N900 Wireless Charging - Page 2 - maemo.org

pichlo | # 11 | 2014-06-04, 21:48 | Report

A naive question here: can a charger like that be applied directly to the battery and bypass the N900's USB charging circuit altogether, as per sixwelledbeast's post #2? I too would like to keep my phone intact but I would not mind sacrificing one of my many spare batteries for the experiment.

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woody14619 | # 12 | 2014-06-04, 22:51 | Report

Speaking of huge... Mind the size of the pad. Some are wider than the N900. Consider orientation and dimensions when making your selection as well.

woody14619 | # 13 | 2014-06-04, 22:59 | Report

Originally Posted by pichlo View Post

A naive question here: can a charger like that be applied directly to the battery.

I'm going to say "unlikely". AFAIK the battery still needs its charging current/voltage to be setup properly to do charging, and a chunk of that circuity is in the phone. Someone with more battery experience like Dr_Frost_DK may have better insight on that than me though. Even if it could direct connect to the terminals, I'm not sure it could do so in a live system, where the device is drawing at the same time.

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pichlo | # 14 | 2014-06-04, 23:06 | Report

Thanks Woody, that's exactly where I was heading with that question. I would not expect to connect the receiver's contacts directly to the battery contacts. But, assuming some magic circuit between the two, would the phone's firmware be able to cope with it? Reporting the correct charge, for example?

Akkumaru | # 15 | 2014-06-05, 00:08 | Report

Originally Posted by biketool View Post

I can say that when installed the Palm Touchstone wireless charging is the bees-knees!
I had it on a N900 with broken USB port and while it is tricky filing down the charge control board to fit inside a Mugen cover with a double Scud battery it is worth is in the ease of use. Clunk and charge overnight, dead easy and no worry about falling onto the USB cable.

But Palm Touchstone only works with it's charger, right?

biketool | # 16 | 2014-06-05, 05:30 | Report

AFAIK the Touchstone only works with Touchstone chargers. Are you seeing another brand in the wild for public use similar to free WiFi?

I did get an email from Estel on a BME trick for enabling charging in software though it seems that it enables a dumb high draw mode which would possibly undervolt the charging system.

Originally Posted by

Hi there, biketool.

I'm writing in stead of Estel - he wanted to reply you since noticing your question in BME replacement thread, but wasn't able to, due to obvious reasons. Here comes his message:

"
It is possible to force device into charging with full power without shorting data pins, if one is using BME replacement. It's as simple as:

Code:

echo dedicated > /sys/class/power_supply/bq24150a-0/mode

BTW, from memory, the possible states of "mode' there may be 'auto', 'dedicated', 'host', and 4th one for client, that I don't remember now. Anyway, when it's 'dedicated', it tries to charge with dedicated charger's power, so don't connect it to PC without reverting to 'auto', or you will get overcurrent prompts from your desktop OS/blown fuse on motherboard.

This setting doesn't carry on through reboots, so either create script/desktop shortcut/widget for it, or event.d script to run it automatically on every boot.

I would like to hear thoughts on using this from BME experts

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Akkumaru | # 17 | 2014-06-05, 05:43 | Report

BTW, are the two contact points of a qi receiver a D+ and D-?

Wonko | # 18 | 2014-06-05, 06:23 | Report

Originally Posted by Akkumaru View Post

BTW, are the two contact points of a qi receiver a D+ and D-?

Well, at least some more words of warning:
Be very sure to know what you are doing as the pins that are accessible underneath the battery do not have any protection circuits, iirc.
See also a link to a post by joergrw in the thread I linked before.
Also have a look at the USB pin-out.

In the end, you do this all on your own risk and responsibility.
There may be many subtle pitfalls that may result in sub-optimal behavior or even worse, e.g., components getting hot or the battery not being fed with the right current/voltage may even result in fire or the like.
As another example: voltage drops at components you put in the circuit may result in a too low voltage for charging etc.
So, while there are reports of working configurations, in the end, everyone does this on her/his very own and may experience widely varying results.

So, to repeat: be sure to know what you do and be aware that you do this on your own responsibility.

Last edited by Wonko; 2014-06-05 at 06:28.

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Akkumaru | # 19 | 2014-06-05, 06:38 | Report

Yep I read all and a lot about USB today, because currently I'd have to take out my battery to charge it. So I've been finding different ways to charge the battery, from repairing the micro-usb, to creating a new usb connection and wireless charging. So far it seems like Touchstone is the safest, although it only works with it's own charger. So if that charger goes missing, I'm doomed and have to order another charger. Creating a new usb connection seems interesting enough, but I'd really like to implement wireless charging. Not sure to go with qi, or touchstone.

biketool | # 20 | 2014-06-05, 07:12 | Report

Akkumaru, is there a more common charger that you are finding compared to Touchstone?