Quick question guys – after a number of electrical issues at my last race, this weekend I decided to replace the battery (gone for a marine unit), plus replaced a number of switches (coz they were falling apart) and the two idiot lights for oil pressure and charging (I’ve gone for LED versions rather than bulbs), and now a strange issue has appeared and I’d appreciate any comments or pointers.
The buggy has a Nissan L20 lump with alternator, the wiring is probably very non-standard but works fine – all the power goes through a battery isolation switch, essentially from there to the ignition switch, which is a standard on-off toggle switch, and then to the starter button – all the rest of the wiring essentially hangs of the output of the isolation switch (in one form or another) none of this wiring has been changed, just the switches and lights, and everything work as I expect.
Well, almost, on firing up the engine since the changes, the oil pressure light goes out but the charging light stays on – at the same time the installed voltmeter shows that no charge is occurring (i.e. the needle’s way over to the left). After a noticeable period, probably 15-20 secs, the charge light goes out, and the voltmeter zips up to around 14 volts – which to my mind would indicate that everything’s OK.
The “problem” is that the delay in charging light going out never happened before the changes, the lamp went out and the voltmeter was up to 14 pretty much as soon as the engine fired. Do I have a problem, or am I just being paranoid??
Cheers ... Kimbo
Hi
I think that the LED bulb doesn't have enough resistance to excit the alternator, try putting a normal bulb in the circuit and see what happens.
Steve
Thanks Steve. Mmm, wouldn't have expected LED units to cause a problem, as I'd always imagined they were just a replacement for the normal bulb varients. But then I'm not very good with auto electrics, I can can trace/replace wires and loose connections etc., but other than that I'm pretty much stuffed, so I'd believe anything could be possible. Anyway, I'll give it a go and see what happens.
Cheers ... Kim
Yes,
I believe Steve has the answer -
the tell tale lamp isn't really JUST a tell tale lamp in regard to an alternator...
The Alternator still needs the current to operate..
You could just add a normal tell tale lamp to the alternator
and still use the LED light in the dash...
or put it back to original
I added a small lamp to an engine a few years ago as the wire to the alternator lamp in the dash had broken [open circuit] and it did the job until I rewired it.. a time later
LEE
PS: LEDs draw very little current and are low voltage devices. and the voltage changes with the color of the Light Emitting Diode ....
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
yep i sadly know
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Sorted - put a normal bulb unit in place of the LED and normal charging service is resumed.
Thanks guys, much appreciated
Cheers ... Kimbo
If the bulb is going to shake around and get busted maybe use the LED light and add a resistor in parallel the same resistance as the old bulb.
Steve
Good idea Steve - may well look at that - the reason I was changing it was because the plastic on the old bulb unit had cracked and one of the terminals had fallen out (the same reason I was also changing one of the switches) - the light still worked when all the connections were in place - given that the LED units, that I can get hold of, are also plastic, the longevity of the unit would still be suspect for the same reason, in any case. However, I'll see how long the bulb lasts and make a decision then.
Cheers ... Kimbo
