LED tail/stoplight bulb (2015)

Ive got the same rear light board and been quite happy with it. Be aware if you swap out to led headlight, the oem zener may be over taxed trying to get rid of excess voltage. Mine failed ans battery bloated from over charging. Now have the TriSpark reg/rec and everythings good.

Tornado said:

Ive got the same rear light board and been quite happy with it. Be aware if you swap out to led headlight, the oem zener may be over taxed trying to get rid of excess voltage. Mine failed ans battery bloated from over charging. Now have the TriSpark reg/rec and everythings good.

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Educate me, please.....
What difference to the zener from either two low draw lights on, or two high draw bulbs off??
Is not the 'excess voltage' greater from the latter.??...

EstuaryBoy said:

Educate me, please.....
What difference to the zener from either two low draw lights on, or two high draw bulbs off??
Is not the 'excess voltage' greater from the latter.??...

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Are you saying you run with headlight and taillight normally off?
Here in Canada motorcycles are required to run a front headlight and rear taillight at all times while operating on the road.

Running with headlight off will put more load through the Zener than when headlght is on. LED headlight means lower consumption and same output from alternator so zener must work harder/hotter to short that excess voltage to earth than when an incandescent headlight is on.
My zener died within a few months of running led head and tail lamps. It lasted 47 yrs with incandescents.

As far as I am aware (and I should be ashamed for not knowing**) the UK does not have any daytime running lights requirements as yet..
Yes, I do run with led pilot and tail light on, but 'lights on' is a fairly recent (or within my lifetime!) phenomenon here, and I would say that running without lights would have been the default position for many before traffic got hectic..
So I would have assumed the charging circuit as built would be okay with that..
Perhaps after 47 years the zener was nearing the end of it's service life??

**Just checked HM Govt website, which states: 'Drivers of vehicles that are not fitted with DRL are not required to turn on their headlamps or position lamps during the day unless visibility is very poor.'

Tornado said:

Here in Canada motorcycles are required to run a front headlight and rear taillight at all times while operating on the road.

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I don't use daytime lights at all unless conditions (fog, snow, etc.) demand it.

As EstuaryBoy says, there's no such law in the UK except in conditions of bad visibility, in fact, for daytime use, lights aren't even a legal requirement as stated in the MoT regulations.
"4.1.1. Presence, condition and operation

A motorcycle or motorcycle and sidecar must be fitted with one headlamp, although additional headlamps may be fitted. Apart from headlamp security, the check only applies to mandatory lamps.

Headlamps are not needed on motorcycles that:

are not fitted with front and rear position lamps
have had their front and rear position lamps permanently disconnected, painted over or masked
were first used before 1 January 1931."

Lovel said:

it works just not at 800rpm and headlights on. 1200rpm works no problem

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Please don't idle your Commando at 800 RPM. Your cam and lifters will thank you.