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Posts: 1,067 | Thanked: 2,383 times | Joined on Jan 2012 @ Finland
#21
Originally Posted by egnat69 View Post
hi! nice work so far!

i wonder how the power management will handle this... usually (i.e. when charging via usb-board) the phone stops charging when the internal battery is full... be sure this also happens when charging via those connectors or you'll end up with some pretty expensive fireworks...

also be sure you don't run into trouble when connecting the phone to a usb-port while this other half is attached (would be double-charging, wouldn't it?)
Charging pins are automaticly disabled when usb cable is connected. And pins have logic that stops charging when its full.
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#22
with Popolu Step-up Regulator U3V12F5.

But Very Importend, use one capacitor 100 uF, i destroy before one regulator, i dont know why, but with a capacitor (vin + gnd) works very well.

i builed in a swither between accu and regulator. i want charge the accu with a palm inductions charger and i dont know how it will handle with connectet regulator.
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Posts: 1,258 | Thanked: 672 times | Joined on Mar 2009
#23
Li-Ion and Li-Poly in parallell are just fine. The important thing is that they are both same voltage when you connect them together, after that they will stay balanced.

Why? Because in lithiun-ion (including lipo) chemistry, the voltage has direct relationship with state of charge, so if you draw 1A from a small battery, its voltage drops faster than the big battery. When the voltage gets even slightly out of balance, the bigger battery with the higher voltage supplies more power. The end result is that both batteries will have become full at the same time when charging, and empty at the same time when.discharging.

Some smartphones and tablets these days use "stacked" batteries, several batteries with different shape and size to fill up as much empty space as possible.
 
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#24
I was thinking about this today and if I'm not totally lost, a simple, mini-usb chargeable external battery TOH could be made for example with these (the phone gets about 8-10 mm thicker from the bottom half):

https://www.sparkfun.com/products/8483
http://www.prodctodc.com/ultra-small...l#.UtVSLLS-FCk

The output usb-port should be replaced with some wire for connecting to the Jolla's 5 V + GND pogo pins. There should be also some protection (voltage cutoff circuit) so that the phone does not draw the LiPo empty. However, I'm not electrical engineer so this is just an idea

Edit: this is maybe better: http://www.adafruit.com/products/259#Description but it does not ouput 5 V
Edit2: all-in-one solution https://www.sparkfun.com/products/11231 Maybe I should do this?

Last edited by skvark; 2014-01-14 at 19:04.
 
Posts: 54 | Thanked: 22 times | Joined on Jan 2014
#25
Originally Posted by shadowjk View Post
Li-Ion and Li-Poly in parallell are just fine. The important thing is that they are both same voltage when you connect them together, after that they will stay balanced.

Why? Because in lithiun-ion (including lipo) chemistry, the voltage has direct relationship with state of charge, so if you draw 1A from a small battery, its voltage drops faster than the big battery. When the voltage gets even slightly out of balance, the bigger battery with the higher voltage supplies more power. The end result is that both batteries will have become full at the same time when charging, and empty at the same time when.discharging.

Some smartphones and tablets these days use "stacked" batteries, several batteries with different shape and size to fill up as much empty space as possible.
so basically frankensteining a second jolla battery onto the existing and covering it with a custom other half should be possible, right? surely, this would mean you'd have to switch your phone off to change from single to dual battery setup... on the other hand you'd have the benefit of a still useful battery percentage on the phone...
 
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#26
It is easier to just have few spare batteries for Jolla...
 
Posts: 1,104 | Thanked: 5,652 times | Joined on Feb 2010 @ Holland
#27
Originally Posted by shadowjk View Post
Li-Ion and Li-Poly in parallell are just fine. The important thing is that they are both same voltage when you connect them together, after that they will stay balanced.
This is an extremely bad idea. Connecting batteries in parallel can only be done with exactly the same type and size. Lipo's are extremely vulnerable.

Originally Posted by shadowjk View Post
Why? Because in lithiun-ion (including lipo) chemistry, the voltage has direct relationship with state of charge, so if you draw 1A from a small battery, its voltage drops faster than the big battery. When the voltage gets even slightly out of balance, the bigger battery with the higher voltage supplies more power. The end result is that both batteries will have become full at the same time when charging, and empty at the same time when.discharging.
This is simply untrue. No two batteries are exactly the same, especially if your mixing types. It will catch fire. Lipo's require a very specific charger that monitors the battery while it charges. You can't even connect two exactly the same Lipo's and charge them parallel.

Originally Posted by shadowjk View Post
Some smartphones and tablets these days use "stacked" batteries, several batteries with different shape and size to fill up as much empty space as possible.
Yes, stacked batteries.. And in the case of Lipo's, they are connected individually to a power management chip. My Lipo laptop-battery as a consequence has 10 (instead of 2) wires coming out.

Originally Posted by egnat69 View Post
so basically frankensteining a second jolla battery onto the existing and covering it with a custom other half should be possible, right?
The comparison with Frankenstein is very accurate. (spoiler alert: everybody dies in the end)
 

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#28
or just go for it, glue it on there and see what happens! don't forget to film it!

#yolo #freestyle #nobatteriesinjollastore
 

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#29
Ok there is a problem. The regulator operates in the first 30 seconds. Then he gets hot and stops charging. tbr gave me the information that if the regulator gets too hot, ceases to work properly. Something like a protection.

He came up with the idea of ​​maybe two regulators to be connected in parallel. I did that. The output is still at 4.95 V and not doubled.
Now he also loads properly and also does not stop after 30 seconds.

Here is a picture about this:


So eventually solved a problem. Unfortunately, the regulators will still have to this very hot in the pants.

he thing is that the regulator is working optimally at 400/500mA. See diagram:


However, the smartphone itself takes on 1000mAh. That's why he overloaded the regulators and are thus hot.

And now I am looking for someone who's good with the kernel
Does anybody have idea how to do that? You may adjust so that the 1000mAh over microUSB remains, but limited for the pins at 400/500mAh!?
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Last edited by cvp; 2014-01-27 at 15:16.
 

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#30
So, receive today the new boards.

3V to 5V DC-DC Converter Step Up Boost Module

i will soldering today, later, and test it if there work better than the pulolo´s Step-Up regulators. Hope it will not so hot like the pulolo boards
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