Are there clocks made with a capacitor backup?

Factual Questions
1

Back story: My daughter-in-law blogged this morning that some sixth sense woke her up at 5:30 to get the kids off to school (her eldest has jazz band practice at 6:30) because they had a power failure and her alarm didn’t go off. I suggested that she get a clock with battery backup. She replied that she had one, but there is no dead battery indicator.

Now they have an emergency gas operated generator that cuts in after ten seconds when the power fails (which is a couple times a year). So it occurred to me that a capacitor could readily supply enough power to operate the clock (if not the display) for ten or twenty seconds, but I am not sure that such exist. Obviously, a capacitor does not go dead since it would be continuously charged.

2

My Philips Dream Machine CD/Clock radio has one. Power only lasts for about ten to fifteen minutes though, so it’s not good for long power outages.

3

I have seen clocks that have battery backup for this sort of thing. It is pretty common.
http://www.google.com/products?hl=en&q=battery+backup+clock&sourceid=navclient-ff&rlz=1B3GGGL_enUS176US215&um=1&ie=UTF-8&ei=hchQS-r2GYOosgOukN3ZBw&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CBoQrQQwAA

4

>She replied that she had one, but there is no dead battery indicator.

I have an old alarm clock with a battery backup. The battery in there must be three or four years old and the last time I unplugged it, it still kept the time. This was maybe 5 months ago. 9 volts self-discharge pretty slowly and I dont think it draws any power unless its unplugged.

>for ten or twenty seconds, but I am not sure that such exist.

I cant imagine there being a big market for caps that hold power for 15 seconds. Heck, to accidentally unplug it and plug it back in is like 30+ seconds, especially when youre fishing for cables and moving furniture. Im not saying they dont exist, but most people would need more time than that.

If she really wants a nice solution, then you can get a little UPS for $40 dollarsnowadays. Probably less if you shopped around and hit the deal sites/ebay/cl. Might be overkill, but she can also plug a nightlight or bedside laptop into it too.

5

Apparently reading comprehension is not common. Sorry for the useless reply.

6

for high profile situations it is possible to use available backups as a second alarm clock, e.g. some wristwatches and some cellphones (plugged into the grid but capable of running on battery during power failure) can both be used. Back in high school before major tests I would routinely use wristwatch in addition to the regular alarm.

7

LCD battery operated tavel clocks with alarms are faily common. Might be a useful backup. Almost all cell phones have multiple alarm features.

8

I’ve got an alarm clock that does keep time briefly without AC power. It’s great for riding out short hiccups.

Amusingly, my rice cooker has the ability to keep time without a battery even when unplugged for weeks. It was a bit surprising to take it out of a moving box recently and find it still had the time after being packed up for two months.

9

I prefer a mechanical (wind-up) alarm clock.

They also have the advantage of lacking a snooze feature, which I am known to abuse. It is very difficult to find an electric clock without that feature.

10

Any recommendations for a good one? I’m looking for one for my wife, who won’t use a cell phane for baackup. So far I have tried a Big Ben (lasted 3 months) and a $75 wind-up from the Czech Republic (3 months). I can’t find a well-built one anywhere.

Thanks in advance.