HACK ? Lipo / Li-ion Battery Voltage alarm.

[user1235423643]

does anyone know how to hack one of these to alarm at a different voltage
it will alarm if any cell drops under 2.7~3.8V

what about alarm on TOTAL voltage rather then per cell?

and a a bigger alarm total range?    (if the battery total cells was 30v... alarm at 20v)

thanks


specs:

1-8S Lipo/Li-ion/Fe RC helicopter airplane boat etc Battery Voltage 2 IN1 Tester Low Voltage Buzzer Alarm

Features:
1-8S Lipo/Li-ion/Fe RC helicopter airplane boat etc. Battery Voltage 2 in 1 Tester Low Voltage Buzzer Alarm
Use for 1-8S Lipo/Li-ion/LiMn/Li-Fe
Voltage detection precision: +_0.01V.
Unit voltage display range: 0.5~4.5V
Total voltage display range: 0.5~36V
1S test mode voltage range: 4-15V
Low voltage alarm mode for 2-8S
Alarm set value range:OFF~2.7~3.8V
 
Specification:
Size: 40mm x 25mm x 11mm
Original box: NO
Net weight: 9g
Color: Red
 
Package Content:
1 x 1-8S Battery Voltage Buzzer Alarm

[amyk]

You would have to investigate the schematic and see how it senses the voltage. If they're using a discrete voltage reference + divider then you can change the resistors, otherwise if they're using a standard lion protection IC (like a DW01) the voltages will be fixed.

[jwrodgers]

The reason it alarms if any cell drops too low is because the cell will be damaged if it is discharged below a certain point. (I prefer not to take any cell in my Li Ion battery packs below about 3.1 volts.) If you only monitor the total voltage, you may miss when a cell is being drained too low due to imbalances between the different cells. The pack voltage may still be ok for the application, but continuing to use it with a low cell can lead to damage in one cell that renders the complete pack useless.

I have assumed here that you want to use it with a battery pack to get longer from it, but you may have an innovative application that I have missed, if so I apologise in advance.

[user1235423643]

so does anyone know how to hack these, or?