A friend just got rid of his car and offered me the battery (long story there), which is as dead as a doornail, but only 1 year old. He said the battery worked perfectly, but eventually lost its charge when he didn’t use the car for months and months.
The battery has a 72-month warrantee. I hate to see it wasted.
Can I store this battery in my garage? Should I charge it first and then store it?
Auto batteries, unlike marine batteries, suffer damage from deep discharge. If the battery is totally dead, it’s almost certainly no good. You could try charging it at a very slow rate, but even if it took a charge (which is highly doubtful) it would not be reliable.
To store a good battery for more than three months:
Disconnect it. Cars normally have low-level electrical consumers, such as computer and radio memories.
Hook up a trickle charger with automatic charging control. Overcharging can ruin a battery in short order.
Not entirely true. Marine and automotive “deep cycle” batteries can and do suffer damage due to sulfation from a severe discharge, like any other lead acid battery, especially if the battery voltage falls below about 10.5 V (for a 12 V battery). They are designed to withstand more of a deep discharge than standard lead acid types, however. It is still recommended that you keep your deep cycle batteries charged if possible, or at least fully charge them prior to storage. Here is some information about the care and feeding of deep cycle batteries.
My Grandfather and father both said to keep batteries stored off of cement / concrete floors. But apparently this is no longer a problem with today’s batteries:
I put my motorcycle batteries on a trickle charger once a month (over night) all winter, out of the bike, and monitor the (acid) electrolyte levels to ensure they don’t boil away. When they get low, I add in a few drops of distilled water to bring them up to the High mark. Some car batteries are sealed and don’t need water added.
Perhaps you can get the replacement and keep it in good condition. Check to see if the setup would allow you to even use it in your vehicle, often the posts are reversed, or on the side or top. Sometime the size, or CCA’s (cold cranking amps) won’t work for you. Depending where it was purchased, it might only be good for the original owner, holder of the receipt, etc…
If it is truly “dead as a doornail” then chances are the cells are chemically damaged. If it’s still under warranty, go get it replaced with a good one, then store the good one properly and don’t let it get discharged to the point where it gets damaged too.
When I replaced a fairly young, but dead, boat battery, I got the new one at Battery Experts. They deal in nothing but batteries and chargers. The fellow there told me that a trickle charger charges just fast enough to evaporate battery water. Once the water falls below the top of the plates, he said, very bad things start to happen, and battery death soon follows. He sold me a BatteryMinder®, which delivers an even-smaller-than-trickle charge. If you store a battery with no charging at all, the battery will soon fail, even if water levels are high. At one time, I nearly understood the chemistry and physics of it, :smack: but I don’t now. It’s just as well. You’re better off hearing it from a Battery Expert. Phone 765-643-6000
I appreciate the thoughtful responses from everyone. Your comments make me wonder about the batteries stored on the shelves of certain retailers. I’ve got to believe that some of these stores don’t rotate their stock very well, meaning that you could purchase a “new” battery that’s actually several months old.
If so, how do these stores keep the batteries at peak performance and what’s to keep them from slowly “burning off” the water inside? Does the fact that modern auto batteries are sealed sharply reduce this burn off? Also: what’s the story on that special battery acid you see at auto parts store? Are you supposed to add it to your battery, rather than distilled water?
And would a marine battery power a car very well? I have no intention of trying it, but I’m wondering how it differs from its automotive cousin. Lower cold-cranking ability?
You can get automotive deep-cycle batteries, too. They cost more than standard lead acid batteries, of course. However, unless you generally go for long periods of time without running your car, they offer no real benefit. Marine batteries are usually deep cycle types because boating is typically a summertime activity, and boats are usually stored or docked for much of the year.
A lead acid battery is just a plate made of lead and a plate made of lead dioxide with sulphuric acid in between. A battery will actually contain several of these “cells” all in one box. Each cell is about 1.5 volts, so if you have a 12 volt battery you have 8 of these cells (or some multiple of 8 in parallel). The lead plate combines with the sulphuric acid to make lead sulphate (PbSO4) and the lead dioxide plate combines with sulphuric acid, plus hydrogen ions, to make lead sulphate (again, PbS04) and water. When you charge the battery, you basically reverse the process and seperate lead on one plate and lead dioxide on the other. If you completely discharge the battery you end up with two pretty much identical lead sulphate plates, at which point it won’t recharge.
The only difference between deep cycle batteries and regular batteries is the thickness of the plates. Regular car batteries use thinner plates to get more surface area in contact with the acid, which gives you more current. A deep cycle battery uses thicker plates, which gives you less current (since less surface area), but for a longer time.
For the same amount of lead, you’ll get more cold cranking amps out of a regular battery. If you get a deep cycle battery with the same CCA rating it’s going to have a lot more lead in it than a regular battery of the same rating, hence it will cost more and will be physically larger.
Nope. Lead acid cells have a nominal open-circuit terminal voltage of about 2 V, and there are 6 such cells in a 12 V battery, not 8. Everything else you said is fundamentally correct.
To be exact each cell is 2.12 Volts fully charged.
An automotive battery has 6 cells. 6 X 2.12 =12.72 Volts fully charged. For ease of calculation anything above 12.6 Volts is considered fully charged.