Does anyone have any DATA regarding what constitutes a weak automotive battery? This would involve a standard 12 volt automotive battery.
I'm specifically looking for what voltages you would read and/or what amperage you would read when you test the battery.
The reason I ask this is that I went in for a State Inspection the other day and the "commercial" facility tested my battery and told me it was weak and should be replaced. I suspect they were trying to sell me a battery, but I would like to know the true data so I can do the voltage/amperage tests on the battery myself.
Thanks for any help you can give.
2007-10-12 06:32:00 · 5 answers · asked by Dick 7 in Cars & Transportation ➔ Maintenance & Repairs
A good fully charged battery measures 12.65 volts at room temperature, but that doesn't mean it's a good battery! You have to do other tests like a "load test". Read the reference below. There's more to batteries than people think. My advice is to replace any battery that's 4 or 5 years old with a new battery because that's their average lifetime, and you don't want to break down on the road or hassle with them for the price of a new battery!
2007-10-12 06:49:56 · answer #1 · answered by bobweb 7 · 0⤊ 0⤋
make sure the alt belt is tight, run it for 10 minutes to warm the battery, check the battery voltage for 13+ volts and about 10 to 12 amps depending on the alt rating, while running, them have someone turn on the lights preset on high beam and the heater fan at the exact same time to see how much it drops on the volt meter. if you notice a drop below 9 volts take it to autozone or the likes and have them do a computer controlled test which will show if it is the battery or the alt.
2007-10-12 20:51:52 · answer #2 · answered by Mr D 3 · 0⤊ 1⤋
12.75 volts is the norm for battery voltage.If you can get your hands on a battery load tester from say napa ,hook the leads up ,engine off ,hold the switch for 10 seconds ,let go and see how your battery rebounds back.10.5 is a little weak 11.50 is acceptible 12.00 is good.start the engine and read the scale,13.25 to 14.50 is a good charging system ,lights off engine running.the newer cars voltage is control by the ecm.,the older cars are internaly regulated alternators
2007-10-12 13:46:03 · answer #3 · answered by mark H 2 · 0⤊ 0⤋
just go to any Auto Zone, Sears, PepBoys or NAPA. They will test battery and charging system for free and let you know what you need.
2007-10-12 13:39:49 · answer #4 · answered by koma 6 · 0⤊ 1⤋
your battery should be around 14to 14.4volts
2007-10-12 13:36:00 · answer #5 · answered by Anonymous · 0⤊ 1⤋