Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Webby the Bear on 17 December 2012, 21:40:47

Title: testing my battery
Post by: Webby the Bear on 17 December 2012, 21:40:47
evening folks. Taking my omega to school on Wednesday to do a hydrometer test on the anti freeze. Want to also check the battery to see how good it is. I have use of a multi meter. So what do i do? Simply put the red probe on the positive and black probe on the negative terminal? If so what should the reading be? Cheers :-)
Title: Re: testing my battery
Post by: Andy B on 17 December 2012, 21:47:30
http://www.omegaowners.com/forum/index.php?topic=90619.0

 :y :y
Title: Re: testing my battery
Post by: symes on 17 December 2012, 21:49:51
Set multi to 20v and yes red to + black to -  or reading will have - in front of numbers eg -13v 
normal voltage about 12.5 if 12v bit flat mate Hope that helps you out :y

Title: Re: testing my battery
Post by: Webby the Bear on 17 December 2012, 21:51:39
oops. Sorry didnt think to look for something like this. Cheers Andy :-)
Title: Re: testing my battery
Post by: Webby the Bear on 17 December 2012, 21:52:53
cheers symes :-)
Title: Re: testing my battery
Post by: Broomies Mate on 17 December 2012, 21:59:56
Worth checking your Multi-Meter alongside another one also.  They CAN be way out.

About 5 weeks ago, there were some electrical gremlins on my Mothers Renault.  I checked the Battery Voltage with the Multi-Meter I keep in my boot and it was showing 15.6v on idle.  Straight away an indication something is not quite right.  For some reason, I questioned the result and tested my own car.  This time it showed 15.4v at idle.

I don't have that multi-meter anymore.
Title: Re: testing my battery
Post by: Webby the Bear on 17 December 2012, 22:50:51
I cant get to the link at the moment as on my phone but i presumed i should be checking voltage with car off. If i then turn car on should i see a drop in voltage?
Title: Re: testing my battery
Post by: Entwood on 17 December 2012, 23:23:28
I cant get to the link at the moment as on my phone but i presumed i should be checking voltage with car off. If i then turn car on should i see a drop in voltage?

The voltage should RISE when the engine is running as the alternator is now working.

Have a good read of Kevin's guide to battety and alternator checking .. :) once you can get to the link.
Title: Re: testing my battery
Post by: Kevin Wood on 17 December 2012, 23:25:23
See if they've got a drop tester at college. This checks the voltage under heavy load, so gives a better indication than a multimeter.
Title: Re: testing my battery
Post by: Webby the Bear on 18 December 2012, 17:06:56
thanks for all the pointers guys. Tested a couple of batteries. One on an avensis. 12.5 then started. It quickly dropped to just above 10. Then went to 14. 4. Teachers said that was good :-)
Title: Re: testing my battery
Post by: I_want_an_Omega on 18 December 2012, 17:21:34
thanks for all the pointers guys. Tested a couple of batteries. One on an avensis. 12.5 then started. It quickly dropped to just above 10. Then went to 14. 4. Teachers said that was good :-)

The lower it drops when cranking the better really.
Title: Re: testing my battery
Post by: Kevin Wood on 18 December 2012, 17:28:18
thanks for all the pointers guys. Tested a couple of batteries. One on an avensis. 12.5 then started. It quickly dropped to just above 10. Then went to 14. 4. Teachers said that was good :-)

The lower it drops when cranking the better really.

It's a measure of the battery's internal resistance, so less drop means less resistance = better.
Title: Re: testing my battery
Post by: Broomies Mate on 18 December 2012, 20:40:17
I feel I need to clarify Roberts post above!  ;D

If standing voltage is 12.5 and the voltage drops to 10.0 when cranking, that will be better than 12.5 at standing and 9.2 at cranking.

So, if a healthy battery of 12.5volts (standing) has a reading of 11.3volts at cranking, it's a sign the battery is doing a very good job.

Not the LOWER the drop (even though that grammatically makes sense in a way) but the LESSER the drop, the better.

Title: Re: testing my battery
Post by: symes on 18 December 2012, 22:13:01
I feel I need to clarify Roberts post above!  ;D

If standing voltage is 12.5 and the voltage drops to 10.0 when cranking, that will be better than 12.5 at standing and 9.2 at cranking.

So, if a healthy battery of 12.5volts (standing) has a reading of 11.3volts at cranking, it's a sign the battery is doing a very good job.

Not the LOWER the drop (even though that grammatically makes sense in a way) but the LESSER the drop, the better.


+1 :y