Rookie electrical question - Dull LED's

[stag888]

Hi,
Am trying to fit a strip of 12v LED's to light up my centre console - all good up to a point , have sourced power by splicing into the power leading to the auto gate light , now switched on and sure the LED's light up , but not very brightly - hardly worth the effort . I remove the auto gate light bulb & presto the LED's burst into the kind of light I was expecting . Obviously am only getting partial power , I need a power supply linked into the lighting system, and that is the most natural & convenient source, but don't really understand how to go about making it happen . Any suggestions , can anyone enlighten me ?
Cheers
Steve

[Peter924]

I've done the same, but had no problem with the brightness of the 3 leds I used. Even had to dim the light with a peace of coloured glass.
The leds were placed in the rubberstrip in front of the autostick surround.
This is what it should look like.

Triumph Stag AM-51-34 dashboard_08h_mail.jpg

Triumph Stag AM-51-34 dashboard_09d_mail.jpg

[Hettiherald]

Hi steve
I think you may have managed to put the leds in series with the bulb somehow, this will have the effect of reducing the voltage to the led lights. The best way to sort it is to put it in parallel , take the feed from the pos side of the supply to the auto light and earth the leds onto the body. If this is what you have already done, then i aint got a clue!!
Dave

[stag888]

Dave,
Didn't think I had , but the fact they dim when the auto light is engaged really does confirm it , The auto light was supplied via a bullet connection , made up a new male bullet and had combined the existing auto power with the LED power ( The splice ) and then both the auto light and the LED had their own earths . I think if I combine the earth points rather than keep them separate that would circle the circuit and put it back in parallel . Shall give it a go when I get back from work.
Steve

[Mike Stevens]

If when you took the auto bulb out the LEDs became brighter, I can't see how you got them in series as without the auto bulb, there'd be no current in the LEDs at all!

You need to get a voltmeter on there and measure what's going on. With the voltmeter -ve lead on earth (body etc) measure around the circuit, at each end of the LEDs etc. This should tell you where you're losing volts.

It does sound very odd though.

Cheers,
Mike.

[Driveshield vehicle track]

Try a new bulb, if is weak it will be pulling extra amps to make it illuminate !?????

[jeffb]

You may need a resistor in circuit with the LEDs to balance the load, if they are specific to auto electrics there should be one already.

[peterl]

Sounds like the current supplied to the incandescent bulb is introducing too much voltage drop into the feed wire. Removal of the bulb will reduce the voltage drop, therefore LED's are brighter.
Either there is a high resistance joint in the feed wire or the wire has too small a cross section to accommodate the bulb and LEDs.
Peter

[stag888]

Thanks for the advise , actually managed to pinch & damage the LED strip as I fitted it to the trim , so have had to pause whilst I order another , Am ensuring all joints are soldered , have soldered straight onto the Auto light input / out , no more splicing , reducing the connections , believe I'm getting there slowly by a process of elimination , hadn't considered wire size , am using 5 amp interior light wire , to connect onward from the auto light fitting to the LED , as the wiring supplied isn't quite long enough , which I thought would be enough based on the fact that the LED wiring seems even lighter weight . Should get the replacement light mid week , and so the saga continues
Cheers

[peterl]

Leds will only draw 10 to 15 milliamps each, whilst a 2Watt globe (assuming it is 2W), will draw about 160 mA, so 5A wire will be large enough. Have you tried replacing the incandescent with a LED? (So that you only have LED loads).
Regards, Peter

[Hettiherald]

Steve.
Just been mucking about with my lights on the gear selector as it was abit dim,( like me). Discovered that the wires that feed the light are wired in series with the ciggy lighter bulb, god knows why, this is why your leds are dim. the blue / red wire feeds the ciggy lighter, the white / red wire comes from the dimmer control.
If you take the pos feed for the lights from the red/white side of the bulb and earth for the leds to the body, they should work
I hate electrics!!!!
Dave

[stag888]

Well received a second strip if LED's , cut to correct length , masked over every other (Otherwise it's too bright ) & sprayed with black satin . Once dried fitted ,as before the light just wasn't bright with the auto bulb in place , however when I then started her up , the light intensity increased , looked really good , just enough to see the heater controls in the dark , and not so bright as to look out of place, looks as if it was meant to be that way . So that's how I plan to leave it for now , as I can't see a situation when I'm likely to use the lights when the engine is not on . However the light does seem to ebb and flow very slightly with the rev,s .
I'm still open to suggestions as I know it's not right but with MOT due tomorrow , it's low now on the list of concerns
Thanks for all the support & guidance
Cheers
Steve