Trying to make use of free lithium ion batteries

2 replies [Last post]
robots4joey
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Joined: 02/17/2009
Points: 2

Hello everyone!

I have been fortunate enough to come across a bunch of used/ partially
defective lithium ion batteries that a company was having to pay to recycle.
Basically there are enough good cells (18650 size: about 1.5cm diameter,
6.5cm long) to make a big battery pack. like 3- 55 gallon drums of batteries
(approx 50% are fine I think)

So here are my questions:
1. how the heck do I charge the batteries in a large scale EV application?

The first task I have before I do anything else is to make sure I can make
battery packs that are useful and chargeable. I have a donated 36V golf cart
with dead batteries that I figured I would use for my initial project. does
anyone know about li-on batteries and using them in a big home made pack???

Here's one thought process:
I'd need about 1,500 of these 18650 cells to create a 100volt 100ampere hour battery.

I have found IC's that charge a single 18650 cell for around $1 each. I have seen these used to charge three cells in parallel, so if I did that that's around 500chargers for a total of $500! AAHH! the batteries are free- but charging them is the killer...

Soooo, what if I use one of these chargers to charge more than 3 cells? how bad for cell life is that? could I do 5 cells? 10?

Other questions, is there a circuit that charges multiple cells on one circuit? that could possibly be cheaper (like $1.50 for 4 cells?) I have no idea if this is available or not though...

let me know what you all recommend!

-Joey

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colin9876
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Joined: 10/23/2008
Points: 289
Re: Trying to make use of free lithium ion batteries

Firstly - these are rechargable Lithium cells? Most of the cells that go for recycling are the once-use Lithium. Which chemistry are your cells?

Secondly, you can charge as many as you want in parrallel, its actually better for the cells to have a slower charge rate. But obviously the more you have the longer it takes.

One of these Hobby chargers can be adjusted to do various volts / Amps charging

dogman
dogman's picture
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Joined: 04/29/2008
Points: 830
Re: Trying to make use of free lithium ion batteries

If you have tool batteries, like for drills and such, those are good cells. See the website Endless Sphere for more info than you can handle on building, charging, and balancing big packs made from these kind of cells. If they are the new disposable lithiums, hope you don't have to pay to get rid of em.

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