Asus E410M not charging battery

[roman728]

Hello friends,

I have this laptop with a not charging battery. This is the 3rd same laptop with exact same problem so there must be some manufacturing design problem. Windows says 0% (plugged in) and percentage doesnt increase. I tried with new battery and also with new BQ24780S charging IC. Laptop works only on DC power, after unplug immediately shut down.

I measure BQ24780S with and withou battery and here are the results :

without battery / with battery
1 19.28 19.28
2 19.25 19,25
3 18.80 18.75
4 24.71 24.26
5 5.98 5.67
6 2.63 2.62
7 0 0
8 0 0
9 0 0
10 5.1 0
11 3.3 3.3
12 3.3 3.3
13 0.3 0.32
14 6 6
15 0 0
16 3.4 3.4
17 0.23 0.23
18 0.26 0.26
19 0.23 0.23
20 0.23 0.2
21 1.16 1.16
22 0 0
23 0 0
24 6 6
25 5.9 5.9
26 0.23 0.23
27 0.23 0.23
28 18.97 18.97

What to focus on next ?
thanks for response.

[mon2]

Re: Asus E410M not charging battery

Measure the voltage to ground of each pin on the battery connector while the battery is connected. Do attach the power adapter as well.

Post each measurement.

[roman728]

Re: Asus E410M not charging battery

Battery connector with adapter plugged in :

P- 0.0v
R 3.03v
C 3.28V
D 3.28V
P+ 0.23V

[mon2]

Re: Asus E410M not charging battery

Is the battery a known good battery? If the battery is locked, it will not charge.

Remove the battery and check the same pins again on the battery connector. Concerned about pin R voltage. One of these pins is used as a battery detect pin. The smbus pins look ok.

[roman728]

Re: Asus E410M not charging battery

I ordered new battery when the 1st laptop with this problem come. It is original asus battery. But i can order another one to try..

[Sephir0th]

Re: Asus E410M not charging battery

Do you have voltage at Pin 27 & 28 with battery only (charger unplugged)?

[roman728]

Re: Asus E410M not charging battery

I dont have any voltage on pins 27 and 28 with battery plugged and charger unplugged.

Without battery on battery connector i have voltages :

P- 0V
R 1,1V
D 3,25V
C 3,25V
P+ 8,6V for a while ten decreased to 0,23V

[mon2]

Re: Asus E410M not charging battery

Locate a sot23 (3 pin) dual diode near the charger IC. This dual diode will select either the adapter or battery voltage to power the charger IC (VCC pin).

At this time, this dual diode maybe defective.

Post pics of the area if not sure. Then remove all power. Meter in diode mode. Measure with red probe on the dual diode side with 2 pins = anode (+).

Black probe on the side with the single pin, cathode(-).

The diode should conduct. Repeat with red probe on the other pin. Should conduct.

Reverse the meter probes. Should block for each test with OL.

Confirm this. The battery voltage should reach this dual diode and pass the voltage onto pin. #28 when the adapter is removed.

[Sephir0th]

Re: Asus E410M not charging battery

This was my assumption, but after the battery has no voltage at all anymore, probably not the case ans if so, just a lucky finding. Should charge anyway.

Without some experience hard to solve. Likely need to dig into every Single resistor related to charging.

[mon2]

Re: Asus E410M not charging battery

I am still suspicious if the battery is being detected by the charger IC. Some schematics hard wire the battery present pin to be always true so not sure if that is the case here. If there is a battery charge, it must reach the VCC pin else diode is blown.

[roman728]

Re: Asus E410M not charging battery

Thanks guys, i will try to measure diode yesterday and post resulst here.

[roman728]

Re: Asus E410M not charging battery

New battery came today, it is charging and working. Case closed, thanks for help.

[huzo]

But why does the batteyry fail? i opened the battery and all three cells have 3.7V,but the battery isn't working...

[mon2]

Between the battery connector that mates to the motherboard and these cells is the BMS module (battery module system). It is possible that the BMS module is in a locked state, for safety reasons.

[huzo]

Yeah,but why did it lock itself? The cells are fine,and i read all over the web that people are having issues with this model...

[mon2]

Test the voltage to ground on the battery pack with the power adapter attached. Is the voltage higher than the marked battery pack voltage? It should be slightly higher than the battery pack voltage. If yes, the battery pack should charge unless it is defective.

[huzo]

The battery is defective,that is true,and new battery works fine...The old battery gets 8.6V while the charge starts for a few seconds and the 0V, altough the battery is 11.55V nominal value it gets only 8.6V, So the old battery probably locked out because something..I forgot to measure the voltage on the new battery while charging but it wen't from 76% to 100%...So the issue is the old battery,but why,since the three cells inside are at 3.7V,so not like one of them died...Is it planned obsolecence?