Creating a High Power Desulfator

Using semiconductors as switches in parallel is feasible and works better when the components are matched in properties. In our battery formation unit we use IGBT blocks as switches for 300 VDC/ 50 Amps. 1 6 batteries of 12 Volts in series and the Acid refrigerated. Just to mention that you do not have to use these in parallel.

IGBT's have very high current capacities. Also work one battery at the time. We work with new stuff that has no sulfide and sulfate deposits.

It all depends on your supply, from which you're going to feed your MOSFETS. I think of reverse voltage in the off intervals, and eventually HF oscillation that can occur when not filtered adequately or when the Ri (Internal resistance) of your supply is too high.

You are not going to do magic recoveries. Desulfation can only be done, almost by accident, on young batteries, without any warranty to recover the battery. What we call lead plates are no solid lead structures but a compressed frame of "contaminated" lead that gets used up in time and easily falls apart.

Yep that's the part they don't tell you about when desulfating batteries.

A battery going bad solely from sulfation is rare. The vast majority have compound failure issues that do them in. I would be surprised to see more than 1 in 10 make it past a 50% recovery by desulfation.

I made a high voltage (180 VDC @ 2 or 10 amps) constant current charger out of scrap electronics parts years ago just for regenerating dead batteries and to be honest I think out of the dozens of stone dead ones I used it on I have maybe had three come back to life to any degree of being usable.

I had a few that temporarily came back and tested good but within a week or less they were dead again.

The majority had internal shorts or open circuits which are not fixable by any reasonable means.

Most IGBT manufacturers have isolated gate drivers matched for their IGBTs that can reach thousands of amps if you need it. All you supply is usually +/- 15V and the control pulses.

You still have to worry about cooling, DC bus filtering... Inductance on the collector / emitter of the IGBT is likely to kill it from over-voltage. You must use the proper circuit configuration and layout. Fast fuses are needed in case the IGBT fails short...

Be careful as lethal voltages can be generated and the battery can explode or splatter acid.

So what type and how big are these batteries and what level of sulfation recovery are you expecting?

I am just curious being that when a LA battery sulphates up they also tend to have a considerable amount of irreversible plate and internal connection damage as well.

My desulfator is for very large batteries. 200Ah and over. It will consist of a capacitor bank charged to 80v. Some parallel mosfets will be used to send the high current pulses into the battery. I looked at a similar project and they don't use any diodes on the mosfets.

I had a set of 6 volt 250 Ah Exide batteries that I used to use with my AE power experiments.

Once they got old and sulfated up the plates were also falling apart and physically shot.

Nothing electronic can fix that which is why I am curious as to what batteries you are trying to restore and to what actual success rate or percentage of recovery you expect to get.