We'll see ![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
The fact that it seems sure that the electric desulfation works does not mean that any desulfator will work.
We should first understand how the electric desulfation works to project a correct device.
Surely, this can't not be based on the stupid principle of resonance of lead sulfate crystals.
As I said before, professionals desulfators produce high current pulses (of the order of 50A peak for a 100Ah battery) of approximately 200 ms every 3 or 4s.
This is my personal theory about that.
For sulfated batteries after a long deep discharge, internal resistance becomes very high and the battery will not accept the charge.
- The acid is transformed into sulfate during the discharge and the electrolyte becomes almost pure water.
The electrolyte is then a poor conductor of electricity, which greatly increases the internal resistance of the battery.
- The sulphate layer is insulative and prevents current flow.
According to my tests, at least part of the battery capacity can be recovered by initially charging the battery with a much higher voltage (30 or 40V for 12V battery) but by limiting the current to about 1A by a serial power resistance. (22R 25W)
Once the voltage across the battery drops to 12V, it can be recharged with a normal charger.
I do not know if we can recover the full capacity of the battery that way.
For batteries sulfated in normal use, manufacturers recommend charging flooded batteries with a higher voltage for an hour each week as a preventive maintenance.
To eliminate this sulfation, the problem is to dissolve the crystals of sulfate.
This is difficult, the purpose of desulfation is to get there by boosting the battery voltage for short periods.
You should know that:
- Sulfate is very little soluble in water, but a little more soluble in sulfuric acid.
- As the electrolyte is saturated with sulfate, it is no longer possible any dissolution of the sulphate.
- It is a slow reaction increasing with temperature rise.