In an earlier contribution to this discussion,
raden wrote:

In message , Set Square
writes
In an earlier contribution to this discussion,
dg wrote:


It *can* be done, but bear in mind that there are a lot of size
variations in these little concentric plugs which feed the
appliances - so one size definitely *doesn't* fit all. Add to that
the range of voltages required and polarity differences (some have
+ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

CPC do an excellent little power supply which comes complete with 8 or
16 connectors which plug into another connector either way around to
give you about every possible permutation

That's that problem solved for the OP'r

But does that require a mains input? AIUI, OP wants it to run off a 12v
battery.
--
Cheers,
Set Square
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