Powerbuilding and Towerbase started

[ibedonc]

Got my slab poured for my Powerbuilding

and also got one of my tower bases done

[ibedonc]

Pic of the tilt tower base

I still have to finish bolting it down

[Experimental]

       Very nice, wish I had more time, to get something like this done -- will keep looking for more pics --- Good job !!  Bill H........

[MountainMan]

How big will your power building be?  In my area I can build a "shed" up to 10 feet by 12 feet without the nuisance of dealing with the county permitting process.  (Heck, maybe I'll just build myself a little villa with about 20 of these little sheds and skip the house altogether - no permits!)

I'm wondering if a 10X12X10 foot "shed" would be big enough for an off-grid power building.  I'm figuring to have a small backup genny, probably 16 8D size batteries, dual Outback 4024's, all the solar controllers and wind controllers, and of course some large electrical panels etc.

If I rig up a way to "stack" the batteries in a verticle column they won't take too much room.  I'll make it so the door opens out instead of in.  I don't know, do those of you who have such a place already think I'm dreaming?  Any chance of getting all that into one "shed"?

Also curious what is the most common building material for this.  I'm thinking probably cement blocks and a metal roof for fire resistance (fire from the outside that is, not the inside).

thanks,

jp

[ibedonc]

8' x 10' , and I will have racks for the batteries strong enough to go almost to the ceiling and I am going to make it a 10' ceiling with a electric hoist , some of my batteries weight in at 100lb's

the slab was poured  6" with 12" x 24" beems and lots of rebar

this is also going house my 40kw Sinewave inverter I am building

[wpowokal]

Note of caution here, it is very wise to house the electrical equipment seperate from the batteries.

Any gassing (if batteries are vented type) may cause corrosion to your inverter etc, not to mention explosion potential.

Also advisable to seperate the generator, from electrics and batteries, if run on a fuel other than propane. Any carbon in the exhaust will find its way into the electronics as will moisture resulting in loss of magic smoke.

allan down under

[MountainMan]

Alan,

Thanks for the interesting points.  Don't most stationary generators have an exhaust pipe that you can run outside?  If not, I think I would want to rig up my own method of venting the exhaust from the shed.

best,

jp

[MountainMan]

40kw??? Decimal in the right place there?  Wow, have you built a smaller one before?  I've built some significant sized power supplies for computer equipment before.  Hard to imagine the size of components needed for a 40kw inverter.  That's about 85 amps on each side of a 240V setup!  

Have you thought about maybe setting your DC storage up as several independent series connected banks to get a DC voltage higher than the AC Peak to Peak voltage?  Then you could build your inverter without any big coils. (for 40kw, they would be huge even at a high frequency - big honk'in wire).  Just thinking out loud.  The output stage of the inverter essentially just becomes a really heavy duty class B amplifier.  Much cheaper and easier to design and build.  Probably more efficient also.

I would be interested to hear more about your inverter project.

best,

jp

[ibedonc]

for a 240vac PWM inverter you need a min of 400v dc to get that

and I have thought about running 32 12v batteries in series to get that

and yes 40,000 watts was not a error

I have the smp cores to get that much

40,000 watts @ 400 volts is 100amps

after the PWM to get your 240v sine it is still 95% of 40kw

volts lower , amps will be higher

[MountainMan]

ibedonc,

I missed something.  If you have the necessary DC there is no need for PWM.  Just a 60HZ sine wave generator feeding a seriously powerful amplifier.  As for 400VDC, it's been centuries since my BSEE - you're probably right.  My worn out gray matter would have thought the 240VAC was RMS voltage, and would have done 240*1.414 to get 340VAC peak to peak...ok, maybe 400VDC for transistor imperfections and safety margin.  Afterall, a little bit of clipping on something like this would cook lots of expensive electronics in a hurry!  32 12v batteries deep cycled to 10.6v is about 340VDC, which is actually cutting it awful close without the pwm.  Might want to goose that up to 36 batteries for safety (without the pwm).

Anyway, why the need for any PWM at that point?  Is my 60Hz sinewave amplifier idea off in the weeds for some reason?

Come to think of it though, 36, or even 32 separate charge controlers adds a fearful bunch of money to the equation.  Maybe need to rethink this.

thanks,

jp

[ibedonc]

think of my PWM as a class-D amp , less energy wasted as heat

and I would charge the batteries as a string with load balance circuits

and would not like them get that low , maybe 11.5 would be the lowest I would go

[MountainMan]

OK, I get it.

But what does the big DC do for you then?  Couldn't you accomplish the same thing with different winding ratio on your high frequency transformers?  I was thinking of it as a way to skip the transformers altogether.  Seemed like that was the only benefit to the high DC input.  I guess the other difference is more reasonable current levels in the low voltage side of the pwm circuit.  Perhaps that's what you're after.  40kw/24VDC=1667 amps, ouch.

BTW, I hate being nosey but I've gotten more and more curious what you need all that power for. If you feel like sharing...

thanks,

jp

[ibedonc]

getting closer , gen pipe adapter just needs some bolts , cables run , and need to be connected