Battery charger voltage
Discussion
if its the same charger i have , i made the mistake of just connectiing to the appropriate terminals and leaving it and nothing happened , thought the battery was goosed. then realise there is a button that if you press first brings up a bike symbol and voltage etc, then if pressed again the display brings up the car sympbol and gives the right voltage and charges pretty quick . mine is the auto xs. just press the mode buton till you see a car, if its the same one i got from lidle. its a cracking charger.
fxman said:
Ok, here's the end of the story.
The non-maintainable battery was completely revived. Full marks to the dumb chinese charger. It can reach places where "smart" chargers can't go. My friends, it's not cheap that's the deciding factor, but to know.
All the cells in the maintainable battery have been revived to perfection. But, it was a complete failure. Polarity in 2 cells were completely reversed. These cells may have been like that since the beginning. But the idea they could be like that was so alien to me that I was blind to them even if I did see them. The battery now has 4v = 2v + 2v + 2v + 2v - 2v - 2v. Based on my searches, this may be fixable by completely discharging the battery and then recharge.
I am working at my limit now. So I may well dispose of the battery should I become tired of the play. Neither battery is needed for anything. I am doing them purely for fun and to re-validate my battery cell revival method. The re-validation was a success, and I am very confident of keeping the unrelated 14 year old battery in my car going indefinitely until I run out of chemical supplies.
How did you check the polarity of each cell?The non-maintainable battery was completely revived. Full marks to the dumb chinese charger. It can reach places where "smart" chargers can't go. My friends, it's not cheap that's the deciding factor, but to know.
All the cells in the maintainable battery have been revived to perfection. But, it was a complete failure. Polarity in 2 cells were completely reversed. These cells may have been like that since the beginning. But the idea they could be like that was so alien to me that I was blind to them even if I did see them. The battery now has 4v = 2v + 2v + 2v + 2v - 2v - 2v. Based on my searches, this may be fixable by completely discharging the battery and then recharge.
I am working at my limit now. So I may well dispose of the battery should I become tired of the play. Neither battery is needed for anything. I am doing them purely for fun and to re-validate my battery cell revival method. The re-validation was a success, and I am very confident of keeping the unrelated 14 year old battery in my car going indefinitely until I run out of chemical supplies.
Edited by fxman on Sunday 22 April 12:59
fxman said:
Polarity in 2 cells were completely reversed. These cells may have been like that since the beginning.
I've never seen that, but I've seen an effect which I imagine could lead to it. One failure mode which seems quite common after a deep discharge is for the electrodes in a cell to distort and form fingers that reach across to the other plate and short the cell out. Applying a brief high current to the battery can burn these shorts out so that the cell can take a charge again. However, if you trickle charge the battery *before* you fix the shorted cell, you can get a substantial charge imbalance between cells. Discharging the battery will now reverse change the cells with the least charge in.
I suppose you could use your 'coat hanger' trick charge the individual cells to rebalance them.
GreenV8S said:
I've never seen that, but I've seen an effect which I imagine could lead to it. One failure mode which seems quite common after a deep discharge is for the electrodes in a cell to distort and form fingers that reach across to the other plate and short the cell out. Applying a brief high current to the battery can burn these shorts out so that the cell can take a charge again.
However, if you trickle charge the battery *before* you fix the shorted cell, you can get a substantial charge imbalance between cells. Discharging the battery will now reverse change the cells with the least charge in.
I suppose you could use your 'coat hanger' trick charge the individual cells to rebalance them.
I decided to give up but still hanging on to the battery in case I change my mind.However, if you trickle charge the battery *before* you fix the shorted cell, you can get a substantial charge imbalance between cells. Discharging the battery will now reverse change the cells with the least charge in.
I suppose you could use your 'coat hanger' trick charge the individual cells to rebalance them.
The supposed solution to reverse a reversed polarity cell through discharging was bunk. I totally discharged the battery, this produced no effected on the reversed polarity cells, they remained at -2v. Once again my gut came to the rescue. It came up with the crazy idea of applying the full charge on the individual cells through my coat hanger dippers. The amount of bubbles it produced was terrifying. I am counting my lucky stars for not blowing myself up from the hydrogen. The polarity was reversed following a long series of short start and stop zaps to the cells.
Now, I do have an imbalance in the cells. When the charger is on, I have 5 cells reading 2.5v each. 1 cell moving up and down around 0.5v. If I want to bring that cell back by itself, I need a 2.5v charger. I don't have such a charger and I am not going to buy one. The only recourse I have remaining is to continue to zap that cell and hope a miracle will happen.
Charging the battery in its current state in not useful because I will over charge 5 cells producing too much gas and risk burning the house down. I am nearing the end of the road on this one.
You don't need a 2V charger - you just need a suitable load in series with a 12V charger. An ordinary 12V bulb should do the trick - for example a 5W bulb taking about 0.4A might need a few days to fully charge a cell, but it would get there in the end.
(I still think that deep discharging a battery will have damaged the cells and the current and charge capacity will be reduced even if you get all the cells back to a nominal 2V.)
(I still think that deep discharging a battery will have damaged the cells and the current and charge capacity will be reduced even if you get all the cells back to a nominal 2V.)
I'll call it a loss. Although the reversed polarity could be reversed temporarily by high voltage zaps, it could not be fixed. As soon as normal charging starts, the polarity slowly shifts in the wrong direction. The cell is physically damaged. I can handle sulfation, but not a shorted cell.
One peculiar thing that happened was when the bad cell was zapped, the adjacent cells lost their voltage and became 0v. Not sure what that means, but seems unusual.
One peculiar thing that happened was when the bad cell was zapped, the adjacent cells lost their voltage and became 0v. Not sure what that means, but seems unusual.
fxman said:
As soon as normal charging starts, the polarity slowly shifts in the wrong direction.
That's unexpected and makes me wonder whether you're measuring what you think you're measuring. Anyway, I'm sure you're right that the battery is beyond recovery. I've had cells drop to 0V and then recover far enough to produce a nominal 2V again, but they're never any use afterwards.GreenV8S said:
That's unexpected and makes me wonder whether you're measuring what you think you're measuring. Anyway, I'm sure you're right that the battery is beyond recovery. I've had cells drop to 0V and then recover far enough to produce a nominal 2V again, but they're never any use afterwards.
I measured voltage dropping in the bad cell as the charge progressed. That cell had been "hardwired" by the damage to charge in the opposition direction. It is quite capable of accepting a full charge because the sulfation was removed. But that charge will cancel out the same amount from the other cells when voltage is drawn across the battery posts.Most batteries die from sulfation rather than damage. The normal charge and discharge cycle always leaves behind some sulfation. This builds up over time and leading to eventual battery death. If the sulfation can be removed then the battery will come back alive. Since the problem is created by the charging process itself. Charging a dead/weak battery will simply add to the problem rather than fixing it. If a battery is not physically damaged like mine is, then it can be bought back non-eletrically. A relatively new battery wouldn't have as much sulfate built up and therefore stand a better chance of revival from charging alone.
Edited by fxman on Monday 23 April 11:07
fxman said:
That cell had been "hardwired" by the damage to charge in the opposition direction. It is quite capable of accepting a full charge because the sulfation was removed. But that charge will cancel out the same amount from the other cells when voltage is drawn across the battery posts.
If I understood you correctly, the voltage across the damaged cells is dropping as you charge them. I don't see that as charging in the reverse direction, just that they have been damaged and are no longer capable of taking charge. In any case, the battery is clearly knackered.GreenV8S said:
If I understood you correctly, the voltage across the damaged cells is dropping as you charge them. I don't see that as charging in the reverse direction, just that they have been damaged and are no longer capable of taking charge. In any case, the battery is clearly knackered.
Well it comes from deduction. if it starts at 1.8v and drops as charging goes on, imagine if I didn't zap the cell and that cell is at 0v, Upon charging it will drop below zero and become negative. This is how it attained -2v before I notice the odd polarity. Anyway after sitting overnight, it had reverted to -1.3vYes, it's knacked and yielded some knowledge. If I had that knowledge, I wouldn't have wasted my time and supplies. But I would have done worst if I randomly discarded batteries. I would not have saved the second battery. It's holding charge at 13.13v. It's a calcium/calcium battery, said to have low self-discharge. Hopefully its true, because I am just letting it sit.
fxman said:
Upon charging it will drop below zero and become negative. This is how it attained -2v before I notice the odd polarity. Anyway after sitting overnight, it had reverted to -1.3v
That doesn't make sense. The only way I can see a cell getting a negative charge is to have reverse current through it. That can happen quite easily if you connect a flat or dead cell in series with healthy charged cells, and then discharge the battery. I can't see any mechanism for a lead-acid cell to pick up a negative voltage while being charged forwards, and I think that would probably violate some pretty basic laws of physics.GreenV8S said:
That doesn't make sense. The only way I can see a cell getting a negative charge is to have reverse current through it. That can happen quite easily if you connect a flat or dead cell in series with healthy charged cells, and then discharge the battery. I can't see any mechanism for a lead-acid cell to pick up a negative voltage while being charged forwards, and I think that would probably violate some pretty basic laws of physics.
I wouldn't know about the physics. But my readings are accurate. I put it down to crossed wires in the cell. If I have to blame something, I'd still blame the lidl charger. More than 6 months ago, I was charging the battery to assure myself it was still ok, and it was. It was fully charged and had 13.x volts. Then I thought since the charger had a maintenance mode, why not give it a go. Next day, the battery was at 6v. So it all began at that point.Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff