Battery Charger with Round Slots? (What Did I See Today?)

Factual Questions
1

At work we have a “freebie table” in the lunchroom where employees leave, basically, junk they don’t want anymore for someone else to take. Today there was something on that table that I’d never seen before and am not sure what it was I was seeing.

It kind of reminded me of a battery charger (basically a boxy thing with an electrical cord and plug), but there were just four round slots (vaguely D-cell diameter) with metallic electrodey things. I didn’t get a chance to examine it closely and I forgot to get a pic before I left for the day.

Is it even possible to charge D-cell batteries if only one of the battery’s electrodes is touching the charger’s electrodes? Is it likely that a battery charger IS what I saw? Or is it probably some other kind of device?

I will try to get a pic with my phone tomorrow if it’s still there.

2

Sounds like a charger for the batteries for cordless tools, like drills.

3

Ooh! That’s a possibility that didn’t even occur to me.

4

Yeah, with holes that size, it’s pretty much got to be that. A lot of such tools have (relatively) standard battery packs (at least, within a brand; I don’t know if different brands match), so it makes sense to have an extra charger for all of your tools.

5

Something like this?
What color was it?
Red is Milwaukee
Yellow is DeWalt
Green(ish) is Makita
Blue or Neon Yellow is Ryobi

Those would be the basics, Black & Decker, Rigid, Skil and some lesser known brands will overlap the big brands. But if you have a color it should be easy to figure out if that’s what you saw.

6

Not quite like that. It had four round holes in a square formation (2x2). And it was white.

7

I will try to get a pic tomorrow.

8

Sounds like the AC power supply for an electric cooler I used to have. A cord from the cooler that would go into this or had an adapter for vehicle use.

9

I took a better look at it today and I’ve managed to find similar devices with a Google search. Apparently, it’s a European round pin power strip.

10

Which is just a one to four for european mains power… 240 volts.
But the first question(s) asked remains to be answered.
Can one charge a voltaic cell when just one electrode is exposed ?
Could a socket like that be made to charge D cells via one end ?

If just one electrode is connected, no you cannot charge
The +ve electrode on the D cell is only available at the +ve end surface.
The rest of the metal case of the Cell may well be -ve. However in the modern age they are covered with glossy paper or plastic, and only the requisite -ve end is exposed as the -ve electrode.
It would be possible for a brand specific charge to be sure to be touching to case which is -ve.
Can you charge a battery where you might plug in one end of a voltaic cell ?
Well a battery must consist of two or more voltaic cells… Like two D cells touching, or wired, in series, or wired in parallel and any combination of series and parallel.

So no to the commerically available D type cells, you’d need to charge them individually.
6V, 9V ,12 V batteries ? Well sure, because they have the electrodes near each other by design. Why aren’t they called 6V cells ? They are batteries as they have at least two 1.5 volt, or 2 volt for lead acid, voltaic cells inside…

11

Thank you, Isilder!