charging Time on the N9
 

Hi,

I have a Denmark version of the N9 with a UK adaptor.

How long should it take to charge? Mine seems to take between 2 and half hours to 3 hours from completely dead!

The first 30% is done within 30 minutes (as i have power saving mode on at 30% and it wakes up making the low battery noise!)

The plug is warm to touch while charging and gets cooler nearing the end!

I thought the N9 was meant to be relatively fast charging as my girlfriends iphone only seems to take an hour!

thanks in advance for any help!

Edit: Just did some readings during the charge, i get

30% in 30 minutes
57% in 1 hour
90% in 1h50m
97% in 2h30m
100% in 2h40m

seems to slow down! I'm sure this is normal, but it does seem like a long time to charge!

Re: charging Time on the N9
 

Well, there is another side of the equation - life time of the battery. The faster you charge it (i.e. the higher current is used for charging), the faster battery capacity is degrading (this is relative of course).

The battery is not very easily replaceable in Lankku - you need to partially disassemble device to reach it and for doing that some certain skills are needed. So, the less frequent will be the need to do that, the easier will be it's owner's life.

And yes, the speed of charging is decreasing as the charge is closing to the full capacity.

Comparing to N900 (which has an easily replaceable battery and, thus, higher charging current), N9 takes more time to charge, but leaving both on a wall charger over the night gives no noticeable difference. At least for me. :)

Re: charging Time on the N9
 

I just got a kindle and it came with a 1.8amp charger.
If I connect this to the n9, will it current limit itself to 1Amp just like the normal charger. I know batteries are charged with constant current. But the hardware may CONTROl the current internally to its liking, considering nokia is an excellent engineering company, I am sure they have a internal limiter. Can anyone CONFIRM?

Re: charging Time on the N9
 

I confirm, I use my white Kindle power cord (is not really "a charger", is just a USB cable with a detachable outlet plug) to charge my Nokia N9 and everything is fine.

Disclaimer: KINDLE 3, the one with the keyboard, purchased last year. Proceed at your own risk.

Re: charging Time on the N9
 

It doesn't matter because this was standardised last year or 2, when most electronic makers decided to use this micro usb-charger model across all devices they make.

Re: charging Time on the N9
 

The cable doesn't matter, what are you connecting it TO?

Re: charging Time on the N9
 

The connector wiring and connector type were standardized. I am just asking does the n9 do current limiting internally?
I am sure it does, buy I just don't want to ruin it, so I need some confirmation. Since I have no warranty in the US.

Re: charging Time on the N9
 

Oh sorry, yes to that too
It has to or it would destroy the circuit
I'm certain this has been done since years ago, so no reason to change it now

Re: charging Time on the N9
 

I'm using a 2.0A tablet charger (HP Touchpad) and I've noticed it charges just as slow as if I use a standard 1A charger, so I think it is doing some negotiating to throttle-down the charging rate no matter what you charger you use.

Re: charging Time on the N9
 

I think some clarification is needed in regards to the term "charger" here.

Many modern batteries have a dedicated chip inside, which is controlling it's charging process, collects usage statistics and keeps track of remaining battery capacity (life time wise). Good examples of such batteries are notebook batteries. As the process of charging is controlled by that controller, which is limiting charging current (changing it in different phases of charging process), it's not possible to change charging current by using more powerful power supply. It will work other way around though - less powerful supply will limit the maximum charging current till the moment, when it dies because of overload (if it has no overload protection).

Most (if not all) modern mobile devices have charging controller built in into them (not the battery, as doing that would increase battery's size). The "charger" as we call it is in fact just a power supply. By using more powerful power supply we are changing nothing (except, maybe, the efficiency of the energy use, as usually power supplies have their maximum efficiency at their nominal load).

The term "charger" probably comes from those times, when the charging logics was inside of the external charger also for the phones. In that case, usage of the non-standard charger for a particular phone, could provide non-matching charging profile (including usage of higher current) and damage the battery this way.

On the other hand, using charger/power supply with different output voltage (especially higher then expected) will most likely lead to unpleasant results (device and/or battery damaged/destroyed, power supply damaged/destroyed, your house burned down, etc). So, that should not be ever done.

Re: charging Time on the N9
 

Good post ototo, that is very informative. Is there a value in regulating charging speed? I've noticed that both my Pre 3 and iPhone4 (I get around it seems) will adjust and charge much faster if I plug them into the higher output wall adapter. The N9 is much pretty much constant no matter what. I'm assuming that allowing faster charging can be harmful to the lifespan of the battery, is that true?

Re: charging Time on the N9
 

It's a balance between the time needed to charge the battery and longevity of it's life. Besides that, depending on the current capacity and the level of discharge, different charging algorithm might be used.

AFAIK so called "rapid chargers" (those for standard batteries, e.g. AA, AAA) are using pulses of high current in some particular pattern to charge faster. I don't have any factual information on how that affects battery lifespan, but I'm pretty sure it comes with a price.

Same happens with N900 - charging from a computer (by connecting it to an USB port) is noticeably slower then charging from the "dedicated charger". The charging "machinery" there detects the type of the power source and adjusts algorithm.

Again, it's a question of balance.

I haven't checked if it charges faster with a dedicated "charger" comparing to charging from PC's USB port. It might be faster, as more current is available (same applies to special high current USB ports on some USB hubs/notebooks, which provide 1.2 A of current).

BTW, having an AMOLED display on board, device can consume quite a bit of the current provided by the power supply while charging. So, it should be possible to make charging a bit slower, if display will be on and showing some bright image (the brighter is the image, the more power display drains). Adding CPU load to that counts too.

Re: charging Time on the N9
 

Informative indeed.

However, it does not explain the following: if I use an iPad charger (5.1V, 2.1A) my N9 charges more slowly than with Nokia's own AC-16 (5.0V, 1.0A).

So there must be some sort of device identification/"compatibility" going on here. If that's the case, it is pretty annoying.

Re: charging Time on the N9
 

According to USB Battery Charging Specification v1.2, chapter 4.4.3:
where RDCP_DAT is defined in Table 5-3 Resistances as 200 Ohm max.

I have no idea what happens if that impedance is higher than that. If it's very high (e.g. unconnected pins) - the "charger" will not get detected at all (tried with cheap car USB charger).

So, I'd suggest you to measure impedance between two middle pins for both of your "chargers".

Re: charging Time on the N9
 

If the resistance between the data pins is over 200 Ohms, the device will not detect the chanrger as a high current source and therefore limit the current to 100mA. That the current it is allowed to draw from a PC USB port without requesting more power.
Since most wall chargers do not yet follow this new rule, they will only charge very slowly. This is the case with most wall chargers I tested. My solution was to use an USB extension cable and shorten the data wires. This doesn’t hurt at all, even you still would connect it to a computer.


Now, about the charging current:
I created my own external USB battery pack and did some measurement of the charge current. To my surprise, the charging current is highly dependant on the voltage supplied at the USB port. Since I wanted to protect my N900 and N950, I lowered the current to 4.1V. This made the current to go down to 300 mA max, even when the phone battery was completely empty. When I raised the voltage to 5.0V, I now can get 800 mA max. One could go up to 5.25V which is the maximum according to the USB specifications. Since I want to stay on the save side, I will stay at the 5.0V.
This will take maybe 1h for 70..80% and then slow down since the battery is almost full.


Beside of all, the charging electronics in the phone will limit the current. This means you can use any USB charger you have. How ever, if you supply a too high voltage (>5.25V), it might get damaged!

Re: charging Time on the N9
 

@caco3, @ototo

Great info, just finished modding car charger and USB extension cord for iPad charger and charge time on N9 dropped from 1444 minutes to 127!!!

Re: charging Time on the N9
 

Hi all,

Well I tried charging my N9 today with an Ipad charger, and got a message saying that there is not enough power to charge the device! :mad:

Has anyone else had this happen to them before? I live in the US, and thus the charger which shipped with the N9 does not work here.

How are you all charging your N9s apart from sticking it to a computer? Did you get one of those fancy world-plugs? Just a simple adaptor? What worked and what didn't?

Thanks
U_N

Re: charging Time on the N9
 

Whats written on the Ipad charger? All apple chargers I know provide at least 1A which is far enough.

Most likely it doesn’t work due the missing resistor between the data lines. see my post above...

Re: charging Time on the N9
 

I am charging my N9 with a Kindle's charger.

Re: charging Time on the N9
 

Re: charging Time on the N9
 

Totally normal.
Same happens with all devices while being chargedl

Re: charging Time on the N9
 

Yes, it is. When battery i being charged, it's getting warm due to the chemical reaction taking place inside of it. When device is running CPU-intensive applications, it warms up too due to the CPU heat dissipation (circuits are getting heated by the current flow).

So, unless it's getting really hot (might happen in case of very hot weather plus direct sun rays over the extended period of time plus some high CPU load - device will save itself by doing a thermal shutdown), it's fine.

Re: charging Time on the N9
 

Hello, my first post in maemo.org (i'm IT)

To monitor the battery and the terminal I bought BATTERYGRAPH. I do not know how reliable as utility considerations but I would have to do ..
Usually loaded it from off the N9, or the charger and then connected and switched the terminal off. Lately however I put the phone in flightmode and then connect the charger, the results are as follows ...

Connected and then turned off:

http://img.photobucket.com/albums/v674/Fabio1971/A.png

Connected in flight mode :


http://img.photobucket.com/albums/v674/Fabio1971/E.png



Precise: The phone 'was put in office in the evening and back on, switched on the radio about 6.00/6.30 On the morning ..

The first picture (I have several other days and all are equal to this posted) it is clear that the charge is not 'never 100%.

In the other 3 are known as the charge is to reach 100% but after the slow discharge, ie 'lose that 4/5% cold (phone off) ..

I do not know what the program can be reliable but working on the software of the phone I think that there are large margins for improvement in terms of battery life, what do you think?

sorry for the bad translation

Re: charging Time on the N9
 

Batterygraph relies on the data provided my the phone itself, so the values are as good as the data the OS uses itself.
When you switch off the device, obviously no data can be recorded...

There is no reason to switch it off or in flight mode for charging!

Also, most systems never charge up to 100%, because this is bad for the batteries. Usually it gets charged to 90..95%.
This is similar to any other device I had in my hands.

My device lasts on normal usage maybe 1.5 days. How ever I charge it every night to be on the save side. If you keep it in flight mode all the time (how useless this ever might be), it will last several days.

Re: charging Time on the N9
 

n900 charger, any android phone or BlackBerry charger work fine too

Re: charging Time on the N9
 

Old thread, I know, but this seemed like the correct place for this info.

Thanks for the info on the N9 charging requirements.

I purchased a portable mobile phone charger (battery based) and tried plugging in the USB cable. I got the standard message "Not enough power from the USB in order to charge the device".

Thankfully I found this topic.

It seems the Samsung Galaxy Tab also suffers from this issue (or also has the stringent standards compliance).

I have found some cables/adapters to resolve the minimum resistance charging issue. This may be useful for those of us who don't want to have to solder our own cables:

1) Powertraveller Galaxy Tab Cable (Tested, this works)

2) Samsung Galaxy Tab Adapter Wall Charger USB Plug on eBay (not tested)

When using the above cables between the standard USB cable and the charger or portable mobile device charger, normal charge times should be achievable.

I hope that information is useful to someone.

Thanks
:)

Re: charging Time on the N9
 

Yes, normal.
The heat dissipates from both battery and MB (plc, memory, ntw cards...).

Thanks to Nokia for putting such a limitation for the chargers. Remember those cases with phones catching fire due to a faulty battery or charger.
Lithium based accumulators specifically pack a much higher energy density compared to the Ni-MH or Cd, therefore the higher the risk of fire.