Try to charge, LED flashes orange once, phone doesn't boot?
 

Hi,

I've got two of my three batteries into a weird state. When I put them into the N900, it refuses to start: no white LED at all. When I plug in the charger, the orange light very briefly flashes on once (in fact, it seems more intensely than usual), and then it's dead.

Using a multimeter I can see that there is power in the battery: I've tried the battery with 3.5V, 3.7V and 4.08V and 4.22V. At all of those voltages the two batteries behave as above. I also found I can run my N810 off these batteries (using an ingenious system of elastic bands).

My third battery still works fine.

The way I got the batteries into this bad state was by charging them in an external USB charger: one of those little keyring charger gadgets:

http://www.sourcingmap.com/mininatur...n-p-27419.html

It seems it may be overcharging slightly, up to 4.22V. But what I noticed is that when I only charged the battery a little way in the charger, the N900 did boot from the battery, but shortly afterwards crashed. So it seems like something had already gone wrong.

So my questions are:

* Does anyone know what that brief orange flash means? Is it a particular message from the firmware, or is it just some piece of power circuitry dying?
* How can the N900 possibly "know" that I've been charging in the USB gadget, given that the N810 is perfectly happy to use them?

Thanks for any help. And if anyone else is thinking of using one of these keyring chargers, I would highly recommend not doing so!

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

The charger chip in N900 has direct path to make orange on the LED, but I imagine normally the led would be under software control and driven by the dedicated led driver.. FWIW, the led flashes for me when I plug in charger with powered-on N900 too.

Out of interest, could you measure the resistance between - and third pin on all your batteries? Would be interesting data..

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Interesting that the LED flashes on your phone, it doesn't on mine when it's powered on. It might be meaningless. My next test will be to put in a dead battery and leave it plugged in overnight, maybe some magic will happen.

The resistance is 100kOhm, on both my "dead" batteries. It's 120kOhm on my BP-4L batteries for the N810, and 47kOhm for BL-5CA.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Visual inspection of the terminals on the battery, comparing the 3?

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Holy crap! After all that trouble, you're right, it was just physical damage to the pins. There's nothing visible, but a little wiggling with a safety pin to push the clippy bits closer together, and now it works. Hooray!

I guess this means the little USB gadget is OK, provided I don't use it too much and I bring a safety pin with me when I travel. If I keep wiggling the pins like that they'll wear out eventually, so it's just a question of how much the portability is worth to me in replacement battery costs.

Thanks for the help, and I definitely learned some stuff :-)

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

OK, a couple more points to clear up, for anyone else who finds this thread.

The brief orange flash when you plug in the charger happens if you take out the battery completely and plug in the charger. If you see it, a bad connection to the battery is a plausible explanation.

The other symptom I saw was that after charging, it would work for a while, then I would look at it later on and see it had mysteriously turned itself off. I thought it was crashing, but probably it means that it was bumped and the terminals disconnected.

My USB charger has triangular terminals that look almost designed for spreading the battery clips too far outwards:

http://mat.exon.name/diagrams/20100324_003.jpg

I also have a desktop charger, unfortunately far too bulky for my purposes, which has blade shaped terminals like the ones in the phone. Obviously this latter design is far more sensible.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

I guess it would work better if they were rotated 90 degrees and made a bit smaller..

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Just wanted to quickly check if the ORANGE LED is meant to flash even when the display is on? In mine, I have noticed recently that the LED flashes only when Display is off or the Phone itself is OFF. I am not sure if it has happened recently or is this the way it shud function? can we change it so that it flashes always as long as charger is charging the mobile? other led notifications look fine.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Yes it's normal that it's only active when screen is off.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

My N900 got the same recently, my battery is about 3.4 and my phone won't turn on, it's been charging in a very similar charger like the one used by matthew_exon, but my battery is taking hours to charge or I don't know what else, maybe it is death already...

how can I test the battery? not a single 5800 around me, no x6, don't know what to do next...

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

i had the same orange flashinng led issue too few weeks ago and solved it by charging my battery with 5800 for 15minutes. the battery was simply too empty to get even the charging mde booted ;)

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

I had a similar problem, bright orange LED flash on a dead N900 followed by weak red flashes when plugged in.
I wiggled the battery contacts with a safety pin and reinserted the battery, started with about 60 seconds of steady orange LED then the normal pulsing orange.
<few minutes later>
I can now boot up, must have done something when frequently switching between a prepaid sim and the sim from my laptop modem.
I will still need to replace the fall damaged microUSB port to make charging reliable, it requires being set on a book with the cable drooping a bit to charge.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Still having charging issues, sometimes I can boot sometimes I just get the weak red LED flashes. If the USB port is wonky will it show charging when the phone is on or off when the data pins are connected but ground or power are not?

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Flashes are the battery charge chip signaling error.

Just connecting d+ d- together doesn't make bme think charging is happening..

However, having all pins properly connected and then disconnecting gnd or +5V might make the charger chip immediately stop charging, but enough voltage to remain for several minutes to make bme think there's external power available.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Shadowjk,
Then I hope that the replacement USB port when it arrives and is installed will work better. The stock USB port on my used N900 has always been a little wonky and required perfect positioning to get it to charge.
I have finally been able to get host mode working withing the last few days since I repaired the broken USB port and I was worried that this may have started when I had host mode running and added auxiliary power form my laptop USB port to power a portable hard disk.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Hi shadowjk

Do you have more experience with this short orange flashes?
I am building my own external battery with a small DC-DC converter, making 5V out of 2x 3.7V Li-ion cells.
When I put my N900 on, I get 2 or 3 short orange flashes. The phone sais its getting charged, but no current flows. Having a look on my oscilloscope shows that my 5V are steady (as designed), but every time the orange light flashes I can see a power surge ( <2ms) and the voltage drops quickly down to 4.1V. This could be just due the needed power for the LED or it could also be the "intelligence" of the bme.

Any clue how to get it charging despite of that?
My dc-dc converter can supply 5.0V constantly with a load up to 1A, so that cant be an issue.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

Yeah at 4.1 it's probably flashing for "Undervoltage" error.
A led wouldn't use much power.

Try add capacitors on your output as close to N900 as possible?

I myself built a pack out of a 11.1V rc lipo battery and a 5V/3A RC UBEC, and that seems to work.

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

I tried to solve it with adding enough capacity to the output voltage, wasn't happy with the needed physical space. I I was controlling the PWM with an microcontroller, the voltage controlling is quite slow (ADC needs time). So I am now going to try it with an MC34063 IC, that should work.

Did you ever calculate the efficiency of your DC-DC converter? How big is it?

Re: Try to charge, LED flashes orange once, phone doesn't boot?
 

The one I used: http://www.hobbyking.com/hobbyking/s...idProduct=3735

The phone charging was a secondary feature. I have two of those powering heated gloves, and one of them also has a usb port for my n900 :-)