What would be a good load to drain the cells to 0V?

[marty]

Got a bunch of Li-ion cells from Makita power tool packs.

Specifications are close to this data page.
View attachment UR18650W[1].pdf
Nominal Capacity 1500mAh
Nominal Voltage 3.7V
Charging Method Constant Current / -Constant Voltage
Charging Voltage 4.2V
Charging Current Std.1500mA
Charging Time 2.5hrs.

From my understanding if I drain all of the electricity out of these cells, there will be no risk of fire. Is this correct? I want a bunch of dummy cells for photography and pack layout experiments.

What would be a good load to drain the cells to 0V? Light bulb? resister? My plan is to attach a magnet to the + and - ends of each cell. Clip alligator clip to the magnet.

Yes I understand that after the cells go to 0V they will die and never be usable again.

 

[NeilP]

12 v car light buld to start with, run that till it goes out then once the cell is down, just short with a piece of wire to drain any residual millivolts

 

[neptronix]

light, then resistor, i say.

 

[TylerDurden]

Leave em all in a 5gal bucket of water for a week.

 

[Ypedal]

is this like an assited suicide thread ?

i canot partake in this.....

* (( Draining a single cell at a time, not too dangerous... draining cells in series can be bad.. if they are not all equally charged, some will reverse polarity and get REALLY hot.. enough to melt the shrink wrap... ))

 

[TylerDurden]

Meh, more like death by boredom.

More often, we prefer to kill cells dramatically.

 

[dogman dan]

Best method would be to send them to Amberwolf. He'll make a pack out of them, and ride it for a few years. Then return them to you with 0v for your further use.

Seems a shame, but I suppose you aren't talking about killing 100 of em. Wouldn't they be safe enough just drained to 2v or so?

 

[fizzit]

Leave em all in a 5gal bucket of water for a week.

Lithium reacts with water so I think you'd have a bad situation on your hands if one of them were to leak or to corrode through...

 

[marty]

light, then resistor, i say.

Cells are about .5V What Ohm resistor should I use to drain remaining voltage to 0V?

 

[pwbset]

Cells are about .5V

Just dead short'um. Shouldn't be too dramatic at that voltage.

 

[dogman dan]

Yeah, by .5v they are effectively dead. short em, nothing will even get very hot.

 

[liveforphysics]

Empty cells tend to leak solvent and evolve gas as they sit. (not always, but often)

I would just tape over the ends. Or work live, it's only capable of 10-20amps in a worst case situation.

 

[SamTexas]

From my understanding if I drain all of the electricity out of these cells, there will be no risk of fire. Is this correct? I want a bunch of dummy cells for photography and pack layout experiments.

You are being overly cautious. Yes you can remove all store energy from them but it's really not necessary. Just discharge them individually or in parallel (NOT in series) using 12V light bulbs until the light bulbs go out. There will still be some energy left in each cell but it's so minuscule that it can not cause any harm at all (probably less 0.1wh left in each cell).

 

[John in CR]

Or just ship them all to me. I'm sure half will be dead like last time, and I'll make sure those are drained fully and send them back.

 

[marty]

x
You are being overly cautious. x

I agree. Going to stop worrying about cells with less then 1 volt or so. After dissembling Makita power tool packs. Some cells are no good for various reasons. Been throwing the bad cells in a plastic bucket. Put plastic bucket in a 5 gallon metal can. Put 5 gallon metal can in a metal garbage can. Put that metal garbage can in a larger metal garbage can. Put bad batteries in the shed with the gasoline, propane and kerosene. Noticed a few batteries hot and smoking Put the bad batteries outside on a concrete driveway. Anyone want to buy some smoking batteries?

 

[Ypedal]

I just take electrical tape and cover the ends.. then stack them into bricks and tape those together and set them aside ( sometimes on the kicthen table.. or the garage.. depends on my motivation level ) .. I do have a stash of bad Lipo cells and packs in a metal can in a firepit in my back yard however.. even i have my limits..

The blue pack on top is a 36v eZee LiMn foil pouch 10ah pack.. could smell the solvent and had to leave the house..

 

[marty]

x "firepit" x

FIRE! Good battery disposal idea.

 

[Monstarr]

I came across two 'dead' 24V 10ah electric bicycle li-ion packs.
The 10ah prismatic modules in 1 pack have swollen up a little bit, but still all show 4V. I seried all 8 of them and planning to run them dry so i can discard them safely. I dont have low ohm high wattage resistors laying around so im hoping this thread gives me a solution of emptying the pack .

 

[amberwolf]

Piffle. I had some LiCo cells with significant but nowhere near full charge in them that I accidentally completely shorted by being an idiot, and nothing happened:
http://www.endless-sphere.com/forums/viewtopic.php?p=467983#p467983

I wouldn't worry about handling such tiny cells any way you like.

 

[SamTexas]

I love this picture!

 

[Ypedal]

That is so awesome.....