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Charging problems

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Charging problems

Postby ic3mak3r » Tue Jul 21, 2009 9:08 pm

Need a bit of help guys.
My car stopped charging the battery so I automatically thought alternator. I got it checked out and the bearings and regulator were gone so I got it fully reconditioned. I reinstalled it and everything was fine for about 10 minutes and then stopped charging again. I checked out the charge relay and found that to be blown so I replaced it and tried again but again no charge. So i was wondering if anyone can tell me what the cause could be or where to look for the problem.
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Re: Charging problems

Postby grunter » Mon Aug 03, 2009 10:56 pm

Hi dude,
Just a quickie, how many k's has the mu done and what is it that you refer to as a "charge relay" and what was "blown", when the altenator was reconditioned did they check the pos and neg diodes as they tend to vibrate off the heat sinc plate but you wont notice it as they are coverd in silicon, just one being loose will create the problem you are describing and will stop the altenator working. As you got the reg done you could rule out sticky or worn brushes, mate im only guessing as its not sitting in front of me.
all the best.
cheers.
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Re: Charging problems

Postby geeves » Tue Aug 04, 2009 3:05 pm

When these alternators fail they quite often blow the stator windings which cause the whole lot to go high voltage and blow the charge relay. Auto sparky who rebuilt the alternator should of checked this but you might have to take the car to him to check now
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Re: Charging problems

Postby grunter » Tue Aug 04, 2009 8:28 pm

as i was asking before i was wondering what ic3mak3r was calling a charge relay as alternators don't have such a thing. an alternator provides current or "power" to the system once the car is started, it's only other job is to keep the battery charged ready for starting. it feeds all the relays in the car current to run lights spotties etc. the stator dosn't "blow" as such it shorts out either by rubbing on the housing or cooks by trying to provide the system to much current usualy 1 of the 3 phases will burn out. as i said before the diodes tend to vibrate off or the solder on the conections will melt on the top of themeither way the altenator wont work. if it was reconditiond the people might have moved the diode(s) and made conection again only to vibrate apart again down the road. as for asking the kms they usualy only last around 200k as the brushes or slip rings ware out anyway just my 2c.
cheers dude,
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Re: Charging problems

Postby ic3mak3r » Tue Aug 11, 2009 7:58 pm

thanks for the replies fellas. Grunter you are probably right as it was fine for about 10 minutes when I reinstalled the alternator. The clock recons its done 155 000km but who knows. The only reason I changed the charge relay is because I read somewhere to check it if the alternator stopped charging and I found that it was blown. I opened it up and the wire that connected to the coil was broken. Ill check the diodes as soon as I have time. Is it an easy fix or does an auto electrican have to do it?
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Re: Charging problems

Postby grunter » Tue Aug 11, 2009 8:59 pm

Hi dude,
Im still a bit unsure as to what you are calling a "charge relay" and what was replaced, the diodes are part of the recterfier assembly and can de a bit tricky to replace to check them you would have to pull the alt completly apart and unsolder the stator, if you trust a good auto sparky that wont stuff you around then take it to them or take it back to who done it up and ask for a warranty job on it as they "completely" rebuilt it. Please let me know or discribe this charge relay thing so i know what you are talking about.
cheers
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Re: Charging problems

Postby pig75 » Tue Aug 11, 2009 9:47 pm

This might help with what the charge relay does
charge.pdf
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Re: Charging problems

Postby grunter » Sat Aug 15, 2009 8:43 pm

Hi pig 75, thanks for the scematic, im no expert but that just looks like a relay to turn the red warning light off in an older type system, replacing that wont make the alt work again. as far as i know the inturnal regulator on the altenator in the mu takes care of the red light. the only other thing i can think of which could be called a "charge relay" would be the solinoid in a duel battery setup as i dout this was replaced im still interested in what was replaced in the first post.
anyhow thanks again for the info and look forward to a reply.
cheers
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Re: Charging problems

Postby pig75 » Sun Aug 16, 2009 8:25 am

The charge light in older systems is used to excite the alternator if it’s not connected the alternator will not charge. Same as the charge relay
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Re: Charging problems

Postby grunter » Sun Aug 16, 2009 5:01 pm

Hi dude,
I think you will find that the alt gets excitation from the inturnal reg, from your diagram that relay is to turn the red light off.if you pull the relay out and start your car it will still charge,but as the ignition is turned on you wont have a battery light or a few others on the dash as they go through that relay as well. as the original question was asked as to what could be wrong, as he said he changed the charge relay and it still didnt work, i didnt know what was changed, im guessing it was this relay, if this relay "blew" it wouldnt stop the alt from charging all that would happen is you loose a few dash lights. I still think the alt, if fully reconditiond has a loose diode or two. anyhow just my 2c, thanks for all the info,
cheers
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Re: Charging problems

Postby geeves » Sun Aug 16, 2009 6:39 pm

I dont know how it works but if you pull the relay even a good alternator stops charging (12v at battery)
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Re: Charging problems

Postby grunter » Mon Aug 17, 2009 10:33 pm

Hi Geeves,
mate i dont know what you are driving but the mu works this way, just take the 5 min test.
1. start car alt charges,
2. yank relay out alt still charges,
3. turn motor off and restart, alt still charges,
the only differance will be that there are 1 or 2 lights on the dash instead of all of them being lit up when the ignition is first turned on before starting with the relay yanked out as the alt supplies the power to the relay( not the relay to the alt) which then turns the warning light out. the light gets its neg feed through the relay which is why it dosnt come on when the relay is yanked as the circuit is broken. the relay changes from neg to pos when the car is started and if you put two pos conections together the light goes out. hope this helps it worked this way with my mu.
al the best
cheers
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Re: Charging problems

Postby MattMu » Thu Aug 20, 2009 11:43 am

Grunter is spot on and if you look at the schematic you will see the L feed out of the atl is to energise the relay and that removes the earth from the warning lights (so they go out) and completes the batt feed to the heater relay so it will start if its switched on.

The older warning light circuit that Pig is referring to did used to use the light circuit to feed the field windings in the alt...so blown globe...no alt output.

If you blow the charge relay the alt should charge (if it is ok) but the warning lights will not go out and it will look like the alt is not charging. You can only tell if you check with a multi meter at the battery.

Icemaker I think (guessing) you dont have a good alt but you need to check with a multimeter to varify if its charging, then if no output, use the schematic to check all the charge fuses to see if they have blown too (making it look like the alt is at fault).

If your alt overchrged and blew the charge relay it might have blown the charging fuses (main) as well.

Goodluck mate

Matt.
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