LEDs, load equalizers, resistors & current draw

[psychocandy]

So, one of the reasons people convert incandescents to LEDs is to reduce current draw on a bike's electrical system. I've heard that after switching as many bulbs as possible to LEDs, some people have been able to run quite a few more accessories (GPS, hand/vest/seat warmers, driving lights, etc.) than before without blowing fuses and draining batteries.

My question, purely out of curiosity, has to do with situations where in line resistors might be necessary after converting to LEDs. If, say, you "upgrade" to LED turn signals and end up having to wire in resistors to get the right flash rate, are you really lowering the current draw? The resistors are there to fool the flasher relay that there are bulbs (and a higher resistance, right?) instead of LEDs.

How do the resistors work? Isn't a light bulb just a thin resistor that gets hot and emits light? Don't the inline resistors act like light bulbs that don't get hot or light up? If that's the case, aren't you drawing just as much current? It's just not being transformed into light.

Or am I not understanding how resistors work?

 

[teg916]

I think a better reason for converting to LED's is that they last longer and they are brighter. You won't really save much current by changing your blinkers and tail lights. The most savings you might get is if you changed your headlight to a bulb that draws less current, since your headlights draw more power than probably all of your other bulbs combined.

On my stock 2001 ZX6r I run heated grips, a heated vest, and a radar detector and don't have any issues with the battery draining.

Your thinking of how resistors work is kind of backwards. When you add a resistor inline with an LED it reduces the current flow. The higher the resistance the less current flow you have. If you were to add an inline resistor to a regular light bulb, that would reduce the current and cause the bulb to burn dimmer.

What the resistors do when you install LED lights is reduce the current flow through the lights. If you were to put in an LED light without a resistor it would just be reallly bright, and probably burn out. The lower current flow causes the blinkers to flash really fast. When you put a load equalizer on it puts a larger draw on the system to make the blinkers blink at a normal rate. That pretty much makes it to where you are not saving any electricity.

 

[DongeR]

If, say, you "upgrade" to LED turn signals and end up having to wire in resistors to get the right flash rate, are you really lowering the current draw?

yes current flow in a circuit is directly proportional to circuit voltage. more resistance = less current flow. Current can then be increased either by increasing voltage or decreasing resistance

How do the resistors work?

they absorb electricity and turn it into heat.

 

[psychocandy]

they absorb electricity and turn it into heat.

that's what i thought. but the higher resistance restricts current flow, so you're using less battery juice. that's starting to make sense. what's the deal with "load equalizers" then? i realize that replacing all the bulbs on yr bike with LEDs isn't really gonna make THAT much of difference, but i did read about someone who replaced every bulb in his car with LEDs and the difference in current draw that he calculated was surprisingly high. of course, this wouldn't be a primary reason to switch to LEDs, just a small added benefit.

once again, i'm more curious than anything. i suppose i could use the google and the wikipedia, but here i am...

 

[MackJack]

that's what i thought. but the higher resistance restricts current flow, so you're using less battery juice. that's starting to make sense. what's the deal with "load equalizers" then?

Resistors in series reduce current draw while resistors in parallel increase current draw. Load equalizers are just resistors in parallel to the LED's in order to increase current draw and to trip the turn signal relay. At least this is the case for older bikes. On older bikes, more current = blink faster; less current = blink slower (or doesn't blink at all).

It's much easier to replace the relay with one that's designed for LED's than messing with the resistors.

 

[DongeR]

although if you know how to calculate the amp draw using a volt meter, resisters are are really cheap.

One place i use to buy electronics and whatever stuff is a place called Halted

http://www.halted.com/