A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Lights

D3 - Lights Headlights, xenons, foglights. Everything outside the car that glows

Reply
 
Thread Tools Display Modes
  #11  
Old 1st June 2014, 09:12 PM
onetwentie onetwentie is offline
Member
 
Join Date: Apr 2013
Location: Manchester
Posts: 91
Default Not 12V?

Somerandomguy: you mentioned that you broke some using a 9V battery, does that mean that these are not able to take 9V or 12V? I notice that the Maplin ones state that the 'reverse voltage max' is 5V?

I think i've managed to fry so many of mine doing the same testing with a 12V battery? but what I don't understand is that they seem to work intermittently when testing with a 12V battery?
__________________
Current: 2007 Audi A8 3.0 TDI SE Quattro -
Reply With Quote
  #12  
Old 1st June 2014, 10:34 PM
Delboy's Avatar
Delboy Delboy is offline
Senior Member
 
Join Date: Aug 2013
Location: Lowestoft, Suffolk
Posts: 2,492
Default

Most led's are less than 12v,

When used in a 12v situation like a car the a wired in series to prevent going over the forward voltage rating of the led.

So make sure you do your homework and work out the max voltage for each led before testing with a separate power source.
__________________
Del

Reply With Quote
  #13  
Old 2nd June 2014, 06:40 AM
ScottD3's Avatar
ScottD3 ScottD3 is offline
Senior Member
 
Join Date: Oct 2012
Location: Plymouth
Posts: 1,888
Default

like Delboy said.

Most of the LEDs in cars seem to be 5v.
Slapping 9v or 12v through them will cause them to burn out.

They run 12v from the car power source cause they are done series or has resistors to step the voltage down.

If you want to test a LED to make sure it works, get your multimeter and set it to continuity mode and use that.


The LEDs won't very bright but you can check colour and if they work.
Don't forget LEDs will only work if the positive and negative is connected the correct way round.
__________________
[center]
06 3.0TDI Quattro:
Options:
Soft close Doors & Boot, Electric Blinds, Keyless Entry & Start, Bluetooth HandFree, Quad Zone Climate, APS+, 3 Spoke Sports Tiptronic Multi Function Steering Wheel, Heated Seats All Round, Black Leather Comfort Seats, AMI, Sunroof, Drivers & Passenger Electric Memory Seats, Auto Dimming Mirrors, Bi-Xenons AFS2, Dab, Digital TV, Reversing Camera, AV Inputs, Fridge, Solar Roof, TPMS, facelift rear lights, 3G, remote boot closure, Tow Bar.
Reply With Quote
  #14  
Old 2nd June 2014, 07:15 AM
Somerandomguy's Avatar
Somerandomguy Somerandomguy is offline
Senior Member
 
Join Date: Apr 2012
Location: Kent
Posts: 229
Default

Yep, as Scott says, they are 5v wired in series with some resistors to drop the voltage down from 12v. The indicators for example are three individual banks of 10 LEDS - i didnt realise this at first and put 9v across on of the banks, as a few LEDs had already failed this meant that the voltage was still too high.

I quickly learned the lesson but not before a few more went. After this I started using a 3v button cell to test them as you can use it to power each bank (by just holding it against the solder of one of the LEDs in the bank).
__________________

2004 A8 3.0 TDI Sport Brilliant Black
Came with: Black Valcona/Alcantara Leather, KESSY, rear blind, flappy paddle gear change, Phone Prep, TV
Added:Bluetooth, AMI, Hybrid TV, Parking plus, Ski hatch, towbar, DAB, Umbrella Holder, Reversing camera, Auto lights, Wheel refurb
Things to fix: Turbo fault, power drain
Reply With Quote
  #15  
Old 2nd June 2014, 05:11 PM
onetwentie onetwentie is offline
Member
 
Join Date: Apr 2013
Location: Manchester
Posts: 91
Default

Some very useful and interesting info there guys, mucho thanks.

Scott - I till check my multimeter and see if I can figure that setting out to test.
Somerandomguy - what's a 3V button cell?
__________________
Current: 2007 Audi A8 3.0 TDI SE Quattro -
Reply With Quote
  #16  
Old 3rd June 2014, 06:22 AM
Somerandomguy's Avatar
Somerandomguy Somerandomguy is offline
Senior Member
 
Join Date: Apr 2012
Location: Kent
Posts: 229
Default

Its one of these
http://www.amazon.co.uk/Energizer-CR...eywords=Cr2032
__________________

2004 A8 3.0 TDI Sport Brilliant Black
Came with: Black Valcona/Alcantara Leather, KESSY, rear blind, flappy paddle gear change, Phone Prep, TV
Added:Bluetooth, AMI, Hybrid TV, Parking plus, Ski hatch, towbar, DAB, Umbrella Holder, Reversing camera, Auto lights, Wheel refurb
Things to fix: Turbo fault, power drain
Reply With Quote
  #17  
Old 3rd June 2014, 06:55 AM
ScottD3's Avatar
ScottD3 ScottD3 is offline
Senior Member
 
Join Date: Oct 2012
Location: Plymouth
Posts: 1,888
Default

3V button cell, used in PCs, Laptops and car remotes mainly.

Or you could use a 3V battery from a 35mm camera.
__________________
[center]
06 3.0TDI Quattro:
Options:
Soft close Doors & Boot, Electric Blinds, Keyless Entry & Start, Bluetooth HandFree, Quad Zone Climate, APS+, 3 Spoke Sports Tiptronic Multi Function Steering Wheel, Heated Seats All Round, Black Leather Comfort Seats, AMI, Sunroof, Drivers & Passenger Electric Memory Seats, Auto Dimming Mirrors, Bi-Xenons AFS2, Dab, Digital TV, Reversing Camera, AV Inputs, Fridge, Solar Roof, TPMS, facelift rear lights, 3G, remote boot closure, Tow Bar.
Reply With Quote
  #18  
Old 4th June 2014, 06:14 PM
onetwentie onetwentie is offline
Member
 
Join Date: Apr 2013
Location: Manchester
Posts: 91
Default update.. still not resolved!

So I managed to get a similar battery 'tester' - picked this up from Farnell's the other day - definitely better than sticking 12V to the LED's!



Then got myself some (50) of these:



...however soon realised that compared to the existing ones, these are too tall - they still allow the board to fit onto the tail light, which is a relief, however I wonder if that affects the way the lights look when the LEDs are lit.



I think these are 5mm and the existing ones are 3mm high. Also the brightness on these is definitely different, and when the whole unit lights up, you can see the difference. Which means I have to agree with M-A8 with the suggestion of changing ALL the LED's - I'm tempted. That said, it may be prudent to get some 3mm LED's (assuming that the originals are 3mm tall?)

Can anyone confirm the size and luminosity of the original LEDs? maybe someone with ELSA or ETKA or whatever they're called!

Finally this is what back of the unit looks like, it is the boot lid one, driver's side (for those who haven't seen it):


..the board which is sat over the top of the other two I think i've fried! or should I say the rain corroded. As a result I have a used one I purchased (whole unit) - question is, are these boards coded to the car? they seem to have some EPROM chips on them if i'm not wrong?

the saga continues..
__________________
Current: 2007 Audi A8 3.0 TDI SE Quattro -
Reply With Quote
  #19  
Old 4th June 2014, 09:53 PM
Delboy's Avatar
Delboy Delboy is offline
Senior Member
 
Join Date: Aug 2013
Location: Lowestoft, Suffolk
Posts: 2,492
Default

The board you are referring too is the control board that i mentioned in the PM,

You ought to be able to test via that connector using 12v as the board will have the correct load / resistance to allow you to do that.

There is no mention of LED's in etka as the pcb's are not for sale seperatley which is a joke.

If you change all the leds for brighter ones you will then have an imbalance with your inner / outer lights so unless you changed them all you would be best trying to match them the best you can.

farnell or RS components must have what your looking for IMO

I had a quick look through RS and filter out most of the irrelevant ones, you can further refine the search using the dimension filters to the left side.

RS Online

If you look at the forward voltage on the specs of the led's most of them are 3v some more some less so the battery pack you have at 6v may well still do damage to the led's if you are testing individual led's

Hope that helps
__________________
Del


Last edited by Delboy; 4th June 2014 at 10:31 PM.
Reply With Quote
  #20  
Old 5th June 2014, 10:27 PM
onetwentie onetwentie is offline
Member
 
Join Date: Apr 2013
Location: Manchester
Posts: 91
Default

Quote:
Originally Posted by Delboy View Post
You ought to be able to test via that connector using 12v as the board will have the correct load / resistance to allow you to do that.
I connect the connector to the car using the tail light unit, but the LED's don't light up? whereas they do if I test them separately on the board using the battery (though I take your point about the voltage on my test bed battery)

What can I do to progress the testing of the control board?
__________________
Current: 2007 Audi A8 3.0 TDI SE Quattro -
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 01:40 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.