the charging of batteries from a solar panel -
A Shunt controller regulates the charging of batteries by short-
Some clever marketers now call this old "On/Off" type of charging strategy "Low Frequency Pulse Width Modulation" due to the pulsing effect when reaching the finishing charge state. However, this is not to be confused with true Pulse-
A series controller regulates the charging of batteries by open-
In effect, it will push the batteries up to a preset voltage regulation setpoint and then instead of turning off, it will begin to taper the charging current from the solar panels. This strategy has been proven to maintain the highest state of charge with the least amount of water consumption.
In comparison, the shunt-
There is a "new kid on the block" which adds Maximum Power Point Tracking (MPPT) to the proven Taper charging strategy. This controller has the ability to "boost" the charging current coming from the solar panels under certain conditions. It does this, in essence, by converting some of the "excess" voltage developed by the solar panels into increased charging amperage. The biggest boost will come when your solar panels are cool and your battery voltage is very low. As the solar panels heat up and the battery voltage rises, the "boost" effect will be somewhat diminished.
Some versions of these controllers aren't truly "tuned" for the needs of the RVer. However, we worked with some manufacturers to design some new controllers with MPPT that are tunable for the needs of the RVer. Check out the 2512iX and the TriStar Maximum Power Point Tracking Controllers