[Gta04-owner] charging gta04 on my bicycle

Michael Spreng handheld-linux at m.spreng.ch
Sat Jul 12 01:18:33 CEST 2014

On 11/07/14 18:37, Andreas Kemnade wrote:
> Hi,
> On Fri, 11 Jul 2014 08:55:10 +0200
> "Dr. H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>> Hi,
>> the charger is a little critical about the VBUS voltage. It reports an issue if >5.2 V and drops charging if <4.4 V.
>> But charging is only (re)started if VBUS goes below ca. 1.5V.
>> So there is a situation for VBUS voltages where it does not charge even if you have 5.0V.
>> Andreas has modified things to make it work on a bike:
>> http://www.ohsw.de/gta04-otg.pdf
>> http://www.ohsw.de/gta04-bike.pdf
> Just the most important things at a glance:
> echo on >/sys/bus/platform/devices/twl4030_bci/lin
> is the key to charge at a bike. That will give around 500mA.
> Then it tries to charge with whatever voltage Vbus is. You should turn
> that off again after cycling.
> I did a lot of experiments with my bike+electronics. So you see a lot
> of things in the slides which is not necessary for just charging the
> gta04 with a hub dynamo. I started to cycle with a gta0X in the Summer
> 2008. So that presentation is a bit of a summary of all things I tried
> out. 
Thank you all for the answers and information. I will try this

echo on >/sys/bus/platform/devices/twl4030_bci/lin

and report on how it went. I probably won't have time to solder extra
hardware unfortunately. Thanks for the links to the presentations, nice
to see that I'm not the only crazy one trying to hook up my GTA0x to a
dynamo :)
> btw: That photo with me and my bike near the north cape tunnel was also
> taken by a swiss cyclist doing a long trip
> One thing about airport security: In Stockholm-Skavsta I boarded a
> plane with the electronics dismounted in 2008, In Trondheim (Norway) I
> left the electronics at the bike (with the hub dynamo disconnected)
> while boarding the plane in 2011. Both times no problems.
I will travel by train to Budapest, so no concern with airport security
fortunately ;) Then I will follow the Donau back to its source.

> That is a good reminder to finally put my schematics online.
> Greetings
> Andreas Kemnade

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