pop the top on a maintenance free battery?
- Thread starter Master ACiD
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This threads answers many questions for me. Thank you Master Acid. I will now be topping off the batteries in our vehicles with distilled water left over from my last coolant change, and hopefully they will last longer than the 2-3 years I've been getting recently. Texas heat kills batteries and mostly due to them losing water. Can't find a low-maintenance battery ANYWHERE worth the asking price. So a cheapo 5-year "maintenance-free" $40 AutoZone battery ought to last me 5 years now that I can maintain it without worrying about having the case not go back together.
a) batteries give off hydrogen and water vapour in any decent quantity. What else do you think they're losing? Electrolyte is typically sulphuric acid, H2SO4. Hydrogen and oxygen can separate and recombine as part of electrolysis and none of my batteries have ever stunk of sulphur emissions.
The lead in the plates changes between lead sulphate and lead or lead oxide. As a battery ages, precipitates form and reduce the effectiveness of ion transfer to the plates or drop to the bottom of the cell and short the cell. I don't believe that the addition of more H2SO4 can save a battery in this condition despite the fact that this adds more sulphate ions. There are de-sulphating trickle chargers that use a certain frequency pattern to break up sulphates (or so they claim). Sulphation is made much worse when a battery is not kept at 100% charge at all times.
b) I never stated that the *only* way for a battery to lose capacity was by exposing its plates to air.
today i find the reciept for the battery. what do you know its only 1.8 years old and its got a 2 year free replacment. so exchanged it for a new one.
maybe the original battery would have lasted longer sence i popped the top, but sence i got free replacment, i dont care. a new battery is awalys better.
i also made SURE to get a replacment battery which has removable caps. so i dont have to go through this again.
maybe the original battery would have lasted longer sence i popped the top, but sence i got free replacment, i dont care. a new battery is awalys better.
i also made SURE to get a replacment battery which has removable caps. so i dont have to go through this again.
It's good that you got a 100% free replacement. A new battery is always great, but not getting stranded in the first place is better
I try to regularly check the specific gravity of my batteries. When fully charged, this will tell you how much of the original design capacity is remaining in the battery. When it drops below 50% I start thinking about a new battery. With my annual/semi-annual distilled water topups this seems to be every 5-6 years or so.
I hung onto one of this batteries since it was still "50% good", within a couple of months it had a shorted cell. I did a reasonably good job of keeping it fully charged. Lesson is - that battery would likely have stranded me within a couple of months of replacement.
I try to regularly check the specific gravity of my batteries. When fully charged, this will tell you how much of the original design capacity is remaining in the battery. When it drops below 50% I start thinking about a new battery. With my annual/semi-annual distilled water topups this seems to be every 5-6 years or so.
I hung onto one of this batteries since it was still "50% good", within a couple of months it had a shorted cell. I did a reasonably good job of keeping it fully charged. Lesson is - that battery would likely have stranded me within a couple of months of replacement.
I feel your pain, California heat kills batteries too. The water loss is one part, sulphation build up due to the high external temperatures is another.
Craig in Canada is now on the right track, these precipitates in the battery world are called sulphate crystals. As they grow and age they become harder, the growth process expands the plate, the plate has nowhere to expand since it is sandwiched into to the battery under pressure to resist vibration, so the plate buckles causing the crystals to fall to the bottom of the battery.
Only if you do not over exceed the 1280 specific gravity limit, if you do you will destroy the battery as it will enter into a self-short phase.
Good, so why is the specific gravity going down if nothing is being lost from the battery. Craig you are getting there.
Master ACID good thing you kept your receipt, at least they honored the warranty, I already lost my 36month free replacement receipt, hope that the California heat will not kill my battery.
Speaking of batteries and hot weather.
While my wife's 2001 Catera was under the original 4 year warranty the dealership had to exchange the Delco battery every year,one original and three replacements, because of our hot Vegas summers and the cheap GM batteries. I asked them why don't you give us a better battery and they replied "we have so many we have to get rid of them ". Of course it cost them money to send out a truck and tech to swap batteries,
so much for General Motors financial problems!
While my wife's 2001 Catera was under the original 4 year warranty the dealership had to exchange the Delco battery every year,one original and three replacements, because of our hot Vegas summers and the cheap GM batteries. I asked them why don't you give us a better battery and they replied "we have so many we have to get rid of them ". Of course it cost them money to send out a truck and tech to swap batteries,
so much for General Motors financial problems!
Nothing IS being lost from the battery.
The specific gravity is going down because of "sulphation"-- "hard" lead sulphate that cannot be converted back into lead and sulphuric acid by the recharging process. This is why batteries lose capacity.
I fail to see how adding acid to the battery can resolve this problem.
He's betting that the S04- ions tied up in the sulphates can be replaced by adding sulphuric acid instead of just water and actually make a difference. If done in conjunction with a specific gravity test, this might be beneficial.
For the purposes of this thread, however, most people add water because their charging system "boils" it off (electrolysis), or it evaporates, not because _liquid_ level in the cells is somehow lost due to sulphation. In the _normal_ case of joe-blow-non-chemist, adding H2O would be the _normal_ maintenance to be performed. Even if the SO4 ions are replaced after sulphation, the presence of the sulphates themselves kill the battery with warped gunked up plates and crystaline cell shorts, not the lack of SO4 ions in the electrolyte.
The specific gravity test can give you an indication of the sulphation condition of your battery and hence its useful capacity. Adding H2SO4 will trick the specific gravity test but isn't likely to make your battery actually perform better IMO.
For the purposes of this thread, however, most people add water because their charging system "boils" it off (electrolysis), or it evaporates, not because _liquid_ level in the cells is somehow lost due to sulphation. In the _normal_ case of joe-blow-non-chemist, adding H2O would be the _normal_ maintenance to be performed. Even if the SO4 ions are replaced after sulphation, the presence of the sulphates themselves kill the battery with warped gunked up plates and crystaline cell shorts, not the lack of SO4 ions in the electrolyte.
The specific gravity test can give you an indication of the sulphation condition of your battery and hence its useful capacity. Adding H2SO4 will trick the specific gravity test but isn't likely to make your battery actually perform better IMO.
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If this were true why do so many people here report corroded terminals on their batteries, especially the negative terminal. What happens during charging is that O and H gasses are released during electrolysis, they alone cannot corrode battery terminals, but what happens is that as they bubble to the surface of the battery they create a fine mist, this fine mist consists of electrolyte which is water + sulfuric acid. When the electrolyte mist leaves the battery it then settles on top of battery contacts, the electrolyte reacts with mostly the negative terminal, causing a one way discharge and the electrolyte turns into a white powder, the sulphate crystals which are also formed on battery plates when batteries are being discharged.
This is why it is very counter intuitive to be suggesting adding acid to a battery, most people assume that only water is being lost either by evaporation or being broken down due to electrolysis.
Sulphation is only one part of the reason, remember that chemistry also tells us that no chemical reaction, however violent it may be, will never completely react, there will always be some amounts of reactants or products left behind, another reason why specific gravity starts inching down. The reason why sulphated batteries lose capacity is because when batteries are left at a discharged state, or a semi discharged state these sulphate crystals harden, hard crystals are much harder to convert back to active electrolyte.
Reason why sulphated batteries lose capacity is because there crystals take up real estate on the plates, battery current is directly proportional to how much plate surface is available. Some hard crystals break off due to vibration as mentioned before, they fall to the bottom of the cell into the space underneath the plates, they are for ever lost and cannot be converted back to active electrolyte, another reason why batteries lose specific gravity.
So the question is how to battle sulphation in high heat environments, increase temperature from 10C to 20C and you are doubling the kinetic motion of the atoms. Battery that can last a full year at 10C before being discharged will only last ½ the time at 20C. Raise the ambient temp to 30C and we quadruple the kinetic motion of molecules when compared to 10C thus our battery will only last ½ of the already ½ so it will need recharging every three months.
One way is to connect the battery to a slow trickle charger, hard crystals need more time to convert back to active electrolyte. Likewise when we have a semi-discharged battery, the crystals on the plate cause resistance, the battery does not accept charge as easily so when it is blasted with a high current from the alternator voltage rises instantly to a charged state. The regulator falsely assumes that the battery must be charged as it is no longer accepting any incoming current so it drops the charging current to accommodate the state of the battery. Trickle chargers are designed to slowly force electricity back into the battery regardless the charge level, thus helping to battle sulphation.I personally use a much hated de-sulfator here on all my batteries as it has produced consistent results across a wide range of batteries. And believe me, heat in the central valley punishes all of my batteries, no matter how good they may be.
When we decrease the specific gravity of electrolyte, it is much tougher for ions to get from one plate to the other. This is called resistance R, when batteries are charged or discharged they dissipate heat due to (Isquare)R loss. So the lower the R in our equation, the higher the efficiency of our battery.
Sometimes when new ideas are being brought forth we as humans tend to look at them like the prisoner in the Allegory of the Cave written by Plato, new knowledge is like the sun light striking out eyes, it hurts we don’t like it because we have never seen the sun before, we want to close the door and go back to our old ways of thinking or doing things as we feel much more comfortable in our old world that the new.
The regulator has no idea how much charging current the battery is taking. The regulator cannot distinguish between a 30-amp load from the engine cooling fan (for example) and a 30-amp load from the battery.
What does happen is that the voltage regulator starts cutting back on the alternator's output voltage as more current is drawn from it, I believe this is due to (1) the temperature compensation built into most voltage regulators (more heat=less voltage) and (2) the alternator/regulator heating up due to the current draw.
This would result in the typical alternator putting MORE voltage into a battery that is not taking a lot of current from the alternator.
In order for the alternator to falsely assume that the battery is fully charged and then drop the charging current, it would have to cut back on the voltage output when the current draw decreased. (The only way to drop the charging curent is to drop the voltage going into the battery--this is Ohm's law).
I have never seen an alternator operate in this manner. Such an alternator would also increase the voltage output when the current draw increased--exactly the opposite of the behavior I have observed.
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The trickle charger I have never exceeds about 14V into the connected battery. I have measured it. The electrical system of most cars varies between 13.8V and 14.5V depending on outside temperature, with about 13.8V in the summer and 14.5V in the winter. (Temperature compensation).
I don't see what a trickle charger is going to do that the car's electrical system won't. Volts are volts, and ohm's law tells us that a battery with a given state-of-charge being fed a given voltage is going to consume a given amount of current no matter whether it comes from an alternator or a trickle charger.
If you're talking about an unregulated trickle charger that outputs, say, 16V when there is little current draw, that is a different story. I would not use those chargers on any battery where you cannot add water because they WILL cause gassing and subsequent water loss unless you disconnect them as soon as the battery is charged. Perhaps applying high voltages to sulphated batteries will revive them but I didn't have much luck with that when I tried it.
I suspect that is more due to a crack or separation between the plastic case and the battery post which is allowing electrolyte to exit the battery. Perhaps this is caused by people hammering battery terminals on and other types of abuse. I've actually prevented this problem on a battery that had a pretty severe corrosion problem by putting silicone grease around the base of the terminal where it came out of the top of the battery. I didn't put the grease anywhere else on the terminal--the top of the terminal and the battery clamp itself had no grease. It stopped the corrosion.
The vent caps I've seen seem designed to prevent electrolyte mist from leaving the battery. And, for that matter, liquid electrolyte itself. I had a deep-cycle marine battery tip over on it's side and wonder of wonders NOTHING leaked out of it.
Patent on a ganged vent cap:
http://www.patentstorm.us/patents/5549986-description.html
It is designed to prevent spillage and to prevent mist from leaving the battery.
http://www.patentstorm.us/patents/5549986-description.html
It is designed to prevent spillage and to prevent mist from leaving the battery.
While I don't have time for another interesting/lengthy reply, I will state that I have a maintenance charger with de-sulphating function. It has a MAX charge rate of 2A (I don't think it actually reaches that on a battery in any reasonable state of charge) and switches from charging to desulphation mode when the terminal voltage reaches a certain value. When the terminal voltage drops below a particular voltage (there is a hysteresis curve involved) it will go back into low current charge mode.
The desulphation mode is supposed to be a low current signal of a particular frequency designed to continue to break up hard sulphates while not applying a real charging current that will cause off gassing or hydrolysis. Even if it's all marketing-speak, it was a decent automatic maintenance charger which senses voltage and has cabling and connectors that was easy to work with so either way it fit my needs.
I used to have a seasonal, low mileage special interest vehicle on which this charger lived most of the time. Once in a while I put it on my "daily" driver for a couple of days.
The most important thing is to keep your batteries charged to slow sulphation effects. I've generally found that my road vehicles' batteries are often not quite fully charged and will accept a couple of hours on the maintenance charger before switching to desulphation despite having a good resting terminal voltage. Modern vehicles have more onstar, lojack and alarms drawing small current when fully shut down and that doesn't help the issue.
The desulphation mode is supposed to be a low current signal of a particular frequency designed to continue to break up hard sulphates while not applying a real charging current that will cause off gassing or hydrolysis. Even if it's all marketing-speak, it was a decent automatic maintenance charger which senses voltage and has cabling and connectors that was easy to work with so either way it fit my needs.
I used to have a seasonal, low mileage special interest vehicle on which this charger lived most of the time. Once in a while I put it on my "daily" driver for a couple of days.
The most important thing is to keep your batteries charged to slow sulphation effects. I've generally found that my road vehicles' batteries are often not quite fully charged and will accept a couple of hours on the maintenance charger before switching to desulphation despite having a good resting terminal voltage. Modern vehicles have more onstar, lojack and alarms drawing small current when fully shut down and that doesn't help the issue.
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I've read that before. Would be interesting to put a scope on the output of that charger.
I've heard some claim that the 60Hz output of typical plug-in AC battery chargers (the output is not filtered so it's pulsing DC) helps sulfated batteries.
I agree with the statement about corrosion around battery terminals being from cracks or such around the posts. I've had that issue in the past, and found the simple solution was the felt washers (red and green) you can buy from any automotive parts store. These perform the same function as putting silicone around the base of the posts, but look neater. I would guess that if the corrosive gasses were coming from the vent covers, the tops of the battery posts and battery terminals would still get corroded. But if it comes from cracks around the posts, the felt washers "seal" it or somehow neutralize the acidic gasses. That's my guess.
And like all ready stated, a lot of people actually hammer their battery terminals on the posts. I can see how this could cause hairline cracks in the plastic surrounding the posts, allowing gasses to vent straight up the post.
Interesting info on the sulfation problem and how to prevent it (trickle charger). I've been meaning to get a battery charger for general use, and need to gather info and opinions. It would be used mainly for periodic maintenance of automotive batteries that may be a little low due to non-use or lights being left on. But it would also be used on my riding mowers 6 volt to maintain it between cutting seasons. Being able to "refresh" a battery (due to sulfation) would be a definite plus. Like already posted, today's vehicles have constant electrical draw that can't be good for the battery. My last one in my Maxima lasted just past the 2 year free-replacement. A new one was pro-rated, but it's still inconvenient to deal with. Our Louisiana heat is apparently not nice to batteries from what I've read.
Dave
I think it might actually be electrolyte that is slowly leaking out of the hairline cracks around the posts--consider that the electrolyte sloshes around as you drive the car and it seems very likely that a small amount of it will leak out there, enough to cause a bit of corrosion.
This is the patent I found on the underside of a ganged vent cap from a Costco (Johnson Controls) battery:
http://www.freepatentsonline.com/5284720.html
This appears to be a common design found on most Johnson Controls batteries.
From the patent:
"The two problems previously mentioned, i.e. electrolyte spillage and gas evolution, are really interrelated and equally important in the construction of an effective vent cap system. For example, electrolyte may enter the vent cap through several mechanisms. One mechanism is through vibrational or tilting spray of electrolyte into the cap, and another is through a mechanism frequently referred to as pumping. The latter occurs when gas evolved in the battery bubbles from the cells and carries or forces electrolyte out the fill hole and into the cap. When electrolyte enters the caps of prior designs it may be carried out the exhaust passageway to cause damage to external battery components such as the battery terminals or adjacent engine components."
This patent was filed in 1993, by the way.
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Oh really...
Just because something is patented, that does not mean that it will necesairly work as proved time and time again on this board. It's a unique way of solving a particular problem wile not allowing the competition to copy a particular design.
It seemed to work well when that deep-cycle battery tipped on it's side. *Nothing* leaked out. I repeat, *NOTHING*.
Sealed batteries actually are designed to hold some pressure, either 2 or 6 psi, I can't remember which. This, along with a bit of calcium, essentially "recycles" the fluids. There is a valve to vent excess pressure if it's charged too rapidly and outgases too quickly.
If you pop the tops, you'll basically lose the "maintenance free" element because it won't hold any pressure. I've popped the tops and never found them low on fluid. Ones I've seen have the plates lower in the cell with more water available to lose before they dry.
Interesting note, the maint-free batteries require a slightly higher charge voltage than the regular batts, due to the different chemsitry. That's why some of the higher-dollar automatic chargers give you a switch "gel/maint free | standard" or the like.
General rule of thumb, warmer climates should use regular batts, check fluid regularly. colder climates should go sealed.
Also interesting to note that some manufacturers (never been able to confirm this one) calibrate the vehicle for one type or the other (voltage set to battery type), depending on whether its a sealed battery or not, based on the climate (hot vs cold) it's sold in, in the US.
Me, I wont pop the top on a sealed batt again. Done twice. They were aged, sluggish to crank, still had plenty of fluid, so no gains there.
Mike!
If you pop the tops, you'll basically lose the "maintenance free" element because it won't hold any pressure. I've popped the tops and never found them low on fluid. Ones I've seen have the plates lower in the cell with more water available to lose before they dry.
Interesting note, the maint-free batteries require a slightly higher charge voltage than the regular batts, due to the different chemsitry. That's why some of the higher-dollar automatic chargers give you a switch "gel/maint free | standard" or the like.
General rule of thumb, warmer climates should use regular batts, check fluid regularly. colder climates should go sealed.
Also interesting to note that some manufacturers (never been able to confirm this one) calibrate the vehicle for one type or the other (voltage set to battery type), depending on whether its a sealed battery or not, based on the climate (hot vs cold) it's sold in, in the US.
Me, I wont pop the top on a sealed batt again. Done twice. They were aged, sluggish to crank, still had plenty of fluid, so no gains there.
Mike!
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