that is correctIt looks like the Cap bank decaying from 20V to 15V. ( inverted)
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?
A little update...b4 & after pics of a -ve buss bar in the same battery cell.
1125 Spec. Gravity:
View attachment 94489
1265 Spec. Gravity:
View attachment 94488
Yes, I had too much focusing probs (thru the electrolyte meniscus) with non tangential lighting. It is a factor that weakens the science quality.You after photo is more in focus, and has more tangential lighting, biasing the effects.
Try to be more consistent with both deep top lighting ( endoscopic) and side lighting (lateral-scopic), use both methods .
Hi,
So what are you showing here? Is this a picture where before treatment the plates have an oxide coating, then after treatment it is gone? That's what it looks like anyway, which seems good. How did you get that to happen though?
Also, do you know where the oxide went...ie back into the solution or drop to the bottom of the battery case?
Also, does specific gravity tell us anything relevant here, other than state of charge?
I time lapse movie of still shots would be epic.Focus was good, just better :LED for lighting.
They would, but the gassing will make things tricky to discern, not to mention the acid vapour from the bubbles will prob destroy my cheapie endoscopic cam in short order.I time lapse movie of still shots would be epic.
MIkeML as you know the evaporation rate of electrolyte generates a lot of H2 above 15V, which when above 5% exceeds the LEL or lower explosive limit where detonation can occur. Hope you have good ventilation. THat can be effective agitator of plate sulfation at the expense of reduction in acid level.
I have done parametric tests on motive power batteries that would not accept a charge and restored them to new after a week using only 5 watts of pulse power. In every cell, SG, ESR and capacity was restored to normal load cycle rates. THis unit draws so little power but 100x stronger harmonics (tr=50ns) than Mosaic's much more powerful sledge hammer pulses which are slower (10us?). Our small unit was intended for permanent installation on trucks, motive power batteries and those applications where replacement cost savings was a no brainer.
Consumer batteries is more a matter of battery environmental abuse than original quality and in the hot Carribean, Arizona and similar climates batteries probably only last half as long as the rest of North America due to the thermal acceleration effects on Sulphation.
I was Eng Mgr at the time for a Contract Mfg (C-MAC Canada) who made products for dozens of companies including the tiny one that had the patent on this technology at the time. We would make about 25k units a year and now the company that bought him out is qualified with Volvo trucks. ( meaning passed all performance, safety and EMC tests.)
So I can vouch for the validity of some designs, but know that all are not the same and know that not all batteries fail from the same reaction, but I expect he ought to get a significant rejuvenavation rate in that climate.
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