Solar Charge Controller

PWM passes just the amps from the panel to the battery. Hence any panel voltage (and power) higher than the battery charging voltage is lost. It cost less and works good with "12V" panels.

Higher voltage panels need MPPT which converts the panel power (volts and amps) to amps (more amps than the panels can produce) to charge the battery. It costs more than PWM controllers.

Many other factors are involved including required power, panel size/location, cost/watt, wiring, etc.

PWM (Pulse Width Modulation) clips voltage to what the battery needs for charging. Typical panel is 18 volts and is clipped to 13.2/14.8 range depending on program. So you will get Isc x 14 volts as the wattage vs the rated wattage of the panel. Lower cost.

MPPT (Maximum Power Point Tracking) converts wattage by reducing volts and adding amps for correct battery charging. The conversion loses about 5% of power. MPPT is generally used with higher voltage panels or multiple panels wired in series. Higher cost.

With "24v" panel arrays (those from about 190w and up in wattage), you must get an MPPT controller. With "12v" panel arrays (those from about 190w and below in wattage) you can use either PWM or MPPT.

There is no easy way to learn solar for RVing, such as by getting a few tips here. You actually have to do some work yourself. Allow a few months for that :)

Thanks, I know how to use Google...I was looking for an answer and maybe a recommendation from some of the folks here.