modified protection circuits in series?.... need help please.

[morse w]

Hi all, i hope someone can help.
i'm making a portable stereo from scratch to run from 3 lithium cells in series and i've aquired the balance charger and protection circuits but as i'm a novice i've become a little stuck.

my problem is the recycled protection circuits cut off at about 2.3v (too low) i was thinking of placing a schottky diode between the batteries and protection circuits on all 3 cells (0.4v drop) as this would fool the circuit to thinking the voltage was 0.4v lower than the actual battery voltage, therefor cutting out at a new higher cell voltage of about 2.7v.

the protection circuits interupt on the negative terminal and i want to use this "interupt" to switch 3 individual transistors which will in turn switch off a power transistor, basicaly the first to drop out will switch the whole lot off.

i've got a whole load of general purpose transistors, a couple of TIP31 power transistors (1a rated), and quite an extensive parts bin so any ideas or suggestions would be most appreciated.
another question.... can i use 2x TIP31 in parallel to provide more amps?

PS. i'm making it on the cheap from mostly recyled stuff, i know i could buy a high current 3s protection module but the cut-off is still too low on them, so decided to use a bunch of matching phone batteries (for their circuits) on some 18650 in a 3x2 arragement (3S2P) = 11.1v to run a TDL7297 audio amplifer, 50w peak 8ohm speakers.

 

[ikalogic]

It's hard to imagine without a circuit...? can you post one?

 

[morse w]

Hi Ibrahim, thanks for taking the time.
i'm unable to post a circuit diagram as i'm not exactly sure what i'm doing or how to connect them, all the parts i have are mostly recycled, the battery protection circuits are from new matching nokia batteries and the negative supply cuts off at 2.3v....... i need a way of raising this to about 2.7-3.0v to prevent overdischarge of the cells and i would idealy like the three pairs individualy protected but still connected in series to provide enough voltage.

the protection circuits alone will not provide enough output amps on their own when connected in series, but i though there might be a way of using them to break the continuity should one pair of batteries become discharged beyond rescue.

 

[ikalogic]

okay, do you at least have some references of those components..? datasheet links?