communicating with li-ion battery

[kloppy]

i am trying to communicate with an existing li-ion battery through SMbus to get some information about the battery. has someone ever done anything like that?

[kender]

I haven't done anything like this, but I'm currently researching this topic. In case you haven't done this already, you can open your battery pack, find the battery monitor/charger/superviser IC, who's datasheet might have the communication protocol. Also I heard that there is a push for a standard communication protocol for the smart batteries (sorry, I don't rememeber its name).

What kind of battery pack are you hacking?

Sincerely,
Nick

[kloppy]

it's a battery from a notebook.
unfortunately i'm not allowed to open it (the battery) and i also don't know the manufacturer of the battery. so i thought maybe there's a standard protocol for batteries...

[gaul1]

I did it a long time ago, with the I2C-Protokoll
it's quite simple, you have 'just' to find out the SDA and the SCL connections.
then you can read the battery similar to an serial EEprom (i.e. 24c04 )

be careful ! you can overwrite the manufacurer name, and the memory, where the configuration is stored for properly charging.

I recommend to make a backup of your battery before changing the memory.

Was this, what you want to know ?

gaul1

[kloppy]

yes, thanks.
but how do i know at which adress i can get which information (manufacturer, cell voltages, etc.)?

[kender]

I'm just curious - are you building a custom charger?

Nick

[kloppy]

no, i'm trying to build an equipment that can measure the available capacity of a battery and find out how long the battery will work (approximately) in a laptop if it is full charged.

[kender]

On the TI website I came across a fuel gage IC, wich supports a standard called SBS 1.1. Here's the datasheet http://focus.ti.com/lit/ds/symlink/bq2084.pdf . It looks like the description of the stsndard is there.

Nick

[kloppy]

ok thanks, i'm gonna try that