The battery in my 1997 Subaru Legacy Outback sounds like it's starting to have trouble turning over the engine when I start it, and the battery is a good 4 years old or more (I think car batteries are only designed to last maybe 5 years).
Is there a way I can use my multitester to determine what shape the battery is in? (Is there a level of voltage and/or current it's supposed to put out or something like that?)
2006-08-04 11:44:21 · 14 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
Put your multitester in a mode to read DC voltage, put it across the battery, and have someone else start the car. First, notice the voltage before they put the key in. It should be 12.0 to 12.5V. If it's lower, you have a dead cell in the battery and it should be replaced. If it's higher than 12.5V, something is wrong and you should have your electrical system checked out at a shop. Next, notice the voltage while the starter is turning the engine over. The lower it goes, the weaker the battery is. As a general rule, if it stays over 8 V, that is probably OK. A brand new oversized battery will only get down to 11 V or so; a marginally usable battery might get down to 6V. Thirdly, watch the voltage after the engine is idling. It should come up to 14.0 to 14.5V in a few seconds. If it doesn't, something is amiss in your charging system. Try giving the engine a little gas for a couple of seconds. If that brings it up to 14.0 or 14.5V, the charging system is weak, but still OK. If even that doesn't bring voltage up to 14, you should get your charging system fixed before ruining a new battery.
2006-08-04 11:59:05 · answer #1 · answered by sprinter_boi 3 · 1⤊ 0⤋
Usually, if it looks like the battery is going bad, it is going bad - it's 4 years old anyway, if it's not dead yet it will be soon, just replace it. With the multimeter you can only check the voltage which doesn't indicate the state of the battery. The battery tester they use in the garage measures the voltage under the load that was plugged in for some time. If you want to be sure it's the battery take it to a garage and ask for AVR test (battery and charging system test) it's not expensive.
2006-08-04 12:39:43 · answer #2 · answered by mmd_774 2 · 0⤊ 0⤋
You can do a simple load test with your Multi-meter.
Place your meter on the DC volt scale and measure the voltage across the POS+ and Neg -. should be a little more than12 Vdc. While you read the meter have some one turn the starter over. ( it helps if you pull the coil wire so it won't start.) The reading should be no lower than 10 volts while turning the engine over. if it is less than 10Vdc during the starter run, have a load test done at a parts store. I have found they will check your battery for free. Look over their shoulder while they run the test.
Wal-mart will do the check and if you need a battery they are reasonable and have good warranties.
Yours; Grumpy
2006-08-04 12:00:58 · answer #3 · answered by Grumpy 6 · 0⤊ 0⤋
All 12 volt car batteries should read 12.6 volts. They will drop a little when starting the vehicle. Put your tester on the battery, get a reading, then have someone start the vehicle while u watch the meter. It should not read below 10 when starting! Also, u can check your alternator in the same way. With the vehicle running, the tester should read between 13.5 and 14.5. It may be a little over 14.5, but that's okay, but if it reads below 13.5 it needs to be replaced!
2006-08-04 12:31:31 · answer #4 · answered by blacksrt4acr 2 · 0⤊ 0⤋
It should have 12.5 to 13.2 volts measured from the positive to negative.
Heres a trick;
if you can remove the cell covers, place the negative lead on the negative post, place the positive lead in the electrolyte of the cell closest to the negative terminal care full not to touch the lead plates only the liquid. Record the reading. Now place the positive lead in the next cell. This reading should be twice the first reading. And so on down the line. If the readings are not progressively higher you'll find the dead or low cell. Replace the battery. If all cells record the progressive readings, batteries GOOD.
2006-08-04 11:56:13 · answer #5 · answered by biker77bill 2 · 0⤊ 0⤋
There could be other factors of your car having trouble turning over. one could be the battey, if you have a multi tester, the voltage should be anywhere from 12.5 to 13.5. If that voltage is good, a load test wouldnt hurt. a battery can have a good voltage, but a bad load test. If that checks out ok, then I would be looking at the possibility of a bad starter. It wouldnt be a bad idea to check alternator either. while the vehicle is running, it should read between 13 and 14.5.
2006-08-04 12:29:43 · answer #6 · answered by bobby 6 · 0⤊ 0⤋
Your battery should be pushing out about 12.2v cold. Have someone start the car while checking the batteries voltage. If the volts drop below 9v then the starter is drawing too much power from the battery. Once you get the car started, check to make sure that the car is showing about 14.4v running.
2006-08-04 11:56:18 · answer #7 · answered by theGODwatcher_ 3 · 0⤊ 0⤋
with a multi-tester, check across the post with the meter set on dc volts. A charged battery will read around 12.8, anything 12 volts are close is dead. Check without engine running and wait until it has not be driven for awhile to see if battery is holding a charge. If battery is 4 years old then probably time to replace.
2006-08-04 11:54:18 · answer #8 · answered by Anonymous · 0⤊ 0⤋
One more thing to check. Make sure the belt that drives the alternator is adjusted properly. A loose or slipping belt will keep the alternator from generating enough voltage to run car and charge battery.
2006-08-04 15:32:41 · answer #9 · answered by Larry T 5 · 0⤊ 0⤋
Unless you have a load meter you can not use a meter to find if your battery is good or not. Most batteries go from 4 to 7 years depending on the usage and weather
2006-08-04 11:52:01 · answer #10 · answered by george m 3 · 0⤊ 0⤋