[time-nuts] Power Back-up

[J. Forster]

When considering a battery backup you really have two ways to go:

Battery -->  Inverter -->  Load
Battery ---> Load

The first option is generally easy to implement, but a lot of the battery
capacity goes up as heat in the inverter. As others have pointed out,
inverters are not very efficient or electrically quiet, and they sop up
quite a bit of power w/o any load at all. For this reason, the second
option is better, IMO.

I have persnally opted for the second arrangement, with two marine 12 V
batteries in series and has yet to fail to power my HP 107 and Austron
2100F in the 20+ years I've been running them.

There are even purpose built battery backup supplies available for running
oscillators, receivers, and such. Sadly, the NiCds tend to be bad and are
quite expensive to replace.

If you need something like +/- 15 VDC for some GPS hardware, there are
small, isolating DC/DC converters that will be far less wasteful of
battery capacity than an inverter and AC-> DC supply. You can use diodes
to make an OR circuitto switch automatically between DC supplies when the
line fails.

Best,
-John

==============




> Jerry,
>
> My favorite are golf car batteries, Trogen brand if not too expensive :
> http://www.trojan-battery.com/Products/GolfCart.aspx
>
> Second on my list would be 12volt RV/Marine Batteries, not the marine
> starting battery.
>
> Get mine at Sam's, shop around they went up in price last year with the
> price of lead and not everyone reset the price with the lower lead price.
>
> Do read up on the regular maintenance required and plan on replacement
> before they fail.
>
>
> Stanley
>
>
>
> ----- Original Message ----
> From: "gsteinba52 at aol.com" <gsteinba52 at aol.com>
> To: time-nuts at febo.com
> Sent: Saturday, August 8, 2009 11:55:21 PM
> Subject: [time-nuts] Power Back-up
>
> Weather projections for California this winter are WET, which implies
> local power failures (lasting up to perhaps eight hours).
>
> What do time-nuts do for backup power? I have one of the TAPR TBolt
> systems along with numerous other toys (OCXOs that should probably be kept
> running to avoid retrace errors). Automobile batteries? UPS inverter
> systems?
>
> Thanks,
> Jerry
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