Author Topic: Junk Laptop & Tool Battery Packs  (Read 931 times)

plongeur66

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Junk Laptop & Tool Battery Packs
« on: September 05, 2016, 06:42:19 PM »
Pop them open (I prefer to use a cutoff wheel in a dremel, but don't cut too deep!) and you'll likely find...18650 lithium cells:

Test with a voltmeter, anything less than 2 volts should be tossed in order to avoid an explosion. You can search for "18650 USB bank" or something similar on feebay. A holder and circuit board for one cell will cost you all of 99 cents:

This will allow you to charge the cell from USB. You can then use it to run small lights or charge a phone.
You can also remove the charged cell and use it in a flashlight or whatever you want. 18650 flashlights can be had on feebay for less than $3. A USB bank that holds 6 cells in parallel can deliver 18000MAH and costs all of $4.
You're actually better off harvesting scrapped cells than buying unbranded Chinese ones. Laptop batteries will have honestly rated name brand cells (Panasonic, Sanyo, Samsung). People have been burned buying unbranded "10000MAH" cells that only deliver 900MAH. Then there's the occasional bang and fireball. :o
I disassembled that defibrillator battery I dived back in June:

It contained 11 26650 cells:

These all tested out at around 2.8 volts, the electronics in the battery pack kept them very well balanced. I couldn't find any 26650 USB banks, but have a couple other uses for these. For starters I sawed off the barrel of a beater 3C flashlight:

Decent brightness, could run for days non-stop.
I also picked up a Rat Zapper Ultra for a buck:

With cooler nights, those pesky squirrels and chipmunks will likely soon infest my shed. Rat Zapper manual said not to use rechargeable batteries due to low voltage (4.8 volts for a string of 4). I wasn't looking forward to buying a set of 4 alkaline D cells every other month (not easy to dive those). The 26650s from the defibrillator supply 3.2 volts each. They are capable of supplying a 100 AMP surge. 2 in series should be enough to cook a rodent to 180 degrees internal temperature.  ;D
Will hook up a couple of clip leads and charge one pair while another is in use.
The Trustfire charger I picked up for a buck has a selector for the lower voltage:

Interesting coincidence. Those batteries were manufactured to give a shock. Now they'll do so once again - on a different species for a different purpose.
« Last Edit: September 05, 2016, 06:49:22 PM by plongeur66 »

Scav

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Re: Junk Laptop & Tool Battery Packs
« Reply #1 on: September 05, 2016, 07:14:53 PM »
Very neat. I had no idea these were a thing. You say anything below 2 V is dangerous. How dangerous is it?

I've been trying to learn more about electronics by watching some Youtube videos for the last few months, and I recall hearing about low voltage cutoff circuitry. Does that little USB device have that kind of circuitry so you don't discharge a battery too much? I might need to pick some up cause that's awful handy to have.

https://www.youtube.com/user/bigclivedotcom is one of the channels I watch quite a bit of, by the way.

You're quite knowledgeable and if you had a better connection, I'll bet you'd be pretty dang successful with electronics videos.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #2 on: September 05, 2016, 09:06:17 PM »
Low voltage left that way too long MIGHT be dangerous. If you have an easy time coming across battery packs you can just harvest the best cells and jettison the rest. No point in hoarding a couple hundred. There is a protection circuit in the "USB bank" boxes. Charge stops automatically, it will also shut down before the battery gets too low when you are powering a load.
Cell is unprotected if you remove it and use it in a flashlight or something else. Measure the current your light uses and preferably turn it off before using 80% of the battery's calculated capacity, or at the first sign of it dimming in any case.
You want to know what is going on with lithium batteries at all times. I use this Matek USB power meter to monitor the current and MAH thats gone into the cell:

Good enough to approximate. Unfortunately it shows a 30ma load just to power itself with nothing connected. It took about 6 hours to charge that 2200MAH cell, so subtracting 180MAH from the indicated 2489MAH is in the ballpark. Lithium battery charging is very efficient, so not much more than the battery's rated capacity should be going in to it before the charger terminates.
I'd be worried if the charger was still going after putting 3000MAH into the battery - and the battery would likely be hot.
Measure the voltage as you take the battery off the charger. These 18650 laptop cells should be very close to 4.2 volts as they come off charge (might vary + or - 0.1 volt depending on the charger). Check them an hour later, a week later, a month later. Dropping voltage or heating up while charging or being used indicates a dangerous battery.
Cells other than from a laptop might have different voltage and chemistry. The defibrillator batteries are LIFEPO4 technology and show 3.3 volts when fully charged. Trying to run them up to 4.2 volts by using the wrong charger would likely result in a BOOM!
I'm sure searching "lithium battery explosion" would turn up lots of stuff on youtube. Don't let it scare you too much as long as you are diligent in monitoring voltage and heat. I feel safer using branded cells from a laptop rather than unbranded Chinese crap in any case.
Typical price and capacity for one name brand 18650 cell is $11 @3000MAH. Beware the "10000MAH" cell for $2. Sold by the same guys that offer "30000 lumen flashlight, runs for 500 hours on one AAA battery!".
http://lygte-info.dk/info/batteryDisassembly9900mAh%20UK.html
525MAH from a new cell rated for 9900MAH: http://lygte-info.dk/review/batteries2012/UltraFire%20SZ18650%209900mAh%20%28Yellow%29%20UK.html
Videos typically aren't my thing for learning, pics and text usually show me what I need to know a lot quicker.
« Last Edit: September 05, 2016, 09:43:16 PM by plongeur66 »

Jayfosters

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Re: Junk Laptop & Tool Battery Packs
« Reply #3 on: September 06, 2016, 12:47:20 AM »
Very interesting. If the grid fails at some point (And I fully expect it to likely due to a cyber attack) this will be very valuable information. I have a pretty good stash of battery's but never really got in to testing them.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #4 on: September 07, 2016, 01:51:44 AM »
You should definitely test your stash once a year. I just threw out about 50 lbs. of alkalines that went flat or leaked. One leaky one can destroy several more around it. Alkalines are easy to test. Battery tester is a voltmeter with a load resistor built in. Here are two of mine:

Tester reading won't tell you how much is currently in a rechargeable battery, or how much it is capable of holding. To test, you will want to charge them fully. Then remove from the charger and let them sit for a week or two so you will be able to spot self-discharge.
I then put the cell into this "Tac-light" I bought for $4:

I don't much care for the round beam this light throws....looks kind of like I'm shining my dive light through the core of a toilet paper roll.
But the 3 watt/300 lumen rating for this is real. It will pull 2 amps out of a good cell and get quite hot doing so. Low setting pulls 400MA - good for testing AAA cells. Normal run time for an AA cell in this on high should be about 75 minutes. 150 minute on low for a AAA cell.
I just fire up the light and set a timer for 40 or 90 minutes. If the light is still bright when the timer sounds, the cell has at least half it's rated capacity and I will keep it. Anything that quickly goes flat gets tossed.
You can also solder a calibrated resistor across the battery holder of a mechanical travel clock that's set to 12 o'clock. If you've been drawing 200MA and the clock stops at 9 o'clock, that's 1800MAH capacity for the battery.
Most of my remaining alkaline stash, probably 80 lbs. worth:


plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #5 on: September 09, 2016, 06:37:58 PM »
Got some tail last night  ;D

The lithium-modded rat zapper works. Peanut butter in a bottle cap for bait.
« Last Edit: September 09, 2016, 06:40:40 PM by plongeur66 »

Scav

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Re: Junk Laptop & Tool Battery Packs
« Reply #6 on: September 10, 2016, 06:07:06 AM »
He looks shocked.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #7 on: September 10, 2016, 02:15:44 PM »

Looks peaceful, like he just fell asleep. No thrashing for 5 minutes with smoke billowing out his ears. He never knew what hit him.
Got another one already today, the pair are currently doing the 69 in my fire pit.
Not sure what I will do with all the carcasses if I get several per day. A big mound of them would stink and likely attract larger animals looking for a free meal. I set out poison also, so I won't save them for the stew pot. Wouldn't want to eat one that ate poison and then crawled into the zapper. I could see myself making a bear zapper out of a 100 gallon plastic tote and a microwave oven transformer.  ;D
These rodents are getting out of hand and pissing me off, and it's not even  cold out yet.
Most recently, I went to check on a $200 Columbia screenhouse that I had in storage. It stank of urine and was full of holes. Holes chewed in the walls of my shed.
Had one get in my car and eat my insurance cards and money. Fortunately my credit union replaced this:

They've been known to chew through gas hoses and brake hoses, the end result is predicatable. Flooded houses have resulted when they have decided to chew through PEX. Fortunately I have no indoor plumbing to worry about.
Several sleeping bags and backpacks also destroyed in years past, more holes and urine. Clothes dryer didn't want to stay running a couple of years ago. After multiple tries, I turned the drum by hand. I heard a squeak and clunk, then the dryer works normally. Major stink a couple of days later. Apparently the serpentine belt bisected one of the little furballs. No telling what they have done to the insulation under my floorboards. Hopefully the poison bait stations will mean a lot less "pitter-patter of little feet" as winter comes:



Jayfosters

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Re: Junk Laptop & Tool Battery Packs
« Reply #8 on: September 10, 2016, 02:20:45 PM »
Works like a charm. If it will take out a squirrel then it will also keep the rats out.

Your pic takes me back to my youth when I would squirrel hunt with my dad. We actually skinned and ate those nasty things. You could not pay me to eat one today, unless of course I was starving.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #9 on: September 10, 2016, 02:47:03 PM »
Not much meat on the things. If not for the poison, I would skin, gut, and freeze. Time for stew or stir-fry once I had a dozen or two.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #10 on: September 11, 2016, 03:25:20 PM »
Bagged another tree rat today. 3 for 3 so far! I hide the trap in a Walfart bag as I bring it out of the shed to dump a carcass. I don't want them to see and get wise to it. Heard some irate screeching yesterday as their buddy's carcass hit the ground.
Trap is not quite as easy to maintain as the instructions imply. Red light indicates a strike and disables the trap. Supposedly you can just dump the carcass and then repower the trap to get a green READY light. No luck with this. I've had to follow the deep cleaning procedure (soak base of trap in a pan of soapy water no more than an inch deep for several minutes, then brush and rinse) after every kill. Trap is out of service for maybe 30 minutes, as I speed drying with a hair dryer.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #11 on: September 17, 2016, 08:48:52 PM »
So I blew up a tool battery:  :o

Picked up a garage sale drill and battery without charger for 50 cents. Hooked the 13.2 volt nicad pack to my universal/variable charger and dialed in a 200ma charge rate. Found out the hard way that this charger doesn't have regulation against line voltage swings and seems to actually amplify them. My power line usually reads 125 volts when I don't have any heavy loads running. My mistake was cooking lunch in the convection oven while setting the charge rate. Input to the charger would have been about 117 volts while I was cooking. The charge rate likely jumped to over 1000ma without me noticing when lunch was done. I was asleep when it blew, did not wake up. Found pieces scattered all over the living room when I got up, I might not have found everything yet.
Fortunately my lithium battery chargers are safe and regulated, but I'm not going to charge ANYTHING from now on unless I'm sitting right next to it keeping watch. Lithium explosion would likely have burnt the house down and killed me.
Be careful who you're standing next to. Those recalled Samsung notes are like terrorist bombs:
https://www.youtube.com/watch?v=utHRQtuzuYo
Only 15% of them have been returned. People are saying it's too much of a nuisance to program a replacement phone and just keep using theirs.
 

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #12 on: December 19, 2016, 01:11:03 PM »
Just got back to this project. Had been charging/swapping batteries in the rat zapper monthly, but not caught anything in 6 weeks. Yesterday a tree rat stole the bait. He also chewed some wood and made a mess in the shed - something I hadn't seen since I installed the trap in the summer. I was thinking the trap had gone bad, and was ready to take it apart if I had the bait stolen again. I went out this morning to see a blinking red light and a pleasant surprise:

Trap is still kicking. My best guess is that the plates of the trap must have been frosted over and effectively shorted out when he crawled in there yesterday. Don't know if he would have been able to stretch his neck out far enough to grab the bait container without ever putting his feet on the plates. Trap back in action after disposing of the carcass.
Here's the battery/charging system:
2 ANR26650 lithium cells from a binned defibrillator battery pack. Connected in series with a clip on each end. Also a clip to the center point, used for charging only. Charger is a Trustfire TR-001 that I picked up at a garage sale for $1. These particular lithium cells require the "3.0" charge voltage setting on the trustfire. Charger has a DC jack on the side, likely intended for connecting 12 volt power from a car electrical system.:

I decided to repurpose that jack for charging output while using the AC cord. Negative from a battery holder was already connected to the shell of the jack. I cut the circuit board next to the center pin of the jack, and then soldered a jumper to the positive terminal of one of the battery holders. Now any cell connected to the jack can be charged the same as if I'd put it in the battery holder. I made up this pigtail, with kNot in the Negative to stay aware of polarity. :

Here is the pack connected to charge one cell at a time, which takes about 2 hours per cell:

I made up 2 packs so I can charge one while the other is in use, here is pack # 2 in the trap and ready for action:


Scav

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Re: Junk Laptop & Tool Battery Packs
« Reply #13 on: December 22, 2016, 06:04:17 AM »
Nice to see it's back in action.

Probably going to see a lot more action with the colder temps.

plongeur66

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Re: Junk Laptop & Tool Battery Packs
« Reply #14 on: January 18, 2017, 11:30:29 AM »
My original Rat Zapper is still in action. It is the Agrizap version which a lot of online reviews say is much better than the newer version made by Victor. An identical-looking trap to mine is sold as "Raticator" for about $60 without power adapter.
I had bait stolen a couple of times. As expected, it was due to moisture shorting out the plates and diverting current around the rodent.
I had to scrape some blackened plastic out of the trap to prevent continued arc-over.
I put one of these heat mats under the trap to keep it warm and dry, this may make it even more inviting to rodents:

Mats are rated for 8 watts. I bought 2 and one uses 9 watts while the other uses only 5. Adequate for my purposes, but has me wondering if the random wattages might have somebody roasting their lizard.
I bought a couple of cheap traps on feebay, $20 each with power adapter. I needed a 6 volt power supply for my Logitech speaker, so I promptly repurposed that from one of the new traps. Lithium defibrillator cells will power these traps as well:

I went out this morning and found a trapped tree rat. He was in there sideways and smelled burnt.  ;D Apparently the cheap traps work just fine. I figure most of the people complaining are using dollar store batteries or letting the traps get damp. 
« Last Edit: January 18, 2017, 11:32:01 AM by plongeur66 »