Thread: SWCC Battery Life
02-15-2017, 03:04 PM #1
- Join Date
- Aug 2000
SWCC Battery Life
There was a thread about dry cell life (short or long) to power Self Winding Cocks a year or so ago. I don't recall if there were any test results posted.
There was a few comments then, mostly regarding brand and dry cells used to provide electrical power for the most common antique battery clocks made by the Self-Winding Clock Company.
Our family clock is viewed at least twice daily by five who "live by" the "clock on the wall" a restored SWCC #22. It has two "D" cells inside the case, the movement is the old type with the hourly wind rotary motor and beats 92 to the minute.
I decided at to reply to the "contest" with my own test data.
I replaced the two "D" flashlight cells and noted the install date right on the two cells, common "DURACELL" copper top MN1300 Alkaline Dry Cells, and noted the install date of November 18, 2015 on each of the two series wired dry cells.
I replaced the two noted cells on February 14, 2017 (St. Valentines Day) yesterday because the whirring sound of the winding motor was beginning to become excessively long after the one-year and Four months which speaks well for the Duracell brand. The clock didn't stop but the winding period seemed to be getting slower and slower. Both cells have a no-load
voltage of 1.3 V DC. (certainly somewhat depleted but not dead)
I/we have noted the clock has apparently been slowing over the year and I don't know why. Maybe on account of the slowing winding period which is noticeable but shouldn't, according to theory, be a factor. I'll give you a good answer in a year or so of continued observation with the newly installed dry cells. (same lot package)
The rate of the clock has been very good over the year of observation with only a slowing rate of about three minutes between annual DST hand setting. Zero movement maintenance !
Les Lesovsky in Alhambra, CA
Last edited by eskmill; 02-15-2017 at 03:07 PM. Reason: (fat fingers)H.J. (Les) Lesovsky, Alhambra California
02-15-2017, 03:14 PM #2
- Join Date
- Dec 2011
- Brockville, On Canada
Re: SWCC Battery Life (By: eskmill)
I haven't seen you on here much, but I think I can recall that you are an electrical guy. Although the ocv of 1.3 v isn't all that bad, I wonder what the dc impedance has changed to. You could do a volt drop test with a known reasonable load on a good cell and compare with the ones that you just took out so see what the difference is, assuming you still have the old cells.
02-15-2017, 05:10 PM #3
Re: SWCC Battery Life (By: David S)
I have had a similar battery life experience with my 80 beat Style F vibrator movement, although I haven't noticed any change in timekeeping over the past year+ using the same two Duracell D cells. The winding cycle is getting to the point where the sound is intrusive, so it's probably time to replace the batteries. I do have a synchronizer installed, however, so less likely to notice any change over an hour's period before it resets the minute hand. The movement was overhauled by Frank Manning several years ago, and functions perfectly.
Mark PowersSi non caste, tamen caute...
02-15-2017, 09:22 PM #4
Re: SWCC Battery Life (By: Ingulphus)
In my two SWCC clocks, I use the same Duracell batteries Les referred to above. Mine are the same 80 beat Style F vibrator movement as mentioned above. I have monitored the time between needed battery changes, and in each unit, I have received almost exactly two years of service, with no appreciable decrease in the accuracy of either. I've been pleased with the batteries' performance. This has been over a full six year period. The clocks are well maintained (probably more so than when in original service), and we keep the house at between 69-71 degrees year round. We live in East Tennessee, with fairly mild winters and very hot, humid summers.
Possibly a small departure here, as I'm now talking about my two American Clock Company timepieces, both of which throw a weight up to the top if its travel at each "winding" episode. With these units, I always use the same Duracell brand and model as above. My clocks were made to run at 3 volts (of course two 1.5 volt cells in series), but in my units I only use 1 cell, as with two I get quite a "thump" at each winding episode. The clocks are well-maintained and operate flawlessly, "rewinding" at about a six minute interval. So far on average, I have gotten three years and two months out of each battery, for the last 9 years and six months. I've been very impressed with the batteries' performance. I know that my units have a much smaller current draw than do my SWCC units, so this of course is a contributing factor to battery life.
In all cases, I use fresh D cell units. All electrical contacts are cleaned at three month intervals, and all cabinets have been pretty well sealed against dust infiltration. (I use removable foam-type insulating strips to accomplish this, with no permanent or irreversible damage to the clocks.)
Les, thanks for your always-informative postings! I look forward to them.
Warmest regards to all,
02-18-2017, 09:16 PM #5
Re: SWCC Battery Life (By: eskmill)
I replaced the batteries in my clock last weekend. I was building a NiCd battery pack and that got me thinking about my SWCC clock. I decided to check how long it's been since the batteries were changed. The last battery change was 11/25/12. This was when the clock was restored. The cell no load voltage was 1.3V Short circuit current was 2A. For comparison, a fresh cell is 1.6V with 4.5A current. The cells still had some life left. I decided not to push my luck and changed them. 4 years is long enough. The last thing I need is for old batteries to leak inside my restored clock.
The clock is due for cleaning. Oil in a few of the oil sinks is starting to darken. I'll be cleaning it as soon as I can free up some workbench space.
No way to compare this with your battery life since I'm using a different size and quantity of cells. I'm using 8 C cells installed in fake # 6 cells. 4 in parallel inside each fake cell. 8 C cells are good for at least four years.
02-18-2017, 09:22 PM #6
Re: SWCC Battery Life (By: lmester)
Just curious here- do you really need all of that amperage from the parallel-wired batteries to operate the clock?
02-18-2017, 11:38 PM #7
Re: SWCC Battery Life (By: George Nelson)
Running batteries in parallel is generally not recommended and can cause problems. If you use identical cells you can get away with it. In this case, it looks like the extra capacity was not needed.
This does show how much that batteries have improved. I know that the original #6 cells were intended to last a year in the clock. I've no idea how much reserve capacity they had. I would expect at least a few months. You don't want the clocks stopping because the service tech was a few weeks late. Also no idea of what the AH capacity was of these antique cells. It may have been far less than a modern D. More likely is that modern alkaline has a much lower self discharge rate.
The cutoff voltage for alkaline batteries is normally .9V. Cutoff voltage is when the battery is considered dead. At that voltage there is little power left. The old cells measured 1.3v. Still some power left in them. It would have been interesting to see how long they would last. It's likely that I could get another year or two out of them. I'm just unwilling to risk it. Four years is long enough. It's just not worth the risk of a leaking battery. I spent too much time restoring this clock.
The battery capacity that I now have is really overkill. The clock is due for cleaning before the batteries have died!
02-19-2017, 01:25 AM #8
Re: SWCC Battery Life (By: lmester)
Thanks for such a complete reply, Luke. It is appreciated. Enjoy your clock! I have several self winders and love each one!
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