Testing a battery with a mulitmeter

Post by **dubman** » 10 Feb 2008, 16:09

Hi , bit of electrical help needed if possible , i was reading the other day on here or brick-yard that its possible to test state of battery with a muli-meter rather than buying one of those volt gauges that just kampers sell.Trouble is im not to sure , what to use on my meter , i set it to dcv 20 and got a reading of 12.7 one battery and 12.3 on the other , is this right ?

can anybody explain how to use this thing ?

cheers folks.

[IMG:800:600]http://img.photobucket.com/albums/v288/ ... -meter.jpg[/img]

Post by **Titus A Duxass** » 10 Feb 2008, 16:17

That meter will only give you a no-load reading of your batteries.
Those figures are fairly healthy, but again they are no load situations.

A proper battery test will load up the battery and show you a true reading.

The only thing that you can do is use the current setting (amps) to see if there is any drain on the batteries. disconnect the positive connectors and place the meter in line i.e. connect the negative connector to the battery and the positive connector to the positve wires. But do this with the ignition off! Set the meter to the highest current level. Which on your meter is 10A.

Do not attempt to start your bus with the meter connected in this way because it will blow the fuse in the meter (if it has a fuse, if it doesn't have a fuse it will fry the meter).

If you get a reading then you have a current drain somewhere.

Are you having problems or is this just out of curiosity?

Post by **dubman** » 10 Feb 2008, 16:26

no problems , im just looking to find a cheap way to keep an eye on my batteries when camping im using one battery to hook up stereo , lights , dvd etc , and the other is car main battery.

Post by **dubman** » 10 Feb 2008, 16:43

This was the type of thing i was thinking of getting to keep an eye on there levels http://shop.justkampers.com/product_inf ... s_id/10014

is my multimeter just doing the same job ?

Post by **jamesc76** » 10 Feb 2008, 17:44

ive got one of those but its only really any good for a rough idea of what voltage is in the batterys not how long it will last!!!!!

Post by **lloyd** » 10 Feb 2008, 17:57

Yes, reading the voltage of your battery with your VOM is the same. Also the same as using a voltmeter that some vehicles have in them. 13.8 when charging, 12.8 when parked, getting below 11.8 is time to recharge. These figures are not written in stone, so some variance is expected.

Post by **rolling road block** » 10 Feb 2008, 20:50

12.2v on a battery is only 50% charged. 12.6 12.7v volts is fully charged. a faulty battery can cause a amp drain but should be no more than 0.2amps with everything off. to test the starting battery leave van running for 5 mins, switch off make sure battery voltage is above 12.2v after leaving lights on for 10 - 15 secs this get rid of standing charge that builds up. stop the engine from starting eg coil wire/ diesel fuel pump then crank for 15 secs whilst monertering your multi meter, volts should not drop below 9v if does battery not holding charge under load. hope this helps