Strange oscillations while charging Battery

[jonnybgood]

Hi,
i tried to charge a lead acid 12V battery with a small power supply with max supply current of 500mA, and when probing with digital and analogue volt meter i can detect these strange oscillations. First I was thinking that the smoothing capacitor in the power supply is too small and that it is discharging too fast, but now I realize that it is a switch mode power supply. Any clue of what it might be happening exactly please?

YouTube - ‪Stange Oscillations while charging.‬‏

thanks

 

[FvM]

You didn't tell about the involved power supply. Depending on it's current limiting behaviour, the result may be normal operation. It can be expected, if the power supply has overcurrent shutdown rather than clear current limiting. Not all power supplies are suited as a battery charger.

 

[jonnybgood]

it does have a current limiting circuit, i realized that the battery's open circuit voltage was reduced even to 5V instead of increased to 13.xV. Now i am charging it with a car battery charger and it already went up to 13V.