On 2/2/2011 5:15 PM, V G wrote:
> Hey all,
>
> I want to compare the Eneloops that I got from Dealextreme with the ones =
I
> got from Dell to see if the DX ones are genuine Eneloops (there are very
> slight physical differences, but the performance never led me to doubt th=
eir
> authenticity).
>
> I figured a simple way to profile them was to measure under-load voltages
> while draining the cells with some resistors at around 500 mA. But this
> would mean current drain would decrease as the battery voltage decreases.
>
> 1. Would this still be a reasonable way to profile the batteries? Can I
> still mathematically compute the battery capacity using the graph?
>
> Another option would be to make a simple constant current source circuit
> that would ensure a constant current drain on the batteries.
>
> 2. Can anyone recommend circuits for making one of these?
>   =20

This months Circuit Cellar:  http://www.circuitcellar.com/magazine/

ABOVE THE GROUND PLANE
Parallel NiMH Cell Measurement
by Ed Nisley (USA)
Got batteries? You need to test them. Here you learn how to build an=20
eightchannel parallel cell tester, with an Arduino Mega microcontroller=20
board providing PWM DAC outputs to control the discharge currents, ADC=20
inputs to measure the cell voltages under load, and serial output over a=20
USB connection for data logging. p. 52
--=20
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