TIP: How to charge laptop battery with PSU

[ktmmotocross]

Hello.
If u need to charge laptop battery for check if laptop work on it when it would not work on charger.

So here's the tip:

U cannot only connect it with plus and minus, because nothing happend = power consumption 0 mA

U need to connect plus and minus and other minus cable connect to pin next to minus pin as a start. Then u see some current.
Than u need to find voltage suitable for charging, because if u overvoltage it, the battery charging for maybe one or two second and stop charging. then u need to disconnect starting second minus pin, lower voltage and try again until battery is charging constantly. change voltage by 0.1V and see when battery stop charging, than lower it.

i attach pictures where u see overvoltage, constant charging voltage and pins connect



Hope this will help u. if u have another tip be free to post it

[Techtiger]

Re: TIP: How to charge laptop battery with PSU

Thanks for Sharing this

[eccerr0r]

Re: TIP: How to charge laptop battery with PSU

May want to mention what brand/model, as batteries come in different requirements to start charging. I was thinking about this when I glanced at this Toshiba NiMH pack I have on my desk and it "lies" about what terminals are + and -, there's another two terminals I need to short to get those terminals to be + and - --- and I could have used one of those two terminals as one of the battery poles and ignored what it said were + and - on the pack...

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

the start pin and other pins can variate due to brand, so if somebody have other pinout please post it.


thi pinout i used is from SONY VAIO

[on/off]

Re: TIP: How to charge laptop battery with PSU

Thanks for sharing.

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

Now i have newer DELL laptop battery and it looks like dell is change its charging

pinout looks like awerage one side 2xplus other side 2x minus and third pin behind minus is switch.

but now the switching pin must be unconnected from minus and connected every 30seconds

so i just use some mosfet with computer generator through audio output to switching that switch pin to ground every 29seconds

[razu]

Re: TIP: How to charge laptop battery with PSU

Thanks for share...................

[brew99]

Re: TIP: How to charge laptop battery with PSU

great tip...I'm always learning from this site. I have a question in regards to battery voltages.

I have an internal battery pack from an Asus Vivobook that measures no voltage at the battery pack terminals. I did directly charge the 3 cells as I could get at the terminals, so I know the pack has about 12V now, but nothing shows at the terminal that connects to the mobo. Is it normal to not show voltage, or is it possible that the packs internal PCB circuit is not working, and doesn't pass the voltage.

This is my first look at a battery pack. laptop runs from AC, but not battery

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

did u connect switching pin to minus pin?

[brew99]

Re: TIP: How to charge laptop battery with PSU

It measures 12.3V at the terminal pins +- on mobo when the battery is not installed and charger is in. If Ac adapter is in along with batt., then it will run, but there is now no voltage at the +- terminals of battery connector and as soon as I remove the ac adapter, it shuts off. Its almost like the pack is telling the BQ24780S charger IC that it is "crap" and shuts off the 12V to it.

I was just wondering if I remove the battery pack and try and measure the o/p voltage of the pack, I am getting nothing to show. Is this normal? When installed on mobo, it shows nothing also, unless the ac adapter is in, then it shows 12V at the terminals. Just trying to narrow it down to a crappy batter pack board, or something on the mobo.

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

battery have connect to charger ic and KBC with two signals/DATA a CLOCK/ that comunicate by I2C/i think/

[piernov]

Re: TIP: How to charge laptop battery with PSU

Battery has internal protections managed by the BMS. If something goes wrong (cells get unbalanced too much for example), then it can enter permanent failure mode and blow the fuse. You'd need to reset the BMS (with external programmer and specific software, requires the key as well which may be included in the software) and replace the fuse.

Conclusion: replace the battery
Better not play with lithium batteries. They *are* dangerous.

[brew99]

Re: TIP: How to charge laptop battery with PSU

Thanks for info. I did find info on the BMS IC (as i took the board off, to have a look), checked the fuse (which was ok), but do not have a programmer or the software. Looks to me like the BMS chip is not providing gate voltage to turn on the FETs, so that the batt voltage can pass onto the terminals. I've ordered another battery, so hopefully that will solve it.

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

that's why when u want to replace cells u must use working battery, even if it works for a 5minutes.

[razu]

Re: TIP: How to charge laptop battery with PSU

Thanks for share

[gabiz_ro]

Re: TIP: How to charge laptop battery with PSU

Battery communicate with EC or charger via SMBUS,something similar with I2C.
Pinout may be different.On some there is sys_present that tell battery that is connected,batt_present that say to motherboard battery is connected.
But in all I see there is no balance,just monitoring.If one pair is out of range charging is disabled.Even more they blow fuse,disconnect elements,etc.

[brew99]

Re: TIP: How to charge laptop battery with PSU

Thanks for info. I did find info on the BMS IC (as i took the board off, to have a look), checked the fuse (which was ok), but do not have a programmer or the software. Looks to me like the BMS chip is not providing gate voltage to turn on the FETs, so that the batt voltage can pass onto the terminals. I've ordered another battery, so hopefully that will solve it.

So got my new battery in and it measures 12V at the terminals directly at +- without being installed (which my original did not). That tells me the original battery (which I do not know the history of) BMS has definitely inhibited the o/p (fuse is still fine, but it has locked it down in memory I guess). Put new battery in laptop, and all is good. Man, these batteries are getting way to smart!!

I've ordered a small programmer and will try and read/write to the old battery just as a learning experience.

[ktmmotocross]

Re: TIP: How to charge laptop battery with PSU

nowdays batteries are so cheap/and weak/ that replacing cells is just as a sport or hobby