Led's headlight issue

[portishead]

Hi all,
I dont know if this is the right place... But I am after a little help. I have swapped out my daytime running halogen bulbs in my car for a couple of led bulbs. These bulbs (only £10) Nothing expensive say they are canbus error free however, the bulbs work nicely but bring up the warning lights on the car error system. I guess the leds are less power and the car thinks the bulbs have blown?? Does anyone know a work around for them or what I could use to correct it???

These are the bulbs if its of any help....

Thanks all

http://www.ebay.co.uk/itm/252415530198?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Alec_t]

Presumably the LED bulbs have inbuilt (or associated) electronics for current control? If so this will interfere with the bulb tests the car does.
BTW, have you checked with your insurer that they're happy with the modification to your car? Some insurers can be picky and may invalidate the policy.

 

[Tha fios agaibh]

I would put the original headlamps back in, measure the current they draw and see if the fault goes away. Then, reinstall your leds and check amperage again. The error free leds should have a resistor added so they draw the same current.
I assume these are made to fit your car model?

 

[portishead]

Yes they are made for the car , well for the particular terminal type anyway. Seller states the f30 BMW anyway. Standard bulb design holder.
I have swapped the originals in and out several times the warning fault goes instantly . The originals are24w bulbs.
How would I check the amperage on my multi Meter? ?

 

[Tha fios agaibh]

Use a clamp on DC meter or an ammeter capable of handling at least 2amps.
You can break apart the wiring at a splice point in the light circuit or pull the fuse and insert the leads across it to complete circuit.

 

[portishead]

Thanks. I'll try it on daylight and let you know results

 

[Bluejets]

24w for headlight bulb seems rather small.
55W would be normal.
55w/60w for low/high beam.

 

[portishead]

Technically they are a daytime running light drl . 24 watt.

http://go.redirectingat.com/?id=231.../threads/leds-headlight-issue.279967/&xtz=-60

These are the standard bulb...

http://www.ebay.co.uk/itm/NEW-GENUI...en:F30&hash=item1c6a7b3bf0:g:4E0AAOSwJMhXERun

 

[portishead]

View attachment 28238 Use a clamp on DC meter or an ammeter capable of handling at least 2amps.
You can break apart the wiring at a splice point in the light circuit or pull the fuse and insert the leads across it to complete circuit.

So, testing as you mentioned. I have my meter set on dca 20. The led shows 0.12 & the halogen is 1.71. Both sides are the same. Is this the difference that causes the problem? If so can we fix or adapt ?

 

[Sunnysky]

Instrument panel will have some threshold current sense to detect faulty halogen filament.
Thus a dummy load current perhaps 1 A is needed or 14W. This is Trial and error to determine lamp fault threshold indicator on instrument panel.

 

[portishead]

So, when it gets to component level I need pointers!!! What should I be looking to buy? And from where?

 

[Sunnysky]

Try the smallest 12V bulb that works with fault light out
e.g 3W and measure its resistance.

If you want a resistor instead.

search here http://www.digikey.com/product-search/en/resistors/through-hole-resistors/66690?k=&pkeyword=&FV=fff40001,fff80482,4043d,4043f,40445,40886,40942,40e47,8000a,8000b,80010,8004c,8004d,80068,8006a,8006d,80075,8022a,8022b,803a0&mnonly=0&newproducts=0&ColumnSort=0&page=1&stock=1&quantity=0&ptm=0&fid=0&pageSize=500

or Mouser or RS

 

[portishead]

So what your saying is I need to add in another light bulb behind the led to make the led work and not bring on the warning light? Cant be a permanent fix surely! !

 

[Sunnysky]

Other than finding the threshold for bulb resistance in the instrument panel self test, I think so, or just ignore it. The LEDs work but the lamp fault light is ON.
This is a common issue.

 

[portishead]

I thought i had to solder a resistor . Would it get hot?

 

[Sunnysky]

yes.
A bulb has resistance and gets hot, but wears out.
A resistor gets hot also and must be larger to run at a lower temp.
Trial and error testing would determine the best value, starting around 10 Ohm 5W rating but uses 1.4W.

I Have no idea what current is needed to turn off fault lamp .

If you had 2 same halogens in series, current would be = 1.71A /2 = 0.85A and 14.2V/0.85A= 16.7Ω

Then you could use 16Ohms or so ... This is trial and error. The least hot part that works is best..

 

[Tha fios agaibh]

Trial and error testing would determine the best value, starting around 10 Ohm 5W rating but uses 1.4W.

If you had 2 same halogens in series, current would be = 1.71A /2 = 0.85A.

10 ohms sounds good, but how did you get 1.4 watts?
I was thinking that .12a would be drawn by each led with supplemental parallel resistors added of about 9 ohms that would draw an additional 1.47a totaling near the original 1.71a drawn by the bulbs. This would require 25watt resistors.
(Assuming 13.2 volts)

 

[Sunnysky]

I used 10 Ohm or 1.4A roughly 82% power point. You can start anywhere like two halogens in series as half power to hunt for the threshold.

 

[Tha fios agaibh]

Sunnysky, your 5 watt recommendation sounds way too small. (Or am I missing something?)

 

[Sunnysky]

sorry. 20W