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how to power 9 10 watt leds from a automotive battery? Answered

I am building a under water array using 9pcs  10 watt green leds, and will be powering from a automotive battery. the led data is.
10 watt green
900 lumens
voltage dc 9-10.8 
current 900mA
integrated approach 3 and 3
My current build has them in parallel due to not wanting to lose all leds if one fails but will change this if its not possible. I am having issues finding  a step up dc to dc adjustable driver that will allow a output of 10.8 volts an a current of 8100mA . Anyone have ideals or a better solution. Thanks.

Discussions

0
steveastrouk
steveastrouk

3 years ago

LEDs
can't be run with a constant VOLTAGE supply. They need a constant CURRENT, and ideally you would put them in series, but since 9 x 10V is 90 odd volts, you won't want to immerse it either.

You could find a 3Ohm
resistor, rated at 3W, and run EACH of them with a resistor on a 12V
supply in parallel arrangements. You will be burning an extra 30W for
your 9 LEDs.

An alternative is these very cheap regulator blocks

http://www.aliexpress.com/item/High-Quality-Specia...

These will run very nicely on EACH LED, and reduce the wasted power.

Then, as DU35M says, you need to worry about the supply requirements.

0
Downunder35m
Downunder35m

3 years ago

You need proper LED driver for this.
There is a reason why a complete LED lamp often costs a lot more than just the LED module ;)
Considering the limits of a car battery and the power requirements you won't have long running times either.
Even a proper deep cycle battery would need to be of considerable size to allow for proper run times.
The keyword here is AH - ampere hours.
But you also need a battery that is able to provide the current you need.
For example a battery with 20AH and a max current limit of 10A would only power the LED's for a bit over 2 hours a 50AH battery for around 6 hours...

Better option would be a parallel/series combination of LED's with only 4 or 6V requirements...
Of course that still requires proper drivers for these high power LED's....