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Battery Driven Alarm Clock Mystery

Discussion in 'Power Electronics' started by Bolixt, Apr 18, 2011.

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  1. Bolixt

    Bolixt

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    Apr 18, 2011
    Twice I have mounted 2 different battery alarm clocks (analog - with hands) in my sailboat. They stop and/or lose time during transit to/from the lake. Otherwise they keep perfect time; on the lake, on the trailer at home for days at a time, riding in the truck, in the house. What is happening?

    The first one I got so disgusted I removed the battery and thru it in the lake. Stupid thing floated!! I retrieved it and use it in the house where it's kept perfect time for 2 years.

    Travel time each way is about 25 miles (5 on curvy mountain road), 30 minutes. Clock time lost is about 20 minutes. Trailer is steel. Boat is fiberglass. Mast is aluminum and lays fore-n-aft about a foot above the boat. Travel is predominately east-west. New clock. New battery. 2 different trucks. 2 different clocks.

    I know it sounds crazy but could it be the earth magnetic field?
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    more like the batteries working loose with vibrations on the road :)
     
  3. Bolixt

    Bolixt

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    Apr 18, 2011
    If the battery came lose then the clock would stop completely. When I get to the lake or home it's still running but has lost time.

    I have another boat which had a 6" Westclock mounted in it which ran several years, perfect time, till it got filthed up with bugs. The clock - not the boat.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    The direction of the vibrations whilst on the road may affect the mechanical timing. Maybe it prevents the gears from moving ahead correctly, or perhaps it allows them to sometimes go backward.

    Does the clock keep time correctly whilst on the trailer, but parked? Can you try removing the clock and placing it on something which absorbs some of the bumps (say sitting it on a towel)? Does it then maintain time whilst you travel?

    Maybe you can change the mounting slightly to include some rubber between the clock and the boat. If the previous test works, then this *may* be enough
     
  5. MattyMatt

    MattyMatt

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    Mar 24, 2011
    I agree with Steve on this one... I shook an analog clock for a few minutes... mostly because this posting intrigued me... it lost about 30 seconds for about a minute or so of shaking... though I was being pretty rough... I would say that this mechanical issue would be more likely than an electrical... BUT I would defiantly try to eliminate as many variables as possible... as Steve was suggesting.

    As for mounting... you could try mounting it on a spring and some rubber or something of the like... to dampen the vibration (kinda like a turntable?).

    Good luck!
    Matty-
     
  6. Resqueline

    Resqueline

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    Jul 31, 2009
    What size is the battery, and which way is it sitting? With + up to a firm contact and a spring in the bottom then I could imagine it loosing contact imtermittently on bumps.
     
  7. davenn

    davenn Moderator

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    Sep 5, 2009
    exactly my thoughts :)
     
  8. Bolixt

    Bolixt

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    Apr 18, 2011
    Well I never got around to experimenting. By the way I remember now it is a total of 3 clocks; 2 analog and 1 digital.

    Batteries analog clocks AA and sit horizontally and are plenty tight. The digital clock probly had a AAA battery as it was quite small.

    The vibration isolation seems self evident - I shoulda did that. My bigger boat with the Westclox is heavier and perhaps the vibration was damped out better. This is a bit embarassing - I shoulda did it. It's the FIRST thing I shoulda did. BUT! I have the clox fastenend down in the boat so I can read em while sailing in adverse conditions (high heel angles etc).

    Next trip out I will correct that lapse. Isolating vibration can be an intriging (intreeging?) task. Will let you know but it may take time.
     
  9. Resqueline

    Resqueline

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    Jul 31, 2009
    Admittedly it's intriguing and might seem like an x-file case, but it has to have a simple explanation. We'll be waiting patiently for the "next episode".
    Analog clocks are things that just barely works, there's not much room for disturbances or increased friction etc.
    With the battery horizontal it seems unlikely that power dropouts is the problem, unless there's some unfortunate geometry around the positive pole.
    You said it works riding in the truck, but maybe it was in a different position then, plus I know trailers may have significantly harder suspension than cars.
     
  10. Bolixt

    Bolixt

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    Apr 18, 2011
    Vibration insulation solved the problem.

    Expanding just a bit: The problem occurred with 3 clocks over 2 summers - this is the 3rd season - but the solution was from just 2 runs; 1 to the lake and 1 home. That's good enough for who it's for. No need to beat it to death.

    My next separate post will show how I insulated the clock just in case anyone gives a rip.
     
  11. Bolixt

    Bolixt

    5
    0
    Apr 18, 2011
    Here are several pics showing my approach which was to go completely overboard and make for damn sure it was insulated from vibration. No point it sneaking up on it.

    1st pic shows the clock as I use it; glued to a piece of construction foam and just sitting on the cockpit floor. Even at 40º heel it sits tight.

    2nd pic shows the clock snubbed down on foam with a board to keep the foam from wrapping around the clock and rocking forth-n-back. This is foam from a pillow and fairly soft and the snubber keeps the clock from bouncing.

    3rd pic shows the clock nestled in a carton with more foam which I had so I just stuffed it in needed or not.

    4th pic shows the carton on a thick pad of fairly high density high quality foam from a couch cushion so it's stiff enough that it doesn't crunch to zero when you sit on it. The whole thing is mounted in the boat and snubbed down to prevent bouncing.

    In the bottom of the carton I added a couple 3.5 pound lead ingots to increase the momentum of the whole thing to inhibit (hopefully) high frequency bouncing. I almost feel like an engineer again; an occupation I gave up 41 years and 14 days ago.

    Pehaps I will try a soft foam pad under the clock and current blue pad combination but most likely will just carry it in the P/U.

    5th pic, of course, the boat
     

    Attached Files:

  12. MattyMatt

    MattyMatt

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    Mar 24, 2011
    Looks pretty insulated to me! Glad you got to the root of the problem.

    Good luck and have fun boating
    Matty-
     
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