Weird LED BPF Bulb Behaviour?

Status
Not open for further replies.

Tornado

VIP MEMBER
Joined
Dec 5, 2017
Messages
4,464
Country flag
I've now tried three BPF type LED bulbs in my '74 850. First one seemed to perform fine for a few rides, then after checking high beam one night, noted it would not switch back the just low beam. Took it to bench and same issue...both sides of the LED bulb came on no matter which terminal I feed with negative power (these are positive earth type LEDs).
I worked with the vendor (DynamoRegulatorConversions) in the UK and they sent me out a new, updated bulb (after many months being on back order). In fact I received two for some reason. Welp, both new ones seem to be doing the same thing...only full beam comes on no matter what terminal is feed negative power.
Thought it might be something screwy in the Commando wiring/switching but why does this also happen in bench testing direct to battery?

Here's the ordering page for pic and description:

http://www.dynamoregulatorconversions.com/led-bulbs-especially-for-motorcycles-shop.php
 
I think I've figured out why high beam is always on. Took the handlebar switch apart to check/clean contacts. Testing bulb using just dismantled switch by pressing contacts gave same situation. Tried removing high beam indicator bulb and then low beam could be on without high and toggling high/low worked correctly.
So issue is the warning lamp must pass sufficient current along high beam pathway to allow high beam to turn on.
I need to decide if a resistor or diode is needed in line to the warning lamp. I believe the bulb vendors sells something to prevent that warning light from being on with low beam, so that may be the solution.
 
I think I've figured out why high beam is always on. Took the handlebar switch apart to check/clean contacts. Testing bulb using just dismantled switch by pressing contacts gave same situation. Tried removing high beam indicator bulb and then low beam could be on without high and toggling high/low worked correctly.
So issue is the warning lamp must pass sufficient current along high beam pathway to allow high beam to turn on.
I need to decide if a resistor or diode is needed in line to the warning lamp. I believe the bulb vendors sells something to prevent that warning light from being on with low beam, so that may be the solution.
Perhaps if the indicator bulb is also a LED?
 
Yes, that might be a solution. Will check with vendor and see what they recommend. I've no issue changing out the warning lamps. Both turn and high beam...my Assimilator warning have already be swapped to the SparkBright voltage indicating LED and Assimilator component binned.

Now I'm stuck looking for one of the tiny screws holding the switch gear board in the cover...it fell out, I heard a metallic clank, then nothing further and have spent better part of one hour searching for its landing place. Looks like I'll need to drill/tap the fixture to accept a more readily available screw.
 
Last edited:
Yes, that might be a solution. Will check with vendor and see what they recommend. I've no issue changing out the warning lamps. Both turn and high beam...my Assimilator warning have already be swapped to the SparkBright voltage indicating LED and Assimilator component binned.

Now I'm stuck looking for one of the tiny screws holding the switch gear board in the cover...it fell out, I heard a metallic clank, then nothing further and have spent better part of one hour searching for its landing place. Looks like I'll need to drill/tap the fixture to accept a more readily available screw.
I have a chronic case of dropping small hard to replace parts. Sometimes sweeping the area with a magnet - especially the ones on the end of a telescoping rod - cures the condition. Also worth looking under things that are so far away that there is no chance the item ended up there. If all else fails sometimes doing the sweep up that you've put off for the last few months yields results.
 
Yes, that might be a solution. Will check with vendor and see what they recommend. I've no issue changing out the warning lamps. Both turn and high beam...my Assimilator warning have already be swapped to the SparkBright voltage indicating LED and Assimilator component binned.

Now I'm stuck looking for one of the tiny screws holding the switch gear board in the cover...it fell out, I heard a metallic clank, then nothing further and have spent better part of one hour searching for its landing place. Looks like I'll need to drill/tap the fixture to accept a more readily available screw.
I recommend disassembling the switchgear inside a plastic bag, the little buggers can't escape then.
 
<-----That is all LED, headlight,pilot light, taillight and gauge lights. The switch I'm using may have been a headlight switch or a blinker switch, I don't know. Got tired of fiddling with 4-position Lucas ignition switches and changed it to older-style off/on keyswitch. Everything comes on, but the headlight (both beams) only work if the blade switch is flipped one way or the other. If both were coming on at once, I'd suspect the switch.
 
I have a chronic case of dropping small hard to replace parts. Sometimes sweeping the area with a magnet - especially the ones on the end of a telescoping rod - cures the condition. Also worth looking under things that are so far away that there is no chance the item ended up there. If all else fails sometimes doing the sweep up that you've put off for the last few months yields results.

Only works if the part is magnetic and the magnet is right on top/next to it!!
 
Never did find the dropped screw. Found. #4-40 screw at hardware store that seems to thread in OK.
Went on a test ride with the LED headlamp on low beam...during daytime so can't comment of light output, but the SparkBright voltage monitoring LED shows much improved charge volts while riding amount town. With the incandescent bulb, indication was showing 12v or lower while idling near 1k, stopped at lights. Now it's showing 12.5v idling and quickly goes to good 13v charging range when blipping throttle to 2k. This was all with the high beam warning light pulled out to prevent the current leakage issue discussed earlier.
 
Status
Not open for further replies.
Back
Top