Charging problems

I realise this has been covered a few times but am experiencing charging problems, on my way home from work thursday evening i noticed a few electrical items acting odd. My rear wiper motor failed, stereo started turning on and off repeatedly, aorbag light came on and then the dial cluster failed altogether. Car died a few seconds later. Called out the AA akd the guy was kind of useless but threw a new battery into it to get me home and took it back when i got there.

Ive since charged the battery and reinstalled it and friday evening was getting 12.5v engine off and 14.3v engine idle. Which means my alternator is fine. However today i decided to test it again and noticed my battery wasnt charging as it was only reading 12.5v with the engine running.

What could cause an intermittent charging issue such as this? I plan on checking and cleaning the battery earth tomorrow but as far as electrics go my knowledge is very limited. Any ideas as to where to test would be much appreciated!

Tldr; alternator intermittently charging battery, why?

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I'd check the brushes / voltage regulator anyway as it may have been making decent contact for a while but because it's worn won't do it consistently.

https://www.micra.org.uk/threads/alternator-tear-down-repair-help.63589/

Unlike in that thread I've changed brushes / regulators a couple of times on my old camry before the alternator eventually died at about 450,000kms some 5 or 6 years after first changing the brushes, it may be possible to carefully clean up the slip rings with emery tape or a file etc but I just popped them in... Only done it in a camry not a micra though...
 
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I'd check the brushes / voltage regulator anyway as it may have been making decent contact for a while but because it's worn won't do it consistently.

https://www.micra.org.uk/threads/alternator-tear-down-repair-help.63589/

Unlike in that thread I've changed brushes / regulators a couple of times on my old camry before the alternator eventually died at about 450,000kms some 5 or 6 years after first changing the brushes, it may be possible to carefully clean up the slip rings with emery tape or a file etc but I just popped them in... Only done it in a camry not a micra though...
I sincerely doubt this is the case as the alternator had a full rebuild only 5000miles ago. I'll still check it out though if nothing else jumps out at me

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It may be that the battery is bust.


Cheers Kieran
I had contemplated this as an option however the battery is less than two years old and has never been exposed to any real stress. I need to first determine if the alternator is or isn't putting out a consistent 14.4v and go from there...

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I do. The barry was charging fine friday night as was getting a reading of 14.4v across the battery but last night i was only getting a reading of 12.5v so the problem seems to come and go which is what makes me suspect a bad contact or earth somewhere

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Check to make sure the wires on the Automator are tight and havnt come lose. I'll see if I can find a wiring diagram of it if you want?


Cheers Kieran
 
Is the battery/charge light coming on - either before you start the engine or when the engine is running and the voltage is 12.5V ?
Battry light illuminates as normal when ignition on and turns off as normal when car running and doesnt come on again.

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Check fuse 5 [10A] and fuse 11 [80A] in the battery fuse box. Make sure the contacts are all good and there is no sign of overheating.
The only other place to look is the electrical grounding of the alternator itself - make sure it is bolted in securely and the whole alternator/engine is well [electricall]y connected to the body of the car.

If these items and previously mentioned checks are all OK, then the problem must be inside the alternator.
 
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Check fuse 5 [10A] and fuse 11 [80A] in the battery fuse box. Make sure the contacts are all good and there is no sign of overheating.
The only other place to look is the electrical grounding of the alternator itself - make sure it is bolted in securely and the whole alternator/engine is well [electricall]y connected to the body of the car.

If these items and previously mentioned checks are all OK, then the problem must be inside the alternator.
I will double check the fuses but all appeared OK at first glance. Shall double check the alternator mounting as well. Thanks :)

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No problem mate the percs of having auto data on your phone. It's dead handy. Just a shame I don't understand them lol


Cheers Kieran
 
I will double check the fuses but all appeared OK at first glance. Shall double check the alternator mounting as well. Thanks :)

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Yes - check all possible current paths between the alternator and the battery - the alternator is capable of supplying a large amount of amps and even the slightest bad contact will result in no current flow and, hence, the voltage will read only the battery voltage.
If there is a bad contact, it is likely that there will be heat generated at that point.

If nothing is obvious, try running the engine, monitor the voltage at the battery and load up the electrical system until the voltage sags from 14+V down to the battery voltage - then start looking for hot spots.

Big electrical loads are:
Wipers
Blower
Heated rear window
Lights
Just turn everything on!
 
Yes - check all possible current paths between the alternator and the battery - the alternator is capable of supplying a large amount of amps and even the slightest bad contact will result in no current flow and, hence, the voltage will read only the battery voltage.
If there is a bad contact, it is likely that there will be heat generated at that point.

If nothing is obvious, try running the engine, monitor the voltage at the battery and load up the electrical system until the voltage sags from 14+V down to the battery voltage - then start looking for hot spots.

Big electrical loads are:
Wipers
Blower
Heated rear window
Lights
Just turn everything on!


I don't know why the above text has been struck through - I didn't do it [knowingly] !
 
OK just took some readings.
Engine off 12.5v
Engine running no load 14.3v
Engine running with all electrical items on 14.1v.

So it would seem its charging OK now. But I've done nothing to remedy the problem which means is eventually going to stop charging...

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Got the fuse out but not in one piece so unsure if I broke it in the process or was already broken? Had it been broken previously the battery light would have come on though yes? Also should the two prongs seen in the pic have come out with the fuse?

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The 80A fuse is not right - it should have come out - might have been a little difficult to extract, however should have pulled out. The two 'arms' should have come out with the fuse - looks like the problem might be in the fuse box.
Does the battery/charging light stay on when the 80A fuse is not in?
 
I figured they should have come out I must have broken them off when yanking the fuse, they're properly welded in there tho so I expect this is where my problem lies.

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one time when my new battery was drained whilst driving, it was caused by some light corrosion of the spacer washer between the alternator connection loom and the alternator internal circuit stud.
I simply wirebrushed all the oxide off all electrical connection points and it restored the charge.

to check if the alternator is working reliably, disconnect the battery whilst it's running and it should keep running.

if it's reading 14v whilst running but battery dies shortly after stopping, cruise for a while whilst at 14v to fully charge the battery, stop engine & disconnect battery, then monitor the battery voltage overnight. it should maintain 12.3-12.6v no problem.
if it simply drops below 12.3v then its duff
 
one time when my new battery was drained whilst driving, it was caused by some light corrosion of the spacer washer between the alternator connection loom and the alternator internal circuit stud.
I simply wirebrushed all the oxide off all electrical connection points and it restored the charge.

to check if the alternator is working reliably, disconnect the battery whilst it's running and it should keep running.

if it's reading 14v whilst running but battery dies shortly after stopping, cruise for a while whilst at 14v to fully charge the battery, stop engine & disconnect battery, then monitor the battery voltage overnight. it should maintain 12.3-12.6v no problem.
if it simply drops below 12.3v then its duff
Will try this once I have sorted my battery fuse (see above pic) it broke when extracting and the two contact prongs are welded to the fuse board it would seem. Can't get them out for the life of me!

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If you don't have a replacement fuse, you can temporarily bridge the two prongs with a 'homemade' fuse - 6 strands of copper wire is approximately 80A
 
If you don't have a replacement fuse, you can temporarily bridge the two prongs with a 'homemade' fuse - 6 strands of copper wire is approximately 80A
Good to know! A friend is actually on his way to bring me to get a fuse but my issue still remains, can't budge the remainder of the fuse from the contacts. Any suggestions? Pulling and twisting with a pliers is only tearing the metal...

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It doesn't look good for the fuseholder - the ends of the fuse prongs must have got seriously hot to be stuck in that well - you might need to strip the fuseholder assembly and find out what's going on in there - you may even need to replace the whole unit....
 
It doesn't look good for the fuseholder - the ends of the fuse prongs must have got seriously hot to be stuck in that well - you might need to strip the fuseholder assembly and find out what's going on in there - you may even need to replace the whole unit....
Was really hoping it wouldn't come to that as its well past my abilities...may need to call an autoelectricion....

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My MGZR (now sold) was like this and i think the alternator was on the way out, just after starting the voltage was a strong 14.5v and charging well, but after time it would drop to 14.1v or even 13.8v and most of the driving would be like this... Was going to try a new alternator, but my new car arrived and saved me the hassle...
 
My MGZR (now sold) was like this and i think the alternator was on the way out, just after starting the voltage was a strong 14.5v and charging well, but after time it would drop to 14.1v or even 13.8v and most of the driving would be like this... Was going to try a new alternator, but my new car arrived and saved me the hassle...
See if I hadn't had the alternator completely rebuilt 6 months ago it would have been the first thing I did but I have a feeling it's something else just can't figure what. Now I've made a balls of my fusebox am gonna have to sort that before I can go any further. Plan was to put the Micra up for sale next week too. It's as if she knew and is putting up a fight ha


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Success of sorts. Got the broken fuse ends out. But have no ways of getting a new one today so looks like she's parked up for a while....
1f421df40f359cdd1f0e8e2b87b263e6.jpg

No corrosion either which makes me think this wasn't the cause of my problem...

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Have you taken the plug off your alternator and had a look in there? I'm just taking a shot in the dark but seeing as you had it rebuilt its possible they damaged a seal around the plug and its allowing corrosion to form in there. Those two little terminals are what energise the alternator to begin outputting power.

I guess its also possible that the rebuild you had done might have damaged something internally, I'd personally see if they're willing to pull it apart and take a peak, they may charge you for this though they really shouldn't if you've got the receipt for the work done. A loose connection inside would give all these same results too, especially the fact that this is an intermittent problem.

Here is a photo of the plug in question, I just grabbed a picture from eBay;
micra k11 alternator.JPG
 
I agree - the contact areas on what's left of that fuse would indicate good electrical conductance. To get you going temporarily, you can still try the 6 strands of wire.
The next area to rule out is the grounding of the alternator [and engine] to the bodywork - if that checks out, then it all points to the alternator.
 
Well I managed to get a replacement fuse and shes charging just fine at the moment. If it dies again I'll have to have the alternator looked at I reckon. Thanks for all the help guys!

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