-
18th June 2012, 07:04 AM
#31
When you were checking for12 volts at the alternator plug did you have the instrument cluster plugged in?
-
-
18th June 2012 07:04 AM
# ADS
Circuit advertisement
-
2nd July 2012, 12:34 AM
#32
Main or aux battery? Not an isolator?
-
-
5th September 2012, 06:34 PM
#33
have you fixed this issue yet if so how my 01 gu has the exact problem
-
-
7th May 2021, 07:58 PM
#34
Originally Posted by
Ben32
Just testing my batteries and i have eliminated one from the circuit and the power output has dropped to 7. i am now charging the other battery and trying that one just to make sure it isnt a battery issue. If anyone has any other ideas please help.
I might be a stupid question, is your battery AGM or Normal battery. AGM batteries cannot be charged with conventional alternators if below capacity. It happens on 2003 Landcruiser. It might help ..
-
-
2nd August 2022, 09:57 PM
#35
Why do people not come back and actually tell others how they resolved their issue? Oh I fixed it, don't need the forums help anymore.
-
-
29th September 2022, 12:29 AM
#36
Hi all, I'm facing same issue. I know this is an old thread and hoping I can resolve it.
6months back my alternator failed and stopped charging my battery. I thought it was old battery so replaced with a brand new one and it got drained. I sent the car to a garage and they replaced the alternator with a used part from the wreckers. So far it worked properly until a week ago I noticed that the voltages were dropping as below:
1. Ignition switch "On Position" - voltage read 11.8-11.9v
2. On start/ crank - voltage reading drops to 7.8-9v
Car starts almost immediately without any issues(long cranking starts etc).
Note: these voltage readings are taken from my aftermarket android stereo.
I am yet to test the battery with a multimeter(will be done on Saturday only). Besides testing the battery, is there anything else I should be testing or inspecting related to this issue?
2008 Nissan Patrol GU Y61 TB48
Mods: De-Cat, Custom Cold Air Intake with Heatshield, Aftermarket headers, AoR center exhaust box
-
-
29th September 2022, 04:05 AM
#37
Originally Posted by
Ecronic
Hi all, I'm facing same issue. I know this is an old thread and hoping I can resolve it.
6months back my alternator failed and stopped charging my battery. I thought it was old battery so replaced with a brand new one and it got drained. I sent the car to a garage and they replaced the alternator with a used part from the wreckers. So far it worked properly until a week ago I noticed that the voltages were dropping as below:
1. Ignition switch "On Position" - voltage read 11.8-11.9v
2. On start/ crank - voltage reading drops to 7.8-9v
Car starts almost immediately without any issues(long cranking starts etc).
Note: these voltage readings are taken from my aftermarket android stereo.
I am yet to test the battery with a multimeter(will be done on Saturday only). Besides testing the battery, is there anything else I should be testing or inspecting related to this issue?
HOW did the alternator fail? (rectifier, bearings, windings?) Might give some clue.
Those voltages seem incredibly low and to me suggest an undersize battery or one with low internal resistance. Resting voltage should be 12.2-12.8. This may drop significantly on cranking but I wouldn't expect below 10. Glow plugs will soak up certain current but not enough to cause that kind of voltage drop.
Charging (engine running, alt working) voltage should be 13.2-14.4 depending on batteries current charge state.
I wouldn't trust a -stereo- (??) unless it's wired directly to the battery with wire sized apropriately for the current and cable length (10A minimum)
Testing for parasitic drain is done with a clamp or ammeter in between the main hot wire and battery terminal. There will be certain "standby" current for computers, clocks, etc. if there's anything over 1A that would be cause for concern (to my mind, new cars will have more electrickery) - with the ammeter still in circuit, pull house fuses one by one until the current goes low, then you've identified the circuit drawing power.
It seems maybe this is a common fault? And no-one's worked it out?
Alternators require a "field" or "sense" wire and this may be undersized, worn, shorting, etc. I would run a new wire direct from positive battery terminal to this "field" pin/pole/terminal, 5A wire should do as it's only measuring voltage (batteries' current charge state) and providing the excitation for the field. But bigger wire never hurts and 10A is cheap enough.
Try and find a wiring diagram for the alternator but I think the field pin is normally marked "B"
If it's all going through some f*cking computer...then it's probably the f*cking computer.
Alternators are simple devices, and the three things at the top are about all that can go wrong. Re-wiring a rectifier bridge isn't hard and costs <10$ in diodes. Bearings are same as any other bearing job. Windings, unless you're in BF-nowhere, would be throwaway/replace, but it would be good to know WHY they failed.
- 1990 LWB Safari flatdeck, TD42 -
- 1988 LWB 7-seat Safari, TD42 -
1989 LWB 5-Seat, TD42
-
The Following User Says Thank You to mihit For This Useful Post:
-
9th October 2022, 06:08 AM
#38
Originally Posted by
mihit
HOW did the alternator fail? (rectifier, bearings, windings?) Might give some clue.
Those voltages seem incredibly low and to me suggest an undersize battery or one with low internal resistance. Resting voltage should be 12.2-12.8. This may drop significantly on cranking but I wouldn't expect below 10. Glow plugs will soak up certain current but not enough to cause that kind of voltage drop.
Charging (engine running, alt working) voltage should be 13.2-14.4 depending on batteries current charge state.
I wouldn't trust a -stereo- (??) unless it's wired directly to the battery with wire sized apropriately for the current and cable length (10A minimum)
Testing for parasitic drain is done with a clamp or ammeter in between the main hot wire and battery terminal. There will be certain "standby" current for computers, clocks, etc. if there's anything over 1A that would be cause for concern (to my mind, new cars will have more electrickery) - with the ammeter still in circuit, pull house fuses one by one until the current goes low, then you've identified the circuit drawing power.
It seems maybe this is a common fault? And no-one's worked it out?
Alternators require a "field" or "sense" wire and this may be undersized, worn, shorting, etc. I would run a new wire direct from positive battery terminal to this "field" pin/pole/terminal, 5A wire should do as it's only measuring voltage (batteries' current charge state) and providing the excitation for the field. But bigger wire never hurts and 10A is cheap enough.
Try and find a wiring diagram for the alternator but I think the field pin is normally marked "B"
If it's all going through some f*cking computer...then it's probably the f*cking computer.
Alternators are simple devices, and the three things at the top are about all that can go wrong. Re-wiring a rectifier bridge isn't hard and costs <10$ in diodes. Bearings are same as any other bearing job. Windings, unless you're in BF-nowhere, would be throwaway/replace, but it would be good to know WHY they failed.
Thanks for your reply mihit.
The issue is sorted. Actually there was no issue to begin with as the reading from the stereo was quite off. The steady idle voltage the stereo displayed was 13.2-13.6v but just the on position and crank voltage was completely off. So, to test correct values I did the following:
1. Connected a DMM to the battery - reading was 12.8v
2. Turn the key to on position - reading was 11.6v
3. Cranked - reading was just below 11v
I also kept the DMM connected and did a high idle test to 2000rpms and the voltage started increasing so I'm sure now the alternator is charging the battery as well. Not going to rely on the stereo voltage display.
The alternator failure cause wasn't anything electrical. It was just life failure. It was never changed since I bought the car so basically it failed after literally 14years. To be honest though couple of times I have stretched the use of a dying battery a couple of times previously, the start was long, service advisors asked to change the battery but delayed until car was completely dead at times and also due to this, my starter has also given up. Lesson learnt though, no more stressing other parts due to weak battery. Just change it in time.
I do have quick query though, I'm planning of using a very simple system to monitor the voltage when the car is running. I just can't decide what would be the correct way of having the voltage display. Could you guide me if any of these are the correct and of course a safe way.
1. 12v LCD voltage display with inline fuse of 10A connected to the internal fuse box to a switched power source.
2. 12v LCD voltage display on a USB charger connected to the lighter(not sure about the fuse in it but if I'm not mistaken most of them come with 1.2-2.5A)
thanks
2008 Nissan Patrol GU Y61 TB48
Mods: De-Cat, Custom Cold Air Intake with Heatshield, Aftermarket headers, AoR center exhaust box
-
-
9th October 2022, 09:36 AM
#39
everyone loves a happey ending
Well... since all my alternators have been going for ~30 years... it does strike me as odd that after "only" 14... one should fail
I would find a "hot-when-on" wire (on the gq this is second relay from firewall beside RH battery) and splice into that to trigger a relay.
Relay obviously to run power to the voltmeter. (I assume GU no longer have voltmeter on dash??)
- 1990 LWB Safari flatdeck, TD42 -
- 1988 LWB 7-seat Safari, TD42 -
1989 LWB 5-Seat, TD42
-
-
10th October 2022, 02:53 AM
#40
Patrol Guru
GU dash does not have the four lateral gauges as the GQ does. Only fuel and water temp, which is a shame and also make the dash look full of nothing.
-