[aprssig] Shack backup power

Bob Bruninga bruninga at usna.edu
Sun Jun 5 14:19:23 EDT 2011

> But you've avoided my question which was to name 
> the manufacturer of the plug-in grid-tie inverter. 

Just googlee the words "micro grid-tie inverter" or something like that.
That is how I find them.

>> But even then the system has to be desigend
>> for the worst sun in December to still meet that minimum
>> load.  By DFINITION, then in the summer, when there is
>> TWICE the total energy available, there is just no place 
>> for it to go.  The load is the same.  THe other HALF
>> is all wasted... That's why grid-tie wins hands down. 
>>  Every penny of solar energy is credited to you no matter 
>> how or when you use it.

> So just put some extra load on the system in the summer.
> ... so run a mini-fridge in the shack with the spare power...
> ... Or pump some water into a storage tank... [and then]
> water flows back out at night into a generator to supply 
> nighttime power.  How about using the excess energy to heat 
> water and take some load off the main hot water heater?

Sounds like an awful lot of effort to either find a way to use the energy
later (pumped water) or to find ways to waste it, when the beauty of
grid-tie is that you get 100% value for every watt generated and you can use
it anytime, anywhere, even months later for full credit.  No moving parts,
nothing to maintain.

> You make [battery storage] sound all doom and gloom and 
> it's not.

Ok, lets just day then that for -me- personally, investing huge amounts in
batteries for storage that is only 60 to 70% efficient, requires maintenance
and replacements periodically for life, and which cannot store excess summer
power for later winter use is pure gloom and doom.  When with grid-tie, I
get 100% free storage, no moving parts, no maintenance, and full credit at
RETALI rates plus free use of my stored power at any time of the day or year
just seems better to me.

> Grid-tie isn't a one-fits-all solution.  It works in 
> many cases but you can also make a battery system work 
> without waste, too.  You just have to be smart about it.

I guess we will just have to agree to disagree.  

There is just no way that a typical house (10,000KWH per year) energy system
can EVER be cost effective with batteries which, by the laws of physics lose
30 to 40% of all the solar power stored in them and cannot store the DOUBLE
power excesses of summer for use during the winter.  Compared to what is
being done every day now by the millions across this country because
grid-tie has finally made it economical for the full sized home system to
provide power at those levels, with basically ZERO maintenance for life.

Again, I am talking about large home-sized systems.  There is still very
good reason to have a battery or two for emergency backup shack power..
COMpletely different issues.  Who cares about the extra watts lost when it
brings you backup power.  But not on the scale of homes, then waste is not
economical on that scale.

Bob, Wb4APR

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