Trouble calibrating my new N900 battery
 

My old battery was so worn out that I got a 1600 mAh replacement.

I charged my battery on Thursday in the late evening. bnf reported that VDQ = 1.

I was mildly using the phone during the next day, checking e-mail, browsing the net, calling - nothing unusual.
IIRC when I went to bed yesterday, it was still VDQ=1, voltage V ~= 3400 mV.

Today I woke up, VDQ=0, voltage V ~= 3300 mV. After a while BME decided the battery is almost dead and the deviced turned off.

Why did VDQ turn to 0 when the device was idle? Can I do something to calibrate my battery?

Re: Trouble calibrating my new N900 battery
 

First of all I would stop bme (when battery is low) to give battery chip chance to calibrate. Then it's a matter of few full charge discharge cycles.
Turning on/off display is very power hungry so maybe lower your brightness next time.

Re: Trouble calibrating my new N900 battery
 

Why will the battery not calibrate with bme on?
Will it be enough to modprobe -r bq27x00_battery (using the bme replacement)

You think that turning the screen on caused vdq=0?

Re: Trouble calibrating my new N900 battery
 

Its explained here http://talk.maemo.org/showpost.php?p...&postcount=846. BME can turn off device before calibration complete but AFAIK Pali's BME replacement have different voltage threshold and it working better.
Still you need avoid high pick current which could lead to decrease voltage and cause turn off.
I am not sure about display and vdq issue but turning it on lead to ~10mA -> 200mA so voltage can drop.
I have never serious problems with battery calibration. With stock BME I just disable it and leave phone with display on and low brightness until it shutdown. Similar with bme replacement but I don't need to disable anything. Try 2 or 3 times and there is no way it will not work.

Re: Trouble calibrating my new N900 battery
 

Left for the night yesterday, with ~3500 mV, VDQ: 1. With disabled GSM, screen on the lowest brightness. Woke up, voltage ~3450 mV, VDQ: 0. :(

Re: Trouble calibrating my new N900 battery
 

Which battery do you bought and from where?
It can be very useful.

Re: Trouble calibrating my new N900 battery
 

Maybe its because bme replacement. It's well know fact it behave strange e.g. in specific situation it can give you no information about your charge level.
Did you try watch -n 5 bq27200.sh (probably you will need add -f option to i2cget commands)? It will give you much more info.

From documentation:
A learning cycle can be disqualified by any of the following conditions:
1. Cold temperature: Temperature ≤ TCOMP[3:0] (°C) when the EDV1 threshold voltage is reached.
2. Light load: A capacity learning cycle is disqualified if average current is less than or equal to 2 times the
initial standby load when the EDV1 threshold voltage is reached.
3. Fast voltage drop: VOLT ≤ (EDV1 – 256 mV) before EDV1 is set.
4. Excessive charging: Cumulative Charge > 255 NAC counts (910 µVh) during a learning discharge cycle
(alternating discharge/charge/discharge before EDV1 is set).
5. Reset: VDQ is cleared on all resets.
6. Excessive self-discharge: NAC reduction from self-discharge estimate (0.195%) performed 64 times.
7. Self-discharge at termination of learning cycle. If self-discharge estimate causes NAC ≤ LMD/16, VDQ is cleared.

http://www.ti.com/lit/ds/symlink/bq27200.pdf

Re: Trouble calibrating my new N900 battery
 

I have a maxximus replacement.

I downgraded bme to stock, see what happens here.
What's interesting: vdq turned to 1 before the green led lit!

Re: Trouble calibrating my new N900 battery
 

Any news about a battery? How long it keeped a charge?

Re: Trouble calibrating my new N900 battery
 

Hi,

I removed the BME replacement, on stock BME it calibrated without any hassle, without even turning off BME.

I measured 1282 mAh, so much less than given. But it's not much less than the original battery, and the price is almost the same, so I'll keep it.

On GSM, normal usage, connecting to WiFi on-demand (my normal usages) I get up to 2 days of use.