Mosaic
Well-Known Member
First off, let's not have another dispute over whether batteries are recoverable by desulfation or not. I intend to do some science regarding the matter and that's what this thread is about.
I have devised an approach which I'd like to discuss. Here it is:
Assumptions
1) The equalizing charge (@15V+) serves the purpose to minimize creeping sulfation due to under charging which can happen to individual cells as they age and chemistry alters cell to cell. Thus occasional higher voltage charging has benefits.
2) Analyzing each cell (6 in a auto batt) voltage under constant current charge will reveal differences in cell internal resistance. A higher relative cell Pd => sulfation or grid corrosion etc. An unusually low cell Pd => a developing short etc.
3) After a charge, discharge, equalize cycle, data from step 2 can reveal weak or faulty cells and serve to justify attempts at service or designate for recycling.
4) Swept frequency pulse charging modulation on top of the regular charging current won't harm the battery and 'may' enable enhanced ionic activity in a sulfated cell.
5) The enhanced ionic activity is derived from sharp rise time pulses treating a sulfated cell as a capacitor. Such a cell would otherwise have reduced ionic activity due to IR and Pd increase. Such a cell would induce other series cells to be undercharged due to a faulty end of charge battery voltage being detected. This in turn induces 'creeping' sulfation in other cells.
6) Perhaps 40 to 50% of battery 'failure' is due to sulfation from poor charging regimens.
The science I intend to perform involves dismantling an old battery with bad cells as determined by spec. gravity after proper charging. Reassemble said battery in a transparent polycarbonate case with access to all cells. Examine samples of battery plates under a microscope and take imagery of the samples. Log all this data and assess which plates are sulfated.
Assuming that several cells have sulfated plates (quite likely from a battery put down for a year or 2) the following is carried out:
a) Internal resistance of each cell is measured by both ac and dc methods.
b) Sulfated cells are discharged and then pulse charged with varying frequencies for a fixed time with the same pulse charger.
c) New measurements of internal resistance are taken. Plate samples are taken for inspection under microscope.
d) Results are compared and an assessment is made which may justify further pulse charging cycles.
Am I missing anything useful?
I have devised an approach which I'd like to discuss. Here it is:
Assumptions
1) The equalizing charge (@15V+) serves the purpose to minimize creeping sulfation due to under charging which can happen to individual cells as they age and chemistry alters cell to cell. Thus occasional higher voltage charging has benefits.
2) Analyzing each cell (6 in a auto batt) voltage under constant current charge will reveal differences in cell internal resistance. A higher relative cell Pd => sulfation or grid corrosion etc. An unusually low cell Pd => a developing short etc.
3) After a charge, discharge, equalize cycle, data from step 2 can reveal weak or faulty cells and serve to justify attempts at service or designate for recycling.
4) Swept frequency pulse charging modulation on top of the regular charging current won't harm the battery and 'may' enable enhanced ionic activity in a sulfated cell.
5) The enhanced ionic activity is derived from sharp rise time pulses treating a sulfated cell as a capacitor. Such a cell would otherwise have reduced ionic activity due to IR and Pd increase. Such a cell would induce other series cells to be undercharged due to a faulty end of charge battery voltage being detected. This in turn induces 'creeping' sulfation in other cells.
6) Perhaps 40 to 50% of battery 'failure' is due to sulfation from poor charging regimens.
The science I intend to perform involves dismantling an old battery with bad cells as determined by spec. gravity after proper charging. Reassemble said battery in a transparent polycarbonate case with access to all cells. Examine samples of battery plates under a microscope and take imagery of the samples. Log all this data and assess which plates are sulfated.
Assuming that several cells have sulfated plates (quite likely from a battery put down for a year or 2) the following is carried out:
a) Internal resistance of each cell is measured by both ac and dc methods.
b) Sulfated cells are discharged and then pulse charged with varying frequencies for a fixed time with the same pulse charger.
c) New measurements of internal resistance are taken. Plate samples are taken for inspection under microscope.
d) Results are compared and an assessment is made which may justify further pulse charging cycles.
Am I missing anything useful?