 | Home > In Car Electronics > Wiring in LEDs to interior lights [It's finished!] |
 
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| shaun.mobile Member Since: 12 Dec 2011 Location: England Posts: 156   
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Doesn't the defender have a speed sensor somewhere?
If so it may be possible to take a signal from it through a power transistor to switch the lights on when the vehicle is stationary. |
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24th Apr 2013 6:44pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610 
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 No good of course if you're a private detective on a stakeout! If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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24th Apr 2013 7:02pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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 Mal you've found me out already! 
⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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24th Apr 2013 9:07pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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Steve....It says 'stakeout' not 'steak out'......  If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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24th Apr 2013 9:11pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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What are you implying...
  ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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24th Apr 2013 9:18pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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Nothing at all!  If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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25th Apr 2013 3:07pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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I did a test on the same circuit the other day with a small LED strip and that seemed to dim to off just like the interior light. I can only assume with the LED's that the issue is that the power load they use is so small that it takes a while to fully discharge as you mentioned. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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25th Apr 2013 3:28pm |
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| XS Pete Member Since: 13 Jan 2011 Location: Suffolk Posts: 632 
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Guys,
I'd be extremely cautious about doing what you're suggesting here. I don't think the dimming period is controlled by a simple capacitor, as the discharge period would change dependant upon load. If you had a filament lamp fitted, then it would be much shorter than when using LEDs. The interior light function is controlled and driven by the 10AS unit, which has a 'stepped' open collector output for this function. This can be witnessed when 'certain types' of LEDs are used in the interior light fittings, when dimming, they appear to quickly transition from bright to off through a series of discrete decreasing steps. This phenomena is not noticeable with a filament lamp because of its analogue characteristics and general hysteresis. These LEDs which you can pretty much get anywhere these days employ different techniques to derive their needed supply voltage from the vehicle 12V. Most white chip LEDs need around 3.5V to function whereas the vehicle supply is obviously 12V, which is too much. To achieve this, some use simple integral shunt resistors, which kind of defeats the power-saving attibutes of an LED, as the extra power is simply wasted in the resistor, and you end up with a light which consumes as much as a traditional filament bulb. Others (less common, and more expensive) use tiny precision regulators, which is a much better solution as it better handles the different operating conditions i.e. the range of supply voltages you get from the vehicle supply 11.5 - 15V etc). The problem becomes more complex when you look at the construction of multi-chip LEDs (those little lamps which have 3 or 6 LED elements, or PCBs with 20 or more on). Depending upon how these are physically configured, as they can all be in parallel, or pairs or fours in series/parallel), and then you take into account the fixed diode voltage-drop associated with each element, you can end up with some very strange loads indeed. This is probably the reason that in one of your experiments the LEDs never fully extinguished, as the output of the 10AS could not properly 'see' gound due to all the diode drops. If you'd have continued experimenting further, you'd have probably also found strange behaviour of the alarm functionality. Without some close inspection and measurement of the actual LEDs you're planning on using, it's very difficult to predict the outcome. So, in a nutshell I suppose what I'm saying is that unless you can guarantee by measurement that the overall circuit impedance is the same or close to the original factory set up, I'd steer well clear of doing this, that is unless you've got a spare 10AS unit in the shed. Pete |
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26th Apr 2013 11:21am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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XS Pete - Some good reading there.
I've done some more testing today and will post up later what I've found out ect. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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26th Apr 2013 12:35pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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Not really worth posting up the results of the testing I did really as it's all jargon really no use to anyone except me. I also think my Multimeter ammeter is not working either unless it's my inadequacies using it.
 
Anyway I'm far to busy at the moment to touch it at all but I did notice tonight that there is a green version available too: http://www.halfords.com/webapp/wcs/stores/...yId_272449 Whether that would be a good colour match to the dash green lighting I do not know.  ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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26th Apr 2013 8:42pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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May have a chance to have a look at the mA load figures and so on later. I have a feeling the draw will be below but near the standard incandescent bulbs power draw at 10w. Ideal IMO and what I was hoping to get near but not over of course. The standard filament bulb is approx 0.83A / 833mA
The LED's use a lot less but as there is more than one the load adds up more but all in all so far I'm happy. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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30th Apr 2013 10:31am |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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Okay, In the end I did indeed do some proper testing and got my Multimeter working correctly too.
1 mA = 1/1000 A = 0.001 A 10 mA = 10/1000 A = 1/100 A = 0.01 A 100 mA = 100/1000 A = 1/10 Amp = 0.1 A The standard 10w incandescent interior light bulb draws 833mA (milliAmp) / 0.83A (Amp) My 2 x Red LED interior light festoon bulbs draw 32mA each or 64mA the pair. As I am using just the one light fixture 32mA is applicable. Changing down the current draw from the incandescent festoon bulb to the LED festoon is 883mA Minus - 32mA = 851mA safe spare to use* Without exceeding the standard draw of the incandescent festoon. So with the LED festoon still powered this leaves me 851mA to play with without causing any overload. (An obvious no no anyway) The 4x door handle LED's use 1.26mA total for all four. 851mA Minus - 1.26mA = 849mA. This still leaves me with a spare 849mA of current to use. (More plans later on once completed  )
Now before I bore you with details.... The issue with the Series and Parallel wiring with the door handle LED's. I have taken these reading once the system has dimmed the interior lights to off. And also with the LED festoon bulb in place which draws nothing 0mA. 2x LED's wired in Series 0mA draw with lights dimmed to off. (As desired) 2x LED's wired in Parallel 0.07mA with the lights dimmed to off. This also produces a faint glow which doesn't seem to go off at all. For the whole set of 4x LED's that would be a constant 0.14mA draw not good at all and not going to work out. It's pretty obvious that it's not a good idea to wire in this way as the LED's will stay illuminated partially constantly and also causing battery drain. I shall not be wiring in in Parallel but how much draw would 0.14mA be on the battery at rest? I.e. how much in comparison with other functions like the constant live clock. Personally IMO no draw on items such as this should be hence why I will not be fitting this way. Shall keep quiet now.
⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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30th Apr 2013 5:14pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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Steve,
I've done some number crunching and your calculatios are wrong.....See the bold bits you've inadvertantly added 50mA...
EDIT***Previous entry I put here was rubbish....To increase the current draw you will need to find diodes with a significant lower resistance than the ones you have, approximately 360 ohms lower. To draw 833mA the diode needs to be 14.4 ohms yours are 375 ohms. If you go through life with your head in the sand....all people will see is an ar5e!! Treat every day as if it is your last....one day you will be right!! Last edited by K9F on 30th Apr 2013 9:23pm. Edited 1 time in total |
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30th Apr 2013 8:57pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20299
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Mal - I think your probably right. I was using an on-line calculator as I didn't have one to hand so probably did miss that out.
I shall review it again at some point and do a thorough check. I had quite a few figures so it was ones work to get it onto here and calculate too. ⭐️⭐️God Bless the USA 🇬🇧🇺🇸 ⭐️⭐️ |
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30th Apr 2013 9:21pm |
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