Li-Ion 18650 power supply and charger + DIY EASY

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nubie
Posts: 58
Joined: Thu Feb 22, 2007 1:03 pm

Li-Ion 18650 power supply and charger + DIY EASY

Post by nubie » Mon Nov 05, 2012 1:01 pm

Want to use 18650 batteries in a project? They are stinking cheap, like $2 or less a cell, they hold tons of power, they have double the voltage of a NiMH or NiCd per cell.

Premade:

I found this USB boost pack that uses 18650 batteries (also I found quite a few 4 packs of 18650 batteries for around $8)

http://www.ebay.com/itm/300744677598" onclick="window.open(this.href);return false;

Basically it has USB port for charging cellphones etc, and a Mini USB port for charging the pack itself.

I think it is connecting the batteries in Parallel, so you could use just a single cell if you wanted. If the ebay item is sold, I used the search string 18650 USB (I always use price + shipping lowest first, and Buy-it-Now as options, if you want to see it this month check the US only button, but be prepared to pay 2x or 3x the price.)

Good:
  • One thing to buy
    Includes charger and protection
    5v output
    Battery meter
    Flashlight
Bad:
  • Only 5v output
    batteries are in Parallel (Maybe)
    Only USB Mini charging
    Case is large, PCB isn't easy to solder too

DIY Option:

If you want to DIY you can use a LM2596 regulator, $1.53 (maybe more than one if you need several voltages), this great thing can step down to any voltage you want, up to 30 or 40v!!. Input voltage must be higher than output, turn the little Potentiometer screw to set the output voltage.

Another bonus is dual voltages with only 1 regulator. The high pack voltage will allow you to run some parts of your project directly from the pack, 2 cells are good for near 7v, 3 cells for 12v, 4 cells for 15v.

LM2596 Regulator $1.53
http://www.ebay.com/itm/110950894139" onclick="window.open(this.href);return false;

Battery pack 2x - 4x $0.99 - $1.71
http://www.ebay.com/itm/140652926896" onclick="window.open(this.href);return false;
3x:
http://www.ebay.com/itm/290756182593" onclick="window.open(this.href);return false;
4x:
http://www.ebay.com/itm/150706506724" onclick="window.open(this.href);return false;
http://www.ebay.com/itm/390490690963" onclick="window.open(this.href);return false;


And you will need a charger, maybe two if you have more than 2 batteries $3 from China, $4 from USA
http://www.ebay.com/itm/280638594652" onclick="window.open(this.href);return false;
http://www.ebay.com/itm/330789765786" onclick="window.open(this.href);return false;

USA Charger:
http://www.ebay.com/itm/190687970923" onclick="window.open(this.href);return false;

Good:
  • Choose your voltage
    Higher Output
    High pack voltage (2 cells: 6.6v-8.2v, 3 cells: 9.9v-13.2v, 4 cell:12.2v-16.8v)
    Use a bunch of single cell holders to put the cells around the portable/project where they will fit.
Bad:
  • No protection as far as I know (you could add protection, OR use protected cells)
    Separate Charger needed
Last edited by nubie on Mon Nov 05, 2012 10:47 pm, edited 1 time in total.

nubie
Posts: 58
Joined: Thu Feb 22, 2007 1:03 pm

Re: Li-Ion 18650 power supply and charger + DIY EASY

Post by nubie » Mon Nov 05, 2012 1:06 pm

*Saved for the DIY*

Check back in a couple weeks because I chose to get all the parts from China for a cost saving:

$10.27 total for:
  • 4x 18650
    2x cell holder
    1 regulator
I had a charger, so add $3-4 if you don't

(eventually I hope to have a Raspberry Pi inside an original Gameboy with a 3.5" 'backup' camera screen, maybe USB Wifi)

nubie
Posts: 58
Joined: Thu Feb 22, 2007 1:03 pm

Re: Li-Ion 18650 power supply and charger + DIY EASY

Post by nubie » Wed Nov 14, 2012 4:14 pm

I got the converter, but no battery tray yet, so I hacked a battery pack I found at a yard sale into a sweet cellphone/portable charger.

The stand-offs are cut from a Nintendo DS, there is a washer cut from a soda can because the DS screw head goes right through the hole.

The USB ports are from an Xbox 360 motherboard, free cut with a hacksaw blade.

I added a switch to disconnect the ground side of the circuit and the USB ports, this means there is still 6-7 volts going to the USB when off. Since I can't see anybody getting a ground connection to complete the circuit it is fine for now.

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