Battery light on after i Inflated my tires?? electrical help please
Submitted: Friday, Jan 04, 2008 at 07:47
ThreadID:
53098
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3522
Replies:
8
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11
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Ozboc
Hi guys --- this problem pertains to my Nissan patrol 4.2 TDI (99 )
spent a nice day at
stockton beach yesterday - and before i left -- inflated my tires with my own pump ( which did not miss a beat )
Done one side off my AUX battery ( 2 tires) then the others from my main battery - I had My accessories on ( motor off ) but not ignition on - so the radio was playing.
Well , when i jump back in to leave - start the beast up - Battery light is on - water in fuel filter light is on and Subtank light is on. i dont have a multimeter with me so i
home i go ( 2 hour drive ) and made it easily .....( sub tank was not draining and everything was working - even subtank when i did turn it on)
Now , i have just tested all the fuses in the cabin ( all 20 or so , of them ) all the ones under the bonnet - and have continuity through them all --
quick
check from earth to alternator + shows only 12.2 v ( exactly the same as battery ( main ) and when i pull the power off the battery - motor cuts out - also indicating i have no power from alternator.... -- now is there a charger relay somewhere that controls the alternator? and i find it hard to believe that just pumping up my tires with my pump would burn out the alternator even when motor was not running -- anyone care to shed some light for me as i don't want this happening to me in a few weeks time when i am out in the middle of nowhere for a week ...
thanks
Boc
P.s yes in the future i will only use the aux battery for pumping up my tires
Reply By: Member - Roachie (SA) - Friday, Jan 04, 2008 at 08:02
Friday, Jan 04, 2008 at 08:02
G'day mate,
Quick lesson: the alternator is under no load etc when you are using the batteries with the motor turned off.
I would suggest that you check/replace the regulator. This is the black "box" on the back of the alternator. I had to replace
mine a few months ago....various dash lights coming on for no apparent reason.
Will cost you about $60- for a new one and they DO wear out.
Just as an aside, I tend to leave my motor running when I use my compressor.....however,
mine is permanently wired to 3rd battery and I have "plumbing" right through vehicle, so I can plug-in the air hose on the bullbar and at the rear of rig too.
Cheers mate
Roachie
AnswerID:
279692
Reply By: Member - Bucky (VIC) - Friday, Jan 04, 2008 at 08:14
Friday, Jan 04, 2008 at 08:14
Ozboc
You obviously made it
home ok , and with lights on everywhere you would be a little pysed off. So would I ...
have you tried to do a cold re-boot,, ie disconnect battery's for at least 1 hr,, hook them up and re-start,,
See what happens !
should work ,, but there are no guarantees of course !
may need to do it overnight !
Hope you get it sorted
Cheers Mate
Bucky
AnswerID:
279697
Reply By: furph - Friday, Jan 04, 2008 at 08:26
Friday, Jan 04, 2008 at 08:26
Definately an alternator problem, as Roachie suggests the electronic regulator has given up the ghost (although they are very reliable) but could also be the field brushes worn.
However, a very big NO NO is disconnecting the battery with the engine running. This is a sure fire way to destroy the alternator diodes or blow the bum out of the regulator. The alternator, without the battery to provide the voltage reference, can instantly develop voltages in the order of 150/250v.
Have done it myself so learned the hard way!
furph
AnswerID:
279699
Reply By: Mike Harding - Friday, Jan 04, 2008 at 10:25
Friday, Jan 04, 2008 at 10:25
Interesting.
A DC motor (your compressor) is, electrically, an inductor and when you abruptly switch off the current flowing through an inductor the voltage across the inductor rises a lot – maybe 200+ volts – the exact value depends on lots of factors.
One possible issue which may have occurred (although I have never heard a proven case of it happening) is that when you disconnected/switched off the compressor a brief spike found it’s way into the vehicles electronics and has destroyed something, perhaps this was “helped” by the ignition being in the accessory position? Vehicle electronic designers go to a _lot_ of trouble to protect the electronics against spikes but a big enough spike will destroy things.
A “back EMF” diode across the compressor will remove the spike but it would need to be a big-ish diode and would be awkward to fit, I suspect.
Most times, _if_ the compressor is connected directly to the battery, the battery would probably absorb the spike but there are no guarantees…?
Let us know what the final problem is please.
Mike Harding
AnswerID:
279718
Reply By: Sand Man (SA) - Friday, Jan 04, 2008 at 14:33
Friday, Jan 04, 2008 at 14:33
My guess is a diode or something has gone open circuit in the alternator.
Measure across the primary battery terminals with the engine running and if you are not getting around the 14.1 volt mark, your alternator is sick.
I always run anything extra from the auxiliary battery. After all, that is what it is for. In a dual battery situation, with the ignition off and the engine not running, there is no electrical path back to the alternator or primary battery, as it is "isolated", by the dual battery controller.
AnswerID:
279758
Follow Up By: Ozboc - Friday, Jan 04, 2008 at 16:24
Friday, Jan 04, 2008 at 16:24
HI there , i have a Redarck isolator , so both batteries are in parallel until the Main ( primary )
battery falls bellow 12.6 v ( or somewhere near that ) only then does the 2 become isolated from each other, so i think there may be a path back to alternator.. --- and vice versa -- second battery will not begin charging untill the main is at full voltage
someone please correct me if i am wrong ....
Boc
FollowupID:
543911
Follow Up By: GerryP - Friday, Jan 04, 2008 at 22:21
Friday, Jan 04, 2008 at 22:21
Yes you are correct Ozbloc. To "force" isolation with the Redarc simply put a small toggle islolating switch in the small black wire. Breaking circuit on the black wire will disconnect the circuit connection between the batteries. Note that it does not require a beefy switch.
Cheers
Gerry
FollowupID:
544010