Thursday, November 10, 2016

The pull-up does not work?

My charger charged 950mA NiMH Eneloop, when GE A1455 dissipated them. But one has not been fed at all as shown the chart.

DSO showed CH1:171mA and CH2:52mA each, when the batteries were on at first. The charging current wave includes much noise. Because this one has high charging terminal voltage, I think. And AVR does not run any signal processing like DSO averaging.

So I enforced to discharge it by my discharger. The discharging lasted 43 minutes. It shows that battery 11 has a capacity to drive my wireless sensor, although initial inrush charging current is 60mA only.

I began charging #11 again. The initial charging current increased, but low charging current includes much noise as before. I reset #11 to CH1. The current increased twice 100mA. I have recorded the data for 8 hours, but Windows 10 Anniversary began to rest abruptly, because my PC sleeps everyday. Alas! I cannot show the data. I checked default maintenance off.

I think that the pull-up circuit for 2SK1290 does not work well.

  • Increase pull-up transistor 2SC1815 base current 10 times
  • Increase 2SK1290 inrush current 2.2 times
  • Add a capacitor suppressing DIF amp oscillation off battery

Low level current flew as shown in the chart. But noise is big. DSO shows the noise as follows,

CH1: 5.6mVpp
CH2: 17.6mVpp
Acquire: 64 averaging, 20mV/div, 2.5ms/div

LM324 has little 5mA sink current. It is not fit to apply for driving FET. Though the pull-up generates much noise, it can measure deteriorated low level charging current.

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