6 2900mah 18650's for $16.50

The following battery pack should have 6 2900mah cells. Seller is fairly new, but in the US. I took a chance and bought one. They have 8 left.

http://www.ebay.com/itm/New-Genuine-Acer-10-8V-5800mAh-White-Laptop-Battery-UM08B52-/261091081289?pt=Laptop_Batteries&hash=item3cca3dbc49

I think it says “cells made in Japan”, but it is hard to tell. Top line on far right of label.

link looks incomplete

Fixed. Thank you.

One site lists this battery as having 12 cells, which would make the cell output very small.

I don’t think I have ever seen a laptop pack with 12 cells (10 is the most I have seen), so the description of 12 cells is very suspect.

Still, $16.50 is a great price if there is something good in there.

I must resist. I have 200+ pack pulls already. I must not buy.

Resistance lasted about 20 seconds. I’m in for one.

I think I better start looking for the nearest chapter of batteries anonymous.

Wow. Sounds like you are set up for the upcoming zoombie apocalypse. I’m still working on it.

>>>>>>Sounds like you are set up for the upcoming zoombie apocalypse.

At first I thought it was harmless. Just an outgrowth of my semi-hoarding collecting nature. I like to collect stuff and then get rid of that stuff and collect something else.

But the problem with li-ion batteries is that I’m strating to be concerned about the risk, sort of like rock-and-rollers being concerned about flying. They fly so much that it raises the chances of them being in a plane crash, consdiering many are forced to take small planes in dubious weather. Many great pop stars have died in plane wrecks.

Same thing with li-ion batteries: The more I get, the bigger the chance that I’ll get a bad one that will self-immolate, setting off 200 others, which will make for quite a fire from what I’ve seen of scary li-ion vids. I try to keep ’em stored away from each other but I only have so much room here. Plus I’m in the desert and high temps are bad for ’em so I can’t just leave ’em in an outbuilding because of the heat.

I’m sure that I’m being paranoid, but I do think about the fire danger. I really do need to get rid of some, give more away. One hundred was manageable, but 200 (or more at this point) is just too much. Time to thin the herd. Just need to find some time to put up some giveaways on BLF.

I have about 30 new (counting the 6 on the way in this pack) and probably double that in used pack pulls. The ones not in flashlights are kept in the refrigerator. I figure lower temperature mean less activity in the cells, but I’m not worried either way. It seems like the risk is low if you get rid of the ones that don’t hold charges or have been taken too low more than once. There are who knows how many millions of people and businesses with Li-ion batteries in their laptops, cells, etc. Increasing your risk from 1 in some billions too 200 in some billions doesn’t seem like an increase in risk.

The hording is another thing. I, my friend, am trying to tackle that issue myself.

Hi,

I think that the Acers have a standard battery, and, typically, an extended battery. That might explain why some might have 6 cells, while others might have 12 cells?

Is there any difference in performance & charging methods considering these are 3.6 volt and not the usual 3.7?

Not that I’m aware of. Most laptop packs I have encountered have 3.6 cells.

Battery arrived. Good news. The pack appears to have never been used and is in what appeared to be factory static bag. It contains 6 of 2900mah Panasonic NCR18650’s. The cells have date code “9511”. So they were manufactured on the first day of the first week of May 2009. The cells are at 1.9v. Looks like these may be a lucky find. I would not have found them if it wasn’t for ohaya’s find in the following thread:

First pick is a tip on how to open these packs.

Hmm, 1.9V is really low. They may have been uncharged for about four years. They may not have been below 2.5V for more than the last month or so. Better charge them slow to start with, then capacity test them if you can.

We went through all of this in the above linked thread. I’ll still be cautious, but they will probably still have full capacity, low resistance and relatively high discharge rate capability.

I purchased one of the packs from the other thread. I charged and discharged the batteries one cycle. Charged the battery up again to full capacity and discharged at a rate of 3 amps. I got a little over 2700mah’s at a rate of 3 amps, discharged down to 2.7v. For some reason the batteries just seem to be a sleep. From my test and others on the other thread they seem perfectly and happily healthy. As if they where just made, even though the cells I got where 3 1/2 years old.

Well, good news on the 2900s! Adds up to one of the luckiest weekends ever! Yesterday scored a brand-new string-trimmer power pack from the home depot recycle bin that contained not five, not 10, not 15 BUT 20 (!!!) Samsung 18650 13q high-demands, all charged to 4.10 volts. Power pack goes for $120 new. I have no idea why someone tossed this away, but it was still in half of the clamshell display box. Never opened.

Then I walked out in the parking lot and saw a green piece of paper blow by in a wind gust. Took a couple steps and grabbed a 20-dollar bill. Thing looks like it has been blowing around the desert for 10 years, but it’s still usable.

THEN my wife and bought our usual 2 lottery tickets and won $35 between the two of us.

So, news of 6 nice 2900s on the way for $16.50 really tops the whole wekend off.

As a side note, I thought that recent home depot power pack I posted about a month ago was hard to open …. This one was worse. Well, it was actually easier to open but this was the hairiest cage I ever worked on. No 12 volts here. Ten batteries on each side putting out 40 volts per side! Had to pull the welded tabs off BEFORE I could get each battery out. About 1 inch to work in or sparks would fly (twice).

Not high mah like the 2900s, but these are pretty cool cells.

And i got 20 of em for free!

Well with my limited experience I’ve noticed about half the packs I come across are rated at 11.1 volts. Mostly newer stuff though like netbooks etc. Anyways good to know there isn’t much difference.

I've considered like edcplus that the best use of those batteries is probably left as an already built pack ...tearing them apart makes sense if you NEED batteries which clearly not many of us do ..An assembled tough pack is starting to make much much more sense ,Maybe a dedicated bike light with a battery pack that snaps in under your seat .

When tearing these packs apart it gives one pause for thought about overall quality of it's construction ..about 7000 times tougher than a laptop pack

Ubehebe, you’re going to laugh when/if you break down this pack. It was even easier than ohaya’s find.

I have a pack I have not broke down yet. I think I’m going to take Boaz’s advice and wait on breaking it down. All I would need to figure out is which terminals to connect to and I would have a 10.8v protected battery with self contained charger.

Valid points on the pack, but I don’t have the charger and what would i do with a pack putting out 40 volts? I was thinking of selling it on fleabay but I don’t really know if the thing works or had some kind of defect.

And from reading the link I posted, these are some interesting batteries. For example, I ran one for 30 minutes in my test flashlight and got 4.01 volts after 30 minutes. I have BRAND-NEW Panasonics and Samsungs that don’t do that well, so these things are worth further investigation.

>>>>>>>if you NEED batteries which clearly not many of us do …

No, I definitely do noT need the abtteries, hoo hahahahha. I haven’t needed another battery since like last October. I definitely have a battery problem and might have to check into battery rehab shortly. :wink:

Asking me to not open a pack is like placing a pound of heroin in front of a junkie and telling him not to touch it.

I have a li-ion monkey on my back. :–0