brainstorm: extending n900 battery life (mods)
 

I just ordered 3pcs 1100mAh backup batteries for n900. Now I started thinking ways to have longest possible continous battery life.

Of course driving battery to the limit and wait until device dies and then switching batteries is an option. but why not consult the community about it. hope we come up with different ideas.

• power over usb to keep device running when switching batteries(experts opinion needed)
• hardmod one battery with connectors continously plugged in and glue it into cover(probably too extreme but doable)
• other way to feed power to keep the device alive during battery switch
• tweaking os for hibernation?!?!

any suggestions?

remember!! also stupid ideas count!!!! there can be a modification that makes a stupid idea brilliant!

Re: brainstorm: extending n900 battery life (mods)
 

I vote for your second option, except I would glue all three batteries together and wire them in parallel and mount to the back of your N900. Of course, then, you must wire three chargers also in parallel to handle the increased current of three batteries.:rolleyes:

Re: brainstorm: extending n900 battery life (mods)
 

that could be solved with a switch. 3 batteries bundled together is so big that one could attach multiple dip/other switches and the size wouldn't chance so much :)

Re: brainstorm: extending n900 battery life (mods)
 

Great idea, except use mini relays instead of the dip switches.:rolleyes:

Re: brainstorm: extending n900 battery life (mods)
 

How about building an external power-pack from the two spare batteries, with a USB cable to attach to the device. Of course you are still left with the problem of charging the power-pack. I've used a PowerMonkey with my N800, but I might need to get a new adaptor for the N900 when it arrives.

Re: brainstorm: extending n900 battery life (mods)
 

OK... Maybe I'm just thinking in the box... but why not just an EXTENDED battery. Or: I have a mini/micro usb charger that's 1700 mah, and I keep it in my bag. OR: I liked the first option. Run the device on USB while switching out the battery and replacing it. That's my fav.

Re: brainstorm: extending n900 battery life (mods)
 

And don't forget the fork-lift for carrying around your N900 (or pants with very very large pockets) :) All those batteries will make a non-negligible mass to carry...

(edit: I approve the continuous supply from the USB port)

Re: brainstorm: extending n900 battery life (mods)
 

Remember, he ordered three extra batteries in addition to the battery that come with his N900. If he decides on building up the external power pack that you suggest, I think he should order three more batteries for even more power!

Re: brainstorm: extending n900 battery life (mods)
 

i know next to nothing about electricity, but would this be possible: having thin wires connected to the surface where the battery connects to the device - to those wires could a second battery be connected (even if only by holding it together) for the short while the almost dead battery gets removed and a third battery gets inserted. alternatively one could try to slide the second battery in place and then quickly remove the wires.

Re: brainstorm: extending n900 battery life (mods)
 

I think I love you. :D

Re: brainstorm: extending n900 battery life (mods)
 

Good idea, except how about using conductive paint that also glows in the dark. Then you can find you N900 in the dark. :rolleyes:

Re: brainstorm: extending n900 battery life (mods)
 

i would be scared from a glowing ghost n900 in the dark... O.o

Re: brainstorm: extending n900 battery life (mods)
 

If you make the wires thin enough, they will glow, but only for a short time.

Re: brainstorm: extending n900 battery life (mods)
 

/me thinks hibernation is cool :-)
That's also the easiest way since involves no hardware modding.
Not that I have any idea how to start though...

Re: brainstorm: extending n900 battery life (mods)
 

Why wouldn't this work? It works with the N810.

http://www.nokiausa.com/find-product...gers/dc-8?r=-1

Re: brainstorm: extending n900 battery life (mods)
 

I'm hoping #1 works. That'll open up so many simpler options:
- external charger\reserve battery packs
- temporary power for battery swaps

Re: brainstorm: extending n900 battery life (mods)
 

Just found this on JR.com, it has a bigger lith-ion rechargeable battery built in, so even more juice for the N900.

http://www.jr.com/nokia/pe/NOK_DC11/

Re: brainstorm: extending n900 battery life (mods)
 

that would be the greatest solution. if it really works that way. because i think new symbian phones will shut down even when charged if you remove the battery...

and bundle 2 batteries together to usb reserve could be the smartest solution. one could first use two batteries with no external gadgets. and when second is wearing out, with external pack one could almost double the uptime(1100+1100mAh vs 1350mAh+1100mAh)....

on an other hand, regulator eats some of the batteries power when connecting 2x3,7v -> >7v and regulating to usb 5v. so it isn't really 2200mAh compared to plugging batteries to battery contactors. maybe the simplest solution would be 6pcs cheap AA-batteries and a 5v regulator just to keep the device running during the change.


could someone confirm that does the device stay on when removing battery while charging?

Re: brainstorm: extending n900 battery life (mods)
 

the hibernation seems a good idea.

the backplate could be extended to the edges of the camera and stand to fit a bigger battery.

the whole case could be painted with CIGS to have it charged or at least assisted.

I dont want the mod to change overall sizelimits to still fit in my pockets and I dont want to carry any additional stuff with me apart of a spare battery (hibernate change)

Re: brainstorm: extending n900 battery life (mods)
 

If it's USB reserve, the link I posted from JR.com has both a USB plug and standard power plug built in on the portable charger

Re: brainstorm: extending n900 battery life (mods)
 

Um wouldnt hibernation kind of defeat the whole point of this device being a phone as well as a tablet. I cant see myself ever wanting to miss phone calls etc.

Re: brainstorm: extending n900 battery life (mods)
 

power consumption in idle is near zero anyway...

Re: brainstorm: extending n900 battery life (mods)
 

well if you say that one can switch battery without hibernation & without reboot, we can close this thread right away.

Re: brainstorm: extending n900 battery life (mods)
 

Not from what I've read :P some blogs say that you can get a few days out of it in standby mode without GSM radio turned on! So... near 0 is far from correct if your phone dies 2 days after no radio usage and in idle-sleep mode.

Re: brainstorm: extending n900 battery life (mods)
 

Hibernation and most suggestions on lesswats.org aren't or are barely interesting on ARM and other mobile/embedded devices. You'd need to write all the data in RAM to swap, and read all that again when powering it up. That uses a lot time, and also resources/juice, while the ARM in idle mode barely uses juice. You might as well leave no application open instead, put all receivers and transmitters off, or only leave voice open for phone/SMS, or suspend an application which uses a lot of resources. When battery almost empty Symbian has option to disable cellular data. Alternatively, something like powertop or iotop or htop could help debug (in SDK or on real device). All these 3 run on Linux/ARM.

A battery pack is interesting. Theoretically one could have one which supports the Nokia charger, but also one which supports USB charging. The latter allows one to also use other devices to charge via USB. However, USB charging is slower than using the official Nokia charger.

You could even use USB on your laptop to charge your N900. Not sure that works when laptop is on suspend or hibernation mode (I doubt it, may depend on case-by-case, hardware guru can clarify hopefully). Why would you do that? Well because you're on the go and your laptop is not required right now whereas your phone is. Then better give juice to the phone then. Or you actually only use your laptop as battery for your N900. Or the reserve battery of your laptop. I think I've seen such 'mods' for iPhone. Problem with reserve batteries is to store them for longer time you need to have them not fully charged, instead 40%, and that doesn't yield much, although OTOH a laptop battery would. And it could be a life saver so to say.

[EDIT]When I was in train from Belgrade to Munich I had only one power source, and I had to switch my laptop and phone constantly (tethering drained the phone's battery). Had I been able to charge my phone on my laptop's USB I would not have to switch them whole time.[/EDIT]

Re: brainstorm: extending n900 battery life (mods)
 

ok so hibernation is totally off limits because it would be probably the same as shutting device down, switching battery and turning it on again.

I think that I'll order a holder 4xAA plus one 5v regulator and usb connector after someone confirms that the tablets stays on when plugged in and battery is removed or then i'll test it myself later when my n900 comes knocking to my door...

Re: brainstorm: extending n900 battery life (mods)
 

I like the look of the PortaPow USB battery, from £17.50. Anyone tried one?

http://www.portablepowersupplies.co....atterypack.htm

Re: brainstorm: extending n900 battery life (mods)
 

if you are going to extend it through portable charger, why not thinking about solar? Either you attach it to n900 or modifying the portable charger.

Also, check this out: http://www.instructables.com/id/DIY-...adio-for-%245/
If someone up to try this, try to link AAA batteries together (I am not sure about 5800/N900 battery size/space so probably this might or work. Anyway linking 4 of AAA's batteries with each 800mAh (you can find higher) this means 3200mAh.

Now for people who are interested to know the difference this will gave them , simply use the ratio to determine your extra running time.

Now if I remember n900 is having 9 hours as a call time (Forget this , unless you want to compare your gain to it) I will consider 6 hours in extreme using

(3200mAh/1350mAh)* 6 hours = 14 hours and 22 minutes in extreme using conditions
now for the talk time:
(3200mAh/1350mAh)* 9 hours = 21 hours and 20 minutes of continues talking

Re: brainstorm: extending n900 battery life (mods)
 

that reserve battery will do just fine, but device will reboot when you switch the battery. I think the HW itself supports the hibernate mode for some seconds, but it's not enabled. Time to start looking at omap3 docs and do some kernel hacking. (eh, for some of you, me, I'm just fine with the battery as it is)

Re: brainstorm: extending n900 battery life (mods)
 

I second external battery packs. Lots of them available already, as previous links point!

I wouldn't use AA batteries, but rechargeable AA cells instead... Think of the environment! Put 4 or 5 of them (4.8V or 6.0V - someone prove me wrong, please!) together, add expensive, top-quality regulator, USB cable, some casing and you're done. First I laughed at chargeable chargers - out lout - but if they pack enough power, they just might save your week...

How about solar cells? Limited use cases, but hey, free power! Also widely available...

Re: brainstorm: extending n900 battery life (mods)
 

With the talk about mAh, what about the differing voltages? i.e. a NiMH battery is typically 1.2v, so 2100mAh isn't the same as a 5v USB battery extender rated 2100mAh.

Re: brainstorm: extending n900 battery life (mods)
 

I've had a look at the solar panels available after not having much luck in the UK with a fairly big twin solar panel charging 5x AA batteries... and the output of such panels maxes out at about 100mA in optimum conditions. Maybe good in LA or somewhere :)

Re: brainstorm: extending n900 battery life (mods)
 

Charging at a distance seems to have become practical, judging from newspaper articles I've seen. Easier charging is almost as good as having a longer battery life.

Re: brainstorm: extending n900 battery life (mods)
 

You need to compare energy. 3.2Ah * 1.2V versus 1.35Ah * 3.7V:

3.84Wh vs
4.995Wh

In reply to another poster, n900 is not likely to function on charger without battery. The charge circuit isn't able to regulate power that way.

Re: brainstorm: extending n900 battery life (mods)
 

I mentioned AAA (AA is more bigger than AAA)
Check this: http://en.wikipedia.org/wiki/Battery...ttery_lifetime
Still, you are right about using battery cells.

By the way, I noticed that I didn't mention what I attended to in my previous post.
I was thinking of replacing Nokia original battery with 4 rechargeable AAA cells and connecting through a circuit where it also takes a power from a solar cells that is mounted on the battery cover (Or mounted in any better place?).

After all, I am sure people won't like to do this mod while their warranty remains unless someone made this in a good product and replaceable.

Re: brainstorm: extending n900 battery life (mods)
 

How about the cases with a battery built in like they make for the Iphone? As soon as the phone is put in the case the phone battery gets topped up.

Re: brainstorm: extending n900 battery life (mods)
 

@kamakazike: I think it'd be way too thick if they design it like the iphone's battery packs (the sleeve designs).

Re: brainstorm: extending n900 battery life (mods)
 

Nokia has a solution for this already (although not available with a USB pug yet)

http://www.mustaporssi.fi/files/midd...iddle_dc-8.jpg

Re: brainstorm: extending n900 battery life (mods)
 

according to nokia, the n900 sales package contains an adapter so you can use your old 2mm charger with n900 too. i imagine dc-8 has that?

Re: brainstorm: extending n900 battery life (mods)
 

how can u use the Nokia charger adaptor (CA-146C) i mean does it charge the battery when pluged ? and how can u charge that adaptor and how much power it contains ?
And is it true that when i get the device its better to charge it 12 hours before real usage ?
thanks