settled the inverter question

[mobile_bob]

because i plan on being offgrid in the future, having an inverter(s) is basically a fact of life
the questions were what manufacture, modified square wave, modified quasi sine wave, superduper modified whateverwave
and various pure sine wave units, and finally what voltage.

as most probably know, 12volt systems will work, but higher system efficiency generally can be had going to 24 or even 48volts
and most appliances prefer pure sine wave over the cheaper modified whatever wave.

did my homework and really wanted to get to where i could scrape up enough money for an Exeltech MX series system
and thought i would like one powered by a 24 volt system,, that is where all my support equipment was aimed at the 24volt
nominal system.

well i got really lucky a while back and found a rather large installation of exeltech mx series 48volt system
between myself and a partner we managed to amass about 60kwatts of capacity, they can be setup as singlephase
split phase 120/240 or even a 3 phase system (which i might very well do).

we got an excellent deal on the lot, and apart from some rather bizarre ebay seller problems and the way he packed the darned
things and then shipped UPS it is a wonder any of it got here in one piece.

but it all got here, and so far all of it works

as for exeltech mx series inverters, they are pretty much the industry gold standard for having the lowest distortion rated at
less than 2% and frequently on most loads under 1%, mtbf of 20 years, they are also hot swappable and redundant and load
into racks so if one inverter fails the rest of the rack keeps right on like nothing has happened. the inverters are 1kwatt each
and surge for 3 seconds to 2.2kwatts.

the best part is any exeltech mx series inverter that ever fails they will fix any repairable failure for a flat fee of 100 bucks
thats not bad at all in my books.

i am pretty excited about the system, and look forward to working with them or rather living with them when the time comes.

anyone thinking about inverters check out exeltech at exeltech.com
and watch ebay, they do come up every once in a while.

so i guess we call this thread a product endorsement or gloat?



bob g

[Henry W]

I checked out exeltech's site a little over a month ago and I believe that will be the way I will go in the near future. I picked up the little Cat to run two Leece-Neville 160 amp alternators. I think this will be a fun project and I can't wait to start. Need to start drawing prints.

Henry

[Capt Fred]

Great score Bob!

I've got five years on my outback - no problems - no complaints.

Buddy of mine is running a 48volt grid tie outback inverter with 120 to 240 transformers - he's taking the 120volt output from the st head running thru two transformers (one for each leg) which is reduced to 60 volts then bridge rectified to d/c - and badda bing, ya got a grid tied 'roid - without alternators - works awesome!

Fred

[mobile_bob]

Fred: that sounds like a good solution to grid tie and a lister

Jens:  the exeltech mx series are not grid tie capable,, not sure if exeltech is into the gridtie market yet
with any of their products.

bob g

[Jedon]

I am intrigued. I am just getting my Metro 6/1 running and it's hard to get it to feed reliably to my two Xantrex 5548's, one pole of the ST-5 to each inverter. I had originally thought the inverters would clean up the power from generators but it doesn't, it just passes it right along. The problem is the lister when under load drops the voltage down to under what the inverter wants, but when I give it enough throttle to run at say 115V under load, it's at 132V at first, I hope that isn't getting passed on to my computers! I have about 360W of solar right now hooked directly to the 48V battery bank and will be putting in more panels plus hydro next year so I'll need a charge controller anyway. So... explain to newish guy how to hook the ST-5 to a XW-60? Thanks!
PS. Even my Onan gas genset isn't making good power, drops the Hz down to 55 and my UPS's have an absolute fit.

[veggie]

Great score Bob!

I've got five years on my outback - no problems - no complaints.

Buddy of mine is running a 48volt grid tie outback inverter with 120 to 240 transformers - he's taking the 120volt output from the st head running thru two transformers (one for each leg) which is reduced to 60 volts then bridge rectified to d/c - and badda bing, ya got a grid tied 'roid - without alternators - works awesome!

Fred

Capt Fred,

Just curious, why use transformers to make 240 vac ? Does the ST head not produce 240 already ?


Veggie

[Capt Fred]

He is using them to step down the voltage from 110 to 55 A/C then rectify to D/C for the grid tiie inverter to put back into the grid.

Not the most efficient - but he runs the 'roid on wvo so reasonable inefficincies are't much of a bother.

Been running this for a year - only problem is the transformers are kinda "light duty" for the job - had to rewind them with bigger gauge wire.

Will be doing the same as soon as I can get ahold of a sunnyboy inverter - no need for the transformers with them - just rectify to D/C .

Cheers, Fred

[lowspeedlife]

Hi Capt Fred,
I'm havin' a little trouble following this, so if i'm reading right:
He's making 240 ac & stepping it down to 55/60 volts ac thru  two transformers (one each leg), rectifiying it to dc to feed it into a grid tied inverter, that changes it back to 120/240 ac to feed the grid.
Is this correct?.   Thanks, Scott R.

[Capt Fred]

Hi Scott

Yup, that's pretty much it , except its 120 to 60.

Here's what "George" (not his real name" is doing.)  Running a 12/2 listeroid driving a 10kw ST head - total combined output of the ST head is  240 volts (2 120 volt legs)

He has a stepdown transformer wired into each of those 120 volt legs so each transformer outputs 55 - 60 volts A/C - he then rectifies that 55-60 volts A/C to D/C for the inverter - which can then take that and put it back to the grid.

System needs a shutdown, cutoff or alarm in the event the grid goes down so you dont overcharge batteries (and our grid is pretty crappy) so that part is really important.


Hope this  helps.

Cheers, Fred

[Jedon]

Does this work without the grid part? I don't think my XW 5548's take DC as input.
I do have a huge 14Kw UPS system that has 10 12V AGM batteries at 120V DC and has a huge transformer that outputs 240V, it's designed to provide a lot of power for 30 minutes not a little power for 24 hours but maybe it could be part of the process?

[Capt Fred]

I would imagine that without grid tie one would be better off with a surplus golfcart or forktruck charger.

[lowspeedlife]

Thanks Fred, sound interesting.
  scott r

[Capt Fred]

I'm looking for golfcart or forktruck charger along with the sunnyboy - we have unreliable power in addition to typhoons that disrupt power, I like the idea of having something more substantial than the internal inverter charger to charge batteries.

[mike90045]

I am intrigued. I am just getting my Metro 6/1 running and it's hard to get it to feed reliably to my two Xantrex 5548's, one pole of the ST-5 to each inverter. I had originally thought the inverters would clean up the power from generators but it doesn't, it just passes it right along. The problem is the lister when under load drops the voltage down to under what the inverter wants, but when I give it enough throttle to run at say 115V under load, it's at 132V at first, I hope that isn't getting passed on to my computers! I have about 360W of solar right now hooked directly to the 48V battery bank and will be putting in more panels plus hydro next year so I'll need a charge controller anyway. So... explain to newish guy how to hook the ST-5 to a XW-60? Thanks!
PS. Even my Onan gas genset isn't making good power, drops the Hz down to 55 and my UPS's have an absolute fit.

The XW's operate in a "Generator Support" mode, as you found out, they will sync to genset, and and support it.  If you can convert your crankshaft power to 50VDC, and feed the battery bank, then you fire the inverter section up, and feed your loads/grid clean power.

[WGB]

I'm looking for off grid inverters myself!
Have some pics of your equipment Bob?