[Gasification] DC to AC inverters: was ((Re: Something Might beWrong (OT??))

[Peter Singfield]

At 12:42 AM 4/14/2007 -0400, you wrote:
>On Friday 13 April 2007 11:56 pm, Harmon Seaver wrote:
>>    Hey guys, there's an awful lot of 24v inverters out there, and also
>> some 36v and 48v inverters. Look around. Anybody doing serious off-grid
>> with batteries and DC does not use 12v -- most any 12v inverter is
>> bottom of the barrel minor league stuff for truckers and small RV's and
>> even then most serious truckers and RV's use 24v.
>
>Hi Harmon,
>
>Your correct and they are better because they draw less current but all seem 
>to be out of my price range.
>
>
>Jeff
>

Found these Jeff -- though not as cheap as the Chinese ones -- they do
already "stack" -- so you could stack three together -- pulling 12 volts
from three separate taps into your 36 volt battery pack.

12 Volt DC input - 1400 Watt 220 Volt AC Output, 60 Hz
(2,800 Watts Surge!) Only $245.99

http://www.survivalunlimited.com/inverters/militarynavy.htm

They are also up on Ebay.

So -- for a total of $750 you would have 4.2 kw of AC power -- and run off
your golf cart --

Have appended but some of the text from that sight.

I sell those one KW inverters I have here for $220 Bz -- or $110 US each --
but they can't be stacked -- and more the "shame" -- but maybe we can fix
that in the future??

Anyway -- for those that have in interest -- see the above WWW site -- in
regards to why one needs to stack!!

Gasifier power plants should be especially interested in this kind of
technology -- and here is "why"

It is much easier to have "attended" gasifier power plant operation than
"Unattended" -- the automation required to run a gasifier power plant
totally "unattended" by a human is costly -- complicated -- and prone to
breakdowns and high maintenance.

So what to do -- what to do!!

Well -- I am importing some really neat Permanent Magnet DC Dynamos -- 90%
plus efficiency.

These produce up to 6 kw in the 23 to 32 volts DC range (they are used as
portable electric welders in China)

So -- you hook one of these to your gasified power plant -- run the plant
for 3 hours or so as required to charge your batteries -- then run off
inverter the rest of the time.

Battery packs live longest if operated in their sweet spot -- that being
not more than 30% discharged -- 

To top off that charging cycle requires long periods of low charge rates --

However -- I have been running an experiment at my farm power plant.

We hard charge at maximum amps for two hours -- twice per week.

We never discharge more than 20 %

Every few months we hard charge for an hour or so extra -- boiling the
batteries a little.

I( am using four standard el cheapo 12 volt car batteries for a 24 V system --

We are 18 months into it now -- and the batteries are still like "new"

I use a special multi voltage -- non-"smart" charger.

It is huge -- heavier than an electric welder -- is rated 50 amps
continuous for 48 volts charging -- but also has settings for 6 volts -- 12
-- 24 -- 36.

Each setting also have five extra positions -- slow to fast "charge"

To "boil" the 24 volt battery set a little -- we run the charger in the 36
volt setting -- number 2 position charge -- which even on fully charged
batteries - -will still draw 30 to 40 amps!!

We do that for about 15 minutes -- voltage goes up to about 33 or 34 -- at
the batteries -- you start hearing the light fizzing -- then you wait 10
minutes -- shut it down.

The technical term for this is called "equalizing" your batteries.

In the real world -- gasifier operators are going to have to learn some of
all of this --

Ergo -- inverters -- chargers -- batteries -- is not off topic.

The very best solid state AC to DC charger I have found for 24 volts packs
is this high efficiency DC electric welder - -which I use for welding her
all the time.

Jeff -- you might want one of these:

http://www.usaweld.com/products/index.htm

Using mine -- I can pump out 100 amps into a 24 volts battery pack easy!!

You have a dial on the front -- that give welding amp strength -- that is
not click position -- but continuously variable -- 

You hook up your voltmeter to the battery pack and dial in the power you want!

It does very good DC stick welding -- and TIG as well!!

Some models do even plasma arc cutting to.

Gasifiers for small power plant operation for us "poor" people will always
be about "batch-mode-operation"

Harmon -- you should be happy your so rich as not to be concerned with real
issues.

So can make statements such as you did:

"Hey guys, there's an awful lot of 24v inverters out there, and also
some 36v and 48v inverters. Look around. Anybody doing serious off-grid
with batteries and DC does not use 12v -- most any 12v inverter is
bottom of the barrel minor league stuff for truckers and small RV's and
even then most serious truckers and RV's use 24v"

Inverters are an expensive part of the scene -- have a tendency to blow up -- 

Better a number of cheap ones than a single -- fancy -- large and terribly
expensive one.

The reason 12 volt inverters are so common is due to transistor logistics
-- low voltage high power switching transistors (MOSFETS) are much easier
to make -- thus much lower in costs.

I believe that at least 48 volt DC power packs is best. For reason of
current load -- as you specify.

It is what I would want -- but what I need is never the same.

The lower volt transistors also live longer. Take more punishment without
going "boom"

Ergo -- use 12 volts -- but "stack" them!!

The survivalist is right when he stated:

"The days of having a single BIG inverter are numbered!"

But granted -- in a land of to much and far to rich -- to far disconnected
from actual hands on survival -- seeing things clearly can often be very
difficult -- so for now Harmon -- your excused -- and knowing you -- you
will be checking out those urls -- and maybe even researching a little
deeper -- and deriving your own conclusions -- which I certainly will be
interested in reading.

The "point" is -- learning about inverters -- chargers -- batteries -- is a
must for any serious gasifier power plant project!!

Harmon -- I'm learning the hard way -- and that has hurt me financially to
a great extent -- I cry when I think back on it.

I paid $1500 US for 48 volt DC to 120 volt AC -- 2400 watt -- Tripplite
inverter -- state of the art - -and heard it blow it's transistors but two
months later!!

I then went on to lose over $3800 USD in ordering up numerous kinds of
inverters from China -- from 1 kw to 3 kw -- all 48 volt DC -- and all
blowing their transistors -- some in a couple of months -- some in 6 months.

I then bought -- here in Belize -- a cheap 1 kw 12 volt inverter -- that I
saw the Mennonites using -- and that opened my eyes to "reliability"
questions.

I then sources some of those from China --

They have proven very "indestructible"

They are very efficient as well!!

I have no scop here to check out the sine wave produced -- but we have
developed another simple way for testing that.

Here in Belize we are over-run with cheap compact fluorescent lights. Some
of those are bad news -- and need very perfect sign wave to work.

They work poorly -- burn out fast -- when drawing down power from a two
pole generator.

They still flicker -- though very slightly -- and do not burn out fast -
-when powered from a four pole ST generator.

So here -- among us instrument deprived peoples -- we use the cheap CF
lites to test inverter quality.

The first cheap Chinese inverter I bough here in Belize could not even
light up a cheap CF unit -- and smoked it trying to!!

These cheap chinese inverters I have now run cheap CF lights at the farm
always -- and with no flicker at all -- and for long long hours (in 8
months -- not one burned out yet)

So Harmon -- understand how things advance in real 3rd world -- it could
come in handy -- cause maybe that will become part of existence soon for
many living in the great industrialized countries -- eh??

Harmon -- the future lays in stacking these cheap inverters!! 

The future also lays in learning how to recycle burned out car batteries
into high quality Plante style lead acid power plant batteries!!

so one can recycle lead for ever!! And not be tied down in huge capital
costs replacing battery power packs all the time.

For me hear -- at the "front" - -these are vital and crucial projects -
-they should be for folks on this list to!!

Check out this PDF on how they are approaching battery recycling in El
Salvador.

http://www.ilmc.org/Basel%20Project/El%20Salvador/Visit%20Reports/PDF/Visit%
20Report%20El%20Salvador%20Record%20Batteries.pdf

So many real things to do -- but so few people to help get anything done --
they all sleep to deeply -- dreaming in great colors.

I guess that is what fluoridating the water does to the people??

By the way folks -- stacking 1 kw inverters is not for supplying power to
one personal residence.

It is about supplying power for a number of residences in a small village
setting -- and also -- extra power for one "shop" (store) -- maybe to
supply refrigeration.

The entire "project" is in a continuous state of evolution due to the ever
changing circumstances and the always horrendous learning curves.

I was playing with my burn anything stove last night -- feeding it coconut
husk -- which it just loves -- and burns up smoke free.

I see now how to design another small unit specially tuned for burning
nothing but husks. With no need to chop them up -- at all!!

More later -- if I find the time ---


Peter/Belize

************appended***********

POWER ARRAY
° Stackable Power Inverters
° Modular Array Design
° Build up as much or as little power as you need!
° These inverters may be used alone or in multiples!
° Each power inverter in the stackable modular array is rated at 1400 watts
° You may put together as many as you wish for all the power you ever need!
Design notes:
° Units stack on the AC side in parallel ONLY but NOT in series
° 110 + 110 in series will NOT work out to be 220 volts
° The computer will shut both units down as a fault or a short 
NEW communication cable technology allows one inverter to talk to all of
the others keeping them all in phase together! Each of these "SMART"
inverters has a powerful micro computer on board. Amazing new technology
will sweep in a new era for all power inverter designs to come! 
Put 10 together and get 14,000 Watts with 28,000 Watts surge! 
Enough power to run a large home!


Put 100 together and get 140,000 Watts with 280,000 Watts surge! 
Enough power to run a small town!


Put 1000 together and get 1,400,000 Watts with 2,800,000 Watts surge! 
Enough power to run a small city!

• If one inverter fails the rest of the array still works! 
• Redundant dependably at its best,,, just like the internet. 
• The days of having a single BIG inverter are numbered!