Why does my new globe/indicator flicker, produce an error code, or function intermittently?
LED lights offer greater brightness and greater volume with the benefit of using less power. This is a perfect combination, however, does offer some challenges when being retrofitted to vehicles that are not originally designed for them.
Back in the old days, the headlight circuit was a really simple system. It was simply an on/off 12v switch… Unfortunately, that is no longer the case.
Modern vehicles now use sophisticated electronics to control and monitor your vehicle’s headlights and ancillary systems. When you remove and replace the stock incandescent/halogen light bulbs in your vehicle, you might run into an issue with the vehicle’s lighting computer thinking there is a potential problem.
Many new vehicles have a standalone computer that specifically controls the different lighting functions on the vehicle and it’s programmed to know exactly how a standard light bulb functions. As soon as this computer “sees” something that doesn’t line up with its programming it either puts the system into a diagnostic mode or keeps functioning and throws an error.
Now for some maths. A normal halogen globe for the low beam is typically 55w. This 55w globe will produce approximately 850 lumens and consume 4.58a @ 12v. The engineers of your modern vehicle would have programmed the computer (likely) with an operating range of 3.8-5.0a. This range would allow the halogen globe to fluctuate with the given vehicle voltage without alarming the vehicle's computer. If the globe was to dip below this operating range (globe fails), the computer will log this error, and throw a warning light on the dash to let you know.
Now for a comparison. If we use our Copperhead globes as an example, they consume 1.8a @ 12v, albeit, offering a 207% improvement in lumens (1760lm) over a 55w halogen globe. So if we remember back to the vehicles programmed operating range, anything below 3.8a will be considered as an error, even though there is nothing wrong with the globe.
How do I fix?
With a Canbus module/decoder! They look deceiving in nature, however, contain very powerful circuits within. They contain a resistive, capacitive and bridge rectification circuits. The latter two, I will explain later. The first is what we are concerned with at the moment. Our Canbus modules are a simple plug and play affair. Plugging them in before the aftermarket globe will provide extra resistance and load to mimic the current draw of a halogen globe. Depending on how your vehicle's computer is programmed, a Canbus module will be sufficient in 95% of cases and will “trick” the computer into thinking, nothing has been changed at all.
What if I don’t have an error, but my new headlights flicker?
Great question! Flickering could be caused by many different things, however, in the case of modern vehicles, it will likely be caused by PWM (Pulse Width Modulation). PWM, is a technology to reduce the heat value of halogen bulbs, help the bulbs last longer, and save more power while operating. Pulsing power to a halogen globe will not have any visible effect to the human eye. If the PWM is set to 50 times a second, the halogen filament will not have an opportunity to cool down enough for our eyes to see a visible dimming effect, but (oddly) will drastically extend the life of this globe.
An LED globe requires a smooth direct current to operate correctly. They are HIGHLY reactive to current variation and will instantly “flicker” on a PWM circuit. On a 50hz system, the human eye will see the globe flicker 50 times a second. The module’s large capacitance will basically store up power to eliminate the pulse and supply the LED headlights with a constant current.
Why do I need a Canbus module in my ancient Landcruiser?
It is not required for any computer function, rather, to “flip” the negative trigger nature of the headlight system into a positively triggered system that the LED circuit is able to understand. LED’s are essentially one-way valves, and as such, are only able to accept a positively triggered input of power. The “Bridge rectifiers” inside the Canbus modules will facilitate the function of this ‘one-way’ circuit.
I have bought your indicators and they flash really weirdly and intermittently?
Our dynamic indicators are designed to operate their strobing function at a standard flashing interval. Prior to removing your original indicators, you may remember their normal tick…tock…tick…tock flashing interval. If you have ever had an incandescent indicator globe fail, you may have noticed an extremely fast tick.tick.tick.tick hyperflash and wondered what was going on until you realise that you have blown a globe. When load is removed or reduced from the flasher module/can/relay, it is designed to hyperflash to alert you of an error. It is quite a crude system, albeit, highly effective.
Now, you’ve received your new Stedi dynamic indicators in the mail, and have completed the install onto your, say, motorbike. You’re excited; turn your ignition on, then turn your indicator on, and realise you have weird intermittent strobing/flashing that is far from consistent, and instantly think they are faulty. That is perfectly understandable. Stay calm, all is well. As mentioned above, a reduced load on the flasher can will cause it to hyperflash, creating a perceived “faulty” indicator.
To further break this down; you may have sat at a set of traffic lights behind an old ute, with the (brand new looking) indicators going absolutely nuts like a disco! Old mate simply hasn’t added any load resistors into the circuit to ‘mimic’ the load of the original globe. The original globe would likely have been 21w and 1.75a of current draw. The replacement LED could well be sitting at 0.3a. Its absolutely no wonder the flasher can thinks you’ve blown a globe.
Now using the motorbike situation above, many bikes are absolutely fine with the reduced current draw, however, the few that end up flashing intermittently will require a load resistor inline before the indicator unit, or the use of an LED specific flasher relay.