Battery





















A modern battery won't discharge any faster on concrete than it will on a wood or a metal shelf.





A modern battery won't discharge any faster on concrete than it will on a wood or a metal shelf.
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Actually cold temps slow down the discharge rate but it gets a little complicated depending on the state of charge the battery has.
You never want the electrolyte in a battery to freeze. The point at which a battery will freeze depends on the state of charge the battery has.
A fully charged battery (100%) will freeze at -77* F (-67* C)
At a state of 75% charge it will freeze at -35* F (-37* C)
At a state of 50% charge it will freeze at -10* F (-23* C)
At a state of 25% charge it will freeze at +5* F (-15* C)
Fully discharged (0%) it will freeze at +20 F (-6.7* C)
So as you can see, if the battery isn't kept at a high level of charge in very cold temps the possibility of the batteries electrolyte freezing increases. If the battery does freeze it is pretty much ruined and will need to be replaced.
For batteries that are stored or left in the vehicle for long periods it is always a good idea to leave them hooked up to a battery maintainer like a Battery Tender. There are different brands that work well just make sure you use a computerized maintainer.
They use various stages of charge rates to keep the battery charged without overcharging. The old "trickle" style chargers will not provide a fully charged condition like the new ones do. The old style chargers can actually do more harm than good if left hooked up for long periods. The new ones maintain a full charge with no danger of overcharging.





If you leave the battery in the car without a charger, at minimum always disconnect the neg. terminal.
If an unattended battery drops below 12.4 volts, sulfation will start which is usually irreversible. cold cranking amps will start to drop off. Get a cheap volt ohm meter to check this.
As others have said give it a high amp charge followed by continuous maintenance charge.
If the battery falls below 11 volts a cell may be compromised. The cells can be checked by removing the caps and using the VOM probes from positive term. to acid in first cell, then cell by cell. All cells should check 2.1 volts, anything much below 2 is suspect.
The general condition of a battery can be determined after a complete charging and letting it set idle for 8 hours then checking resting voltage with a VOM, should be 12.6 volts.
In a completely discharged battery sulfuric acid level goes from 25% to zero, freezing will soon follow.
I am currently experimenting with a desulphating maintenance charger (Battery Minder)
to bring back older batterys out of my boat. One has a resting voltage of 12.3 and the other 10.8 (two of the cells check low).
Andy
Last edited by ahphares; Jan 23, 2011 at 11:10 AM.

Mr.Bill





If you leave the battery in the car without a charger, at minimum always disconnect the neg. terminal.
what would that do? i wonder how much of the battery is being used if the car is not on?

Once the car is on it doesn't use any battery.
Andy





If you have changed the battery before and had no radio problems then either you do not have the Theft Lok radio or the lock code is not set.







last time i changed my battery i dint need a code, were would this code be located at?
