battery not charging

subarooster · Post by **subarooster** » Fri Apr 03, 2009 7:21 pm

not sure how to test it. But autoelec might charge like $20?

Diode's are located within the alternator on the rectifier. A good autolec can tell a blown diode just by running the alternator up on the test bench.

tex · Post by **tex** » Sat Apr 04, 2009 5:50 am

subarooster wrote:Okay... The two smaller wires coming from the back of the altenator is Battery sensing and light circuit. The light in the dash is used to excite the diodes in your alternator and if it flickered for a while and then cut out, i'd say u have a blown diode or 2. But seeing as tho u replaced it, it may be that a wire in your "light circuit" has been damaged somewhere. If thats the case then your alternator will not charge because it needs that light to start the charging. You notice that your lights on with ignition and then after you've started the car, it stays on for maybe 2 seconds or so? This is because it is exciting it t start charging is your new alternator second hand? if so, then i'd be taking it to an autoelectrician and tell them to check the diodes. Hope this helps
Cheers.

In other words as well as the diodes it could be as simple as the fuse under the dash or the light bulb itself to stop the vehicle charging and strangely enough these are the weekest links. Also lots of older vehicles have a very faint glow from the battery light.
In an ideal world the alternator produces 14.4 volts to charge the battery.

kevmif · Post by **kevmif** » Sat Apr 04, 2009 9:55 am

FIXED!!!

The connection on the back of the alternator was a little corroded. A simple test between the charge wire and neg terminal produced about 14 volts with the motor off (I think my multimeter is a little off, its very old). Turned the motor on and got nothing.

Spayed some INOX onto the contacts and had a bit of a fiddle and its now producing 17 volts, which drops by half a volt or so when the lights are on. It even runs with the neg terminal off

Thank you all very much for your help!

The bad news though is that this may be my last encounter with a Subaru problem for a while. Have decided to sell the Brumby, it will probably be going today (got a relative who can tidy up the paint a bit and sell it for me

). Its been fun times but I don't have the money to keep pouring into it. Down the track I am hoping to get a later model with dual headlights and no rust hehe - might even consider a Hilux as my other car is a Toyota and they are just awesome but not quite as good as Subarus!

Thank you all for every bit of information and assistance you have provided and for having patience for my stupid questions and lack of knowledge!

subarooster · Post by **subarooster** » Sat Apr 04, 2009 11:13 am

17 volts?

Thats good that its fixed and only the plug. (No light circuit so alternator wasn't charging) but also clean up the battery sensing one because it usually runs straight to the battery where it reads the voltage and tells the regulator to dump heaps of charge in or regulate. Should be regulating between 13.8 and 14.2 volts. It would be a good idea to clean the battery sensing one anyway if your getting 17 volts because that can start killing electrical things.

If theres a bad connection there then the altenator reads that there is low or no volts so it charges at full capacity.

kevmif · Post by **kevmif** » Sat Apr 04, 2009 11:51 am

I'm a d**khead - was reading the wrong scale on the multimeter. I think its fine

subarooster · Post by **subarooster** » Sat Apr 04, 2009 1:57 pm

haha, all good then. :d

kevmif · Post by **kevmif** » Fri Apr 10, 2009 11:56 am

Guys sometimes when I turn the ignition on the light is still off. then I crank it and it comes on but goes off again.
The wiring appears to be ok from what I can see.
Could my ignition switch be stuffed (again - last time it wouldn't crank).

Actually - I will go test that now by shorting the appropriate wires!

kevmif · Post by **kevmif** » Fri Apr 10, 2009 12:21 pm

ok its not the ignition module. I really can't wait to get rid of this car. I used to be good until I started tinkering hehe!

tex · Post by **tex** » Fri Apr 10, 2009 1:10 pm

OK light that doesn't always go on when the ignition does is a bad thing I would check the fusible links (funny looking coloured wires with a braided sheath usually in the small fuse box next to the battery) as these have been known to blow and sometimes short to form a temporary circuit just pull the wire out and swap it for one of the same colour, There is also the connector on the front of this box where the battery wire comes in Check these two things then go through the other steps as listed in this post then let us know how you go!

kevmif · Post by **kevmif** » Fri Apr 10, 2009 2:15 pm

Links are fine. Sometimes the light is on, then when you give it a quick crank it goes off. Crank it again a few more times and it may or may not come back on.

I think the car had elec problems once before as the ignition plug has a slight deformity and the cover for the fusible links has also been melted in a small area at one stage. These issues are only recent, I have had the car for over a year before it started giving me this problem. I know that the ignition plug was deformed well before this started happening as I had to replace the ignition module almost a year ago. Note its not serious, just melted a little on one end.

twilightprotege · Post by **twilightprotege** » Fri Apr 10, 2009 7:24 pm

thought i'd add my experience - i replaced the alternator with a reco'd unit and the dash light comes on now, so all is good. i havent started the engine yet as the front of the car is up on stands, but i assume with the light on, everything is back to normal. got the reco'd unit from sunspares at yandina for $75+post. thought that was a good price

twilightprotege · Post by **twilightprotege** » Fri Apr 17, 2009 4:07 pm

just an update from me, engine has started, just over 14v at the battery. new alternator did the trick