Bad laptop pulls

7 posts / 0 new
Last post
Boaz
Boaz's picture
Offline
Last seen: 6 hours 46 min ago
Joined: 11/07/2010 - 09:31
Posts: 6170
Location: Birthplace of Aviation
Bad laptop pulls
i was in lowes the other daybuying plumbing supplies so i went over to tghe recycling bin and grabbed a couple handfulls of batteries to play with …… i don’t think i’ve ever seen batteries as bad as the LGDBB11865 from a Dell laptop pack Six batteries /nice color/solid green kind of like a samsung25R . I was a bit excited to see they had a 3,7V charge on all six so I cleaned them up a little too much before charging. The first clue was when placed on the liito-kala 500 at a half an amp they started to climb very quickly….kind of like when the cell has an under 2v charge . I didn’t note the time it took to charge but all 6 terminated at 4.20V The next day I decided to drop one in a light and had my meter handy, so I checked voltage …..3.94V//3.90V///3.94 etc …

I’ve never seen a battery drop so far so fast just sitting ….The internal resistance before charging was 125 which I thought was not great but not horrid either . i’ve torn apart lots of battery packs but have never seen anything drop that far that fast .

Has anyone seen this before ? If a battery seems to charge too fast is that a sign it’s bad ?

καὶ τὸ φῶς ἐν τῇ σκοτίᾳ φαίνει καὶ ἡ σκοτία αὐτὸ οὐ κατέλαβεν

Milan
Offline
Last seen: 1 day 13 hours ago
Joined: 05/08/2012 - 12:13
Posts: 281
Location: Czech Republic

Worn batteries have not just higher internal resistance and lower capacity, but they are also – how to describe it – kinda “slow”. Meaning they cannot be charged or drained in few hours like new cells, so even half amp is too much for them.

To get full capacity out of them, or full charge into, it will require longer time – at least 4 – 5 hours, but the lower the better. Charging such batteries with 0,1A is the best. Also using them for low loads or intermittent use (so they can “rest”) is ideal.

snakebite
snakebite's picture
Offline
Last seen: 8 hours 18 min ago
Joined: 11/20/2013 - 20:21
Posts: 1609
Location: dayton oh

the lg “spicy mustard” colored cells from dell packs are worse.
laptops are hard on batteries and some age worse than others.
panasonic and samsung being the best.

Barkuti
Barkuti's picture
Offline
Last seen: 3 hours 22 min ago
Joined: 02/19/2014 - 14:46
Posts: 1905
Location: Alhama de Murcia, Spain

Buying cheap replacement laptop battery packs may be worth it, for cell harvesting I mean.

Used packs? Not worth the required cell assessment and tune up time I believe, though it all depends. 

 

Cheers Smile

everydaysurvivalgear
everydaysurvivalgear's picture
Offline
Last seen: 22 min 37 sec ago
Joined: 07/31/2015 - 10:25
Posts: 2494
Location: sydney australia (GMT+10)

I got some laptop pulls here and they are okay. Both Sanyo cells the lowest voltage i encountered was 1.8v.

They all still work but not the best quality or i should low amperage draw more made for longevity and not power. Actually the better cells came from an old Lenvo laptop they are very well aged lol. But still work good! Sanyo quality.

My LG HG2 are wearing bad maybe its just an LG thing?

gauss163
Offline
Last seen: 2 hours 45 min ago
Joined: 10/09/2013 - 18:04
Posts: 726
Location: USA

Milan wrote:
Worn batteries have not just higher internal resistance and lower capacity, but they are also – how to describe it – kinda “slow”. Meaning they cannot be charged or drained in few hours like new cells, so even half amp is too much for them.

To get full capacity out of them, or full charge into, it will require longer time – at least 4 – 5 hours, but the lower the better. Charging such batteries with 0,1A is the best. Also using them for low loads or intermittent use (so they can “rest”) is ideal.

Highly degraded cells charge slower because the very high IR / impedance forces them to enter CV phase sooner, so more of the charge is done at lower current. Similarly the discharge termination voltage will be reached sooner unless you lower the current, so they are typically useful only for low current apps.

snakebite
snakebite's picture
Offline
Last seen: 8 hours 18 min ago
Joined: 11/20/2013 - 20:21
Posts: 1609
Location: dayton oh

as for digging in the recycle bin for packs many such packs are worn out.
but some get recycled due to a busted laptop or a bricked bms.those can give some very good cells.