Asus UX433FAC - batery dead after short on VIN rail

[ktmmotocross]

Hello.
Have this Asus UX433FAC that came with shorted mosfet on main power rail. After replace laptop works ok, but battery is dead. Laptop show charging but voltage on battery is 0.2V. when remove battery voltage on battery connector goes to 8.5V, but when connect battery again it goes down to 0.2V.

can that short shorted battery? batmon show that battery is full at 80%

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

Sounds like a crap battery. Test with a fresh one.

Check the voltage to ground on the SMBUS lines (SDA / SCL) on the battery which spit back data from the BMS inside the battery pack.

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

Sounds like a crap battery. Test with a fresh one.

Check the voltage to ground on the SMBUS lines (SDA / SCL) on the battery which spit back data from the BMS inside the battery pack.

SMBUS lines looks ok 3.3V when connected and charger attached. measured mosfets and all looks ok. Battery was ok before. batmon shows good capacity. dont have another battery so i like to be sure that problem is battery because battery is not cheap

i unwrap battery and cells is all 4.1V. on some points of BMS i measure 12.5V

can be bms measured if it is ok?

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

maybe when capacitor shorted and system was on battery BMS detect overload and cut off cells

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

1) to test the BMS, you will need an I2C /smbus master like an Arduino. Then using the 2 wire interface, you can ping and read out the battery vital stats.

Review the black hat article posted here:

https://www.badcaps.net/forum/showthread.php?t=113773

There are numerous public articles on how to use an Arduino to dump such data out of laptop battery packs.

https://github.com/ArminJo/Smart-Bat...fo_For_Arduino

2) if the battery is on your work table, there is a valid output voltage on the battery pack contacts?

This voltage goes to ~zero only when mated to the logic board?

If yes, the mosfets on the logic board are still suspects.

3) which battery charger IC is onboard this logic board? Is it the 'BQ' series?

4) remove all power/no battery. For each mosfet, measure the resistance across the mosfet pins:

Source & drain
Source & gate
Gate & drain

Post each measurement.

It is possible that battery or another mosfet is leaking. That is, the mosfet is enabled when it should be off.

For example, often, the battery mosfet should be off when the battery adapter is connected.

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

1) to test the BMS, you will need an I2C /smbus master like an Arduino. Then using the 2 wire interface, you can ping and read out the battery vital stats.

Review the black hat article posted here:

https://www.badcaps.net/forum/showthread.php?t=113773

There are numerous public articles on how to use an Arduino to dump such data out of laptop battery packs.

https://github.com/ArminJo/Smart-Bat...fo_For_Arduino

2) if the battery is on your work table, there is a valid output voltage on the battery pack contacts?

This voltage goes to ~zero only when mated to the logic board?

If yes, the mosfets on the logic board are still suspects.

3) which battery charger IC is onboard this logic board? Is it the 'BQ' series?

4) remove all power/no battery. For each mosfet, measure the resistance across the mosfet pins:

Source & drain
Source & gate
Gate & drain

Post each measurement.

It is possible that battery or another mosfet is leaking. That is, the mosfet is enabled when it should be off.

For example, often, the battery mosfet should be off when the battery adapter is connected.

thanks i will look at it. i have airduno and some UART reader

2. battery packs have all 4.1V and together 12.3V . I mean that without battery on bat. connector on board i have 8.5V, but when connect battery it goes to 0.2V. not fast so it more looks like controlled

3. it is BQ24790

4. measured and all lokks good 500ohm/infinity

Looks like the battery can be problem, because i found shorted mosfet on BMS. remove it and it is really shorted S-D. but after replace still same behavior. on one of that output mosfet i have 12.3V but nothing on battery output

so controller can store hard fault

can i use battery from other laptop with same connector and pinout?

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

What is the voltage on the battery connector while the pack is not connected to the laptop? This is the contact on the actual battery pack, not the logic board connector.

Just interested to know if the battery cells are working to output a valid voltage or not.

Mosfet resistance should be in hundreds of Kohms or higher if they are not defective.

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

What is the voltage on the battery connector while the pack is not connected to the laptop? This is the contact on the actual battery pack, not the logic board connector.

Just interested to know if the battery cells are working to output a valid voltage or not.

Mosfet resistance should be in hundreds of Kohms or higher if they are not defective.

without connected battery, no voltage on any pins of battery connector on battery. i know how to test mosfet

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

No direct experience with your other question so proceed with caution. As noted by others, it is a fire hazard and risky topic. I believe that events like yours can lock up the BMS. The Arduino tool may confirm this.

Also, on AliExpress, you can purchase clones of the EV-2400 tool which with the software from TI, you can communicate with the BMS. We just placed an order for another tool to perform some tests. We have the original as well from TI but is much higher cost. In summary, it is a usb to smbus bridge but the TI battery tool searches for this tool and respective usb headers.

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

We ordered this one to compare to our original:

US $27.00 | EV2400 Battery Metering Chip Programmer UAV Battery Debugger Compatible With EV2400 EV2300 For TI Voltmeter Chip Writing Tool
https://a.aliexpress.com/_m04Jm8m

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

With no voltage, I think the BMS is dead or locked up.

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

With no voltage, I think the BMS is dead or locked up.

i think that too. that tool is interesting, but this is first time that i will need it for few years. can it check all batteries? it is not expencive so maybe i buy it for fun

[harp]

Re: Asus UX433FAC - batery dead after short on VIN rail

i unwrap battery and cells is all 4.1V. on some points of BMS i measure 12.5V

Do simple thing first.
If you have correct voltage on batt and no voltage on connector, first check the fuse (fuse with heater). If it is ok, then trace and confirm where is output plus pin on connectot (who no voltage) and do briefly about half second or so a connect thru 47R to plus on battery (12v).
Check if voltage on connect return.

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

I am far from being an expert on this topic but learning through the internet.

From my understanding so far, there are common commands that you can throw at all battery packs using the USB to SMBUS bridge (2 wire mode = I2C style).

The TI tool should allow you to extract this block of BMS information from any pack using the common commands.

Then there are register specific commands that only TI based BMS devices can interpret. This tool allows for that access.

For example, it appears that the TI BMS fuel gauge chips are buried inside the Macbook battery packs so you can dig deep - including unsealing which requires a passcode but the passcode for Macbook packs is public. Proceed with extreme caution as that level allows you to adjust the calibration data for the battery cells.

The software tools are available from the TI website. You should be able to download it to get a feel for the tool.

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

i got that analyzer you recommended but cannot find anything on that TI site. it is huge company so have huge website

[mon2]

Re: Asus UX433FAC - batery dead after short on VIN rail

https://www.ti.com/tool/EV2400

https://www.ti.com/lit/zip/sluc674

[ktmmotocross]

Re: Asus UX433FAC - batery dead after short on VIN rail

thanks mate