Auxiliary LED Lights

[TimGz]

What options do I have for installing LED auxiliary or fog lights on my 74 Triumph Trident. I was ready to purchase a set on EBay but remembered the pos ground issues. Has anybody else found a set that works with these electrical systems?

 

[Greyfell]

Well, there is a work-around, without changing your existing wiring system. You will have to make sure you get lamps suitable for the voltage of your current system. Then you can wire the lamps in reverse of what is thought to be standard. The negative of the lamp (black) gets connected to the negative of your harness (red or white); and the positive of the lamp (red or white) gets wired to the positive of the harness (black).

You should also draw out a simplified wiring diagram indicating this, to remind yourself, or to pass on to a new owner if you sell the bike.

 

[Rudie]

What options do I have for installing LED auxiliary or fog lights on my 74 Triumph Trident.
pos ground issues.

wire the lamps in reverse of what is thought to be standard. The negative of the lamp (black) gets connected to the negative of your harness (red or white); and the positive of the lamp (red or white) gets wired to the positive of the harness (black).

This is completely wrong. DC works exactly the same irrespective of "ground" ... The power source is the battery, there is no such thing as a "positive ground" battery or a "negative ground" battery; physical constraints aside, you can take a battery out of a modern "negative ground" Hinckley Triumph and connect it to the electrics of a pre 79 Triumph made at Meriden, or vice versa.

Then, standard 74 Triumph Trident electrics (any pre 79 British bike electrics), while plain White wires are negative, plain Red wires are always positive and plain Black was not used for any wires.

The short answer to the o.p.'s question is anything electrical will work as long as the component has separate negative and positive wires and the component does not "ground" through its mounting.

If the component mounting is not plastic or other electrical insulating material, test for "grounding" through the mounting with an Ohm meter or the Ohms function of a multimeter.

Then, as long as the component's negative wire is connected to a bike's negative wire and the component's positive wire is connected to a bike's positive wire, the component will work. Additional components' connections to a standard 74 Trident's negative wires should be chosen depending on the component's switching requirements:-

. Brown/Blue is unswitched, the component will work as long as the battery is connected;

. the ignition switch turns White wires on/off;

. the lighting switch turns the Brown/Green and Blue wires on/off; auxiliary or fog lights will most likely be connected to one of these wires.

However, considerations to be aware of are: despite the low power consumption of LED, there is almost no spare generating capacity in any standard Lucas/Triumph electrics, particularly at lower engine rpm; generating capacity can be increased with later alternators but the Lucas rating of the standard main Brown/Blue wires was exceeded by the standard RM21 alternator ...

If your Trident's lights are standard, I can quite understand why you are considering additional lights ... Nevertheless, more information on the underlying problem you are experiencing might help suggest lower cost and/or other solutions?

 

[TimGz]

Well, there is a work-around, without changing your existing wiring system. You will have to make sure you get lamps suitable for the voltage of your current system. Then you can wire the lamps in reverse of what is thought to be standard. The negative of the lamp (black) gets connected to the negative of your harness (red or white); and the positive of the lamp (red or white) gets wired to the positive of the harness (black).

You should also draw out a simplified wiring diagram indicating this, to remind yourself, or to pass on to a new owner if you sell the bike.

I understand the process. My concern is trying to find a light that does not have the positive wire grounded to the light internally. I guess I am just going to have to order the lights and check them with an ohmmeter. I am hoping that someone responds who has purchased such a set. Thank you for your input!

 

[Rudie]

My concern is trying to find a light that does not have the positive wire grounded to the light internally. I guess I am just going to have to order the lights and check them with an ohmmeter.

If your Trident's electrics are standard, you would want "a light that does ... have the positive wire grounded to the light internally", because standard Trident electrics are "positive ground" ...

So, unless your Trident's electrics are non-standard, you mean you do not want "a light that does ... have the negative wire grounded to the light internally".

Fwiw and ime, you will be very unlucky to encounter any modern electronic component with negative and positive wires that has either connected its mounting.

 

[TimGz]

If your Trident's electrics are standard, you would want "a light that does ... have the positive wire grounded to the light internally", because standard Trident electrics are "positive ground" ...

So, unless your Trident's electrics are non-standard, you mean you do not want "a light that does ... have the negative wire grounded to the light internally".

Fwiw and ime, you will be very unlucky to encounter any modern electronic component with negative and positive wires that has either connected its mounting.

Thanks! Right I do not want a negative grounded light! I plan to go ahead order and check with am ohmmeter. I also am wondering what the max wattage I can get away with?

 

[Rudie]

wondering what the max wattage I can get away with?

Unless you change the alternator, not a lot ...

As an example, changing the standard 45/35 headlamp bulb for a 60/55 (both Watts main/dip), main beam draws another Amp and a bit, dip draws nearly another two Amps; standard alternator, the engine needs to stay above 4,000 rpm a lot of the time or the battery will gradually flatten.

As I asked in an earlier post, it would help to know what you are hoping to achieve with auxiliary and/or fog lights? It would also help to know if the lighting is standard at present, when you expect to use the extra lights and under what conditions you mainly use your triple (especially knowing 4,000 rpm in top gear is over 70 mph)?

 

[TimGz]

Sorry Rudie. I missed your one reply. I was trying to make my bike more apparent to cage drivers. I figure the more visible the better nowadays!

I was looking at 30 watt auxiliary lights. I have the older 2 wire stator and plan to keep the bike under 4K.

I totally understand your electronic discussion.

 

[Rudie]

trying to make my bike more apparent to cage drivers. I figure the more visible the better nowadays!

Ime, the average cage driver is not looking, confirmed by firefighters over the years who, in the UK, are usually in big trucks painted bright red with both headlights and blue lights flashing and two different sirens sounding ...

plan to keep the bike under 4K.
have the older 2 wire stator
looking at 30 watt auxiliary lights.

The original Lucas company rated the standard 74 T150 RM21 alternator for 10.5A @ 5,000 rpm; however, also according to Lucas, it only produced 75% of that @ 2,400 rpm (< 8A) and the workshop manual test with a 1-Ohm resistor says 9A AC @ 3,000 rpm. Also, this assumes good rotor magnetism; original rotor in your bike would be 48 years old ...

Ignition coils draw between 3A and 4A unless you use a Tri-Spark electronic ignition, but even they only cut the draw by about 0.5A.

Plus the ignition, standard headlamp 35W dip filament draws 3A, or a bit more if the bulb has been replaced with 50/40; standard tail lamp draws another 0.5A; good to have spare alternator capacity above total constant draw, to keep the battery charged after periods of very low rpm, using turn signals, horn, etc. 30W auxiliaries would draw 2.5A so, if the engine spends a long time below 4K rpm, you would only be able to use the auxiliaries or the headlamp, not all at the same time.

The UK has never had a lights on in daylight law and, until recently, I have never ridden with lights on in good visibility. However, because so many European countries do have the law, numbers of all vehicles with lights on all the time have been increasing for years by default, it has become increasingly difficult to spot a completely unlit vehicle, especially a bike, even in clear visibility.

Fwiw, I have long used a bright pilot bulb in bike headlamps in poor daytime visibility and under streetlights at night; ime, works well because it 'fills' the headlamp with light to other road users in front of the bike, but does not dazzle any one. Current bright pilot 'bulbs' are https://www.ebay.com/itm/284599576488; one replaces the standard pilot bulb and holder, the LED's 23 mm diameter is bigger than the hole in the headlamp reflector, it is secured in the reflector by clamping it with the nut and a washer outside the reflector. I now use that in daytime as well.

If you have tried to find a LED replacement for the rear bulb, you will know it is difficult because the bulb hangs vertically, so most LED replacements would point the brightest LED at the licence plate instead of at the driver behind ... However, I have recently found these - I appreciate it is a British site but I am guessing there is similar in the US?

plan to keep the bike under 4K.

I hope not a long term plan; it will not do a triple engine (or a Triumph twin engine) any favours. If you are concerned about road speed, Hurricanes and some T150's were fitted with 18 tooth gearbox and 53 tooth rear wheel sprockets; does not do anything for top speed but would allow higher engine rpm for a given road speed. Gives a triple's clutch an easier time too.

 

[TimGz]

Ime, the average cage driver is not looking, confirmed by firefighters over the years who, in the UK, are usually in big trucks painted bright red with both headlights and blue lights flashing and two different sirens sounding ...


The original Lucas company rated the standard 74 T150 RM21 alternator for 10.5A @ 5,000 rpm; however, also according to Lucas, it only produced 75% of that @ 2,400 rpm (< 8A) and the workshop manual test with a 1-Ohm resistor says 9A AC @ 3,000 rpm. Also, this assumes good rotor magnetism; original rotor in your bike would be 48 years old ...

Ignition coils draw between 3A and 4A unless you use a Tri-Spark electronic ignition, but even they only cut the draw by about 0.5A.

Plus the ignition, standard headlamp 35W dip filament draws 3A, or a bit more if the bulb has been replaced with 50/40; standard tail lamp draws another 0.5A; good to have spare alternator capacity above total constant draw, to keep the battery charged after periods of very low rpm, using turn signals, horn, etc. 30W auxiliaries would draw 2.5A so, if the engine spends a long time below 4K rpm, you would only be able to use the auxiliaries or the headlamp, not all at the same time.

The UK has never had a lights on in daylight law and, until recently, I have never ridden with lights on in good visibility. However, because so many European countries do have the law, numbers of all vehicles with lights on all the time have been increasing for years by default, it has become increasingly difficult to spot a completely unlit vehicle, especially a bike, even in clear visibility.

Fwiw, I have long used a bright pilot bulb in bike headlamps in poor daytime visibility and under streetlights at night; ime, works well because it 'fills' the headlamp with light to other road users in front of the bike, but does not dazzle any one. Current bright pilot 'bulbs' are https://www.ebay.com/itm/284599576488; one replaces the standard pilot bulb and holder, the LED's 23 mm diameter is bigger than the hole in the headlamp reflector, it is secured in the reflector by clamping it with the nut and a washer outside the reflector. I now use that in daytime as well.

If you have tried to find a LED replacement for the rear bulb, you will know it is difficult because the bulb hangs vertically, so most LED replacements would point the brightest LED at the licence plate instead of at the driver behind ... However, I have recently found these - I appreciate it is a British site but I am guessing there is similar in the US?


I hope not a long term plan; it will not do a triple engine (or a Triumph twin engine) any favours. If you are concerned about road speed, Hurricanes and some T150's were fitted with 18 tooth gearbox and 53 tooth rear wheel sprockets; does not do anything for top speed but would allow higher engine rpm for a given road speed. Gives a triple's clutch an easier time too.

Thanks Rudie. That is a lot of good information regarding the Trident’s electrical capacity. I did not realize how close the max was particularly below 4000 rpm. Meant to say for the most part regarding the 4000 rpm. I had two twins before, Yamaha 650 and a BSA lightning and for the most part did not rev them like this bike is accustomed. I had a couple Yamaha 2 strokes and a CB650 before that that and actually was missing the thrill of going through the gears in those higher rpm’s. I have never ridden this Trident. It was my brothers whose first love was his Bonneville. I have spent the last two plus years stripping this bike down and restoring it. The engine was gone over and a new clutch was installed by the mechanic who was on the Triumph race team here in Ohio and the bike was ran in the local 24 hour race events in the Seventies. As sop as the temperature gets back into the forties I am going to start this for the firs time in 20+ years!
Before and after pics attached. Just waiting to have it painted!

 

[Rudie]

You should find the Trident happier to rev more like the CB650; in fact, depending on cam timing, 4,000 rpm is about when a triple starts to pick up, you would miss that keeping it below 4,000 rpm.

Standard electrics on Triumph and BSA were poor even when they were new. When your T150 was new, Lucas made a more powerful alternator - the RM23 - and, for example, better headlamps; Norton at least offered them as options on the contemporary Commando, Triumph and BSA consistently fitted the cheapest and lowest quality.

Aside, by the time of the T160 and electric start Commando in '75, both the bikes were being made by NVT. The T160 was around 10 mph faster than the Commando but still fitted with the RM21 alternator and same dismal BPF (British Pre Focus) headlamp as your bike ... the Commando had the RM23 alternator and 60/55 quartz-halogen headlamp as standard ...

Once you have had a chance to ride the Trident, if you want to invest in better electrics, Lucas made 3-phase alternators from 1978, even the "high output" (14.5A @ 5,000 rpm, 85% @ 2,400 rpm) version is the same physical size as the RM21 fitted now, a pattern version of that RM24 is available new from Wassell/Emgo. It would require the existing rectifier and Zener be replaced with a modern combined regulator/rectifier, but they can be had from Ebay for very little money, and some other wiring changes are necessary. But thereafter you would have more freedom to fit and use a better headlamp and/or additional lighting without concern about the length of time riding at low rpm.

 

[viclava]

What options do I have for installing LED auxiliary or fog lights on my 74 Triumph Trident. I was ready to purchase a set on EBay but remembered the pos ground issues. Has anybody else found a set that works with these electrical systems?

I have always purchased mine off of Amazon. Inexpensive and never had an issue and installed on numerous MC's.

 

[EndaWolf]

I recently saw an amazing set of amazon light bulbs, but unfortunately it may have already been sold out since the last copies were left there. Perhaps good fluorescent headlights will suit you, which will shine bright at night. I don't know if they are sold as a set so that you can replace all the headlights on your bike, but they are not so expensive at retail.

 

[EndaWolf]

I recently saw an amazing set of amazon light bulbs, but unfortunately it may have already been sold out since the last copies were left there. Perhaps good fluorescent headlights will suit you, which will shine bright at night. I don't know if they are sold as a set so that you can replace all the headlights on your bike, but they are not so expensive at retail.

Maybe you can ask some seller for a discount on them and it will be very cool. I would like to see your bike, so if it's not difficult for you, then post a picture of your bike the next time you publish a post on this forum. I wish you good luck and hope you find what you need!

 

[Rudie]

I would like to see your bike
post a picture of your bike

Post #10.