my p.w.m & mppt charge controller

A Solar Charge Controller might well be the most complicated part of the whole solar electric system, even more so then most inverters. To start with there is MPPT (Maximum Power Point Tracking) and PWM (Pulse Width Modulation), Diversion loads, Equalizing charge, Bulk charge, Float charge and many more terms.

An MPPT charge controller is the top of the line charge controller on the market. It is able to track or trace the input power from your solar array and the voltage from your battery bank. It then re-adjust the voltage for the highest amp output to charge the battery bank. An MPPT charge controller is capable of taking a higher voltage and down converting to a lower voltage. In my testing of the MPPT I have found about a 10% to 12% loss of power from the input side of the charge controller to the output side which is about the best you can expect. A Charge controller uses power to do their job just like any other electrical device.

Keeping things simple lets use a 24 volt solar array and a 12 volt battery bank. If the solar panels have an output of 24 volts and 5 amps and your battery bank is at 12 volts. The Mppt charge controller will down convert the voltage from 24 volts to 12. And while doing this it will double the amps to 10 amps. So you would have 12 volts and 10 amps to charge the batteries with.

One other great trick Mppt the mppt charger is capable of, It adjust with cloud cover or edge of cloud brightness. With my 810 watts in panels I have seen output to the battery bank of as much as 1048 watts. I am sure this was edge of cloud performance. A non mppt charge controller would have suppressed this spike and the extra charging boost would be lost.

A standard charge controller without MPPT when charging connects the panels direct to the battery