This will show you how to make your solar charge controller into a desulfator.
This couldn't be simpler. All we need to do this is:
4 6800 Microfarad 50v capacitors
Soldering iron with flux and solder
Some really thick copper wire. 10 or 12 AWG will do.
Step 1: Solder All Capacitors in Parallel and Connect Up
You will need to strip enough wire to go across the terminals of the capacitors. You just need to cover the wires in solder to make two thick bars across the terminals. You then solder your 2 wires for + and - in the middle of the two bars to keep the load sharing as uniform as possible across the capacitors. You then simply connect the capacitor bank in parallel with the solar panel input on the controller. And that's it.
Before I did this, the solar charge controller was silent as the pulse current would only be equal to about 45 amps which is the maximum the panels I have can give. Now, between pulses when the battery mosfets are off, the capacitors charge. When the mosfet is on, the charge is released instantly as a series of high current pulses which are great for desulfating and extending the life of your batteries.
The result is the wires now make an audible ticking noise and putting a magnet next to them makes it louder as demonstrated in the video. My solar charge controller is only 30 amps and it will overheat at 45 amps. That's why I water cooled it.
Ans that's all there is to it. The higher current pulses will help to reduce sulfation and will extend the life of your batteries. It worked wonders on a 255ah Lifeline AGM battery I have.
Here is a video of it working.