Using cellphone batteries for LED?

[Flummo]

Cellphone li batteries are easy to get and can be found at low prices if you know where to look. I was thinking about taking two or three cellphone batteries and 1-3 powerleds to make a flat small flashlight with alot of light compared to its size. My pockets are way too full of other junk allready, so it HAS to be small...

Are cellphone batteries suitable for this kind of use? Can they handle the output currents needed?

 

[Crosswire3]

I use cellphone batteries to direct-drive CREE LEDs all the time with no problems. Most are relatively small 3.7v Li-ion in the 600-1200mah range, so you should be pretty well off.

 

[Flying Turtle]

Hope you come up with a nice design for us, Flummo. It would be nice to put those batteries in my old cell phones to use.

Geoff

 

[VidPro]

many cell and PDA batteries have built in protection in the pack, as long as you dont go over 1-2AMPS not only will it work but it will work great.

even if there is a serial data stream (info), and/or thermistor (heat protection), and other things in the pack, usually (which is not to say always) you can find the power, hook it up and both charge and discharge via only 2 connections, WITH protection, which is a good thing.

there does exist ones without protection, but most of the "packaged" ones in the plastic containment do have protection. they come in both canned and bagged , meaning there are canned flat cells for some items.

it a lot simpler than it looks at first with the 4 and 5 connections, but once you figure it out you will wonder why there is not more FLAT light outputting things in existance, and lightweight too.

 

[Flummo]

Staying below 1A for each battery will not be a problem, as my idea is to stack 2-3 batterys on top of eachother, and drive one or possibly two Seoul P4 (max 1000mA each) with it. As long as I don't use optics on the LEDs there is plenty of room for them on the end of the batteries.

The exact design needs a bit of thinking... :thinking:

 

[fxstsb]

Hope you come up with a nice design for us, Flummo. It would be nice to put those batteries in my old cell phones to use.

Geoff

Probably could mount one id an empty Zippo lighter

 

[KrisP]

I was wondering the same thing... I can get 1,200mAh flat batteries from personal navigation products and plan to make a 4 or 5 cell pack to run a PT EOS headlamp. 4.8-6.0Ah is much better than the 900-1,000mAh of the AAA's

 

[Fallingwater]

Note that LiPo cells meant for RC applications have slightly higher energy density and much higher power density than cell phone LiIons, and they may well be cheaper. You do, however, need to use them in a rigid enclosure and never overdischarge them, as they are significantly more likely to catch fire if mistreated.