Battery dying?

[Mitevo8]

I had a volt guage installed. recently the volt reading reduced slowly from the usual 13.8v to now only 10.2v. Before i crank my engine, the reading was 10.2v and aft cranked the reading remain the same. Engine still able to crank thou and everything seems normal except the guage reading.

 

Is the battery dying? do i need to change it now or wait until the telltale signs like slow cranking. Or mayb the volt guage is getting faulty? I m using stock battery and my car is barely 1 yrs 3 months old.

 

i think there's nothing wrong with my alternator. cos aft i started the engine, i removed the -ve batt terminal connection and the engine did not die. I learned somewhere this is the way to check your alternator's life. correct me if wrong.

[Mivec9]

measure voltage at batt terminal before and after cranking...

 

before shd be around 12v and after crank around 14v

[Yeobh]

If the battery reading is 10.2v , there is no way you can crank over the engine.Clealy the voltage gauge is faulty or the live or ground wire to the gauge is loose.Give a hard a tap on the face of the gauge, maybe the needle is sticky.

NEVER EVER disconnect the battery cable terminals when the engine is running. By doing so the alternator control circuit will sense a no load condition and chances the the alternator ampere ouput will increase to more than the preset value resulting in damage to the diodes ( which control the amp max output) and may seriously cause damage to the on-board computer.

[Mitevo8]

i dun hv a handheld voltmeter, so only rely on the guage.

[Toyo]

I have seen mechanics changing battery when the engine was running

[Mitevo8]

Oh my! I did tat while eng is running. hope it wont hurt my on board circuit. trust those stupid website to come out with this test method.

 

I did tap on the guage b4, dun think it's the needle becos when i off the engine the needle swing to 0 and vice versa. mayb will check on the wiring.

 

thanks bro.

[Mitevo8]

really, are they doing it out of convenience or to prevent resetting the ecu?

[Toyo]

I thk they did it to prevent resetting the ecu

[Toalson]

Oh no, when I changed my battery the workshop oso disconnect the battery after the engine is running.

[Vtfoo]

Sorry to borrow this thread cos I dun hv enuff post to create new threads.

Just wanna check any recommendations for a good car battery, preferably maintainence-free. Does make & model of car make a diff?

[Genie47]

Varta. Go to the Varta website and search. Might have for your vehicle. Also note the dimensions, you can more or less gauge from the dimensions listed which is the biggest baddest meanest heaviest battery you can put into your car. A good pointer will be not to waste money buying battery with a high CCA (Cold Crank Amps). Use the minimum required for this weather which I think is 420 unless die die your car needs its minimum CCA in the service manual.

[Adrianli]

Why not borrow a multimeter to confirm the reading on the volt gauge?

 

Or u could get a DC 12V supply to check if the volt gauge reading does give a 12V reading.

 

10.2V is not possible to crank ur car engine but the other electrical stuff will still work like ur head unit. Coz the other time my batts also 10.2V n cant start my car at all but still can listen to music n activate the car alarm.

[Yeobh]

Either they are not well info or just don't want to invest in simple computer memory back-up tool.Anway if there is any hicuup or fried circuit board they will try to BS and the bill is on the cutomer.

Edited December 13, 2005 by Yeobh

[Yeobh]

Yes to prevent the keep-alive memory from data from been deleted. The method is very unprofessional and dangerous !!

[Toyo]

Any idea which shop practice such method? dun want to take risk anymore

[Yeobh]

Shops that handle european vechicles are most likly to have them.For Asian cars, normally only th top end design vehicles have keep-alive memonry to collect driving data.

[Tyreboy]

hi guys, these stuff are of no use....try that before myself and the mechanic....not much help....actually learnt from many mechanics i know.....one of the trusted methods is still the one that disconnect the battery while engine is still running....

[Mitevo8]

Dear all, confirmed it's my volt guage faulty. It happened that when i took out the volt guage to check and gave it a hard tap, guess wat, the needle fell off.

 

Also, i need to take this opportunity to praise the good service of this access shop at syed alwi, Kam Auto. I bot the gauges from them 2 months ago. I went there this afternoon to try my luck w/o my purchase receipt. I told the boss the volt guage is faulty, he saw the needle and w/o any question asked he replaced a new guage for me. Of coz, i m a frequent patron to his shop so the boss sort of knew me. But still tat's wat i called service.