Puddles and Idiot Lights

1982 300td Turbo.

Recently when I hit a puddle of decent size, which are typically on the passenger side, the 'warning lights' come on, very dim for almost a minute.

Seems that depending on the impact of the puddle, sometimes only the battery light will come on, but sometimes all three...battery, pads, parking brake....

Any idea what is happening here? Need for real concern?