Driving 2 Seoul P4's with only resistors, in a Car

[mds82]

What is everyones take on using 2 Seoul p4's as Automotive accessory lighting, and using a resistor rather then a constant current power supply? I've been researching products on the market for auto accessory lighting and a lot of companies are just using resistors? inst that a pretty bad idea??

 

[rizky_p]

What is everyones take on using 2 Seoul p4's as Automotive accessory lighting, and using a resistor rather then a constant current power supply? I've been researching products on the market for auto accessory lighting and a lot of companies are just using resistors? inst that a pretty bad idea??

Be cautious when using a resistor to limit current as it is very sensitive to voltage rises. You car voltage can go as high as 14.7v.

KD has a driver Called "KENNAN" it is suitable for automotive uses i think it is arund 3.5 bucks each.

thanks.

 

[mds82]

Ya i know about that driver, that's a good driver. however i'm looking for a 1000ma output, the BuckPuck 3023 dn-1000 is the driver i prefer

 

[NextLight]

It works and it is cheap. It is not efficient or particularly well controlled.

(Vcar-Vleds)/R = I

So 14.7-(2x3.7) = ~7.3 Vdrop on the resistor.

At 1A, this means 7.3Ohms and 7.3Watts. This is engine running. Engine off, the current would be ~15% less.

Common standard value (next higher resistance and power) is 8 Ohms, 10 Watts. It is on the edge for a hot auto interior. LEDs will require good heatsinking. And it is inefficient... 15 watts for ~300 LED lumens. For what does one want 200+ (net) lumens inside of a car, at distances of less than 4 feet? 50 lumens would cause me night blindness, if I shine it at a map.

 

[TigerhawkT3]

It's not very efficient, but you can just use an LM317T and a resistor from RadioShack for a couple bucks.

 

[rizky_p]

I have 1 KENNAN driver and the latest version seems to delivers close to 1A when connected to 12v power supply.

Thanks.

 

[LukeA]

I would stick with Buckpucks, Kennans (if you can find them), or DX6090/11621 for auto applications.

 

[rizky_p]

New driver @DX for automotive uses.
SKU 13557, SKU 13553 and SKU 13555. Interesting i hope someone tun a test or two on them.