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09-20-2010, 01:16 AM #17
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Re: Harvested some batteries, what are they?

The most common arrangement in laptop battery packs is having 3 cells in series, and several of such series strands in paralel, depeding on battery size. Many laptops come with an option for 6-cell (2 strand) or 9 (3 strand) cell battery packs, depening on wether you want it to be light or long lasting.

Most laptop batteries consist of a collection of 18650 cells in a plastic enclosure.

As far as protection and wiring go: the most common variety is a series-paralel arrangement where you have 3 bunches of 2 cells wired in paralel with sensing leads going to the two junctions. The charging electronics in the laptop will monitor the voltage on each set of paralel batteries, and stop charging in any of them overload.

A series ciruit of 3 cells, resulting in 3 x 3.7 = 11.1 volts is the most common, but some laptops use only 2 cells in series, resulting in 7.4 volts. Others use 4 cells in series, giving 14.8 volts.

If you are harvesting the cells non of it matters though, they are all perfectly good 18650 batteries if the original battery was functioning normally. If it was not, its possilbe some cells are okay but others where discharged beyond repair - measuring the voltages is a good idea then.

The cells that measure 1.8 volts are probably shot, but you could attempt to charge them individually, as long as you keep an eye on it. It might be a good idea to place the charger on a flameproof surface like a plate when you attempt this, and do not hesitate to throw the whole lot outdoors if something goes wrong.

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09-20-2010, 02:55 AM #18
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Crazy Jay
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Re: Harvested some batteries, what are they?

None of the batteries I took out are shot. They each work and charge perfectly fine.

But if I were to get new batteries and put those in the battery case would or would it not be to much voltage?

09-20-2010, 03:57 AM #19
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Toke
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Re: Harvested some batteries, what are they?

Quote:
 Originally Posted by Crazy Jay None of the batteries I took out are shot. They each work and charge perfectly fine. But if I were to get new batteries and put those in the battery case would or would it not be to much voltage?
If you connect the new batteries correctly you will get the correct voltage.
If you connect them wrong you will get twice the voltage and burn off your laptop.

Could you supply a picture of the battery case?
That may make it obvious whether the batteries were connected with soldered on wires, or installed in pockets with metal strips for connections.
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09-20-2010, 04:26 AM #20
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Re: Harvested some batteries, what are they?

Thats awesome i didn't know laptop battery are full of 18650's.
Did you know car batteries are packed full of AA batteries?

09-20-2010, 05:06 AM #21
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Crazy Jay
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Re: Harvested some batteries, what are they?

Quote:
 Originally Posted by Toke If you connect the new batteries correctly you will get the correct voltage. If you connect them wrong you will get twice the voltage and burn off your laptop. Could you supply a picture of the battery case? That may make it obvious whether the batteries were connected with soldered on wires, or installed in pockets with metal strips for connections.
Ah I see. Yes they were strips of metal. 3 connections to the chip. Can't take pics since I separated everything already. I got a ton of 18650 batteries now! I just found out they are Sony batteries too rated at 2200mAh

EDIT: UNICORN HACK!

Last edited by Crazy Jay; 09-20-2010 at 05:14 AM.

09-20-2010, 04:26 PM #22
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BShanahan14rulz
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Re: Harvested some batteries, what are they?

Except unlike mohrenburg's link, laptop batteries actually DO have Li-Ion cells in them, usually 18650. I've heard of people finding 14500's, but I've never seen 'em.

Also, keep in mind that once harvested, these are "naked" cells. They are not protected in any way, short of the over-pressure valve.

Edit:
Well, I STILL think that Crazy Jay is mistaken, but to cover my ass, I'll say that I've never personally come across individually protected cells in a battery pack, and that I've never heard of anybody else come across individually protected cells in a battery pack, except for Crazy Jay. My advice is to treat them as unprotected cells, because that is *almost* certainly what they are.

Most battery packs will only use one protection circuit that monitors each individual cell's voltage, has balancing leads going between each cell in series, has two temperature sensors in two different places between the cells, and has connections made by welded tabs. Many of them use the TI bq series chipsets to monitor number of charge cycles, state of each cell, and to control charging and discharging.

It also seems illogical that they would add extra cost to the whole battery just to protect individual cells that were already protected by the main charge controller board. Not to mention the added weight from having 6 added circuit boards, 12 added chips, and the copper cladding and solder that holds it all together.

So I still think that they are unprotected cells after being harvested, and should be treated as such.

Last edited by BShanahan14rulz; 09-20-2010 at 06:21 PM. Reason: clarify. or confuse.

09-20-2010, 04:46 PM #23
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Re: Harvested some batteries, what are they?

\$25 for an new laptop battery sounds like a great deal, no point in risking anything with the old one.

Cool hack with the car battery.
Quote:
 Also, keep in mind that once harvested, these are "naked" cells. They are not protected in any way, short of the over-pressure valve.
See post #10 and #12 for exception and likely explanation.
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09-20-2010, 04:55 PM #24
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Re: Harvested some batteries, what are they?

Quote:
 Originally Posted by Crazy Jay But if I were to get new batteries and put those in the battery case would or would it not be to much voltage?
As mentioned, if wired correctly, it will give the same voltage as the original battery did.

There is a downside to the procedure though: It doesnt always work. There is some charge controlling electronics in the battery pack as well, and that will interfere with swapping the cells. It may 'think' the cells are still worn and stop supplying power even though the batteries have more capacity left, or it may prevent the battery pack from being able to charge in your laptop, or even powering the laptop.

There are ways to hack this circuitry too, but with plenty of decent '3rd party' batteries available at low cost its rarely worthwhile. I replaced the battery in my Dell XPS with one from dealextreme (\$40-ish), and its capacity is near that of the original (\$129 brand replacement).

I think the only place you'll find 14500 or other non-18650 cells are battery packs for netbooks and ultralights... or in the secondary batteries that can take the place of the optical drive in some laptops.

09-21-2010, 05:12 AM #25
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Crazy Jay
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Re: Harvested some batteries, what are they?

Thanks for the info guys.

BShanahan14rulz. Here's what these batteries are, SF US18650GR. They looked protected to me but I'm leaning towards me being wrong. I thought the indent at the tip meant there was a circuit there but I guess not.

EDIT: http://www.candlepowerforums.com/vb/...87&postcount=4

Last edited by Crazy Jay; 09-21-2010 at 05:15 AM.

09-21-2010, 06:20 PM #26
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Re: Harvested some batteries, what are they?

123 cell protection anatomy revealed - CandlePowerForums
^old info on the PTC protection. Example is of a SureFire CR123a Primary, but the same idea is used on Li Ion secondaries.

Basically, when a cell fails catastrophically, pressure and heat build up inside the cell. I think it has something to do with the lithium forms metalizing and oxidizing.
Anyways, you may have seen the thread about Electron's WL 18650 battery exploding into smitherines. The PTC material (Pressure-Temperature Coefficient) is a washer-shaped disk that conducts current from one face to the other. As temperature or pressure increases, past a certain point the resistance of the PTC skyrockets. This would stop whatever charging or discharging process you were doing to cause the failure. Once pressure reaches a certain differential between the inside of the cell and the outside, venting will occur through the top of the cell.

I'll take a venting fireball rather than a mini pipe-bomb

09-21-2010, 07:34 PM #27
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Re: Harvested some batteries, what are they?

looks like crazy jay hijacked my thread.

09-21-2010, 07:39 PM #28
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Re: Harvested some batteries, what are they?

Quote:
 Originally Posted by Gappa looks like crazy jay hijacked my thread.
From here it looks like you were done with it and he just took over?
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09-21-2010, 08:48 PM #29
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Re: Harvested some batteries, what are they?

gappa, are there any other markings on your pink cells? The markings will not be printed, but rather they might be lightly melted into the wrap. Also, sanyo positive end cap will have 6 evenly spaced vent holes. They might be covered by the red washer.

They sound like high performance sanyo cells to me, but I don't know why they'd be in a laptop.... What laptop did this battery pack go to? Be mindful that if they ARE high-performance sanyo cells, they will have a capacity of around 1200mAh to 1500mAh max., but will be capable of tremendous amperage.

09-21-2010, 09:49 PM #30
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Crazy Jay
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Re: Harvested some batteries, what are they?

Quote:
 Originally Posted by Gappa looks like crazy jay hijacked my thread.
Quote:
 Originally Posted by Toke From here it looks like you were done with it and he just took over?
That's the beauty of LPF. One question leads to another and whoever listens, learns.

09-21-2010, 11:04 PM #31
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Re: Harvested some batteries, what are they?

My Dell battery packs are wired Qty 4 3.7v cells in series for 14.8 volts at 2240 ma, A second set wired the same matched in parallel to double the current to 4480 ma total still at 14.8 volts. A mismatch in the voltage (and current?) may trigger the battery installed in the computer as exhausted. Pulling the battery pack apart as I have done for a couple years yields many good cells. I just cycle them on a good smart charger and load test them on a one on one basis. As has been said, this is a excellent source for batteries as most manufacturers use a better quality cell.

Doug
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Last edited by ff-racer; 09-21-2010 at 11:06 PM. Reason: Added Detail

09-22-2010, 01:13 AM #32
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Re: Harvested some batteries, what are they?

If I remember the laptop was a HP. These do in fact have 6 vent holes and a melted marking with "IO3A" stamped into them. They do power my Arctic very well, but I did end up throwing away 3 of them just because they read lower than 2 volts. I guess they may have been good but why take the chance and get greedy, I ended up with 4 cells in apparently good shape. I have 2 computerized RC car chargers that work very well because I can charge at any amp rate and voltage I choose.

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