charging a new replacement battery before install.

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i have read that a new battery should be charged before installing in a vehicle.wouldnt the vehicle alternater accomplish this? maybe a gentle charge from a battery charger would be easier on the new battery.arent new batteries fully charged when purchased? thanks for any input.
 
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I only buy batteries where there is a month/year date sticker on the top of them so I know how fresh they are. Usually I can get one from the same month. Having said that, I've seen some at W-M that were more than 6 months old. Having said THAT, an alternator is not technically designed to "recharge" batteries. It is designed to keep a certain level of charge on the battery. Alternators can fail more quickly if you make them charge a dead battery too many times.
 
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I always charge a new battery before I install it, usually at a 6 amp rate for an hour or two. I went to a class on batteries, charging and starting systems a few years ago and the instructor recommended charging a new battery before use. He said the battery will last longer if it is charged before use. I agree that checking the date of manufacture is important as getting a fresh battery will result in longer battery use.
 
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I know a store that keeps a handful of batteries on tenders so they're 100% fresh "off the rack" so to speak.
 
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Buy a fresh battery. Last battery I bought from AAP I insisted that a pick my battery from the back room. I demanded a battery made in the current month, not 3 months old.
 
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Originally Posted By: Chris Meutsch
I only buy batteries where there is a month/year date sticker on the top of them so I know how fresh they are. Usually I can get one from the same month. Having said that, I've seen some at W-M that were more than 6 months old. Having said THAT, an alternator is not technically designed to "recharge" batteries. It is designed to keep a certain level of charge on the battery. Alternators can fail more quickly if you make them charge a dead battery too many times.
It doesn't matter to an alternator if it's producing 50 amps to power everything in the car or puttting 50 amps into the battery. It "doesn't know the difference".
 

Kestas

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I always trickle charge my batteries before installing. In fact, ever since I bought my battery charger years ago, and started using it for storage issues, I've had much better luck with battery life and performance.
 
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Originally Posted By: Chris Meutsch
I only buy batteries where there is a month/year date sticker on the top of them so I know how fresh they are. Usually I can get one from the same month. Having said that, I've seen some at W-M that were more than 6 months old. Having said THAT, an alternator is not technically designed to "recharge" batteries. It is designed to keep a certain level of charge on the battery. Alternators can fail more quickly if you make them charge a dead battery too many times.
I get all my batteries at Wally World, with all the batteries they sell I end up with the same month on mine, two months was the oldest i've seen, and no I don't charge a new battery, once installed it always fired right up thumbsup
 
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You should do it with motorcycle batteries where you add the acid. Whatever charge is there isn't nearly enough. I've never done it with car batteries, though you all are tempting me.
 
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If the battery is fully charged it doesn't need charging. The potential problem is that this time of year cars don't have as much spare power to charge so if the battery is low to begin with it might suffer from incomplete charging. A good battery dealer will make sure it is charged, but if you are buying it somewhere to install yourself you should at least check it, and a little trickle charge won't hurt it.
 
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I've always done a high amp charge for about a half hour. Just as a "wake up" for the battery. Typically once it's installed the alternator will top off whatever's missing. And yeah, today's alternators don't like charging up dead batteries, they like to simply maintain. I suppose if you were going down the freeway for 4-5 hours the alternator wouldn't care about charging a dead battery, but how often does this happen?
 
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Modern batteries....the ubiquitous Johnson Controls batteries, which use lead-calcium construction lose charge very slowly when unused. I generally find our boat batteries (our watershow team uses a total of 9 JC batteries to power and start our boats) are nearly fully charged after 7 months of storage each winter. Well above 90 percent charged. I only use "car batteries" the warranty is much better!! The triple rig has 3 batteries from 2007, it again popped right off this spring without any recharging. A battery on a store shelf should easily hold a nearly full charge for many months. Exide: This struggling company still uses lead-antimony construction, same as the batteries our fathers and grandfathers bought. These typically lose 1 to 2 percent of their charge per day, and likely should be charged if they have beeen on the store shelf for a couple of months. Perhaps this was the source of the old superstition that a cement floor sucked the charge out of a battery....yeah it went dead sitting on the floor, but also went dead if it was anyplace else also! Note this conversation does not apply after the battery is in the car, some cars have terrible parasitic drain even when the car is seemingly off. Also, many Mercury Outboards have computers that also drain the battery even when the key is off. (Our team only uses Evinrude ETECS, they have no current draw when off) For those of you unfamiliar with battery chemistry, small amounts of either antimony or calcium is used to alloy the lead plates so they are not way too soft and weak.
 
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A Ford 4G alternator sounds REALLY unhappy when it's charging up a dead battery. Almost sounds like it's about to cry. If it's 12.6+, forget it. Your alternator is never going to find the battery in a better state.
 
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Just check the voltage of the battery before putting it in. Fully charged is supposed to be 12.7-12.8 at about 78 degrees, voltage will be lower in colder temperatures. They do best if they're not charged at more than 10 amps per hour. A typical battery is anywhere from 60-100 amp hours so it depends what the voltage is in determining how long it will take to charge before it reaches a full charge.
 
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THe problem with "dead" batteries and smart chargers is the "short circuit" protection in the charger will prevent such chargers from charging a battery which is so discharged it looks like a short. My son just went through this helping a friend out, he had to use a simple trickle charger to get enough charge into a dead battery to be able to charge it with a "smart" charger. Perhaps alternators in late model cars shut down when they see a dead battery appearing as a short as well, otherwise they don't care where their amps go.
 
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The automatic chargers on boats have the same problem. You have no idea how many times I have gone out to bring $8,000-16,000 in replacement house batteries for a discharged yacht, just to find out that the run-down batteries needed a manual charge before the automatic chargers would take over. Like someone mentioned earlier, they need a good "shock" to get them going too. I usually hit them with 40 amps a piece, after isolating all of the batteries, of course.
 
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