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Update your car’s interior with LED lighting LED interior lamps in this 2004 Honda Accord not only have much better colour rendition than the original incandescents but give a brighter and more even light than before. By LEO SIMPSON REPLACE THESE WITH THESE These LED lamps can be used to replace a variety of incandescent lamps in your car. Are you hankering to replace your car even though it is still reliable and has many years of life in it? It’s a common feeling but one way to at least partially cure that hankering is to make some small mods which make it look more up-to-date. Changing your car’s interior lights to LEDs is an easy and cheap modification which is a really worthwhile improvement. L ET’S FACE IT; incandescent lamps are old hat and LEDs are the new way. More and more cars are now fitted with LED stop and traffic indicator lighting and some are even using high-intensity white LEDs for their headlights. But some cars which use LEDs for their headlights, such as the 22 Silicon Chip latest Honda Accord V6, still use boring old incandescent lamps for their interior lighting. There are two major faults with incandescent lamps for car interior lights. First, they are often not bright enough to let you read a map and second, they pull too much current. In fact, leaving your interior lights on overnight can easily flatten your battery. Some cars have an inbuilt timer which switches off the courtesy lights if they are inadvertently left on but many don’t. Back in the days when cars only had one interior light, it wasn’t such a problem but many cars siliconchip.com.au have quite a few incandescent lamps and they can add up to a sizable drain on the battery. In my 2004 Honda Accord for example, there are three lamps in the roof of the cabin and one in each door. The cabin lamps each pull about 600mA while the door lamps each pull 240mA (at 12V). Hence, if I leave one of the doors ajar, the total current drain is just over 2A which is certainly enough to flatten the battery overnight (fortunately, in the Honda Accord, the cabin lamps turn off after a delay period). However, while the current drain is relatively high, the quality of lighting is poor and looking at them, I was always thinking that they looked so “orange” and old-fashioned. In fact, they reminded me of the headlights on 6V cars (particularly on the VW beetle) which were so feeble that you had to light a match to see if they were on! There is another disadvantage of incandescent lamps for car lighting and that is the lamps get so hot that they can discolour and even char the diffuser. After all, a 12V 600mA lamp dissipates over 7W. Of course, as they get older, the lamps also blacken and that reduces their brightness even further. Ultimately, they die and you are left in the dark; quite disconcerting if it happens just when you want to look at a map! Recently, one of the interior lamps in my car died and I decided to fix them once and for all. Most car interior lighting either uses double-ended “festoon” bulbs or so-called “wedge” lamps which are all-glass construction with connection wires on both sides of the glass “wedge” which pushes into a socket. Now the good news is that there are countless LED equivalents This photo clearly shows the effect of replacing the righthand front roof lamp in this 2013 Honda Accord with a wedge LED lamp. Note the colour difference between it and the original the incandescent lamp at left. Both the front roof lamps in this 2004 Honda Accord have been replaced with LED lamps. They not only have a cool white light but are also brighter and generate considerably less heat than incandescent lamps. to these incandescent lamps and you can get them in a range of colours (cool white for me, thanks, and one sugar), with differing arrays of surface-mount LEDs. Some of these are based on a small PCB with an array of four, six, eight or more LEDs and some have a more complicated construction where tiny PCBs are assembled together to give light radiation over wider angles. Now as far as car interior lighting is concerned, these fancier shapes are unnecessary and defeat an advantage of surface-mount LEDs which radiate all their light in one direction. For The door lamps in the 2004 Honda Accord were also updated with LED lamps and these two photos show the difference between the old at left and the new at right. The cool white of the LED lamp is not only brighter but looks far better than the orange light from the original incandescent lamp. siliconchip.com.au December 2013 23 Which would you prefer – the original interior incandescent lighting shown in this photo . . . interior lamps, there is no need to radiate light in many directions since they will be fitted in a housing which only lets light out in one direction anyway. Identifying the lamps The first step in this process is to identify the particular types of lamps in your car. This can be a bit of chore as some of the diffusers can be quite tricky to remove and there is a risk that you might crack one when attempting to do so. Having removed the diffuser and the bulb, make note of its dimensions. Festoon bulbs come in various sizes, eg, 31mm, 39mm and 42mm long etc, and it is important that your LED replacements fit properly. The same comment applies to wedge lamps – they also come in different wedge sizes. Armed with the type and size details, you are ready to start shopping. Now you will find vast numbers of LEDs and sellers on the internet and undoubtedly many of them are cheap and entirely satisfactory. I purchased a number of different types on the internet but I also visited my friendly local Jaycar store to make sure that I purchased the correct wedge lamps for the doors in my car. I wanted to check that I could buy the exact replacements because many of the LED lamp illustrations on the net do not really show the key dimensions. So . . . or the LED lighting shown here? The two photos have identical exposures and the colours were not retouched. you could buy them and then find they simply don’t fit. In my case, Jaycar had the correctsized wedge lamps (Cat. ZD-0390) I needed for the doors of my Honda Accord. And while Jaycar also have a fine selection of festoon style and other lamps for car lighting, including those for brake and reversing lights, I had already obtained a selection of festoon lamps from on-line sellers on the net. While you have to obtain festoon lamps with the correct overall length, you will also find they are mostly based on a single PCB with an array of six, eight or in one case that we found, 24 SMD LEDs. Be aware that these PCBs can be much wider than the original festoon bulbs and if they are too wide for the particular housing in your car, they simply won’t fit. Nor should you make the mistake of thinking that you should simply fit the brightest LED lamps you can get. There is no point in them being needlessly bright. After all, they are at close range and you don’t want to be blinded. Depending on which LED lamps you choose, their current drain will be a great deal less than the original incandescent lamps. For example, compared with the festoon lamp’s 600mA <at> 12V (800mA <at> 14.4V), the LED equivalents I fitted with six SMD LEDs each only pulled 36mA. So I This rear interior ceiling light in a 2013 Honda Accord has been fitted with a LED lamp on the righthand side only. Once again, the difference in colour temperature compared to the incandescent lamp on the left is obvious. 24 Silicon Chip An incandescent wedge lamp (left) and its LED replacement lamp at right. managed to reduce the total current when a door is left ajar from over 2A to just over 120mA. That’s about one seventeenth! By the way, there are no polarity markings on the LED lamps. It’s just a matter of trial and error to determine which way around they go and there’s no damage done if you get it wrong. Colour variations Another point to consider is that even though you might purchase a batch of LED lamps on the internet for a bargain price, they will not all necessarily be the same colour. We found some that were not well matched within the same batch. You certainly don’t want LEDs of slightly different colour in your car, as it can look quite odd. And while I prefer cool white LEDs, other people may prefer warm white. I just think that warm white is a poor imitation of the same sickly colour as incandescents. It certainly does not provide better colour rendering; most LED lamps are poor in this respect. There is really not much more to say on this topic. The photos accompanying this article show how effective LED lamps are at lighting your car’s interior. They certainly do improve the look of the cabin at night and they should last for the life of the car. Finally, the total current drain of the interior lamps will be drastically reduced, meaning that you could leave them on for several days without flatSC tening the battery. siliconchip.com.au