Battery or Alternator problem?

nos · Post by **nos** » Thu Dec 20, 2012 9:06 pm

Hi guys,

I have been having problems with starting, I recently had a new starter motor put it (last month), but it struggles to start, and today it wouldn't start at all. So i called RACQ to jump start me and the guy said it was the alternator, but i think it could be the battery, the battery is about a year old but its had a hard life (like its been discharged). So i got out my multimeter checked it, it was at 11.5v, charged it for a while until it was at 12v again, and the car started very sluggish, revved the car with the lights on and the lights didn't get brighter (apparently if the lights get brighter the alternator is stuffed). put the multimeter on while the car was running and the battery was at about 13.5v, any other tests i could do before buying a new battery or sending the car away? btw the engine is an EJ22

I will test it in the morning to see if the volts have dropped,

Cheers.

thunder039 · Post by **thunder039** » Thu Dec 20, 2012 9:08 pm

i would imagine if the volts increase while started the alternator is sending power thus working but could be wrong

NachaLuva · Post by **NachaLuva** » Thu Dec 20, 2012 10:23 pm

13.5-13.8V when charging sounds OK. It could be the battery. My GFs battery in her new falcon died after only 2yrs. What made me mad is there's no warranty on new car batteries...how insane is that?!

There is a specific gravity (SG) test they can do...any battery place can do it or you can buy a tester. Dunno what its meant to be though, but it should say on the tester

AlpineRaven · Post by **AlpineRaven** » Fri Dec 21, 2012 6:33 am

I would start looking on connections from starter motor - fuse - battery to ensure the connections are good. Did the battery go below 9volts for short term? (thats good way to kill it!)
Cheers
AP

Post by **Alex** » Fri Dec 21, 2012 7:14 am

What car is your ej22 in?

Sent from my Motorola RAZR HD

Post by **TOONGA** » Fri Dec 21, 2012 9:06 am

Alex wrote:What car is your ej22 in?

A very good question

Could be your battery, could be your alternator, could be the battery leads not connecting to the terminals properly or being worn out.

TOONGA

tambox · Post by **tambox** » Fri Dec 21, 2012 9:17 am

Measure the battery voltage when you are cranking. Record what it drops to.
Turn your headlights on and measure when cranking.
If its the same/similar, your starter is drawing to much current.
If the voltage is lower and it cranks slower, battery or connections.

If it charges the battery when running you will see 13.5-14.2 volts.
Turn your headlights on with it idling and the voltage will drop, rev it up to 2500ish rpm and the the voltage should return to the level it was out without headlights, if so, alternator is ok.
If it goes past 14.2v, regulator is u/s and you are cooking the battery.

LLOUD · Post by **LLOUD** » Fri Dec 21, 2012 10:42 am

Charge up the battery then take it into a battery shop and have it load tested

Post by **Alex** » Fri Dec 21, 2012 10:48 am

If it's in a lseries I'd be checking the fusible links

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rubisubi · Post by **rubisubi** » Fri Dec 21, 2012 11:38 am

Some older cars had regulators inside the engine bay while some newer cars have them built into the alternator, can be deceptive and often the alternator is blamed. Does sound like the battery though. Is it a quality one or cheapo option?

nos · Post by **nos** » Fri Dec 21, 2012 4:46 pm

Hey guys, wow thanks for the responses! So i took it into a battery shop as NachaLuva suggested, and they also claimed it was the alternator. So i got a second hand alternator from a spares place for $88, replaced it, and no difference haha (i think my old alternator was actually fine).

Also i just checked the volts on the battery and it was at 12.5v, started it and shot up to about 13.5v, turned the headlights on and it started to go all over the place, it went down to 9v and back up to 13v again.

So i am thinking the starter could not be getting enough power? it recently had a new starter put it, so maybe they did a dodgy?

NachaLuva · Post by **NachaLuva** » Fri Dec 21, 2012 4:46 pm

KISS - Keep It Simple Son

Check the simple easy things 1st.

The earth connection on the battery is infamous for causing a range of probs. Take it off & use a battery post cleaner or some good ol sandpaper till both mating surfaces look like new. Do the same with the positive.
Cost: 10min

Check the connections at the back of the alternator, if loose, thats your culprit. If dirty, take them off & clean em.
Cost: 15min

Get your battery checked.
Cost: Dunno, but should only be $5-10, if at all.

Take it to a sparky to check the output of the alternator & voltage regulator.
Cost: ~$80/hr

Out of all the suggestions put forward by everyone, you should be able to get it fixed...good luck

NachaLuva · Post by **NachaLuva** » Fri Dec 21, 2012 5:01 pm

nos wrote: Also i just checked the volts on the battery and it was at 12.5v, started it and shot up to about 13.5v, turned the headlights on and it started to go all over the place, it went down to 9v and back up to 13v again.

There's your problem...its the voltage regulator!

What car is it? Is it a conversion? With your EJ22, I'm sure it would have an internal voltage regulator in the alternator. If its an older car like an L or MY, etc, you may ALSO have an external voltage regulator, so the two may be doing funny things. Find it & bypass it...but make sure your alternator has an internal one 1st or you'll cook your battery.

If your alternator doesnt have an internal voltage regulator, find out where yours is & write down the part number on it so the spare parts guys dont make a mistake & get a new one. Put it in, check the voltage again & you should be done

If its not a conversion, you'l prob have to take it to a sparky to put in a new voltage regulator, or maybe you can do it yourself, I dont know whats involved...