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Thread: What is everyone's experince with using NIMH's in wall clocks?

  1. #1

    Default What is everyone's experince with using NIMH's in wall clocks?

    Talking about the quartz analog ones. The ones with hands that move, NOT the digital clocks.

  2. #2
    Flashaholic* mattheww50's Avatar
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    Miserable. I have an 'atomic clock' that takes a singe AA battery (basically a quartz clock that synchs up daily to WWVB). A single AA runs the clock for almost a year. At the low drains used in these devices,you will get nominal voltage from an Alkaline until it is just about dead. Nominal voltage from a NiMh is about 1.25 volts, so almost immediately the clock thinks the battery is going. Generally the self discharge rate on an NiMh is higher than the consumption for the clock. So even if you ignore the low battery warning, you only get about 60 days instead of a year. Eneloops might last longer because of the lower Self Discharge rate, but that doesn't help the low battery warning. My clock goes to 2 second movements of the second hand as the low battery warning, and it then sounds like chicken, with a cluck every two seconds!

    I have another clock that used a D cell, and an ordinary D cell (not even an Alkaline) runs it for several years. Once again unless you are talking eneloops (and I don't think they make a D size), the clock power consumption will be well below the self discharge rate.

  3. #3

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    So far so good. Provided you're using low self discharge NiMH's ("ready to use", "stay charged" etc).

    Started about a year ago to replace alkalines with el cheapo (but lsd) NiMH's in some of the numerous wall clocks in our house. So far haven't had to replace (or even recharge!) any of those NiMH's.

    Whether it saves money remains to be seen. Given the price I got those NiMH's for, just a few recharges could make them come out ahead. But alkalines can last 2-3 years (maybe more?) at a time, and can be quite cheap when bought in bulk. For me it's mostly the "pop out, recharge, pop back in" convenience factor. And reduction in battery waste.
    Last edited by RetroTechie; 03-22-2014 at 02:46 PM.

  4. #4

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    Yup. Works fine, just use Eneloops or some other LSD battery as mentioned. Not cost effective from a battery perspective, but a NiMH battery won't leak like an alkaline, so it's definitely cost-effective if it prevents your clock being ruined by alkaline juice.

  5. #5
    Flashaholic Frijid's Avatar
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    Hmm, you just gave me an idea on what to do with the extra duracell ion core LSD battery i had that i wasn't using. Seeing as how the analog clocks are mechanical, you wouldn't have to worry about the "low battery warning" that matheww50 was talking about. I use some LSD energizers in wireless weather station on the indoor unit. I can charge them up, and after about a week the icon for low battery starts flashing, yet you can let it run/continue to flash for 6 months and it's still going strong. Just checked it the other day, it's been month 6, still flashing low battery, and is at 1.2 volts on my meter. I've got an atomic clock that takes 3xAA's, and i've got 3 sunbeam alkalines in it, and they've been in there for like 2 years now and register 1.25/1.3 volts.
    ~Pray for the best, but prepare for the worst~

  6. #6
    Flashaholic*
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I just started switching from alkaline to NiMH a few months ago. So I do not have any long term data points. However, my wife came to appreciate the benefits of Eneloops when she found a leaking alkaline in her Bulova clock. I had lost about 4 Maglights to leaking alkalines, and found leaking cells In an expensive scientific calculator, all within a fee weeks. NiMH are worth it just to avoid leaking cells. Even if I have to charge them more often than I would alkaline, I expect them to save $ in the long run.

  7. #7

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I tend to use all my high internal resistance NiMH cells in clocks/remotes. That is, the ones that won't charge in the C9000 but will still hold charge for a bit. I only have one wall clock and use a harmony remote though.

  8. #8
    Flashaholic InHisName's Avatar
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I used to use 'dead' alkalines for those clocks. Good for 6 - 12 months. When they die in the clock seems the resting volts are WAY below a volt. I am not just getting some LSD cells apporaching junk status and plan to use those instead to tossing them Even as junk I suspect I get 600-700 Mah out of a AAA and maybe 1500-1700 out of an AA that way. In about 2 more years, I'll have too many junk cells and not enough clocks.

  9. #9

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I can share a little data on this topic. I've recently been using Eneloops in a single-AA Braun quartz travel alarm clock. (I got this clock in the nineties. It still works great and keeps incredibly accurate time.)

    I set aside a pair of first-gen Eneloops (2006 manufacturing date) for this clock. The first fully-charged AA lasted from May 9, 2014 to January 10, 2016, or 611 days.

    When I saw the clock had stopped, I immediately topped-off and installed the second AA from the pair. As of today, it's been going 552 days. If it lasts about the same time as the first one, it should run out in mid-September.

    I'm happy with this performance. I don't mind having to change the battery every 1 year and 8 months. It certainly gives me peace of mind not having to worry about leaks. A current-gen Eneloop would surely last even longer due to the improved LSD.

    (On a related note, I have a different quartz analog clock running on an Energizer Advanced Lithium AA. It's been going since January 9, 2016. It will be interesting to compare how long it lasts.)
    Last edited by percentage; 07-18-2017 at 07:13 PM.

  10. #10
    Flashaholic* MidnightDistortions's Avatar
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    Yep, i use NiMH in just about everything. Even some of the older HSD cells work fine in the low drain devices (but not all).
    LED Lights: ThruNite TN4A, Coast HP7, LEDLenser T7, Fenix E25, Fenix LD41, Maglite 2D, Maglite XL50, Maglite 3D (3rd Gen), AA MiniMaglite Pro+
    Chargers: Maha C9000, La Crosse BC1000, Panasonic BQ-CC17, Eneloop user.

  11. #11

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I put Ultimate Lithium AA cell into my wall clock in 2012. Still going strong...

  12. #12
    Flashaholic* Crazyeddiethefirst's Avatar
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    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I have two wall clocks (analog) that average 14 months on eneloops. If I may deviate off topic momentarily, I am also using NIMH in 4 weather stations(two main, two satellite. They work fine for a few months then go blank(only the main stations, not the satellite stations)-when I test the Four eneloops, two register a negative0.2volts, the other two 1.24-1.3. This has happened at least half a dozen times, a recharge & all four match voltages & everything works fine for a while. Anyone have the same experience with multicell clocks, any idea the cause?

  13. #13

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    By now both of my wall clocks are powered by NiMh rechargeables. One takes an AA cell (that's left over after using the other 3 of a 4-pack of Tronic Eco rechargeables in a soap dispenser) and has been equipped with it on February 7th, 2016. It has been recharged on October 9th, 2016 because that wall clock already fails at a voltage of about 1.21 Volts... well, at least it doen't completely discharge the battery BY FAR. No further recharges needed yet. The one in my kitchen takes a C cell and has been equipped with it some months ago with a non-LSD battery that actually has been last recharged on July 23rd, 2016... but it's the one I've marked with a red X because it behaves a bit different than the other ones I have... it has got a higher internal resistance, but also seems to hold its charge better when not being used. Hasn't needed a recharge yet...

    With the C cells I used a HSD because I've got no LSD ones (and also no adapters for AA to C), but 12 HSD which I actually bought for a small boombox from 1993 which I used for one summer in 2011 because my older boombox broke, but in summer of 2012 it broke as well, so the batteries went sitting there mainly unused.

    I don't have such great experiences with using 9V rechargeables as a backup battery in radio alarm clocks... I've got a nasty one at the moment which will not hold the correct time unless the backup battery is installed, and it will drain the backup battery slowly (over the course of 3-4 weeks) even if plugged in. And it will discharge the backup battery to under 5 Volts before giving notice that it needs to be replaced (or recharged), so for a 7-cell battery that's pretty deep. But that unit will be replaced with a properly working one on October 27th (or sooner, we'll see, my father bought it yesterday for my next birthday on October 27th).

  14. #14

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    Quote Originally Posted by Crazyeddiethefirst View Post
    I have two wall clocks (analog) that average 14 months on eneloops. If I may deviate off topic momentarily, I am also using NIMH in 4 weather stations(two main, two satellite. They work fine for a few months then go blank(only the main stations, not the satellite stations)-when I test the Four eneloops, two register a negative0.2volts, the other two 1.24-1.3. This has happened at least half a dozen times, a recharge & all four match voltages & everything works fine for a while. Anyone have the same experience with multicell clocks, any idea the cause?
    That's normal, if the equipment doesn't have a low voltage cutoff. The cells have a slightly different capacity, so some will be empty while others still have a bit of charge.

    This will get worse, the over-discharged cells are stressed more and will decrease even more in capacity compared to the others.

  15. #15

    Default Re: What is everyone's experince with using NIMH's in wall clocks?

    I have had no issues with LSD batteries.

    Mike

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