Help with power/driving LED unit

[ahmed24]

hello,

I am new to this forum & in need of some help and advice. i have a car LED light unit which consists of 3 high power LEDs. It's a factory sealed unit and I dont know the exact spec of each LED. The unit has a sticker on it that says 12V 6.5W. The 3 LEDs on the unit are wired up in parellel and not in series. The problem is that the unit requires a power supply that costs a fortune (almost 200 bucks). I cannot really justify spending that kind of money on a power supply at the moment.

So i decided to test the LED unit by plugging it in directly to an indoor mains operated PSU. This PSU has a sticker on it that says the output is 12V 300mA. I also hooked up a multimeter inline to see how much current the LED unit draws from the PSU and when I turn it on the multimeter reads 1.15. So I am assuming that 1.15A is the max the unit draws. The thing is I do not want to power the LED's with max current because the unit also costs a fortune so i dont want to risk over driving them and burning them out. Previously I used a 750mA constant current driver on another exact same unit and eventually after 3 days the unit stopped working because it got too hot and blew. So this time I purchased a small 12V Constant Current LED Driver that outputs 10V 350mA. I then hooked this driver to my PSU and powered the LED unit via the driver with the multimeter still plugged in and this time the multimeter read 0.42. The light output hasnt been severly effected and is still very bright for my requirement.

My questions are:

1. Will this 10V 350mA constant current driver do the trick, instead of having to buy the OEM power supply that costs 200 bucks? if so what can be so special about the OEM power supply that they justify charging so much for (i think maybe it also provides some kind of CANBUS feature which I do not need)?
2. I will also use an inline fuse, so what happens in the event that the driver fails? I'm assuming the fuse will save the LED unit by blowing the fuse instead of the LEDs?
3. I am assuming that by providing lower current to the unit, its safer for the LED. Is this correct?
4. Finally, the sticker of the LED unit says 12V 6.5W, by using this lower 0.42 current, how much wattage am I actually powering the LED with instead?

Many thanks in advance

[RoGuE_StreaK]

Which car, which unit? If you give some specifics, might be able to track down more info on what it's supposed to do, and why it's so expensive. May just be because the typical owners are used to paying exhorbitant prices for all parts.

[ahmed24]

Which car, which unit? If you give some specifics, might be able to track down more info on what it's supposed to do, and why it's so expensive. May just be because the typical owners are used to paying exhorbitant prices for all parts.

Its the new renaultsport megane 250. and the led unit is a drl unit. there is 2 in total but i'm attempting to get one worked out first and then i'll apply the same method for the second one. from my initial research it seems that the OEM power supply does a bit more than just provide constant current, it plugs in to existing wiring and is canbus enabled which allows it to work with the cars configuration. however, i do not need any of those features, i just need the power as everything else i've taken care of and the power will come directly from the battery which is switched via a relay

[ahmed24]

oh and here is a photo of the small LED driver that i'm using to power it at the moment. it's working with it but i'm not sure if by connecting the LED unit directly to car battery via this is still potentially overdriving it or within the limits? I want to keep it way within the limits and if possible under-drive it (if there is such word)

[Microa]

It seems like a 350mA constant current LED driver which can drive 1 to 3 LEDs in serial. The current flow into the driver primary will not more than 400mA.

[ahmed24]

Thanks for your reply. Do you think my LED unit will be fine and wont blow out with this driver?

[Microa]

I think this driver will not damage the LED unit. Please take care of the primary input 12Vdc. I am not sure whether it is the absolute maximum voltage. The car battery is about 13.8V when charging by the dynamo and the spark pulses generated by the engine.

[idleprocess]

I think this driver will not damage the LED unit. Please take care of the primary input 12Vdc. I am not sure whether it is the absolute maximum voltage. The car battery is about 13.8V when charging by the dynamo and the spark pulses generated by the engine.

Automotive electrical systems are nowhere near so clean. Alternators typically put out around 14.4V under steady load; at startup or whenever mechanical loads (on the accessory drivebelt) or electrical loads are changing (amps the alternator is putting out), voltage may well be considerably higher or lower. Devices rated to 50V DC or better are commonly recommended for automotive applications.

[ahmed24]

I wired up the LED unit via this Driver but I also added a voltage regulator PCB to regulate the voltage that goes into the LED driver hence creating a more stable current and voltage environment. I've had it on for a while now and all seems well so far.

[MikeAusC]

I've seen some DRLs which dim on one side when the turn indicators are flashing.