Bad Laptop LiCo cells at over $0.50/Wh

S

SamTexas

1 MW
Joined
Dec 29, 2010
Messages
2,712
Location
Houston, Texas
Updated 01/22/2013: I changed the thread tittle to reflect my experience with these laptop batteries.

You guys are luckier than I.

I bought 5 of them. 4 are completely dead (less than 1.0V) and could not be sucessfully revived. They do charge up to 4.20V but drop down to less than 4.00V overnight. The other one has only about than 2000mAh or only 90% of the capacity. My overall cost is now over $0.50/Wh. Definitely not worth it.

I bought them much later than you guys, so I guess all the good stock are gone. Seems like what they have left now are defective/worn out units.
 
There are 12 cells in each of those pack. 3.6V, 2.2Ah or 7.92Wh each cell. Total of 95Wh per battery pack.
C rate is the same for all laptop LiCo cells. 0.5C continuous. 1C for shorter period of time and 2C burst.

The actual nominal voltage is 3.7V. But HP (and other reputable manufacturers) stop charging at around 4.10V (instead of 4.20V) to (presumably) prolong the cells' life.

The above information are what I've found on the web. I have never seen or worked on this battery pack before.
 
fyi...this ebay'r will not ship Lipo Batteries outside US.

RE:
devrait laisser note pour expedition Buyer:
Member id tom1212418 ( Feedback Score Of 32Yellow star icon for feedback score in between 10 to 49)
Oct-04-12 20:33 Feedback conversation


Reply by inandoutcomputersstore (Oct-05-12 05:09):
We can not ship items with LI-ion batteries internationally
 
I BOUGHT 15 PACKS!! That was all he listed, now has relisted them http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200876136977

Took me half a day to take them apart.
14 of the 15 were at 3.81, one was low at 2.5 but charged up fine. My hands are sore from all the work.

Will do some cycles on them tomorrow, as time permits.

Bought them Monday got them today. fast turn around.

they are all returns but all were in original package all taped up. Must been new no sign of any use.

Got 2 packs Panasonic, 2 green label Sanyo, the rest were red sanyo's. Claimed to be 2.2 Ah cells. Find out tomorrow.

Dan
 
Can you post a pic of the cases opened up? Any tabs on the cells?
 
Yes they are 18650's and they are tabed togeather end to end, then parelled in 3s4p. Will try to get some picks.

I don't think i want to take the cells apart as they will work out fine for what I want them for.
the wifes ride and any other loaners i let friends use. No Bms but the controller will shut them done before LVC is hit.And I will have warning on the packs.

Just testing first two packs, so I will see what they are in a couple hours. Even the one low pack charged fine and is doing good so far on discahrge.

Dan
 
Here is the first two packs I tested. Max discharge was 1.5 amps. I need to find the way to increase the currant on the Ichargers, I'm still not sure how it's done.

From 4.15 to 3.5v, the pack that was low when recieved tested at 8564Mah Ri was 29, 28, 29.
other pack was 8443 with ri 30, 28, 27.
some pics comming.
100_3399.JPG
100_3400.JPG
View attachment 2
100_3402.JPG
100_3403.JPG
Will test them again and see how they are. So far not too bad for 4 year old returns. All packs had return stickers with date on them.

So far I think they will suit the need.

Can someone point me to, How to get higher disharge on a 206b Icharger. Would sure cut the cycle time. I was hoping to get at leat .5c or about 4 apms.

Dan
 
DAND214 said:
From 4.15 to 3.5v, the pack that was low when recieved tested at 8564Mah Ri was 29, 28, 29.
other pack was 443 with ri 30, 28, 27.
Click to expand...

I'm not sure I understand here. Do you mean the 'low pack' put out 8.564ah and the second pack you tested only put out .443ah?
 
Cool. I bought two. Should make a cheap boost pack of 12v 16ah.

Thanks for taking the plunge and testing these.
 
You need to connect the charger to a battery to use the regenerative discharge. ie the discharge energy charges the supply battery. Without that you're limited to low power discharge via the resistor in the charger. Status of charge of that supply battery makes a difference, because if it's full, then the charger revert to resistance discharge. It's perfect for my old lead batts. I start them at full with an empty pack being cycled. Charge that pack with energy from the lead batt, and then cycle the next one. There are some losses, so you do need to watch to not completely discharge.

You with a few of your packs in parallel in the middle as a buffer between the 2 chargers , you might be able to discharge from one charger while charging with the other and not need another battery.

John
 
Cells seem honestly rated at 2100mah.
DAND214 tested at +2100mah.

Got 10, + spares, intend on building a s7p16 25.2V 33.6Ah.
Although awkwardly shaped, looks like careful planning will fit all inside the oem eZip battery pack!
3s4p packs won't separate well.
Although I will install balance connectors, after preliminary monitoring, I intend on relying on bulk charging.

For maximum life I intend on a stringent 4.1V max charge and an as yet to be determined ~3.6V ~3.7V DOD.
Pack will be monitored with the 1-8S voltage monitor-alarm, possibly integrated in pack with on-off switch.

Will post progress-results in Homemade Battery thread.

Amazingly, cells were perfectly equalized in every pack, precise to the 100th V!
This might indicate that the oem circuit board actively balances the cells?
If so, an overlapped series of 3, could equalize-balance the 7s pack.

Oh, all except 1 pack had retained higher than 3.5V - every cell.
 
A valid concern, with these 12packs,is that, while they have a nice large X of metal ganging cells in parallel they have a relatively thin band connecting them in series.
This could limit available amp output!
I intend on addressing this by soldering a copper braid between each 4p.

Alternately, placing a rubber band segment inside 3/8" tinned copper braid, then coating with dielectric (conductive) grease and wedging between the 4p banks should up the sustainable amps nicely and reliably?
If the rubber doesn't dissolve ...

I also have a tube of heatsink conductive adhesive.
Folding a braid segment, with folded paper-plastic etc between fold then adhesive to each 4p might work best?
I will test adhesive strength on cleaned as well as roughened surfaces.
I must do an electrical resistance test on its conductivity in its "cured" state, (takes several days to harden).
 
You guys are luckier than I.

I bought 5 of them. 4 are completely dead (less than 1.0V) and could not be sucessfully revived. They do charge up to 4.20V but drop down to less than 4.00V overnight. The other one has only about than 2000mAh or only 90% of the capacity. My overall cost is now over $0.50/Wh. Definitely not worth it.

I bought them much later than you guys, so I guess all the good stock are gone. Seems like what they have left now are defective/worn out units.
 
I got two of them a week or two ago, and the one I opened up looks all good, all near 4v per cell.
 
Lucky you too! I bought mine 5 days ago. They arrived yesterday. Should have done it when I created this thread, but I was busy with other things and didn't really have a need for more battery. Oh well, lesson learned.
 
Alright so I got my two packs paralleled up for 3s 16ah (8p). I'm running it in series with 36v of other batteries, at 20amps max. So it's seeing 5amps (1/4th) uphill.

Voltage sagged to 3.65 or so, with resting at 4.08 before the test. Is this normal? I know in your other thread, Sam, you said laptop cells sag a lot.

What's a safe stopping voltage, under load?

Tomorrow I'm going to do a range test.

My cells were a burgundy color, not sure the make.
 
Laptop cells are specifically designed for large capacity ... at the expense of a decent C rate.
Designed to power laptops for between 3 and 5+ hours, that is a .2C to .3C.
To maximize capacity, laptop cells increase the ratio of electrolyte to anode-cathode - capacity over discharge rate.

Additionally, these HP packs suffer from a severely restricted bottleneck between the "banks".
While the cells in parallel use a wide "X" connecting them, in series the connecting "strap" is very thin. Thinner than I've seen in packs of much less capacity. This would demonstrate as a dramatic sag while under drain.
Cure?
As I mentioned earlier, some form of additional series connection might double the available C rate - reduce the drastic "sag" that is demonstrated from these packs.
I recommended an added strap or a conductive device wedged between the banks.
"Series" Enhancement!
 
I know that some of us got the good and some the bad.
This is the worst of my GOOD luck of the draw packs.

I did not beef up the straps between cells so there will be a lot of sag if used in a high power setup. they will not be used in that way.

After testing and waiting, I built 2 - 6s6p laptop battery packs. Used as 12s6p or 44.4 nominal, peak voltage WAS 49.7 FOR TESTING.

I have a load bank that draws 7 amps at 50v thru my CA SA. After 2 tests they repeated with the same capacity of 11.17 Ah. Peak cell voltage was 4.13 and shut off nder load was 3.4v which rests at 3.6v per cell. Could of gone lower.

I took the low cells of the 15 HP packs I bought. A mix of 1 Panasonic, 1 Sanyo and split a pack of Sony. Both paks got warm after discharge, starting room temp about 64, cell temp of 94f after .

I know they won't power my MAC 8t like my LiPo's do but will do fine on the girl's Schwinn with a CUTE 128. Real light and simple build, 50lbs with batts. It ran at 18 to 20 on 37v LiPo so should be a little faster with 44v.

Must wait for better weather before riding it. Will get back when I get a chance to test them out.

I have 9 packs waiting for me to figure out what to do with them. All tested at 8+AH per pack. I must say it was a lot of work/time/labor getting the packs apart, then splitting a couple to build the packs.

I'm thinking of making more 6s8p packs so I can build for there. So each 6s8p should be 22.2v 16/17Ah. Or should i just do 6s4p and put them as needed? That makes a lot of plugs and rats nest like that.

Start getting em ready, SPRING is just around the corner!

Dan
 
You must log in or register to reply here.

Similar threads

The Smart Ped`aleck
Know Your State Laws
Replies
19
Views
4,063
teklektik
teklektik
S
Info on Laptop 18650 LiCo cells
2
Replies
44
Views
15,918
kje
kje
Philosopher
HELP! I'm about to pay $1600 for a 1500w stand up scooter?!
2
Replies
31
Views
6,374
4LivesPerGallon
4LivesPerGallon
teslanv
Bafang BBS02 750W Mid Drive on Craigslist Hardtail
2 3 4
Replies
79
Views
54,068
WoodlandHills
W
cal3thousand
Xtracycle Edgerunner - Mid Drive build log
Replies
9
Views
4,066
allezdude
A
Back
Top