The hotter the electrolyte, the more it eats the plates. Every 10 degrees C doubles the rate at which the electrolyte chews up the plates
N and S designations have absolutely nothing to do with plate thickness, it is about the density of the specific gravity.
A battery meant for cold climates might have a fully charged specific gravity of 1.300, and a battery meant for hot climates might have a full charge specific gravity of 1.265. The exact numbers are not important, the density of the electrolyte meant for a cold climate is higher than that intended for a hot one.
Do not confuse specific gravity with voltage, I did not screw up the placement of the decimal point.
Likewise a battery that is low on water but is still above the plates, if fully charged, will have a higher specific gravity reading than one which was recently topped off with distilled water, and fully charged. It will also read a higher rested voltage and perform slightly better, holding higher voltage under loads.
How many of you have noticed a battery seemingly beahving poorly, to find low water levels, then fill it back up, to have the battery jump off the cliff soon after? Filling it up reduced the strength of the likely already weak electrolyte on the likely already sulfated battery and then it performed worse.
The recently topped up battery would perform worse on an actual Load test for CCA than it would when its electrolye level was just above the plates.
People in hot climates wanting to extend their battery longevity would not only keep it fully charged, but would top the battery off with distilled water to lower the acid concentration slightly so that the hot sulfuric acid does not chew on the plates as rapidly.
Note that does not mean filling the battery cells to overflowing. There are some arms which hang down into each cell, Fill to within 1/8" of these arms, when the battery is already fully charged. Do not fill it to there on an undercharged battery then try and fully charge it, as then it will likely spew some electrolyte from the caps, which then refilled to the proper level would have less dense electrolyte..
Care should be taken so than nothing other than distilled water enters the cells. Any debris entering the cells, is not good, and with recessed caps it is hard to actually get water in them without introducing any debris into them. It is hard to even clear the debris away from the openings without some Q tips some care and patience.
Wearclothes you do not care about when opening the cell caps, and use eye protection.
I do not think there is any topic more misunderstood on automotive forums, by otherwise wise mechanics or the maintenance minded bitoger, than the lead acid battery and its requirements for reaching near its maximum expected lifespan. Lesser lifespans seem to be acceptable, and the actual sticker on the battery is somehow more important to the consumer, that the actual treatment of the battery, which wants to be fully charged always, and kept cool.
Batteries with removeable caps require a hydrometer to actually indicate full charge, not a floating ball type. A smart charger's green light is a liar, which would be proved by the hydrometer, if one were actually ever employed by those with ultimate confidence in their smart charger and its marketing literature or those who think the vehicle and its 165 amp alternator are the alpha and omega physics defying battery charging god..
Do not assume your vehicle's charging system is actually holding your battery at full charge. it takes no less than 3.5 hours to charge a relatively healthy battery from 80% to 100% and that is with a charging source holding voltages in the mid 14 range for those 3.5 hours, which few if any vehicles will allow. An Unhealthy battery takes longer, and perhaps much much longer.
Once can deplete a 100% charged battery to 80% in a few minutes of blasting their stereo with the engine off, but getting that battery to a true 100% state of charge, is likely not going to occur with a 4 hour highway drive.
Proveable, time and again, with a hydrometer. But nobody will ever bother to use one. They will just abuse a battery by keeping it in a well undercharged state and complain about battery quality when it fails in a short period of time.
