lord loh.
Member
My past few threads have been related to making a battery charger. I have finally managed to make a constant current source. But I am still to decide on it's compliance.
I have to charge 6 NiCd cells in a series.
For this test purpose, I have connected two cells in a series (NiCd 700mAh).
I am going to use the -ve delta technique to terminate charging.
So I am now monitering the battery voltage while the battery is charging and by switching off the supply.
Now I would like to calulate the internal resistance of the cell. How do I do it?
R=V/I
My I is 740mA. But what do I take my V as? The cell volatage while there is no charging, the cell voltage while charging or the sum of the two voltages?
I am right now doing (Vcharging+Vcell)/740mA
The idea is that the cell voltage shall be opposing the charging voltage. So the actual voltage put up by the constant current source is higher than the Vcharging by Vcell.
Or should I do R=Vcharging/740mA
I thank everyone for their help so far...
I have to charge 6 NiCd cells in a series.
For this test purpose, I have connected two cells in a series (NiCd 700mAh).
I am going to use the -ve delta technique to terminate charging.
So I am now monitering the battery voltage while the battery is charging and by switching off the supply.
Now I would like to calulate the internal resistance of the cell. How do I do it?
R=V/I
My I is 740mA. But what do I take my V as? The cell volatage while there is no charging, the cell voltage while charging or the sum of the two voltages?
I am right now doing (Vcharging+Vcell)/740mA
The idea is that the cell voltage shall be opposing the charging voltage. So the actual voltage put up by the constant current source is higher than the Vcharging by Vcell.
Or should I do R=Vcharging/740mA
I thank everyone for their help so far...