Backup batteries don't make me queasy. The easiest,
cheapest backup battery would be a small 6V 3AH sealed
lead acid battery. It is trivial to make a good float
charger using a 3 terminal regulator and a diode, and
they do not leak, vent, or anything problematic. The
little 6V 3AH packs are used in emergency lighting, so
they are readily available. Float them at 6.9V, and
they will last at least 5 years.
I suggested a super cap because they are cheap, and tend
to last a very long time without leaking. 100F will
keep a BBB up for quite a while if it isn't driving the
network, or usb devices.
Regardless of the power safe mechanism, it would be
best that the BBB get an interrupt at the moment power is
deemed bad, and starts an orderly shutdown. To guard
against power bouncing, it should be prevented from
restarting until several seconds after shutdown is
completed... some sort of timer should be part of
the power safe mechanism.
-Chuck Harris
cheater00 . wrote:
If having a battery in the device makes some of you queasy, you could
always put it outside, on the back. But I seriously believe there are ways
to make battery backup which will not leak.
D.
On 27 Feb 2014 06:52, "Chuck Harris" <cfhar...@erols.com> wrote:
That fix presumes that the power line never quits at
inappropriate times. This winter has provided me with
ample reminders that power can go out anytime.
I think a better solution would be to find a very large
"super cap" and power the BBB from that while giving it
a power fail interrupt to quickly sync the file system.
-Chuck Harris
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