Can't find pins of a Battery - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: November 25, 2017, 06:38:45 am
content: So recently by laptop broke, and I would like to salvage the battery, only one and half years old, so still worked fine. But when I probe it with the multimeter on the red and black wires, I don't get any voltage, what could be the correct pins to use the battery, and if I could get it to work, how would I charge it?ThxPS. If you have any questions, or want some more pictures, please ask.Sent from my SM-G900I using Tapatalk

author: Nusa
author_rank: Super Contributor
timestamp: November 25, 2017, 07:39:25 am
content: You've still got the laptop, so I'd examine that for clues on how it was wired at the connector. Typically, there's a line that needs to be pulled to battery ground to enable the battery output. Blind testing with a resistor is far safer than a direct wire...batteries can dump a LOT of energy if you get it wrong.Charging may be a lot harder to figure out, if there's any kind of smarts in the battery pack. In which case, there's probably some kind of i2c-like serial interface implemented. If you're lucky, someone on the internet has figured it out for you.The other approach is to disassemble the battery until you can use the individual cells, at which point you can treat it like any other set of lithium ion cells.

author: skillz21
author_rank: Frequent Contributor
timestamp: November 25, 2017, 10:08:04 am
content: Quote from: Nusa on November 25, 2017, 07:39:25 amThere's is something wrong with the power side of the motherboard, the laptop won't start and the charging led won't light up.To what points exactly would I need to connect ground? Any ideas?Sent from my SM-G900I using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: November 25, 2017, 09:12:35 pm
content: Quote from: skillz21 on November 25, 2017, 10:08:04 amAre you sure the battery is not bad too?

author: Nusa
author_rank: Super Contributor
timestamp: November 26, 2017, 12:07:45 am
content: Plug the battery back into the laptop. At the connector, measure between black and red. If nothing there, try between black and each of the other lines. If you still find no voltage, it most likely means the battery is either dead or so discharged the protection circuit won't enable it. The previous poster has a point...it's possible the battery is the primary failure point in the first place.The logic is that you need a working battery in order for a laptop to start without being plugged in, so there must normally be some kind of power available from the battery when properly connected.As for details on using/charging that particular battery outside of the laptop, that's a research project for you if you decide to pursue it.

author: skillz21
author_rank: Frequent Contributor
timestamp: November 26, 2017, 01:41:28 am
content: Quote from: Nusa on November 26, 2017, 12:07:45 amSee the thing is, the battery was completely fine, the laptop was only just over one year old, the battery lasted for about 4 or 5 hours on one charge.... So yeah, pretty sure it's not dead. Also don't laptops boot without batteries? Other ones that I have taken apart do.....Sent from my SM-G900I using Tapatalk

author: Nusa
author_rank: Super Contributor
timestamp: November 26, 2017, 04:09:17 am
content: "It worked before" isn't a very useful fact when you can't make something work. Let your logic guide you in what you test, but don't reject looking at the unlikely just because it's unlikely.What have you tried? What were the results? So far we don't have any more facts than the few in the original post.

author: skillz21
author_rank: Frequent Contributor
timestamp: November 26, 2017, 07:01:18 am
content: Quote from: Nusa on November 26, 2017, 04:09:17 amI tried to revive the laptop by power cycling it, it was working fine, then i turned it off with 5 second shutdown, didn't turn on again. I measured the power coming from the PSU, it's working fine... Anyway, what about the battery? I tried connecting it to the motherboard and then measuring the black and red wires, I got about 0.20v on the meter..... What the heck is going on?? Surely the battery didn't just die because I did a 5 second shutdown, right?Sent from my SM-G900I using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: November 26, 2017, 11:18:22 am
content: Quote from: skillz21 on November 26, 2017, 07:01:18 amThe battery might be dead. If it's not the cells themselves which are dead, it could be the battery management system, which is integrated into the battery pack.

author: skillz21
author_rank: Frequent Contributor
timestamp: November 26, 2017, 12:28:13 pm
content: Quote from: Hero999 on November 26, 2017, 11:18:22 amHow could it have died so suddenly??Sent from my SM-G900I using Tapatalk

author: TheDane
author_rank: Regular Contributor
timestamp: November 26, 2017, 01:01:07 pm
content: Quote from: skillz21 on November 26, 2017, 12:28:13 pmThe genie inside the system went on an early Christmas holiday???The battery you have taken a picture of, looks very similar to most batteries inside tablets that I have seen. I have fixed a lot of Samsungs, and yes - the batteries do die/short out, sometimes without any warning, or other signs.The power pins I have checked/verified is the red/black ones, on the edges. The middle pins are typically for current monitoring, temp and data connections to the main systems CPU.I have seen a shorted system, with a 'dead battery/no output voltage', come back to life after the battery was charged for a while. This reset the battery gauge inside, and the battery worked somewhat fine after that and the external shot was fixed.If you try this, even without using a lithium charger - do monitor voltage/current/temps very closely. Those batteries are quite dangerous, and will easily catch fire/explode. I recommend never to walk away, not even for a lunch break.I recommend extinguishing a fire, if it occurs inside on your worktable, by quickly power off and then placing/burring the battery in moist sand when it starts to heat and bulge up (50+ degrees C), or using a class-d extinguisher which made for metal fires <-- Messy. Don't breathe the fumes.https://en.wikipedia.org/wiki/Fire_extinguisher#Class_D_dry_powder_and_other_agents_for_metal_firesFaults doesn't come in pairs of one - there can be multiple, or cascade faults - where the initial fault 'blows' everything after it. Most common in power stuff, but even (wet)dirt on an input pin can cause lots of trouble - even blow stuff up when/if it comes out of sync.Good luck fixing it.BTW - some stuff will not work without batteries, some will. Most laptops I own will run perfectly without the battery - could/can yours?

author: skillz21
author_rank: Frequent Contributor
timestamp: November 26, 2017, 01:22:41 pm
content: Quote from: TheDane on November 26, 2017, 01:01:07 pmSame, all the laptops I've taken apart run just fine without a battery, I'm not 100% sure about this one, since there was no reason for me to take it apart. And because the battery was built in to the PC. I let the battery charge and everything, but the charging led on the outside doesn't light up.....Sent from my SM-G900I using Tapatalk

author: TheDane
author_rank: Regular Contributor
timestamp: November 26, 2017, 01:32:58 pm
content: A shorted battery can cause the voltage to go up a few milli-volts.Have you tried to power up the laptop without the battery?Have you tried a full power cycle after removing the battery? It seems to me that most new laptops have some power scheme inside that makes the PC seems like it is turned off, but it really isn't. Makes it hard/impossible to to boot to CD-ROM/USB sticks, without rebooting the machine again through the OS. (BIOS screen - then press F12, or whatever to choose boot device, disappears from the boot screen)Fast boot, or what ever it is called in the modern UEFI terms??Edit - added: A removed battery can also cause a few milli-volts on the battery terminals, as the battery gauge tries to charge the battery, and then turns 'off'. This is normal to me, my experience says