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athelstan



Member Since: 06 Aug 2019
Location: Kent
Posts: 55

United Kingdom 2015 Defender 90 Puma 2.2 CSW Montalcino Red
Interior lighting revisited.
After advice as a result from my previous post I fitted a pair of Philips X-treme vision festoon LEDs to my 2015 2.2 Puma.
Much better than the standard lighting and very pleased with the results.

There is a but however. With the switch set to automatic, on opening the door they are at maximum brightness, on closing the door they gradually dim and should go out completely but they don't quite go off altogether, there remains a very dim glow , which is OK during the day but annoying at night.
Considering that I had to virtually remortgage the house for said LEDs it seems a bit odd.
I have Googled for information and it seem that this is a common ocurrence with LEDs.
It is suggested that I bridge the contacts with a resistor. To me electrics are a black art and I have very little knowledge.
When they say "bridge" I presume that one end of the resitor goes to positive and the other end to negative ie.
across the spring mounting.
My questions are, what sort of resistor do I need and does it matter which way round it is connected.
Apologies for being so long winded but I don't want to do any damage to my electrics. 2015 90 XS Station Wagon Puma 2.2
2015 Morgan Plus 4
Post #837473 16th Jun 2020 9:04am
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bear100



Member Since: 22 Mar 2010
Location: South Wales
Posts: 1867

Wales 2010 Defender 110 Puma 2.4 USW Santorini Black
This will either satisfy you or blow your mind Very Happy

https://www.evilmadscientist.com/2012/resistors-for-leds/


Thumbs Up Thumbs Up 2016 Range Rover Autobiography 4.4 TDV8
2010 110 XS Utility 2.4TDCI
2010 Range Rover Sport TDV8 (gone)
2007 Discovery HSE TDV6 (gone)
1993 110 csw 200 tdi (gone)
1994 90 HT 300 tdi (gone)
1994 discovery 300tdi (gone)
90 hybrid 3.5 v8 (gone)
Range rover bobtail 3.5 v8 (gone)
Post #837478 16th Jun 2020 9:23am
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discomog



Member Since: 09 May 2015
Location: Notts/Lincs Border
Posts: 2494

United Kingdom 2015 Defender 90 Puma 2.2 XS CSW Santorini Black
That's the sort of information you need to digest on a rainy day in lock down. As you say "mind blowing". Defender 90XS SW
Mini Countryman Cooper S
Morgan Plus 8
Post #837502 16th Jun 2020 11:34am
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bear100



Member Since: 22 Mar 2010
Location: South Wales
Posts: 1867

Wales 2010 Defender 110 Puma 2.4 USW Santorini Black
Thud Thud Thud

Its not to bad really, certainly for a rainy lock down day! 2016 Range Rover Autobiography 4.4 TDV8
2010 110 XS Utility 2.4TDCI
2010 Range Rover Sport TDV8 (gone)
2007 Discovery HSE TDV6 (gone)
1993 110 csw 200 tdi (gone)
1994 90 HT 300 tdi (gone)
1994 discovery 300tdi (gone)
90 hybrid 3.5 v8 (gone)
Range rover bobtail 3.5 v8 (gone)
Post #837592 16th Jun 2020 5:49pm
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athelstan



Member Since: 06 Aug 2019
Location: Kent
Posts: 55

United Kingdom 2015 Defender 90 Puma 2.2 CSW Montalcino Red
Stone me! Who wrote that, Stephen Hawking? 2015 90 XS Station Wagon Puma 2.2
2015 Morgan Plus 4
Post #837664 16th Jun 2020 9:14pm
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macfrank



Member Since: 05 Nov 2015
Location: somewhere in the north
Posts: 983

Germany 2015 Defender 110 Puma 2.2 SW Keswick Green
Laughing

erm, well, that page is a complicated explanation for a simple calculation based on Ohm's law.
And I think it may not be the right solution for the glowing LED.

The linked page explains how to calculate a resistor so a standard LED wont blow the moment you switch it on.
That's for just one LED as shown in the photos, not LED arrays like in the festoons.

An LED wants about 2 Volts (simplified). Car has 12V. Way too much.
The resistor (R) should "take" 10 Volts away, so the LED "gets" its 2V.
Ohm's Law: R = voltage / current (simple, eh? Wink)
So we need to know the current the LED draws (you can look it up in a datasheet), let's say 20mA (0,020 Ampere) for an old-school red LED.
R = 10V / 0,02A = 500 Ohms
Done. (but don't do this at home, i.e. for higher voltages!!)

(Why do we use the LED's current to calculate the resistor? Well, along a single "wire" there can be only one current, so it's the same for LED and resistor.)

Unfortunately I don't have a solution for our glowing LEDs. Embarassed
Basically the reason is, I believe, that the AS10 which does the dimming was engineered to work with incandescent lamps. They need a higher current than LEDs, to start glowing.

From here it would get more complex but I'll spare us mutual embarassment. Wink
For me the bottom line was not to risk the life of my ALM ECU, experimenting around. And also not to buy other festoons (re "remortgage the house" Rolling with laughter )
Instead I just don't use the "auto" switch position. Whistle
Post #838459 20th Jun 2020 9:59am
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Martyn668



Member Since: 17 Mar 2013
Location: Cambridgeshire
Posts: 134

United Kingdom 
I fitted the ones from Fourby. Cheap as chips and plenty bright enough. Probably not as good as your Philips ones, but good enough for me. I know MUD UK also do one, which from forum views is apparently very good, but way more expensive than the Fourby option (which retains the original housing).

I bought a festoon from Ebay for my Honda. No fitting issues (except I bought the wrong size first time round - I had no idea they come in so many different sizes!)

However, like you I have a front door light on a PIR on our house. It never goes out. Glows dimly 24/7 until someone comes to the door in the dark, and then it lights up fully. It's actually not a bad idea to have it working like that, certainly at dusk, although it wound me up at first. Supposed to be energy saving, but is it using 100% power even when it's only glowing dimly?
Post #840495 29th Jun 2020 4:35pm
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bear100



Member Since: 22 Mar 2010
Location: South Wales
Posts: 1867

Wales 2010 Defender 110 Puma 2.4 USW Santorini Black
i have these in mine and got to be at leat 8 years old now

And only cost around £2 Shocked



 2016 Range Rover Autobiography 4.4 TDV8
2010 110 XS Utility 2.4TDCI
2010 Range Rover Sport TDV8 (gone)
2007 Discovery HSE TDV6 (gone)
1993 110 csw 200 tdi (gone)
1994 90 HT 300 tdi (gone)
1994 discovery 300tdi (gone)
90 hybrid 3.5 v8 (gone)
Range rover bobtail 3.5 v8 (gone)
Post #840523 29th Jun 2020 6:29pm
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macfrank



Member Since: 05 Nov 2015
Location: somewhere in the north
Posts: 983

Germany 2015 Defender 110 Puma 2.2 SW Keswick Green
Martyn668 wrote:

However, like you I have a front door light on a PIR on our house. It never goes out. Glows dimly 24/7 until someone comes to the door in the dark, and then it lights up fully. It's actually not a bad idea to have it working like that, certainly at dusk, although it wound me up at first. Supposed to be energy saving, but is it using 100% power even when it's only glowing dimly?


Shocked Reminds me of an engineer on the tele who showed that the PIR electronics of some indoor LED lamps draws as much power as the LED itself - and he got furious about it.

In our camper Defender I sometimes use the "glow feature" to get in / out of bed.
So, if you can't come up with a solution, just redefine the problem Laughing
Post #840546 29th Jun 2020 8:01pm
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