Li-Ion discharge limit circuit

[Walt Dizzy]

I'm using a self-built 4x18650 li-ion battery pack for my bike lights. The problem I'm having is that the protection circuit I'm using uses a low voltage cut off of 2.5 volts, which is too low.

At 2.5 volts, my Tenergy balance charger sees the cell as defective and refuses to charge it. I can get around the problem by wiring the low cell to my Maha charger and pumping it up to about 3.0 v. Then I can charge the entire pack on the balance charger.

I'm afraid that taking the weakest cell down to 2.5 volts is going to kill it prematurely. Anyone know how to hack the IC on the protection circuit to make it cut out at, say, 3.0v?

http://www.batteryjunction.com/li-pcb-14v4--.html
http://www.sii-ic.com/en/product1.jsp?subcatID=5&productID=762

Walt

 

[MatajumotorS]

As i know - it is not possible to modify the cut-off voltage of those prot ic's.
Just make a low batt warning light. OR you need light driver with cut-off.