[morzh]

Continuing on the battery.

I have a couple of 357 batteries, 1.5V, of a suitable size.

The battery goes into a heatshink tubing. One end is narrower, and will hold the contact spring I salvaged from the battery holders, damaged by leak. I cut the spring to a suitable height. Since it is narrower, it will keep the spring from shorting the battery, which goes with its negative towards the spring and then facing the bottom of the original battery cup, that fits in the holder.
The top part is practically open, to allow the positive contact to hold the battery down by its positive terminal (the battery case).

   
   
   


Then the whole thing goes, spring down, into the battery cup, which is already in the holder.
   
   

The voltmeter's hooks are clipped to the terminal strip that holds the holder itself and the wires soldered to it.
And then we look at the Voltmeter reading the value.

   

Of course I could've used a flatter battery, but these I already have had.