[Noisebridge-discuss] driving multiple LEDs with minimal batteries

Rigel Christian rigelc at gmail.com
Tue Jan 4 14:11:58 PST 2011


batteryspace, iirc, also has Li-ion coin cells. they produce too much
power when charged for me to power normal bike blinkies, everything
heats up and makes me nervous, but i'm sure that you could design a
circuit around them, and save a ton of money
coin cells are expensive.

On Tue, Jan 4, 2011 at 5:07 PM, Jonathan Foote <jtfoote at ieee.org> wrote:
> A likely problem is the dropping resistors which waste power. Also 9V
> batteries are not great for power density.
>
> Several solutions: as was mentioned, a coin cell battery will happily
> drive one or two LEDs for a good long time.
>
> Another approach is to use a "Joule Thief" circuit and a single AA. JFGI.
>
> In the overengineering department, a LiPo battery (of which there are
> boxes full at NB) plus a constant current SEPIC driver would be most
> efficient, and rechargeable to boot.
>
> Or just use the LiPo with dropping resistors; SparkFun sells a
> charging circuit chip + breakout board so you can recharge it from a
> USB port. No wasted batteries!
>
>
> -J
>
>
> On Tue, Jan 4, 2011 at 12:06 PM, meredith scheff <satiredun at gmail.com> wrote:
>> I'd like to do a soft circuit scarf or three, but I'm always running up
>> against the problem of power. I usually use fairly low power LEDs
>> (<2v) driven by a 9v battery or one of sparkfun's LiPos.
>> I've heard tell of somehow being able to power more, but I'm still learning
>> this EE stuff. Could some kind person point me in the right direction?
>> Meredith
>>
>> --
>>
>> Ladycartoonist.com
>>
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>>
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>>
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