They vary a lot in output and I've been finding out what works with mine. Added to that is some confusion in the Chinese makers' minds about what makes a stop-tail bulb. Some of them simply don't work right, being aimed at the American market, and the presence of two contacts and two pins (even offset) is no guarantee that's what you'll get. However, this is what I bought recently and works fine.
For a 5W equivalent tail light...
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For Stop-Tail equivalent...
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This was just a touch too dim for tail duty...
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P
Peter Hill
Well none of the cars that the usual SMD LED E-bay LED bulbs fit have variable voltage drives.
None of them have PWM drives either.
The E-bay bulbs don't have voltage step up or PWM drivers in the base.
Some do have a parallel resistor to stop a CANBUS system detecting the lack of current as a bulb failure.
Each LED drops 0.6V, a chain of 10 will drop 6V.
Using AC to drive a LED is utterly pointless, it is a DIODE so it will block the reverse voltage and it won't light up. Maybe you are confused with a domestic LED bulb that responds to a triac dimmer? Very few cars have an AC supply, it would need an inverter. A few trials motorcycles with crude electrics powered the lights direct from the lighting coil of a simple flywheel magneto / generator, no battery or regulator. Lose one bulb and all would blow.
AFAIK only the CREE LEDs used for headlamps have PWM drive, the E-bay CREE kits come with a PWM driver module. A pair of headlamp "bulbs" cost about £50. They can output around 1600-2000 lumen which is comparable to
+50% brighter 55-60W halogen bulb but not a 3200 lumen HID D2S. H4 dip/main type are available, they have 2 leds. One LED on top and one on bottom of the "bulb", top one is at dip focus the bottom one at main focus but slightly offset up/down by thickness of the "bulb", also the area of the LED means there will be some blur compared to the halogen lamp. It runs the dip at about 1600 lumen and for main both at 1800 lumen combined. They have cooling fins and a fan.
The same CREE LED lamps with 60W +50% brightness halogen headlamp output, without any means of dipping are being used by cyclists. Some even have 2 on the handlebars and a 3rd on the helmet. So are using lighting comparable to illegal for road use 100W rally bulbs. The max rated headlamp that doesn't require dip on a moped is 25W - about 500 Lumen.
D
Duncan Wood
Actually there's PWM drives in most cars nowadays, they're just not used= =
to dim the headlamps.
It varies, quite a few have a simple linear current regulator.
You're 1/2way there.
YOu're getting confused, cree make leds, the pwm driver module is a =
separate thing.
J
johannes
Halfords cheap - I don't think so. I get my car bulbs from Poundland.
N
newshound
Be aware (as I only discovered recently) that there are two different sorts of pin offset on stop-tail bulbs. What I think of as the traditional ones, where the two pins are at different axial distances from the end contacts, and one where the pins are at the same axial distance, but offset so that the line joining them does not pass through the bulb axis. If that makes sense.
Claims also to be a reversing light but surely these are normally 21W.
Handy links, I might just give these a punt as one of my cars had a spell of blowing them (although it seems to be OK ATM)
S
steve robinson
Some are not compatable with lamp failure warning systems within the vehicle
R
RJH
Yes, I fitted some side light LEDs that were advertised as warning system proof. However, on switching the ignition on they flash and set off the failed bulb warning (BMW Mini 2008).
Is this likely to lead to any complications? The system appears to clear/reset on switching them on/off.
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