Re: Jolla Solar Half prototype
 

You need an energy harvester ic in order to make this work.

Have a look here https://www.youtube.com/watch?v=lrELRVFEx_s

Re: Jolla Solar Half prototype
 

I would personally use LTC3105
http://www.linear.com/product/LTC3105

Re: Jolla Solar Half prototype
 

Hi,
it seems that my first version had swapped + and - although i have checked several times i did it wrong :confused:

Yesterday i redid the whole thing from scratch again. This time i used plasticine for precise copper stripes position and verified with 4.5V battery that charging works - and it worked.

After attaching solar panels it showed no activity under lamp, but later on direct sun the phone vibrated and displayed charging dialog + the white led was shining.

This is ok, but i havent seen that battery charge raised. In idle my jolla normally eats ~7mA, the panels should deliver 25mA so the charging current should be ~18mA. But i wonder if the phone is really idle while charging. And i wonder how to measure it...

Thanks for the link - interesting, but i wonder if it will fit somewhere under the cover...

Re: Jolla Solar Half prototype
 

To get 1% more charge (21 mAh), you have to keep the panels in direct sunlight for over an hour.
18 mA is very very slow charging rate.

Re: Jolla Solar Half prototype
 

Did you mean 21 mAh :)?

Indeed. Assuming 6V (being generous here, the real voltage must be much lower), it means only 150 mW (6V x 25 mA). That's about an order of magnitude less than what I would expect. Either the light level was very low or the panels are too small (covering less than 10% of the back space), particularly poor quality or damaged by the previous experiment with reversed polarity.

Re: Jolla Solar Half prototype
 

Yeah :)

@psonek, could you look what the phone says about the voltage now that the polarity is right (cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin)?

Re: Jolla Solar Half prototype
 

I'm a bit afraid the whole thing will become hot. When I put my WakaWaka in the sun, it will be hot in an hour. Make the solar panel or the OH detachable so the phone can get some shade? :cool:

Re: Jolla Solar Half prototype
 

ehhh

http://www.quickmeme.com/img/e5/e564...df619d4b84.jpg

isn't this the case for every solar oh??

either
-accept it (join the sunny side)
or
-make a detachable third-half with solar panel and battery

Re: Jolla Solar Half prototype
 

[root@jolla nemo]# cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin
Result:4314054 Raw:32057
[root@jolla nemo]# cat /sys/devices/platform/msm_ssbi.0/pm8038-core/pm8xxx-adc/dcin
Result:4514790 Raw:32399

Mostly the values seem to be between 4.3V and 4.5V

Re: Jolla Solar Half prototype
 

Hi,
after a few days i still have not seen the battery being really charged with my solar toh.

I wonder where is problem. Battery status is "Charging", but current_now is never negative. Even more interestingly while charging it seems to consume more power.

In dark on wifi ssh i get values like this:

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
2595

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
8415

Under lamp while solar charging:

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
10618

[nemo@jolla ~]$ cat /sys/class/power_supply/battery/current_now
11876

Maybe while charging the phone wont enter deep sleep?