How many amps should a car battery be at?
battery January 26th, 2009I have a 2001 VW Passat and the battery suddenly died. I have had a charger running on the battery for the last 4 hours. The charger is showing that the battery is only at 1.5 amps. Is that normal? How many amps do I have to let the charger get up to until the car will have enough juice to turn over?
It is a 6 amp charger and the battery is about 4 years old.
Battery technology gets complicated, so, here goes!
A new, fully charged battery produces 2.1 volts per cell or 12.6 volts for a 12 volt battery. You must understand what voltage and amperage mean. Voltage is a measure of electrical pressure. Amperage is the amount of current passing through a conductor. As a battery discharges - goes dead - the electrical resistance increases especially with todays maintenance-free batteries. A 6 amp charger probably will not fully charge your battery since the internal resistance of the dead battery is so high. You should slow charge the battery but I recommend a charger with an output of 10-12 amps, see if you can borrow one. With all that being said, replacing your battery is probably the best thing to do because today's cars operate at very high operating and underhood temperatures and this tends to prematurely kill batteries, especially in warmer climates such as the southern or southwest states. Further, as a battery ages, it's electrochemical action to produce electrical current to your car's electrical system is no where as good as it was fours year ago, when it was new, since the battery plates tend to shed the lead oxide over time. So, pop for a new battery, afterall, one wrecker or service call could pay for a couple of batteries for your car and unfortunately you cannot predict where you'll be when the battery dies and leaves you stranded at some strangers mercy! Good luck.
January 27th, 2009 at 5:14 am
the more the battery is charged the less amps it will draw. This is not a test of the battery, however. you can have the battery tested at most part houses.
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January 27th, 2009 at 5:42 am
The 1.5 amps is how much the charger is putting in to the battery. Not how much is in the battery. If the car will start on it's own then start it up and drive it for half an hour.
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January 27th, 2009 at 6:30 am
1st. How old is the battery? 2nd. The battery should be 12 amps.
3rd. It should register atleast 10 to turn over. You may want to buy a new battery.
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January 27th, 2009 at 7:03 am
Couple unknowns here what is the amps on the battery charger? 1.5 amp will take several hours to charge a battery. Try something hook the charger on a car with a good battery and see output from the charger. I would think your battery has several bad cells. Charging into an open battery.
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ASE Master Technician
January 27th, 2009 at 7:39 am
The charger amperage will decrease as the battery reaches full charge.
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January 27th, 2009 at 7:48 am
amps are just the rate of current flowing to the load, what you need is voltage, and that should be right around 12.5V amps to turn it over. a voltage boooster would help for a quick start. amps all depend on the load the voltage is connected to (resistance).
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engine electrical class in school
January 27th, 2009 at 7:55 am
is this the original or 2nd battery ? they only live for 5 years on average, at 1.5 amp. the thing will need to charge for at least 24 hours, check the sides for temperature, warm is OK, hot is not, when your done charging check the voltage it has to be at least 12 v. anything less and you have a shorted out cell either way it sounds like new battery time
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January 27th, 2009 at 8:39 am
a 4 yr old battery is ready for replacement.. especially if it is a service free battery… The meter on the charger tells you the rate that the battery is charging not how charged your battery is. a slow rate indicates that either the battery is close to being fully charged or that the battery is refusing the charge… if the battery is not service free.. and you can check the fluid level inside the battery then, disconnect the battery check and top up the fluid levels in the battery then charge. Be sure to unplug the battery from the car before charging or the power will seep into the voltage regulator and you will lose the charge.
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January 27th, 2009 at 9:12 am
Battery technology gets complicated, so, here goes!
A new, fully charged battery produces 2.1 volts per cell or 12.6 volts for a 12 volt battery. You must understand what voltage and amperage mean. Voltage is a measure of electrical pressure. Amperage is the amount of current passing through a conductor. As a battery discharges - goes dead - the electrical resistance increases especially with todays maintenance-free batteries. A 6 amp charger probably will not fully charge your battery since the internal resistance of the dead battery is so high. You should slow charge the battery but I recommend a charger with an output of 10-12 amps, see if you can borrow one. With all that being said, replacing your battery is probably the best thing to do because today's cars operate at very high operating and underhood temperatures and this tends to prematurely kill batteries, especially in warmer climates such as the southern or southwest states. Further, as a battery ages, it's electrochemical action to produce electrical current to your car's electrical system is no where as good as it was fours year ago, when it was new, since the battery plates tend to shed the lead oxide over time. So, pop for a new battery, afterall, one wrecker or service call could pay for a couple of batteries for your car and unfortunately you cannot predict where you'll be when the battery dies and leaves you stranded at some strangers mercy! Good luck.
References :