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### Topic: Motorcycle Indicator LED's (Read 509 times)previous topic - next topic

#### SnipeYa

##### Nov 02, 2017, 12:53 pmLast Edit: Nov 02, 2017, 01:05 pm by SnipeYa
So I'm making some LED indicators for my motorcycle, And I've encountered some design decisions that I don't quite know how to make... So I'd like to ask you all some questions.

Each indicator consists of 8 amber piranha style LED's (each 2.0-2.1 volts, ~16 amps)

1: Is it better to have the LED's in parallel with 8 resistors or in series with 1 resistor?

2: The motorcycle has a 12 volt battery, But when running increases to around 14 volts due to the alternator. I haven't checked whether the indicator power is regulated yet but if it isn't how do I go about feeding the LED's with the correct voltage and current?

#### PaulRB

#1
##### Nov 02, 2017, 08:21 pmLast Edit: Nov 02, 2017, 08:23 pm by PaulRB
Quote
~16 amps
You might want to check that again.

1. It depends what you want to do with these LEDs. Simple on/off blinking, or "Audi" style? If the former, then neither of the two options you mentioned. Perhaps 2 resistors with 4 LEDs in series with each resistor. If the latter, then it will need 8 resistors because each led will be on a separate channel.

2. Design your circuit for 14V. It will be slightly dimmer if only 12V are used, but still ok.

#### ChangchungLeds

#2
##### Nov 14, 2017, 09:55 pm
You can find online a led resistor calculator. Just put the ma for each Led how many and the voltage. You must use a resistor to each group of Leds

#### Grumpy_Mike

#3
##### Nov 15, 2017, 11:35 pm
You can find online a led resistor calculator. Just put the ma for each Led how many and the voltage. You must use a resistor to each group of Leds
But these are not relevant for power LEDs, you can't use just resistors to limit the current for power LEDs. You need a constant current supply.

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