Re: Synchronome battery life

John Hubert

I can’t comment on power consumption as I run several clocks from a float charged battery (multiple C sized NiMH cells - now about 15 years old) - but 280 mA is on the low side for a Synchronome.  300 - 330 mA is more usual.  Low temperature will reduce battery capacity, though I don’t know by how much, and will also increase internal resistance, but I doubt this would be significant at approx 300 mA.

The rod is Invar, which has a very low temperature coefficient of expansion.  The iron bob will have a much higher coefficient of expansion.  Atmospheric pressure is also a factor.  

My own Synchronome sits in a relatively constant temperature and has a lead bob.  Variation (per day) is low with temperature change, typically 10 degrees Fahrenheit fall increases the clock ‘rate’ from approx 0 seconds per day to +0.3 second per day, but this is a very approximate measurement by simple visual observation against a Junghans radio controlled clock as reference (and averaged over a week rolling average).


On 14 Jan 2021, at 20:45, via <> wrote:

My Synchronome #2054 ran for 45 days before latch failed to reset. Setup is transmitter and pilot at 11.5 ohms running at nominal 3 volts and 280mA from 2 Energizer Max D batteries. Thought it might do better, how do others get on with running on a small battery pack? 

Since Christmas week clock temperature has been dropping to 1.5C degrees overnight and not much warmer in the day against previous temperature around 12C. I expected the daily loss rate would be reduced as length of pendulum reduced but loss actually increased (from -2.5 to -3.5 per day). Maybe the cast iron bob is contracting more and increasing the overall length or is something else going on?

Not much showing on the forum so thought I might post my casual observations! 
All the best for 2021

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