The AUSubaru.com.au Forums

Hi all,

My wife took her MYO6 Impreza for 50,000km service today. I noticed the battery is weak when cranking. I told her to tell that to the dealer.

After service is done, did a load test & pak file (dunno what it means), tested ok, the dealer said the battery wasn't charging because she only use the car for short trips <10kms and asked her to turn on lights whenever she goes for the trips. I'm confused. She never had that problem with older car before we purchased the Impreza? Wouldn't turning the light on make it worse?

It happened about a year ago and the battery was replaced because it was faulty. Now it does it again.

TIA...

What type of battery are you using at the moment?

The dealer may have told you to use your lights as it will load the alternator. I'm guessing his theory may be that the alternator maybe on the way out. I'd also check the wiring on the back of the alternator to make sure everything's nice and tight - if you need a spanner or screwdriver in here make sure you disconnect the battery first.

I've got the same cranking problem, but I'm thinking my starter motor may be on the way out, but my car is 20 years old an probabily running the same starter from factory...

Good luck with it.

Bennie

Even a 9km trip should easily recharge a battery after one start. In a normally functioning system I can't imagine why you should need to turn your lights on to excite the alternator. I would suggest you check alternator output at idle, immediately after start-up. Is your battery still under warranty?

El_Freddo: I forgot what brand it is. It is a stock from Subaru. I'm not good with cars. So I let the dealer do the checking. As per them, all ok. I don't know if they did any test on the alternator. I supposed they should consider this as a possibility of the problem as it happened a year ago. As per the service record they did a load test & pak file (dunno what it means).

brumbyrunner: that's what I thought too. Just hard to believe when the car is 2006. Why the lights need to be turned on? Old cars I had don't have too. Short trip can shorten the life of a battery. But one year? And this is the second time happening. My common sense tells me it is either the battery is not good or something else is a problem.
It is still under warranty. I think 3 years. It's just disturbing as it can leave my wife & the kids stranded.
How do you check the alternator output?

Thanks again guys...

Yeah this doesn't sound right. Car batteries are designed to be charged quickly by the alternator, short trips should be fine. You shouldn't have to turn the lights on. If you want to test whether it is charging properly, go to Jaycar or Dick Smith and grab a $10-20 digital multimeter. Put it on the 20v DC setting. Put the red lead on the positive(+) terminal and the black one the neg(-) terminal of the battery. With the car not running it should be around ~12.5v, with the car running it should be ~14 - 14.4v. You might need to bring the revs up a little to get the alternator to kick in.

Sounds to me like it may still have the piddlee battery they use to load and unload the cars onto the ships,

My 01 RX Liberty had one of those and I was worried about wearing out the starter before the battery as it would take 3 - 4 hits of the starter to get it fired up so I threw it out in Feb 01 and bought an Optima Red Top and it's still alive and kicking hard in my 03 XS Forester it takes just hit of the starter.

Cold weather will always show any weakness in your battery, have a look at the battery and see if you can see anything that says XXXCCA this well tell you whether the battery has enough Cold Cranking Amps to crank over your engine.

foxx510: Supposed now the battery has been fully charged by the dealer. So, it gives a reading of ~12.5v. How do you tell then if it's charging or not, when it gives a reading of ~14v with the car running?

Subyroo: how do tell if it's a piddlee battery or not? I hope it's not since they replaced one already under warranty. One of the mechanics told my wife that they've had new cars with problem batteries that last only 6 months or so. It sounds to me that they're not using good batteries or as you said only had piddlee battery.

Cheers...

I recommend you take it to a good auto electrician and get him to test the alternator and the battery. There is quite a bit to electrics and if you're not familiar you could be chasing your tail with this for a while. Things like, sometimes when an alternator is on the way out, it needs increasing amounts of revs at start-up just to excite it. Also batteries can die slowly or instantly. If you need a new battery again after all this, buy this biggest & best you can afford.
In the meantime, tell us the CCA of your current battery.

If you go to a Battery world store they will do a free battery and charge test for you. Then armed with this info you can go back to the dealer if need be.

A friend who is a car salesman at subaru said they have had a fair few people complain about flat batteries. He said the subarus dont really get enough charge when driven small distances and/or at low rpm's. He also said most of the complaint's were from older people who were less likely to be hooning around and revving it out.

I also remember my auto teacher telling us that it takes about 7-14mins to put back what you took out of the battery starting it. But im not sure if thats driving or idling, and is probably based on 70's tech kingswood's etc

I dont see how turning the lights on would help.

brumbyrunner wrote:I recommend you take it to a good auto electrician and get him to test the alternator and the battery. There is quite a bit to electrics and if you're not familiar you could be chasing your tail with this for a while. Things like, sometimes when an alternator is on the way out, it needs increasing amounts of revs at start-up just to excite it. Also batteries can die slowly or instantly. If you need a new battery again after all this, buy this biggest & best you can afford.
In the meantime, tell us the CCA of your current battery.

I checked the battery. The one installed now is a Century which is a good battery as far as I know. The one replaced was Fujitsu or something.

Thanks for other advices guys. It may well be Subaru problem after all. I may ask my wife to rev it up...but will drink more fuel. Not happy with the current price:rolleyes:
Cheers...