Reducing Battery Weight

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jpbartow
 
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Reducing Battery Weight

Post by jpbartow »

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I've put together three LED leis using side-light tubing, two fiber optic light sources and a 9v battery pack for each( https://www.adafruit.com/product/4169 , https://www.adafruit.com/product/67 ). Having three 9vs hanging down behind my neck is a bit too bulky so I'm hoping to get a little advice on how to cut down on the weight. I considered 2x coin cell packs but after reading up on this it sounds like coin cells do not work well for LEDs. My next line of thought was to try hooking up 4-6 LEDs on one battery pack. If I did this would I need to solder them all at one junction or can I remove sections of the rubber coating from the 9v lead wires and solder at multiple points? Any other tips or suggestions about reducing battery size/weight are quite welcome as well.

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Franklin97355
 
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Re: Reducing Battery Weight

Post by Franklin97355 »

Since you are not adverse to have batteries hanging on your neck how about a thin wire about the thickness of earbud wire to a battery pack in your pocket?

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adafruit_support_bill
 
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Re: Reducing Battery Weight

Post by adafruit_support_bill »

9v batteries aren't an awful lot better than coin-cells for powering LEDs. They have low capacity and high internal resistance. I'd second the suggestion of a battery pack in your pocket or clipped to your belt. The silicone coated wire is thin and super-flexible. The 4-conductor ribbon can be easily split to make 2 lengths of 2-wire ribbon.
https://www.adafruit.com/product/3892

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jpbartow
 
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Re: Reducing Battery Weight

Post by jpbartow »

@franklin: I was hoping to make it self-contained but I think you're right. I was starting to lean that way when I got thinking about sewing a pocket just below my collar or attaching a fanny pack to the top of my backpack to hold the batteries.

@bill: 9vs seem to work alright with these illuminators based on past experience. I've wrapped a set of ski poles before using a 9v and 1 illuminator (per pole) and they stayed on for about 7-10 days after the season ended when I was too lazy to turn them off. As far as those cables go, can I hook those up to a USB shell? I've got a couple battery banks so I wouldn't mind putting one of them on LED duty.

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adafruit_support_bill
 
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Re: Reducing Battery Weight

Post by adafruit_support_bill »

If the 9v cells give you the run-time you need, that's great. They are not the most efficient energy source for driving LEDs, but if they do the job that is all that matters.

Connecting the cable to a power-bank is not difficult using a USB-A type connector: https://www.adafruit.com/product/1387
The problem is that a typical power-bank puts out 5v and the LEDs you linked to need 9v-12v/.

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jpbartow
 
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Re: Reducing Battery Weight

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Hmm so if power banks won't work with the LEDs then what would you suggest for a power source? You mentioned 9vs aren't the greatest for LEDs so what would you use? If I keep the 9vs I'm thinking of doing 9v Pack > Ribbon Cable > Barrel Connector (so it can be disconnected).

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adafruit_support_bill
 
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Re: Reducing Battery Weight

Post by adafruit_support_bill »

I'd look for a 9v Lithium cell. They are more expensive, but have about twice the capacity and less internal resistance than the common 9v Alkaline variety.

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jpbartow
 
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Re: Reducing Battery Weight

Post by jpbartow »

Update: Solved my issue by purchasing a 10$ dual pistol clip holder from Walmart and looping it on to the neck strap for my Polaroid. Now the batteries are essentially weightless because of the heavier camera counter balancing them.

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adafruit_support_bill
 
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Re: Reducing Battery Weight

Post by adafruit_support_bill »

Good to hear you fond a solution. Thanks for the follow-up.

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