[time-nuts] UPS for my time rack

[Dave Martindale]

How did you find the units that will act as a UPS, without buying
everything on the market and testing them?

I just checked all of those bricks in our house, and none will do it.
There are a couple of PNY units that do not provide output power until a
button is pressed, and don't charge until input power is connected while in
idle mode.  Then there are Tp-Link and Mophie units that switch on the
output automatically when a load is connected (or perhaps the output is
just always powered), but which disable the output and switch to charge
mode when input power is provided.  None of them seem able to pass through
5V power without discharging.

- Dave

On Tue, Oct 13, 2015 at 2:07 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

>
> Recently, as some of my gear works from 5 VDC, those ~2600 mAh mobile
> phone USB backup power bricks make an excellent mini-UPS. The ideal models
> are those without LEDs or on/off buttons so they discharge and charge/float
> seamlessly without manual intervention, even if fully drained.
>
> Multiple units can be placed in series for additional, if slightly
> inefficient, capacity. A good self-test is:
>
> http://leapsecond.com/images/perpetual-USB-power.jpg
>
> /tvb
>
>
>