Forum

[zonggong]

Following more than 2 years of success (and very bright light) in my 2015 B5, and now, 2018 C5 I tried the same LED headlamp in my 1990 12V 350 Bullet. It lasted less than 5 kms. I bought another and that lasted just as long. I have a new battery and the charging voltage is about 13.5 V. The wiring diagrams all seem to show the alternator going through the rectifier and voltage controller before going to the headlamp so, if this is correct, an AC voltage would not be the problem. The LED in question is a replacement for H4 style halogen bulbs and has a small fan on the front for cooling the LED element. Is it just bad luck or something else at play? Thanks for your help.

[stinkwheel]

I don't know which year they went to AC lighting. If the light only works with the engine running, it'll be AC.



Otherwise, could be vibration? Or cheap and nasty LED bulbs? There are a lot of really crappy cheap Chinese ones out there. Or maybe voltage spikes? You can get LCD voltmeters very cheaply if you want to check it out on the fly. Is the switch making a good contact? if it was making an intermitant/buzzy contact, you could be rapidy power-cycling the LEDs without realising.

[Adrian]

One notable difference is of course your EFI Bullets didn't have 25+ year old wiring looms and other electrical components, whereas your 350's might be getting rather tired. I would try running a dedicated earth wire directly back to the battery from the headlamp and see if that improves reliability, the reg/rectifier might also be ripe for replacement.



How smooth is your 350 mechanically compared to the EFI bikes?



A.

[Adrian]

AC headlighting wasn't introduced until 1999 on export models if I remember correctly. As the LED replacement for the H4 worked well in zonggong's modern EFI Bullets I don't think we're looking at a quality issue there, though I suspect it's less tolerant of an ageing electrical system than a tungsten filament bulb might be.



A.

[stinkwheel]

Doesn't follow that the same brand and same appearance are the same lights. I found this out recently. I've had about 10 LED GU10 lights in my kitchen for the last 6 years. No worries, good quality of light and all still working fine. Because of this I got the same brand from the same supplier when I did my bathroom last summer. 4 of the 6 have failed...



Also worth checking the pinouts. Some sealed beam bulbs can be different but use the same connector as an H4.

[stinkwheel]

I'd add, that they aren't necessarily very good quality bulbs? Just a supposition but if the OP was using a high quality LED H4 replacement, I'd have expected more of an irritated "tone" to his post when one popped after 5 minutes. I'd also have expected him to have investigated why before simply replacing it with another one. By high quality, I mean the ones I'm looking at come in at about £40 each. I'm trying a cheap one off ebay first to see if they'll work with AC but don't expect this to last long or be much good.

[zonggong]

Thanks for the help and advice. Selecting a suitable LED replacement is not easy as the rear of the bulb cannot protrude, otherwise it binds on the speedo cable. All the LED bulbs with a rear fan will not fit which leaves the few that have fans at the front. The element is supposed to be less than 2000 lumens - if it is greater then auto levelling is required - here in Australia at least. The first one that blew was transferred from my B5 before I sold it so I wasn't sure if that was bad luck or not. The new bulb that blew last night was identical, although as Stinkwheel says quality may vary. I am irritated but am used to dealing with stuff that doesn't work as advertised. It did flicker a little so it is quite likely that the older wiring and components could be varying the voltage/current. I'll do a few tests and report back. The bulbs are quoted to be suitable from 6V - 36V which should suit most applications. Apart from the very bright light the LED headlamps are good because of their low current draw which is about 1.5 amps compared with the standard halogen which is about 6 amps. With a small alternator, and running the headlamp day and night for visibility, the battery suffers using the halogen headlamp.
To answer Adrians' question about smooth mechanical running, the 350 Bullet, which has only recently been registered, runs very smoothly and sounds great and is fun to ride. The 2018 C5 and 2015 B5 are not as mechanically smooth in my opinion.

[stinkwheel]

I was wondering how "clean" the power supply to it is. As I just found, they don't like AC. I wonder if a standard Indian rectifier is letting a little through, although the battery ought to go a long way to smoothing that out. Difficult to check without something like an oscilloscope. I wonder if it would be worth fitting a simple diode in the supply to the headlight switch?

[stinkwheel]

Sorry for multiple posts, just posting as things occur to me because I'm thinking about similar things for my own bike.



Have you considered using an HID conversion? They draw about 35w and give out the same light as 65W+. Need a "dunt" of power on startup but you have a battery which will sort that out. Ought to be room for the ballast in the headlamp shell somewhere.

[Mark M]

Try an LED bulb from these guys: http://www.dynamoregulatorconversions.com much better quality than anywhere else and Pete is very good at technical advice and after sales.

REgards, Mark