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#11
As far as the e-werk I think you will be dissapointed at the charging rate for a netbook.

For those pointing out the bottle tire sidewall friction dyamos my experience in testing is that a sidewall dynamo is fine for occasional LED safety lighting but will put a noticleble load to drive traditional incandescent headlight and taillight combo or a smartphone on the minimum battery maintinence (not actually charging) amperage.
 
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#12
JBD, the N900 may need a modified charging cable with the data leads shorted if your battery pod doesnt negotiate a charging rate.
Easiest way to do this is to split the outer insulation on a USB cable and use a soldering iron to short the green and white wires together with while carefully leaving the red and black power wires alone. You can seal it up with some shrink tube.
http://en.wikipedia.org/wiki/USB_cable
The E-werk is great for charging a smartphone once you get past the N900 requiring a smart charger to accept power.

Last edited by biketool; 2012-07-29 at 08:40.
 

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#13
Thanks, I will try that.
I found more details on http://talk.maemo.org/showthread.php?t=38230 as well as reports on different cache batteries.

What happens when you charge your Long March battery pack with the dynamo while it's connected to the N900? If you cycle fast enough, do both devices charge, or the long march charges X minutes then delivers current to the N900 x minutes, or ... ? I don't want to loose any "cycling energy", so the current must go somewhere, either in the N900 either in a cache battery, ideally without changing cable connections.
 
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#14
Both devices should charge.
If you can't pedal enough to keep the long march charging the N900 will still charge until the Long March is flat (which is going to take a while).

Edit...
Just tested this and you can't charge a device and the long march at the same time.

Although I can't test it 100% if you supply the long march with power the outputs disconnect.
When you stop pedalling the input voltage will drop and the long march will start charging the N900 until pedalling resumes.

You could therefore ...
...have a switch on the lead supplying the long march to kill the supply and start charging from the long march.

...create a switching arrangement that will switch the supplies around so you can keep both charging or only the long march charging with the above arrangement.
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#15
Originally Posted by quipper8 View Post
[...]

Seems like it would be an even better system if there was storage inbetween, like a DC-8 strapped on handlebar between dynamo regulator and phone so the dynamo charges the dc-16 and the dc-16 charges your phone constantly anyway. I suppose eventually you would need to charge the dc-16 manually, but it should go for a long time.
don't know about DC-8, but DC-16 simply won't do
it can't charge & discharge @ the same time

side note: the DC-16 i got a couple days ago has nothing close to the promised 2200 mAh
barely makes it to 1100 after two complete charge / discharge cycles
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#16
I have not tried the whole system together, maybe I need to make a bypass system that wont try to force power into the USB out port but will funnel power direct to both the phone and pod when the dynamo is turning.
Sadly many of these battery places flat out lie, fortunately we have guys like Dr_Frost_dk doing tests for us.
 

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#17
Maybe i should my N900 in the E-Bike build im doing, i will be using it a few times to get speed measurements from one off those SPEED gps programs

But im not going to use a dynamo when i have battery's on board , also the dual scud last enough time for me
 
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#18
Hello everyone.

I've been charging my N900 from solar for the past year or two using various methods. I am currently doing final testing of my proto USB solar charger Maximum Power Point direct regulator which charges to a maximum of 800mA from a 5w solar panel (ie %80 efficient into the battery). Before I tried this I direct charged my batteries in an adapted external charger. An external charger can be easily modified to run off a bicycle dynamo with a low dropout full-bridge dynamo and some decent capacitance.

When designing any solar or alternative power solution there are two things to consider, the load and source. Work out exactly what your requirements are--the load--and design an appropriate charging solution to meet those needs in the required time-frame--the source.

First thing with a Nokia N900 (N9 too?) charging solution is this. You absolutely need to short the data lines out. Most off-the-shelf chargers do not have this. You need to open the charger up and either solder the data pins (bear in mind this will render the charger useless for i-poh) or make a special charging cable.

There are also several other factors which determine whether the Nokia N900 will charge properly. There are multiple factors at play here but the main thing to remember is that the phone does actually negotiate with the charger to see if it can supply enough current (it seems to do this more than once actually). The first time this is checked by the phone is to see if the power supply cannot at least a few hundred mA in the first few seconds. If the phone senses the charger cannot supply this current it clamps the charging current at 100mA (95mA exactly). Ie if the phone senses that your charger is not capable, your phone will be little more than "trickle-charged" during the duration it is plugged in.
After that it seems to do another check a few seconds later at 500mA, if alls well it can accept a sliding range of current above 500mA which seems to be dependent on a couple of things, my guess is the main one is current the SoC (State of Charge) of the battery at any given point.

If you think this is battery charging hell, you should see what the i-people have to do to get their devices solar charged.

Here is a helpful page
https://en.wikipedia.org/wiki/Univer...rging_adapters
 
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#19
Hello everyone.

I've been charging my N900 from solar for the past year or two using various methods. I am currently doing final testing of my proto USB solar charger Maximum Power Point direct regulator which charges to a maximum of 800mA from a 5w solar panel (ie %80 efficient into the battery). Before I tried this I direct charged my batteries in an adapted external charger. A home-built external charger can be easily modified to run off a bicycle dynamo (as opposed to off a solar charger) with the addition of a low-dropout full-bridge rectifier and some decent capacitance.

When designing any solar or alternative power solution there are two things to consider, the load and source. Work out exactly what your requirements are--the load--and design an appropriate charging solution to meet those needs in the required time-frame--the source.

Every single solar charger bar 1 or 2 on the market right now are glorified external battery chargers with a little bit of solar attached designed to look good. The best way to do solar properly you have to do it yourself (I realise this thread is about dynamo charging but many of the same principles apply).

First thing with a Nokia N900 (N9 too?) charging solution is this. You absolutely need to short the data lines out. Most off-the-shelf chargers do not have this. You need to open the charger up and either solder the data pins (bear in mind this will render the charger useless for i-poh) or make a special charging cable.

There are also several other factors which determine whether the Nokia N900 will charge properly. The main thing to remember is that the phone does check the charger to see if it can supply enough current--it seems to do this more than once actually. It's been mentioned that the phone "negotiates" as per the USB spec, which in effect it does do, but there is no bus or data communication between the phone and the charger to enable this process. The first time the charger is checked by the phone is to see if the power supply can provide at least a few hundred mA in the first second or three (yes that quick). If the phone senses the charger cannot supply this amount of current it clamps the charging current at 100mA (95mA exactly). Ie if the phone senses that your charger is not capable, your phone will be little more than "trickle-charged" the duration it is plugged in.
After that the phone seems to do another check a few seconds later at 500mA, if alls well it can accept a sliding range of current above 500mA which seems to be dependent on a couple of things, my guess is the main one is current the SoC (State of Charge) of the battery at any given point.

If you think this is battery charging hell, you should see what the i-people have to do to get their devices solar charged.

Last edited by independent; 2012-08-16 at 23:13. Reason: for clarity
 

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#20
Originally Posted by dr_frost_dk View Post
Maybe i should my N900 in the E-Bike build im doing, i will be using it a few times to get speed measurements from one off those SPEED gps programs

But im not going to use a dynamo when i have battery's on board , also the dual scud last enough time for me
Just curious how much time are you getting off of a double scud now?
 
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