[aprssig] [OT] RE: APRS Solar Power (I was wrong)

Dave Baxter dave at uk-ar.co.uk
Fri Oct 2 08:43:38 EDT 2009


I don't know about US refrigerators, but over hear they take an almighty
kick to get the compressor motor started.  Not exactly (sadly)
inverter/UPS friendly, or for that matter, small IC engine/alternator
gen-set friendly either.  My 2.5kVA Honda powered gen-set, just will not
start our fridge, and that is an "A" rated appliance, so is a low energy
usage device.  (I forget the Wattage.)   It will run the central heating
system just fine though. :)

I did experiment a while back with a simple change over relay (NOT
recommended!) and found that once the compressor is running, the genny
run's it just fine with hardly any loading.  But it still seems you need
the full 13A of the utility power socket to kick it into life in the
first place, or some warning that it's all about to go dark so as to
"prepare" for it, among other things turn the 'stat to Max (or would
that be Min' for a 'fridge?).

"Absorption" types by comparison, are just a resistive load (heating
element) with a thermostat controller, so they do work just fine on
inverters, there again, the most common Absorption refrigeration items
over here are the "3 way" (12V, 240V, Propane/Butane) types used in RV's
as you'd call them, best to use them on the bottled vapour stuff if the
lights go out.  Assuming you have bottles of the stuff about the place,
and you can get the blessed things to light!   Some of the solid state
Peltier Effect units are getting quite good too.

CFL lamps though, (if you can stand the QRM!) work very well on
inverters I've found, giving an embarrassing amount of light.  Some seem
to flicker oddly (just enough to be annoying) on a Modified Sine
inverter, maybe the harmonics are beating with the lamps own oscillator?

Lead Acid batteries are also not that efficient, when you compare what
you can get out of them, vs what is needed to charge them, in VA terms
that is, and the higher the discharge, the worse they get.  But for most
people, they are the only "practical" system for electrical energy
storage, until the Supercap people get things ramped up that is.

I was watching a re-run of a Top Gear episode last night, where they
tested a prototype Left/Right hand drive, Hydrogen fuel cell powered car
(by GM.)  Apparently it could generate enough electricity to power a
house of course, much like the Prius.   Not a production item yet, and
the process to produce the Hydrogen in the first place needs utility
energy of course.  Emphasising the bottom line, the energy has to come
from somehwere, whatever form you might store it as.  Are there any
domestic "Solar to Hydrogen" converters yet?

Out of curiosity, if you let your Prius run right down, and you had no
fuel for the (slightly) noisy bit up front, with all those solar panels
you have on it, how long before it would have enough charge to be useful
again?  Genuine curiosity, after someone else asked me a question about
this sort of thing.


Dave G0WBX.

> -----Original Message-----
> On Oct 1, 2009, at 2:57 PM, Robert Bruninga wrote:
> That, a few deep cycle batteries, (and using CFL lightbulbs in your 
> house) will give you enough emergency power to operate your full Ham 
> station, all the lights in the house you want plus your refrigerator 
> for as long as you can buy gas.

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