Introduction to LED lighting
One way to reduce the electrical load on your old dynamo charging system is to replace some of the bulbs with modern LED lights. These units require significantly less current than standard incandescent or halogen bulbs, which means that you have more spare wattage to use for other accessories such as perhaps a higher power headlamp bulb. Whilst they are a little more expensive than conventional bulbs, they have the added benefit that they last virtually forever and so should rarely (if ever) need replacing.
This article covers the following topics:
- Introduction to LED lighting
- About LED’s
- Which bulbs to replace
- Conclusions and your comments
Many people think that LED bulbs look better too because they turn on and off instantly, rather than fading in and out like conventional incandescent bulbs. This is particularly noticeable in indicators and brake lights that are regularly turning on and off.
There are a few other important features of LED bulbs though that you need to be aware of. Firstly, they are polarity sensitive which means that they won’t work (or might be damaged) if you connect them the wrong way around. You need to be sure whether your bike is negative or positive earth (i.e. which terminal of the battery is connected to the frame) and order accordingly.
Secondly, LED bulbs are sensitive to voltage. Most of the LED ‘bulb’s that are commercially available will have in-built resistors to make sure that the correct voltage is supplied to the individual LED elements. So you need to make sure that you also order the correct voltage (6 or 12 volt) for your bike.
Which bulbs to replace
Well lets start by considering what bulbs are fitted to the typical old motorbike:
- Headlamp bulb (18 to 35 Watt)
- Sidelight bulb (5W)
- Stop and tail light bulb (21 / 5 Watt)
- Indicator bulbs (21 Watt x 4)
- Speedo or gauge bulbs (3W)
The headlamp bulb might seem to be the most obvious one to replace as it is usually the highest wattage one found on any bike, varying from a rather dull 18 Watts up to an acceptable 25-35 Watts, through to a dazzling 60-65 Watts (probably not a good idea on old Lucas dynamo electrics though!). However, at the moment LED bulbs just aren’t suitable for headlamp usage so we need to look elsewhere.
The indicators (if fitted) are the next obvious place to look. Whilst each bulb is just 21 Watt, two are used at once (one front one rear) and hence the total is 42 Watts. These bulbs can easily be replaced by LED units, but there is one important thing that you need to bear in mind. The old type of flasher relay units need a certain amount of current in order to work; that’s why on some cars the indicators won’t flash if one of the bulbs has blown. LED’s use a fraction of the current and so the flasher relay probably won’t flash. However, more modern electrical flasher units are now available which can cope with a wide range of wattages and so just be sure to order one of these at the same time as the LED’s.
The stop and tail light bulb(s) can also be replaced with dual-brightness LED units. These tend to have an array of individual LED units arranged in a cluster, a few of which light up for tail light and all of which light up for the brake light. The LED unit can therefore be a simple direct replacement for the original bulb.
Actually a new LED rear light option is now available for many classic motorbikes which have the Lucas 564 type of tail light fitted. And this option is really good – I know because I designed and made it myself! It consists of an array of super-bright LEDs mounted on a circuit board which is a perfect fit for the Lucas 564 rear lamp and is available in 12v LED light board and 6v LED light board versions which work with both positive and negative earth motorbikes.
The pilot bulbs which illuminate the speedo and other dials are usually only a few Watts and so it may not seem worthwhile replacing these. But it’s still an extra few Watts saved towards that super-bright high-wattage headlight (or just to take some load of an old charging system)! Other benefits are that LED bulbs do not get hot at all and this might be beneficial where the bulb is in a small enclosure.
I mentioned above that I have recently designed and manufactured a range of LED light units specifically for old motorbikes. This all started because I was having difficulty finding a suitable positive earth LED light for the Lucas rear lamp of my own Matchless motorbike, so I thought I would make one myself. These are vastly superior to anything else I’ve found on the market in terms of quality, brightness, reliability and fitment inside the original Lucas lamp. You can see for yourself by taking a look in my new Matchless Clueless LED store.
Alternatively, have a search on the web for ‘LED bulbs’ and there are now loads of different suppliers that will come up. One web site that I have used quite a few times in the past (for both old car and bike bulbs) is Paul Goff’s store. He stocks direct replacement bulbs specifically for old vehicles so it’s fairly easy to find the right model for your bike. Just remember to order the right voltage and polarity (i.e. negative vs. positive earth).
Hopefully this article has explained what LED lights are, why they could be of real benefit to your classic motorcycle and which of the conventional filament bulbs could be most easily replaced. If you have any thoughts or suggestions for improving this article, please leave me a message using the comments form below.