View Full Version : [WIP] Power Half (2000 mAh)
I just got parts for my Power Half from Sparkfun. I'll be using 2000 mAh 3,7 V LiPo as a external battery.
Power Cell (https://www.sparkfun.com/products/11231) will be used for charging the Power Half and converting the 3,7 to 5 V. I'll take the JST connector off and solder the battery straigth to the Power Cell. It's possible to add a SPDT switch into the Power Cell to control its state. Total cost for this set is about 30 eur.
There's microusb port in the Power Cell so the Power Half will be charged via it.
I have also some 5 mm Copper Tape (https://www.sparkfun.com/products/10561) to connect the power into Jolla.
Thickness increase will be about 5.5mm. LiPo at the left side in the picture is 1200 mAh.
I don't have enough time this week for prototyping (except taking pics of the parts :D) so you have to wait for next week :)
https://pbs.twimg.com/media/BgSUqtAIIAE6pNU.jpg:large
finally! someone who is gonna give us a battery toh!!
IIRC didn't Jolla say that the phone can supply power to the other half? If so couldn't the phone's USB be used to charge the battery making it a lot simpler?
IIRC didn't Jolla say that the phone can supply power to the other half? If so couldn't the phone's USB be used to charge the battery making it a lot simpler?
It can, but output is 3,3 V and the current which you can draw from the phone is pretty low (300 mA max so it would take ~7h to load the 2000 mAh LiPo). And LiPo requires still a special charging logic so this is the simplest and imho thinnest option (of course custom made LiPo can be slimmer).
I have also started the project, too
http://talk.maemo.org/showthread.php?t=91895&page=3
The problem with the story is the following:
The board what I bought, the charge can not keep up.
However, if you use 2 boards, then the charge is very good and quite fast.
If we compare times your board with my:
Power Cell: 3.3V input
Pulolo: 2.5 v-5v input
Cell Power: 5V @ 600mA max
Pulolo: 5V @ 400/500mA
The smartphone itself has a shot of 1000mA. That's why when I connect only a board, he comes after about 30 seconds, no longer with the charging
Therefore, the Board is very hot and overheated accordingly. When 2 boards that I use, charging is perfected, but still very hot.
Now it would be nice to know if the Power Cell is also very hot and only with a board charging perform continually.
The interesting thing about the Power Cell is that he has a Undervoltage lock with it. That is missing in the Pulolo boards.
I'll report here how it performs when I have tested the board.
CSD tool shows about -780 mA and the board gets pretty hot but continues to charge. However, I'll probably find somewhere a boost converter which is capable to ouput 1 A. I have charger-only boards from Adafruit too so I'll just need the 3,7 -> 5 V (1A) boost converter.
Power Cell would work if the current could be limited via Jolla but as far as I can see that is not possible. Of course one can use it, but it gets hot and probably has some efficiency problems at those output levels.
Edit: I think this will do: http://www.ebay.com/itm/New-1pcs-1A-3V-to-5V-DC-DC-Converter-Step-Up-Boost-Module-/191014690726
shadowjk
2014-02-13, 15:57
Anything able to throttle down voltage when approaching overload or overheat should work well...
i order two now two from them from HK, shipping will take 2-3 weeks :(
Wasn't there problems with the charging via the pogo pins? With charging going on and off all the time?
Wasn't there problems with the charging via the pogo pins? With charging going on and off all the time?
No problems during my 15 min test. Only that Sparkfun board got a bit hot, could not touch it.
No problems during my 15 min test. Only that Sparkfun board got a bit hot, could not touch it.
Okay, did you go to 100% charged?
Okay, did you go to 100% charged?
Battery charged from 54 % to 63 % if remember right during the test.
Wasn't there problems with the charging via the pogo pins? With charging going on and off all the time?
pogo pins? with 2 pulolo boards works good and charge, too. It is only little bit hot. I think its to hot if you have the phone in the pocket from your pans :D ... maybe good if its winter.... maybe we can say, that it is a winter feature :p
Got yesterday those boost converters from China. From my endless scrap box I harvested Sparkfun single cell LiPo charger (https://www.sparkfun.com/products/10161).
I modeled last night the Power Half 3D model (EDIT: https://github.com/skvark/TheOtherHalf/blob/master/thepowerhalf.stl) and printed it today. Rest of the stuff was just pretty much soldering and gluing.
There's a power on/off switch at the bottom right side (there's inset so you can't turn it on or off accidentally) and USB terminal for charging.
Charging will light up bright led in the bottom left corner. When power is on there's less bright led at other side. Those leds are embedded to the Sparkfun board and to that boost converter board.
The power switch cuts the power between those two boards so the setup works in these modes:
Charge the phone only from the Power Half
Charge the Power Half only
Charge both simultaneously
CSD tool shows -780 - -790 mA charging current. The boost converter gets a bit warm but not too hot.
Costs for this setup were around 32-35 USD (23-25 EUR). Can be lowered by designing all-in-one board which has LiPo charger circuit + 1A 3,7 V -> 5 V boost converter. Unfortunately I don't have time to do it :)
Parts:
- Sparkfun single cell LiPo charger (https://www.sparkfun.com/products/10161)
- 1 A boost converter (http://www.ebay.com/itm/New-1pcs-1A-3V-to-5V-DC-DC-Converter-Step-Up-Boost-Module-/191014690726)
- Copper tape
- 2000 mAh LiPo (https://www.sparkfun.com/products/8483)
- wire
- some SPDT power switch or something else
Pictures: http://relativity.fi/jolla_power/
http://relativity.fi/jolla_power/power8.JPG
If you ever get the sudden urge to produce and sell these, don't fight it. I'd sign up for one :)
Short demo: https://vimeo.com/88590219
I want this so bad!! It looks really awesome... I need it for my looong trips.
Are you thinking about producing at big scale? I mean,the final version
I want this so bad!! It looks really awesome... I need it for my looong trips.
Are you thinking about producing at big scale? I mean,the final version
I don't have resources or time to produce these on large scale :( But that's why I provided part list, 3D model and other info so you can build one yourself.
zlatokosi
2014-03-11, 16:30
But that's why I provided part list, 3D model and other info so you can build one yourself.
Thanks for all the info and hard work. Please keep us updated on how it's working out (charging/battery time/other quircks...).
Hi,
Very good work!
Can you build one for me please?
Thanks
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