Voltage Tester for Model Batteries

With a suitable load, the terminal voltage of a NiCd or lithium-ion battery is proportional to the amount of stored energy. This relationship, which is linear over a wide range, can be used to build a simple battery capacity meter.This model battery tester has two functions: it provides a load for the battery, and at the same time it measures the terminal voltage. In addition, both functions can be switched on or off via a model remote-control receiver, to avoid draining the battery when it is not necessary to make a measurement.

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Materials

014071-PCB.pdf

Component list

Resistors:
R1,R2 = 47kOhm
R3 = 100kOhm
R4 = 500kOhm
R5 = 1kOhm
R6,R7 = see text (1% resistors!)
R8 = 1kOhm 5
R9 = 1kOhm 2
R10 = 330Ohm
R11 = 15Ohm 5W
R12 = 15kOhm
P1 = 100kOhm preset
Capacitors:
C1 = 10nF
C2 = 100nF
Capacitors:
C1 = 10nF
C2 = 100nF
Semiconductors:
D1-D10 = LED, red, high efficiency
T1 = BC557
T2 = BC517
IC1 = 74HC123
IC2 = LM3914AN
Miscellaneous:
PC1,PC2,PC3 = solder pin
JP1,JP2 = jumper or pushbutton