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maemo.org - Talk (https://talk.maemo.org/index.php)
-   The Other Half (https://talk.maemo.org/forumdisplay.php?f=59)
-   -   SolarJolla (https://talk.maemo.org/showthread.php?t=91933)

benny1967 2013-12-14 14:12
Re: SolarJolla
 
Quote:
Originally Posted by Oblomow (Post 1392590)
I would say yes, 2h in direct summer sunlight should be enough to charge 20% with such a panel (2Wh minus losses). The pitfall is that you have to direct it at least roughly to the sun's direction, and maybe that your phone does not like getting hot.
So the only thing I need to check is if the phone gets too hot in direct sunlight? Nice.

Because my use case would be like: I'm on holidays and I know the batteries sometimes don't last the whole day. This is, in fact, a typical holiday problem: At home, there's a charger everywhere and I don't use the phone so much. When on holidays, I'm out all day long, no place to charge the phone, weak reception eats battery, I use both GPS and cam a lot more often than at home... Now if I could only help the battery survive the day by exposing it to bright sunlight while I'm having a break at enjoying some ice tea... that would be great.

fip 2013-12-23 12:21
Re: SolarJolla
 
Quote:
Originally Posted by dirkvl (Post 1392299)
Some calculations.

-From this post I found that the phone will run for two days with everything turned off. The shortest day in Holland is 8 hours, so for two days I have 16 hours of sunlight.

The phone has a 2100mAh, 3.8V, 7.98Wh battery, which holds 28728 Joules. This amount of energy has to be restored in 16 hours. The solar-charger thus has to have at least 0.5 Watts of power.

The panel I have in mind right now has 0.935 Watts of power. This panel has to be hooked up to a voltage regulator to ensure a steady 5 volts.

With an input of 5.5 volts from the projected panel, the step-up/down dc-dc regulator has a measured efficiency of +- 93%, which leaves a comfortable .87 watts for the phone.

This is about 175ma @ 5 volts. Your regular laptop usb2.0 does 500ma, so its about 1/3rd of that.
it seems that there was a bug with the NFC drawing too much current - standby time can be 500 hours..

dirkvl 2013-12-23 12:33
Re: SolarJolla
 
Thats good news!

In the solar department:

Making a solar charger is hard... Just connecting a solar panel to a dc-dc 5v converter does not work. The voltage on the solar panel will drop and no power is generated!

There needs to be a current limiting device in between. Like a buck converter. Adafruit makes this one, but it only works with 6v panels (while mine is 9v) and is too big to cram in the OH.

The dc-dc coverter I have already is really tiny, so with a tiny buck converter I am ready to go!

dirkvl 2014-09-03 18:26
Re: SolarJolla
 
Quote:
Originally Posted by dirkvl (Post 1392477)
Pre-ordering the solartoh will start in 2014.
polling for demand

http://oi61.tinypic.com/2ry0bko.jpg

chargemon
03.09.2014 16:22:05.139 34% 40.5°C 3.81751 V -77.957 mA 4.32647 V 0.049704 V
03.09.2014 16:22:05.641 34% 40.6°C 3.81780 V -78.343 mA 4.32647 V 0.049704 V
03.09.2014 16:22:06.142 34% 40.5°C 3.81809 V -77.107 mA 4.32764 V 0.049704 V
03.09.2014 16:22:06.641 34% 40.6°C 3.81751 V -74.016 mA 4.32588 V 0.049704 V
03.09.2014 16:22:07.140 34% 40.5°C 3.81751 V -77.493 mA 4.32647 V 0.049704 V
03.09.2014 16:22:07.639 34% 40.5°C 3.81809 V -77.493 mA 4.32588 V 0.049704 V

pichlo 2014-09-03 19:41
Re: SolarJolla
 
Quote:
Originally Posted by dirkvl (Post 1438140)
-77.957 mA
Is it net? If so then that's actually pretty good. How sunny was it? Was the panel positioned optimally (perpendicular to the incoming sunlight) or just lying flat on the desk?

Sorry I am not buying but only because I do not have a Jolla. If I did, then this would definitely be an interesting accessory to buy. If you ever get around to make a combined solar keyboard one, that might even sway me to buy a Jolla phone :)

dirkvl 2014-09-03 21:19
Re: SolarJolla
 
Quote:
Originally Posted by pichlo (Post 1438150)
Is it net? If so then that's actually pretty good.
Net current at battery ports, actual charging current.

coderus 2014-09-03 21:31
Re: SolarJolla
 
Need some hinges to "open" solar panel to the front.

Markkyboy 2014-09-03 22:11
Re: SolarJolla
 
Nice going dirkvl....I'm interested!, will you be printing in black and how much are you asking per unit?
Regards,

wormdrummer 2014-09-04 00:51
Re: SolarJolla
 
I am interested too. How much and what colour options?

Kabouik 2014-09-04 01:29
Re: SolarJolla
 
Interesting and promising project, given the reported values. For the first time, I won't be one of the early buyer of the new OH around though. Not because I am not interested, but because so far my Jolla happens to hold the charge quite well every day, so I would not need it and I prefer using the other OHs I currently have/will have soon. :) I might be interested after the reviews, or for the kitchen sink OH someday.

Keep up the good work!


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