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2010-03-28
, 03:47
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Posts: 61 |
Thanked: 60 times |
Joined on Jul 2007
@ Erlangen
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#32
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i use a sonyo eneloop externel battery http://www.eneloop.info/index.php?eI...729fcc5b6fc3a1
that has 2usb out ports. Using an Y-usb cable from a external harddrive with an adapter to micro usb i get up to 1000 mA out of the battery which seems to charge the N900 the same way the Nokia charger does, at least according to batterygraph. The battery has 2000mAh and was about 35€ on amazon, the adapter and the Y-cable should be about 10€. And my impression is that the battry holds the charge without much loss, i left it for about two weeks in my pocket and the recharged th N900 one time without a problem.
that has 2usb out ports. Using an Y-usb cable from a external harddrive with an adapter to micro usb i get up to 1000 mA out of the battery which seems to charge the N900 the same way the Nokia charger does, at least according to batterygraph. The battery has 2000mAh and was about 35€ on amazon, the adapter and the Y-cable should be about 10€. And my impression is that the battry holds the charge without much loss, i left it for about two weeks in my pocket and the recharged th N900 one time without a problem.
__________________
things we learned from movies
38) No matter how badly a spaceship is attacked, its internal gravity system is never damaged.
things we learned from movies
38) No matter how badly a spaceship is attacked, its internal gravity system is never damaged.
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2010-03-28
, 08:02
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Posts: 22 |
Thanked: 2 times |
Joined on Aug 2008
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#33
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riderman,
are you planning to use NiMH cells? You will not get so much runtime from the alkaline ones.
Some 18650 Li-Ion cells (e.g. from DX) would be even better.
Let`s see, for how long 3 AA Alkaline run the device...
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2010-03-28
, 09:03
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Posts: 1,258 |
Thanked: 672 times |
Joined on Mar 2009
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#34
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Originally Posted by myk
From my observations of N8x0, the charge regulation is done through a slow PWM (about 1Hz). Even if the software set it to the lowest, 1/255, there'd still be a huge current flowig into the battery for 4msecs every second or so..
That is not clear to me.
Isn't it up to the device to draw it's desired current? The charger cannot choose both voltage and current.
Are you saying that the charger is expected to enforce the 950mA current limit? I thought the device would do that.
OK, it is making a bit more sense as I think about it.
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2010-03-28
, 09:26
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Posts: 293 |
Thanked: 76 times |
Joined on Jan 2008
@ Fremantle, W. Australia
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#35
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Originally Posted by riderman
You seem to be under the impression that primary cells last longer. That was true once, but I believe that rechargeables now have a greater capacity than alkalines.
No, my main goal is to be independent from charging-possibility for some days.
The 1.8V lithium AAs have good capacity, but are expensive.
If you want to keep the weight down, just use Li-Ion.
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2010-03-28
, 09:51
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Posts: 909 |
Thanked: 216 times |
Joined on Nov 2009
@ Bremen, Germany
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#36
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Originally Posted by riderman
actually, a few days ago i saw a tv-report on useful gadgets, and they were testing a solar-charger. it was basically just like the official external charger form nokia, just that you dont load that on the wall, but by the sun. and even though it was cloudy, it was loading the battery with full 5V.
The solar-stuff looks cool. But: too expensive and bad for cloudy days.
i guess its worth a try.
i think the other dead sure solution would be one of those devices you have to wind up to generate electricity. takes a lot of time though...^^
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2010-03-28
, 09:53
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Posts: 1,258 |
Thanked: 672 times |
Joined on Mar 2009
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#37
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Li-Ion vs alkaline is a nobrainer, Li-Ion wins.. In extremely low-drain situations, it might be a dead race..
Not sure about the situation with primary 3.6V lithiums.. But I'd be nervous about using those anyway due to safety..
Not sure about the situation with primary 3.6V lithiums.. But I'd be nervous about using those anyway due to safety..
Isn't it up to the device to draw it's desired current? The charger cannot choose both voltage and current.
Are you saying that the charger is expected to enforce the 950mA current limit? I thought the device would do that.
OK, it is making a bit more sense as I think about it.