> Alkaline batteries sound like a possible solution here!

The first thing to do would be to estimate the energy needed to
pull in the solenoid. 4 ohms for > 0.25s @ > 9V. Assuming an
overnight power failure, 8 hours x 120 operations/hr. To get reliable
operation I use 0.5s with a 470uF cap charged to 13V. 0.25s will
work, and voltage can be down to 8V, but pull-in starts to get a bit
weedy. At 13V the initial pull-in is strong. As the capacitor voltage
decays there's enough to hold it until around 4-5V, at which point
the solenoid releases and the ratchet moves the clock's hand

I'm not an EE so have no idea what calcs to use. Joules ? CV ?

> It would be interesting to  see how standard Alkaline batteries
> lasted under a minute trickle charge

Although you're "not supposed to", I do throw mine in the NiCd
charger and use them over and over in the VCR remote. They
came with it - Digitor non-rechargeable alkalines. Lasted for nigh
on 4 years now and they do freshen up in the charger. I tried it at
first JFTHOI but it seemed to work so I kept on doing it. Not looked
into so-called green chargers

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