Forcing Xantrex inverters to give me clean power

[Jedon]

I'm trying to figure out how to get rid of flicker and high voltages in my setup. I have 2 Xantrex SW+ 5548's which are hooked to 16 Trojan L16H in two banks at 48V. The Metro Lister 6/1 CS with ST-5 feeds the inverters at 220V, 110V pole into each inverter with the neutrals bridged. The inverters just pass AC through, using some to charge the batteries. For the first hour or so this is fine since it tends to load both poles evenly. After that it starts floating the batteries and just takes around 7 amps from one pole and doesn't use the other. The problem is that this causes the loaded inverter to pull a nice 107V from the ST-5 but the other inverter that isn't charging the batteries is now unloaded and running at 138V! The ST-5 groans when you load only one side, well it groans if you load just one pole and growls if you load just the other.  The only reason I need two of these inverters is to run the well pump, 5500W is plenty for the rest of my household needs. My idea was to rewire the ST-5 to give me evenly loaded 110V and feed one inverter that would basically function as a charge controller, and pull all my house power off the other inverter which should give me clean inverted power from the batteries and the other inverter would just pull more amps from the CS to keep the battery voltage up. Before I go rewiring my breaker panel, anyone have any thoughts on my hair brained schemes? 
Thanks!
-Jedon

[mike90045]

Get a 240/120 transformer,  and set the ST head up for 240V    Use the 240 for the pump, and pull off the transformer, 120V for the rest. 
It's a big transformer.

for my setup, I'm using a XW6048, and feeding 240 from the ST, into the XW, and charging battery bank from that, and counting on the beefy XW  240 output to handle it all. The XW6048 is a split phase output, no transformers needed. With solar, I hope to only fire up genset to charge every other day in winter.

[Jedon]

Aren't those buck transformers around $500?
I can get 240V out of the bridged inverters, why spend money on a transformer?
Not trying to be defensive, just wondering.
Inverter#1 - powers most of the house and does not have AC input therefore ( I think! ) inverting from DC clean power
Inverter#2 - other 110V leg to 220V well pump as well as some of the house load like perhaps the dryer or something.  Has AC 110V input from the generator and charges the batteries.
I do have 780W of PV hooked directly to the battery bank, no charge controller. Open voltage 65-69V, sometimes gets the batteries up to 52.2V, hopefully more in the summer.

[Jedon]

Hmm maybe I have a neutral issue?
http://www.smokstak.com/forum/showthread.php?t=67923

[mike90045]

I can get 240V out of the bridged inverters, why spend money on a transformer?

Because you use the transformer to balance the ST, then you let the transformer take the imbalance.  But why not parallel the 2 ST windings, and make full power that way.   

Is there a way to parallel the ST windings for 120V, 2x amps? or are you stuck with 2 unbalanced  windings ? MAybe different heads have different options.

Yes, the transformer is spendy, but their bearings last a long time.

[BruceM]

Making a detailed system wiring diagram might solve your problem (i.e. neutral)- we can see what's wrong or you'll find it yourself when doing it.  You will see some very big voltage swings if you end up using the earth grounding system as the primary neutral path.  But ST's are famous for not liking a load imbalance.

Step up/down transformers are pretty cheap now on ebay.  $200 for 5000 watts, less for less.  You can get an extra 8% efficiency with toroidal transformers, if you're in the mood and don't mind the extra bucks.

[Jedon]

Mike, http://utterpower.com/installa.htm
Bruce, Hmm thanks I'll check that out. Any term I should use when searching? 8% better than normal ( 2% loss? ) or 8% overall losses?

[Apogee]

Why not dump the ST head and go with one or two nice 48 vdc alternators instead?  

Power the house et all from the battery bank using the inverters and replenish using the Lister when necessary.

The Lister can cause all the flicker it wants and it won't matter one bit.

Also sets you up for using wind or solar when the time is right.

This has been my plan all along.

Steve

[Jedon]

Wouldn't I need to dump the 48V from the alternator into a charge controller?
I had considered that, I was also contemplating bucking the 120V down to 60V from the ST and rectifying it.

[Apogee]

I believe that you'd just disable the charging on the Xantrex's (so they don't buck against the alternator) and make sure you buy alternators with built-in regulators.

99% of them already have regs built-in to them so it's a non issue.  I posted awhile back (can't remember which forum) regarding 48 vdc high output units that are used in ambulances and rigs like that which need lots of power.  Looked to me to be the perfect fit...

Bob has also talked about rewiring a STC head to take advantage of the 60 volt leg and that would be another option but would need a charge controller.

Steve

[BruceM]

A regular transformer might be 85%, a toroid 93%.  Both vary some based on quality, but toroidal transformers are typically premium made.

Seems like a charge regulator for both PV and AC is what you need.  A smarter charger will make your batteries last a lot longer- temperature compensation and proper peak charging- (not a fixed voltage) are the way to go.

[Jedon]

Ouch 15% loss is pretty high!
Charge regulator is the same as a charge controller? I need a MPPT or just a PWM? I have two PV banks of disparate panels and will be putting in hydro in the next year or so.
Xantrex blurb says the charger has: Multi-stage charging Bulk, absorption, float/silent, and equalize and is temperature compensated.

[BruceM]

Yep, that's a smart charger, will make your batteries last longer, and fill up faster on PV since they'll take it all the way to full much faster than a dopey fixed voltage charger.  PPT is of some help in efficiency, too, in some lighting conditions.

All the smart chargers are using PWM- it's cheap and efficient, though it spews EMI all over your system (though no worse than the inverter).  Someday in the distant future there may be specs on these emissions for biological health reasons. Meanwhile, dirty PWM based systems are all that's available.

[dubbleUJay]

............... though it spews EMI all over your system (though no worse than the inverter).  Someday in the distant future there may be specs on these emissions for biological health reasons. Meanwhile, dirty PWM based systems are all that's available.

Bruce, this it off topic and I don't want to sound nosy, but it seems that you have a big thing against EMI
I read somewhere that you said it influence health issues. An old timer I knew use to "cringe" when we drove near or underneath HT Power Lines and I couldn't understand it, I just thought he was paranoid.
Is there somewhere where I can read up on this, he's dead now, but maybe I could understand it better.

This might be why my "better half" is so full of s*** sometimes and I always use to blame the full moon when she starts! 

[BruceM]

There is slow but growing acknowledgment that about 3% of the population have serious adverse reactions to EMFs, a larger group are affected but not acutely.  An article by in the Jan. issue of Prevention magazine is co-written by a researcher friend of mine, Dr. Sam Milton (MD), perhaps I can forward that to you if you are interested.  

I have MS and Epilepsy following a chemical injury in a new sick building which had aircraft composites being baked in the same closed space as my office, with the exhaust located less than 10 feet and upwind of the building "fresh air intake. Testing showed profound short and long term memory loss, and the  pattern of cognitive impairment that comes with toxic exposure; still genius level in some areas, while functionally retarded in others. It has not improved my mood or personality.

My epilepsy is aggravated profoundly around electronics.  This after a career in R&D of computers, software and electronics.  I can't use a normal computer, or even have one in the house.  I had to develop my own shielded projector, designed for low EMFs and using a line voltage halogen lamp.  I designed an optically isolated, remoted processor,  "passive matrix" keyboard as matrix strobed keyboards have me floored in minutes. The keyboard project was the most difficult, as it must be right in your lap. I developed an analog fiber link for video, audio and fiber keyboard/trackball (also custom), so the computer can reside in my shop while I'm working at my rear projection workstation.  With this work that took me several years, I have had computer access for the last 7 years or so.  I have vision problems which still make it stressful, but I manage.

I can't be in normal buildings for long at all now that fluorescent lights, computers and wireless systems are everywhere.  I like going out but pay later dearly. I can only drive safely for short trips and with a specially modified diesel car (no electronic injection) with a solar panel in the roof to keep the battery topped off.  Until a new cell tower was put in, I could go sailing on a local pond.

My MS gets "turned on" by very low level magnetic fields, so now all my shop tools are air powered.  

What makes me angry besides for the impact on my life quality, is that it is readily technically solvable; we don't have to give up our technology, just learn to use it more wisely.

More than you wanted to know, but yes, I'm biased.

Best Wishes,
Bruce