[time-nuts] Favorite DC power Supply?

Matthew Smith matt at smiffytech.com
Fri May 2 19:28:58 EDT 2008

Quoth Neon John at 2008-05-03 08:16...

> Set each one to 6 volts, hook 'em in series and use 'em to run big 12 volt
> loads.  I ran a homemade true uninterruptible power supply for years using
> that lashup.

OK, whilst we're deviating from time a little, I would like to put a 
time and power supply question to my learned colleagues:

I am building two GPS-driven devices, an NTP server based on an ancient 
single board computer and a Nixie clock.  Our power here is not what one 
might call reliable - we are stuck on a spur of a very long 19kV, single 
wire, earth return supply which plays up a) when there is a thunderstorm 
within 200 miles and b) when it feels like it.

Whilst I could incorporate mains power supplies into both units, I like 
to avoid getting mains in my constructions if I can avoid it.  The SBC 
has a PC-104 automotive PSU fitted and I'm building the supplies for the 
Nixie clock (+5V, +12V, +170V) to operate from about 11.9V (shutdown if 
less) to 15V DC.

My thought was to integrate a UPS component into the design by 
connecting these to 12V 7Ah sealed lead acid batteries, which I can get 
for just over $20 AUD a piece.  If I were to do this, would it be 
sufficient to power the units from a 13.8V supply?  I believe this to be 
within the voltage range for float-charging the batteries so was 
guessing that this may be a simple way to provide uninterrupted power to 
my gear.



Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
Business: http://www.smiffytech.com/
Personal: http://www.smiffysplace.com/
LinkedIn: http://www.linkedin.com/in/smiffy

More information about the time-nuts mailing list