ST1100 LED conversion

[cc2larke]

Hey all! Been updating systems/parts and finally getting around to the lighting. It's a '91 with the stock alternator, so I'm hoping to free up some current for heated grips. I'll get to the big draw (headlights) probably tomorrow, but I got all the other external lights replaced, and some of the dash lights: The four connectors that look like instrument lights don't seem to light when removed from the panel (they have a blue film on them), am I pulling the wrong sockets? All of the hazard lights were easy, except for the low fuel indicator, which seems to have a low current always--is there a good fix to keep an LED from being dimly on? Either a relay on the circuit so it doesn't activate until it's at a higher current, or a resistor to eat up that low current?

As for the headlights--is it worth going with the H4 conversion shims, or cutting the housing to accept untrimmed bulbs? The shims will theoretically pull the bulbs slightly out of the focal point of the housing, but is it enough to make any difference?

 

[DeanR]

Mine has been fine with the shims.

 

[Andrew Shadow]

As for the headlights--is it worth going with the H4 conversion shims, or cutting the housing to accept untrimmed bulbs?

This option will make it easier to replace bulbs in the future. However, in my opinion, the gain in ease is not worth the effort unless you are taking the headlamp housing out for some other reason, in which case the effort is much less and therefore the gain is much more.

Another option is replacing the headlamp housing with a European housing that was designed for H4/9003 bulbs. Beyond them accepting standard H4/9003 bulbs, it has been stated here that they also provide a better beam pattern and better lighting. If it is enough to justify the expense and work I can't say as I have never had a European headlamp housing on my ST1100's.

The shims will theoretically pull the bulbs slightly out of the focal point of the housing, but is it enough to make any difference?

No. Unless you are a lighting engineer who will carefully scrutinize the before and after beam patterns you most likely won't see the difference.
An electrical engineer on this forum who worked tirelessly to develop H4/9003 LED bulbs that actually put the light where it is supposed to be has stated that adding the shims to an ST1100 headlamp that was designed for the Honda proprietary bulbs actually improves the beam pattern, so it might even be beneficial.

 

[Uncle Phil]

Been using the shims for years with first the H4 replacements and now the LED replacements.
Another option is to get a European headlight that needs no modifications.
I looked at cutting the headlight for the tabs and it was too much sugar for a nickel for me.

 

[cc2larke]

Thank you for the replies! I've got some shims on order, it looks like the cost/benefit is definitely in that camp, and the brighter bulbs will likely make up for the difference (which might actually improve?). I also like the euro headlamp version, then I don't have to alter this housing. Were they all the same, regardless of year, or do I need a specific age range? Is the mounting and headlight adjustment all the same otherwise?

I saw in the repair section regarding the low fuel light that the circuit just has a resistor that varies depending on moisture/temperature. Looks like a fairly simple thing to add either more resistance or a relay at the plug, anyone do something similar?

 

[St-Gerard]

Anyone have a link to said shims and led lights?

 

[cc2larke]

These are the parts I'm using:

Shims and headlights:

Amazon.com

Amazon.com

Marker lights (my front ambers are on, so dual filament version for that):

Amazon.com

Amazon.com

Amazon.com

Flasher (with these bulbs, they flash quickly, will let you know how it works with this unit, only one I've found that is the same form factor):

Amazon.com

Dash lights (got a selection of colors, the warm white works well as neutral):

Amazon.com

Did not replace instrument lights, or low fuel light

To be added for license plate (LEDs are red, so light on plate is wrong, will wire these on the tail light circuit):

Amazon.com

 

[Sunday Rider]

Anyone have a link to said shims and led lights?

Here’s a seller in Canada on eBay for the shims

H4 ADAPTER RINGS HONDA ST1100 ST1300 ST 1100 1300 CBR900 CBR1000F GOLDWING | eBay

Find many great new & used options and get the best deals for H4 ADAPTER RINGS HONDA ST1100 ST1300 ST 1100 1300 CBR900 CBR1000F GOLDWING at the best online prices at eBay! Free shipping for many products!

www.ebay.ca

 

[cc2larke]

Any electrical engineers about? Would a Mosfet be an easy way to switch the voltage on the low fuel light? Just put one in line so that low voltage won't trip the LED, but as it increases towards 12v it allows the LED to come on? Connect the feed from the tank to the drain and gate, and the the line from the dash to the source?

 

[Uncle Phil]

Any electrical engineers about? Would a Mosfet be an easy way to switch the voltage on the low fuel light? Just put one in line so that low voltage won't trip the LED, but as it increases towards 12v it allows the LED to come on? Connect the feed from the tank to the drain and gate, and the the line from the dash to the source?

Check with @spiderman302 !

 

[Andrew Shadow]

For the small percentage of time that that bulb is illuminated vs the time that the motorcycle is running, wouldn't it be easier to just leave that one bulb be? That one bulb won't have any impact on the Wattage savings that you are trying to get.

 

[ST1100Y]

Any electrical engineers about? Would a Mosfet be an easy way to switch the voltage on the low fuel light? Just put one in line so that low voltage won't trip the LED, but as it increases towards 12v it allows the LED to come on? Connect the feed from the tank to the drain and gate, and the the line from the dash to the source?

How about a simple resistor/ballast like the one required when LED turn-signal filaments are used on the standard relay...

 

[cc2larke]

How about a simple resistor/ballast like the one required when LED turn-signal filaments are used on the standard relay...

Certainly simpler, but a little less elegant, and I was hoping to make the circuit not generate excess heat if possible.

 

[cc2larke]

For the small percentage of time that that bulb is illuminated vs the time that the motorcycle is running, wouldn't it be easier to just leave that one bulb be? That one bulb won't have any impact on the Wattage savings that you are trying to get.

True, it just seemed a shame to have the one bulb not match. A little too much OCD, but there it is.

 

[Andrew Shadow]

I haven't looked at the wiring diagram for the low fuel light so this suggestion may not make any sense. Added to that I don't know all that much about LED bulbs so this may not be viable at all, but when I was shopping for LED's I seem to recall having seen LED bulbs that have a minimum threshold voltage that must be met before they will illuminate. I don't know what type of LED's they were, or if they were only the actual LED as opposed to a complete LED bulb assembly. This is not what I was looking for so I didn't pay much attention to them. You will have to research it.

You stated that there is always a low current on the low fuel warning light circuit, which means that there is voltage as well. Does the voltage also fluctuate on that circuit?
i.e. Lower voltage when there is not a low fuel condition, and higher voltage when the low fuel warning light is being commanded on.

If both of the above are correct, can an LED bulb that requires a minimum of somewhere between 13 and 14 volts before it illuminates be used?
The LED would only illuminate when there is a low fuel condition that is putting full system voltage in to that circuit. Since the electrical system runs at 14V and above when the engine is running, the LED should only light when the low fuel circuit is applying voltage which exceeds the minimum threshold required to illuminate the LED.

 

[cc2larke]

I haven't looked at the wiring diagram....

Should have started there myself! Anyway, here's the circuit. When you turn on the key, the light illuminates to check function, and then turns to the circuit coming from the resistor (which according to the fix it thread elsewhere on this site, changes based on whether it's submersed or not). I'll have to check what the voltage coming from it in the two states is after I ride tank down a bit, but I know the LED I purchased has a fairly low activation voltage (after the check light it comes on very dimly).

 

[spiderman302]

If you are going to use a standard 5mm led use a 470 ohm resistor for white, or 560 ohm resistor for red/orange. (20 ma)
If you bought one that setup for 14 volts it already has a resistor.
If you want to use a fet you will have to set it up as a current source. A NPN transistor would be better, but both would be way over kill.
The resistor is the best (simple) solution.

 

[cc2larke]

Thanks for the info! How do you come by the resistor values for the different colors?

Is this an example of 5mm that you're speaking of?

Amazon.com

Resistor 560 Ohm 5% 1/4W (25-Pack) - ProtoSupplies

These are 560 ohm 1/4W 5% through hole resistors with strong leads and easy to read color coding perfect for solderless breadboards that come in a 25-pack.

protosupplies.com

What sort of heat generation will there be (or is .25W so low, it's effectively background)? Can I just heat shrink the whole thing, or wrap it in electrical tape? I'm guessing I'll just splice it into the lead coming off the tank, since there's a ton of room there.

 

[Alberto]

ust put one in line so that low voltage won't trip the LED

Didn't have this problem with led bulbs conversion. Got a handful of these led bulbs from eBay (T10?) and replaced all in the dashboard, including warning lights

 

[spiderman302]

The exact value of the resistor is not important, value derived via Ohms law. Power will not be an issue.

5mm refers to :




But the led shown in the post 19 may be a better fit and it has a built in resistor.