Lithium polymer battery as an UPS

RaveenBouy · Published in 2015-3-22 11:39:13

:O look what i found http://www.pimodulescart.com/shop/item.aspx?itemid=5

gaara · Published in 2015-3-25 17:35:23

Edited by gaara at 2015-3-25 10:36

Does someone know if this 3.7V input (under the board) for the battery should work if I use a 12V -> 3.7V step-down ?
If it's possible I would like to have a software gauge in my Android system.
Thanks

lectron · Published in 2015-5-3 14:00:44

Hi gaara I don't know if you still need this information, but if you do this and have the OPI powered by DC in you will have a conflict between the PMU and your converter in clear keep an extinguisher near you when you tried it ! Also it doesn't make sense because in first you supply the bat input with a constant voltage so when the PMU could see battery voltage drop down (battery discharging) !? In second the SATA power is already produced by the PMU (U4 on pi mini drawings) and U10 when the Bord is powered from DC input or battery input . I don't know if my explanation are clear, so let me know if you need more information.

gaara · Published in 2015-5-3 17:57:35

Thanks for your response lectron

You're right, this system is a little bit dangerous. I havn't tried and I will not try, because I have another idea to get the voltage.
My purpose is to get the voltage to display the battery value in Android. Not easy for me, very noob in electronic.

So, my new idea to do this, is to use the normal power input (5V, 2A), and plug between the power (it's a power bank, can delivery 5V) and the Orange a Yocto-Volt, or something like this.
But Yocto-Volt is too expensive for me, so I'm still thinking how to make it...
Perhaps hack a simple usb-voltmeter, but I think it's a engeneer work. I'm not !!

lectron · Published in 2015-5-3 19:45:25

Which type of OPI did you used for your project?

gaara · Published in 2015-5-3 22:10:26

A normal OPi, and my project is here

lectron · Published in 2015-5-4 05:12:26

Nice project, to monitor the battery maybe you could use this don't forget that you have to connect it directly to battery terminals! And to generate the 12 V it could be interresting to use a dc/dc converter with high efficiency ( you could find several on aliexpress).

gaara · Published in 2015-5-7 03:39:01

Edited by gaara at 2015-5-6 21:49

Thanx, but this item is just for one cell (3.7v) ! I have 6 cells to read, or 12v with this configuration 3S2P (3xserial(2xparallel)) .Btw, I just have the idea of reading it via an Arduino (this is not the original), and send the data with usb. Then a library for Android could determine if the battery is full or not.It's just an idea, but this days I'm leaning to use an Arduino, for my usb accelerometer (the board has the same chip, ATMega128). So I'm sure it's possible ! (will I succed? I don't know! :p )
For the 12V, I have tried a step-down, and it's not a good solution. I will stay on 19V (the graphic board can accept 19V), event if my first try was better with 12V.
I'm thinking to buy some big cells, (for quadricopter), like this. I will use the same charger/discharge PCB, with the same configuration. As I know it's possible to change the cells for biggers.

gaara · Published in 2015-5-29 22:53:45

When I power off system , it restarts if battery connected

I have found a solution against this.
In fex file, in [target] section (at the begining) , change
power_start = 0
to
power_start = 1
Now I can shutdown my board even if the battery is connected.

t3l3m4k0 · Published in 2015-5-30 03:17:32

nice to know-
thnx