Originally Posted By: JHZR2
Originally Posted By: 3311
Originally Posted By: Doog
wife's Toyota V6 has the "maintenance free" battery but the eye glass is showing red which says "add distilled water" So I tore off the maintenance free sticker and unscrewed the cell caps and added about a 20oz distilled water. Now it is on the charger at 10 amps for 15 minutes then 2 amps until the charge gauge is at or near zero. The cells are bubbling nicely now and there were no dry cells.
Did I just ruin this battery or is the "maintenance free" thing a bunch of bunk? It is a 2008 battery.
Adding the distilled water is fine. Typically you would add it after its charged though as the levels typically rise after/during recharge.
Contrary to what many "tinkerers" like to spout, avoid unnecessary recharging/equalizing. Only charge/boost enough to get your car running. I don't recommend anything more on a typical consumer battery charger, especially a ferroresonant one, they typically do not have the voltage regulation that an alternator does. High voltage is a quick death for automotive SLI batteries. They are float type batteries by definition and their construction doesn't lend well to over charging especially high voltage, anything over about 14.2 volts or 2.37 volts per cell is to high.
Edit: The reason they have a minimal tolerance for over charging is because unlike deep cycle batteries they have very thin plates and grids which are very sensitive to corrosion(caused by high voltage)as well as a much finer past/lead oxide. Not to mention the positive plate wrapping, essential to keep active material on the grid/plate, isn't thick enough for high voltage recharging like you would see with a deep cycle battery.
Id agree that unnecessary recharging may not provide any value.
However, I have two issues with your commentary:
First, most modern alternators will put well over 14.2V out, which means that the battery is seeing that on "float" duty attached to the electrical system.
Second, the alternator typically is not current limited, and so if a battery is at a low SOC, the alternator may source more current than desirable for a recharge, which should generally be between C/20 and C/5 max. Modern chargers are power electronics based and have pretty fine control of this (as long as the user sets it right). Good ones even have three or four mode charging scenarios to include all the right phases to get an optimal charge, something that an alternator just wont do.
Curious as to why you think that an equalization charge on a battery that is NOT designed for deep cycling, but has been either due to self discharge or misuse, would be an issue. There are a ton of things that seem to offer benefit in terms of sulfidation, balancing, etc. Different manufacturers offer them in different ways. Charging at 8 or 10A on an 85Ah battery and doing these things isnt going to pummel it with a ton of current and damage, and the time at voltage, which is really key, is so relatively short that I cannot imagine that the kinetic effects of corrosion and whatnot are viable, especially at cooler temperatures. In AGM batteries, which are getting more popular, recombination is so much better/faster, that dry-out is not an issue, because offgassing to the ambient is about 1% of a normal flooded battery.
Would love to get more of your thoughts on this, since apparently I am a "tinkerer" who is wrong (yet has batteries in service that are >10 years old).
Let me see if I can address your questions one by one:
-Modern alternators will not put high voltage for vary long if at all. Certainly not long enough to damage the battery.
-High initial current from an alternator is not detrimental. It will only be high(with respect to battery recharging) for a relatively short period of time.
-Equalization is not typically necessary for a battery in float service. What do you think an properly functioning alternator is doing after the high current initial recharge? The battery is effectively being equalized by the float charge its receiving from the alternator. Abnormal sulfation and cell voltage imbalances will occur from repeated under charging, not something an automotive battery experiences if used with any regularity.
-Overcharging is extremely detrimental, even at cooler temperatures, Read the last part of my post you quoted with regard to SLI battery construction. When these batteries are excessively gassing(over 2.37 vpc), even for a short period of time, even on a relatively cool battery you are corroding(abnormally) the positive grid and shedding(abnormally)active material. Look inside the battery after you recharge it. That black/dark red/grey slushy, goopy stuff you are seeing on top of the strap and plates is lost active material. This something we need to cognizant of even on the very large industrial batteries which are infinitely more robust in design and construction.
-AGM/Gel batteries. They are a technology borrowed from temperature controlled Stationary/UPS applications designed to reduce significant maintenance costs/man hours in maintaining these strings of cells. IMO a complete misapplication for automotive use and ridiculously over priced. AGM(Activated Glass Mat)and Gel are "starved electrolyte" technologies, they basically have less electrolyte than a comparable flooded battery. Hence they cannot achieve the same capacity as a flooded electrolyte battery of the same given cube or plate size. Not sure where you heard the "recombination is better/faster", the process is the same, they may recharge faster due to the lower capacity this could be where the manufacturers are getting their efficiency claims. And of course they don't "dry out", they are SVRLA(sealed valve regulated, they only "burp" a few times in their typical life cycle.
I guess I should give the battery manufacturers credit for getting people to buy something that costs less to build, will last half as long, provide half as much power and sell it at twice the price. And before anyone claim about their warranties, there is so much initial profit they afford the long warranties. I promise you none of the manufactures are using these batteries extensively in their vehicle fleets.