[mythtv-users] Netbook as low-power combined back-end / front-end?

[rsh1k]

On Wed, Aug 29, 2012 at 8:35 PM, Michael Watson
<michael at thewatsonfamily.id.au> wrote:
> On 28/08/2012 4:44 PM, Simon Hobson wrote:
>>
>> On the other hand, if you pick a system that runs off 12V (as some of the
>> ION boards do, then in principal you should be able to just hook this up to
>> a 12V lead acid battery and use a 13.8V supply/battery charger instead of
>> going with a full UPS. Also, for things like the mini ITX boards, there are
>> PSUs designed for in-car use that run from a battery and will auto-shutdown
>> on low battery etc.
>
> Not exactly an energy efficient way of doing it, unless your battery charger
> is smart enough to stop charging when battery is fully charged, or not
> charged at all when battery is charged and directly power the PC.  Could be
> super efficient if you used a solar charger to keep battery charged, and
> charge generated was enough to power the machine during non daylight hours.
>


Even so, I've been looking at the numbers, and I'm not sure going
solar powered in this way would *EVER* pay off, even if your system is
100% off-the-grid with an electricity bill of zero...

Perhaps someone else can double check, but it seems like with a
low-power device (~25 watts), electricity at $0.13 to $0.15 per kWh,
and deep cycle batteries at ~$200 with a life expectancy of 4-8 years
(depending on the depth of cycle), when compared to simply plugging
into the wall, you wouldn't even save enough $$ to pay off the battery
before it needed to be replaced again.   And that doesn't include the
startup costs (chargers, solar panels, regulators, etc) - it is purely
just the annual "maintenance" costs.

Is that right?   Perhaps a better option is a much smaller and cheaper
battery, as a short-period UPS only (not deep cycled every night), and
using the solar power from a smaller panel purely to offset part of
the daytime power usage?

- rsh1k