Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

[Dexomol]

Hi,

the laptop doesn't work with battery and doesn't recharge it, although it shows that it is 100% (even when it is disconnected).

Battery voltage measurement:
pin 1 and 2 (+) shows 0.85v
4th and 5th - jumps 3.23v-3.28v
6th - 2.91v
no 3rd pin, 7 and 8 are gnd

I looked for a #EN short for the battery on the board, but couldn't find it.
I also did a check with the BatteryMon program (photo attached).

Measured the voltage on the recharging chip (bq24780S):
1 ACN 19.56
2 ACP 19.56
3 CMSRC 19.1
4 ACDRV 24.52
5 ACOK 6.045
6 ACDET 2.659
7 IADP 0
8 IDCHG 0
9 IDCHG 8 0
10 PMON 0
11 PROCHOT 3.28
12 SDA 3.28
13 SCL 0.27
14 CMPIN 6.096
15 CMPOUT 0
16 BATPRES 0.127
17 TB_STAT 0.236
18 BATSRC 0.267
19 BATDRV 0.236
20 SRN 0.236
21 SRP 1.174
22 ILIM 0
23 GND 0
24 LODRV 6.1
25 REGN 5.936
26 BTST 0.236
27 HIDRV PHASE 0.236
28 VCC 19.27

Any one have an idea?

[Spider1211]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Have you tried with a known good battery?

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Have you tried with a known good battery?

Don't have a good one 🤷
But I'm thinking the problem is with the motherboard, because even without the battery it still shows the battery is 100% full.

[mon2]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Confirm if pin 13 (SCL) is always this low voltage.

It must not be for this to work.

The charger ic communicates it's parameters using the I2C / SMBUS interface using the SCL & SDA pins.

Each of these pins are open drain and must have pull up resistors to function correctly.

Check to see that the voltage on SCL is not stuck at this low voltage.

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

At the moment it's stuck at low voltage, I'll seach what can cause this and update, thanks

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

My mistake, sorry

I copy pasted the measuremnets from the chip with an error - after pin 8 all the pins should have been shifted up.

Took new ones right now, very simmiliar to previous, here are the correct ones for the moment:

1 ACN 19.56
2 ACP 19.56
3 CMSRC 19.1
4 ACDRV 24.51
5 ACOK 6.046
6 ACDET 2.657
7 IADP 0
8 IDCHG 0
9 PMON 0
10 PROCHOT 0
11 SDA 3.27
12 SCL 3.28
13 CMPIN 0.26
14 CMPOUT 6.095
15 BATPRES 0
16 TB_STAT 0.127
17 BATSRC 0.235
18 BATDRV 0.267
19 SRN 0.236
20 SRP 0.236
21 ILIM 1.174
22 GND 0
23 LODRV 0
24 REGN 6.11
25 BTST 5.934
26 HIDRV 0.235
27 PHASE 0.236
28 VCC 19.27

SCL & SDA are high, if 3.27v is considered high for this pins.

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Tried today to charge the battery with a power supply, but no luck, it's completely empty and not charging at all

[mon2]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Issue may just be the deep discharged battery. Search out a known good battery and test again.

[SMDFlea]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Tried today to charge the battery with a power supply, but no luck, it's completely empty and not charging at all

How did you do that, you can`t charge with just + and - wires . Have you checked the battery mosfet on the board .

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Issue may just be the deep discharged battery. Search out a known good battery and test again.

Don't have a good one, only if I'll buy. I'll try to find at the local labs, at least to check if that's the case.

How did you do that, you can`t charge with just + and - wires . Have you checked the battery mosfet on the board .

I charged at the past some old Asus battaries, to check if they are dead or not if they were without a charge at all (some times there's a need to short #EN pin to GND). But it didn't help at this case.

[FrozenHaxor]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

I charged at the past some old Asus battaries, to check if they are dead or not if they were without a charge at all (some times there's a need to short #EN pin to GND). But it didn't help at this case.

You can wake up the BMS of the battery that way, but it will never charge. You need to send a proper command using the SCL and SDA pins for a smart battery to go into a correct mode and accept a charge. If you only enable the battery's system present pins and force a voltage into it, the smart controller will see a reverse current flow and will disconnect the power internally. You can even cause a permanent malfunction flag to be set, rendering the battery useless. It's not easy to reset a smart controller again.


I highly recommend not to attempt such approach to smart battery charging without proper equipment.



Check with a known good battery first. One of the cells might have high internal resistance causing an instant voltage drop, making the system shut down. I've replaced many faulty batteries over the years that would show a full charge but wouldn't keep the system up for even a split second.

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Ok, got it, so my only solution for now is to find a good battery.
Thanks guys, I'll update as soon as I'll find one

[mcplslg123]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Pin5 ACOK-dosnt seems right at 6.046V

[Dexomol]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Pin5 ACOK-dosnt seems right at 6.046V

Why, how much should it be?
From the datasheet it should be Active HIGH

[mcplslg123]

Re: Asus X509FJ-EJ115T (X409FB rev 2.0) - Doesn't work with battery

Should be 3.3V