240 vs 120 volt inverters

Cariboocoot

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

No, but for what it can power, for what I got in it, it is. Try running our loads with just inverters and batteries and solar and wind. THEN you're going to spend some SERIOUS money! The point is that the generator is a pretty compact, relatively cheap high output power source compared to RE things that make power. Don't be afraid to use that generator. With same careful engineering you can maximize its efficiency and get by pretty nicely without breaking the bank.
--
Chris

It is indeed.
In fact many off-grid users do what you do albeit without the added functionality of gen support and autostart: many a cabin has a big gen used only when the large load is needed and taking over all the other loads (including a bit of battery charging) when running.

To build up a battery-only system to the level where it can run very large loads costs a lot of money just as you say. If you only need those loads occasionally it is foolish to do it that way for sure!

NorthGuy

Re: 240 vs 120 volt inverters

verdigo wrote: »

I think Chris has me sold on the XW, but I think the XW4548 will suit me.

It is a very little price difference between XW4548 and XW6048, and there's no benefits that XW4548 has over XW6048. I would suggest buying XW6048 instead. If nothing else, it will run cooler.

XW4548 would be ok for me, but I'm glad I have XW6048.

ChrisOlson

Re: 240 vs 120 volt inverters

Cariboocoot wrote: »

It is indeed.
In fact many off-grid users do what you do albeit without the added functionality of gen support and autostart: many a cabin has a big gen used only when the large load is needed and taking over all the other loads (including a bit of battery charging) when running.

Without generator support, that's a good way to do it. When I looked at maximizing gen efficiency you can always get better efficiency by passing gen power directly to loads than you can by using gen power thru an inverter charger to charge (inefficient) batteries, then later converting that battery power back to AC.

The key is how the generator is managed by the system. The inverters that don't have generator support mostly have to be manually managed, while the ones with gen support are totally automatic and have more adjustments for how you want it to manage your generator power.
--
Chris

verdigo

Re: 240 vs 120 volt inverters

Chris. Your exactly right about my intentions. I know that my Dad's little all electric house is horribly inefficient. For right now I am interested in reliable back-up power while building a system with a foundation that I can expand or even scale back to use at a future off grid cabin if life doesn't otherwise get in the way. The cabin won't have all these big 240v loads. In the mean time I'm having a lot of fun with this. Thanks for the critique. Folks like you and Mr. Cariboocoot and others who seem to spend a lot personal time helping others out I'm sure have made a huge impact on the lives and wallets of people like me who really need some expert guidance. A person would be hard pressed to find the quality of the free information here at any cost.

Thanks again

Dennis

ChrisOlson

Re: 240 vs 120 volt inverters

NorthGuy wrote: »

It is a very little price difference between XW4548 and XW6048, and there's no benefits that XW4548 has over XW6048. I would suggest buying XW6048 instead. If nothing else, it will run cooler.

I think the 6048 is about $700 more than the 4548 at NAWS. That $700 can buy a 4 or 5 kW Champion generator to go with the system. So it sort of depends on the budget for vertigo, I would say. The 4548 is a good fit for a system like he proposes. And he may want to add a PSX-240 to it (which I would highly recommend based on my experience with it). That's another ~$500.

vertigo - you mentioned a 120V inverter with a transformer. These are kind of limited in the power range you need. I think SMA makes some pretty nice ones (also expensive). But the only other real option is the old SW Plus 5548. And those are rare as hen's teeth anymore. Anybody that's got one won't part with it unless it's dead in the water and can't be fixed.
--
Chris

NorthGuy

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

I think the 6048 is about $700 more than the 4548 at NAWS.

When I bought it, the difference was less then $400. I don't know what I would do if the difference was $700. Sorry for the confusion.

ChrisOlson

Re: 240 vs 120 volt inverters

NorthGuy wrote: »

When I bought it, the difference was less then $400. I don't know what I would do if the difference was $700. Sorry for the confusion.

Well, I thought I'd better verify that in case the prices are changed. But it looks like the base 6048 is $3,138 and the 4548 is $2,376
http://www.solar-electric.com/nexaxwseinan.html

Which is a VERY good price on the 6048, though. We paid the premium price for ours (although I did order the SCP, XW Conduit Box, and AGS from NAWS) by buying it from the local dealer. The local dealer has always been really good to us and will provide on-site warranty service if ever needed. So we felt that was worth the premium to get it thru them, as I don't relish the thought of shipping a 200+ lb inverter back to Schneider for a warranty issue.

This is the box our inverter came in and the shipping weight on it was 241 lbs

Attachment not found.
--
Chris

mike95490

Re: 240 vs 120 volt inverters

So 2 realistic suggestions.

1) XW6048 worth the extra bucks. Coupled with an autostart propane genset, and with Gen Support dialed in, you should be pretty good. (PS - I've not gotten the gen support + to work with my generator, any moderate load seems to switch over to the generator, ceasing my battery charging) so Chris is your guru to get it working.

2) AutoTransformer. There is the outback, and there are MANY other transformers that can do the same function. I got a New Old Stock 90# 120/240 - 480 step up transformer off fleabay for under $150, shipping included. Shop around there for a while, run your prospective buys past us, if it's suitable.

3) I'll mention Inductive Hot Plate too, because, you can throw any cast iron pot or dutch oven on it, and have 95% cooking efficency. Way more than an electric range or oven. And if you built a small drywall box to insulate the dutch oven ( and allow for the cooling airflow for the electronics) you will hit really good power cooking/baking efficiencies. Electric range top = 50% (because of radiated heat in 365 degrees) but Induction units are 95% because only the pan is heated.

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

2) AutoTransformer. There is the outback, and there are MANY other transformers that can do the same function. I got a New Old Stock 90# 120/240 - 480 step up transformer off fleabay for under $150, shipping included. Shop around there for a while, run your prospective buys past us, if it's suitable.

Yeah, that's a good point. The PSX-240 is way more autotransformer than you need. The thing will handle a 6 kVA imbalance between the legs, meaning you can shove 6 kVA in one leg, and 12 kVA in the other, and it will balance it. A 5.76 kVA inverter (which the 6048 is actually rated at), with a 4 kVA generator on it in gen support mode, can't even deliver that amount of power imbalance to the autotranformer.

Or what I'm saying is, who's got their panel wired up with enough 120V loads on one leg to put a 50 amp imbalance on the panel? If you do, you're going to torch something, man, and it ain't gonna' be the transformer.

For verdigo's review - I just snapped this photo of our SCP because this would normally be a severe imbalance. My wife was microwaving some food of some kind (~1,500 watts) and the 'fridge was going (same leg as the microwave) along with other normal loads (all the lights are on in my shop, HDTV going, computers and network equipment running, a few lights in the house, and the washing machine going). The three biggest loads, by pure chance, happen to be on L1. There's other big stuff on L2 like the air compressor in my shop, my 120V wire feed welder, the bathroom (wife's hair dryer), etc.. This is an example of why it's almost impossible to balance a panel by swapping circuits side to side in the panel. You can only do that to the extent that you won't overload a utility leg if by chance you threw everything on that happens to be on one side.

When you go to inverter power it's different. The utility is a virtually unlimited power source, by comparison. The XW (and most other split phase model) can only go to a max 75% imbalance before you get a leg overload, and you're dealing with a very finite power source. The total load might not exceed its maximum continuous rating. But if you leg imbalance by 75% it will still overload.

As you can see the L1 and L2 stays pretty nicely balanced with a transformer on the distribution panel

Attachment not found.

The transformer can't balance it perfectly with that much imbalance because it has resistance in the windings and some losses under a big load. But it enhances the inverter's performance by being able to use it at its full capacity without worry of having it shut down due to a severe imbalance that shouldn't shut it down based on its rated continuous capacity.
--
Chris

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

I've not gotten the gen support + to work with my generator, any moderate load seems to switch over to the generator, ceasing my battery charging

Mike - you're using your 6/1 Indian-built Lister clone on the XW? And when you put a load on it drops the charger and switches to AC Pass Thru? That's really a different issue that doesn't involve Gen Support.

The key to making gen support work, and to get the charger to dial up and down nicely is to not set the AC2 Breaker Size too small. Set it to the max of 60 amps. These are my settings for the Honda

Attachment not found.

Attachment not found.

If you don't set that breaker size up so the gen can deliver surge you're going to have problems with the inverter thinking the gen can't handle it. The reason you can set that AC2 Breaker Size to the max is because you go to the Gen Support menu and first enable the feature, then set the amps to the maximum that the generator can deliver on one leg continuously without overloading it and getting too much frequency or voltage sag (58 or 59 Hz is OK and down to 110 volts). You also have to allow enough headroom on the top end for when the inverter unloads the generator. That will vary by how hard you want to "hit" your electronic stuff like the HDTV with voltage and freq surge due the governor not reacting fast enough when the load is suddenly removed from it.

The setting you use for the Gen Support Amps will limit the charger so it can't draw more amps on the AC side than what you have set in that menu item. The caveat with Gen Support is that it's going to initially lug your generator down because the gen is required to accept full load for about two seconds before Gen Support kicks in. This load will momentarily exceed the Gen Support Amps setting, and that's why you need the footroom on the low side so the gen is able to deliver full surge power during that two seconds. Then the inverter will take over and reduce the load on the generator to the Gen Support Amps setting.

I don't know how much surge capacity your Lister clone has, nor do I know how fast its governor is. This may affect how reliably you'll get it to work. Our Honda can put out 5 kVA for 10 seconds without dropping out of 60 Hz, and a brief 6 kVA surge with freq loss down to 55 using energy stored in the rotating mass of the generator along with the iGX270 putting out every last lb-ft of torque it can muster. With really big loads like my 225 amp welder it will lug the Honda right down for a couple seconds until the inverter compensates. So if your Lister clone lugs down like that allow for that in the AC2 settings so it don't get dropped before Gen Support can kick in.

All Gen Support Plus does is connect the transformer center tap to the AC2 neutral to balance the generator legs when the amp output of the gen reaches the max set for the Gen Support Amps on one leg. That's not really that important when you have an autotransformer on the inverter and/or generator. But it can help a little generator keep from being spit off due to leg overload.
--
Chris

verdigo

Re: 240 vs 120 volt inverters

Chris. Just curious. What do you have for batteries?

ChrisOlson

Re: 240 vs 120 volt inverters

verdigo wrote: »

Chris. Just curious. What do you have for batteries?

We got Rolls T12-250's - twenty four of 'em. They are big, heavy 6-cell 12V batteries, 4000-series. They were expensive and they're hard to maintain because I got 144 cells. But the reason we got them is because we run our inverter at full load a LOT off battery power and we get very little voltage sag on our bank with the inverter at full load because each battery only has to deliver 22 amps @ 6 kVA load on the inverter.

If I had it to do over again I'd probably just have one big forklift battery and live with a little more voltage sag at full inverter load, simply because the forklift battery would be a lot less maintenance.
--
Chris

mike95490

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

Mike - you're using your 6/1 Indian-built Lister clone on the XW? And when you put a load on it drops the charger and switches to AC Pass Thru? That's really a different issue that doesn't involve Gen Support.

The key to making gen support work, and to get the charger to dial up and down nicely is to not set the AC2 Breaker Size too small. Set it to the max of 60 amps. These are my settings for the Honda

Attachment not found.

Attachment not found.

If you don't set that breaker size up so the gen can deliver surge you're going to have problems with the inverter thinking the gen can't handle it. The reason you can set that AC2 Breaker Size to the max is because you go to the Gen Support menu and first enable the feature, then set the amps to the maximum that the generator can deliver on one leg continuously without overloading it and getting too much frequency or voltage sag (58 or 59 Hz is OK and down to 110 volts). You also have to allow enough headroom on the top end for when the inverter unloads the generator. ...... .....

OK, so let me see, I'll somehow need to limit the Battery charge amps to something the generator can handle long term, the engine can support about 2500 watts, the generator is 5KW, oversized for the available HP, but it reduces the unbalanced loading issues. The flywheels can handle starting surge of motors, and the governor holds about 4Hz, unloaded-full load.
I'm just feeling a bit nervous about jacking the AC2 up to 60A.

verdigo

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

If I had it to do over again I'd probably just have one big forklift battery and live with a little more voltage sag at full inverter load, simply because the forklift battery would be a lot less maintenance.
-
Chris

I have a buddy with a fork lift repair business. I'm gonna go look at one.

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

I'm just feeling a bit nervous about jacking the AC2 up to 60A.

Don't feel nervous. Just use the Gen Support Amps setting to limit the amp draw from the generator. Also, this same setting will limit the charger draw. But it will still allow for surge from the generator so it doesn't get spit off. Believe me - it works
--
Chris

mike95490

Re: 240 vs 120 volt inverters

Cloudy days again here (and little rain) and I'm running the 3KW generator this AM.
Charging at 30A DC, AC2 is 15A
Wife turns on hairdrier, and the inverter stops charging, and runs the 1200w dryer and house loads off the generator ?
( I can hear the genset unload, and the meters indicate I'm in pass-thru from AC2)
What can cause this? When the hairdryer shuts off in 90 seconds, 30A DC charging instantly resumes, and the genset loads down.
(the inverter handles 2500 ~ 6500 watts of load just fine off the batteries, only when the genset is charging, does it seem to unload the charger, and power loads directly off the genset)

I think when I can understand this behavior, then I'll try the gensupport mode with the following:
AC2 60A (and I may dial this back to 30a if 60 works ok)
Battery charger amps 35
Gensupport 15A
Gensupport + enabled
Would these be the right settings, are there any others I need to tweak ?

(genset is 6hp lister diesel clone with 240VAC 5KW harmonic excited, brushed alternator. only 4 hz Freq sag from No load to Full load. If Load induced frequency or distortion disqualified the generator, wouldn't the inverter cycle through the Re-Qualify sequence before accepting the generator power again. 200+ lbs of flywheel @ 650 rpm should prevent short term frequency glitches.)

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

Cloudy days again here (and little rain) and I'm running the 3KW generator this AM.
Charging at 30A DC, AC2 is 15A
Wife turns on hairdrier, and the inverter stops charging, and runs the 1200w dryer and house loads off the generator ?
( I can hear the genset unload, and the meters indicate I'm in pass-thru from AC2)
What can cause this?

XW will use only 80% of the AC1/AC2 breaker size for charging, leaving 20% for head room for unexpected loads when gen support is not being used. So if you apply a load while it's charging and the load on the generator exceeds the breaker setting, XW has no option but to drop the charger. After all, you didn't holler at it and tell it, "hey - I'm going to throw on an additional 2,000 watts load on here." It has no way to know how big this load is so to save spitting the generator off, or overloading it, it drops the charger so all the gen power can be concentrated on the load.

If gen support is enabled it will still only use 80% of the gen support amps setting for the charger. But when loads comes on during charging with gen support, now the XW will dial the charger back accordingly and continue applying more load to the generator right up to the gen support amps setting where the charger in it finally reverses direction and starts assisting the generator to prevent overload.

In the first method, the generator is on its own, and when something comes on for loads, how is XW to know if it just got hit with a surge, or a constant load? So it does the sensible thing and gets rid of the charger for the generator.

The second method of dealing with the generator and loads can vary anywhere from full power charging to full power inverting within seconds.

Battery charger amps 35
Gensupport 15A
Gensupport + enabled
Would these be the right settings, are there any others I need to tweak ?

The charger amps is set as a percentage. 15A on Gen Support for the generator you got is too much. That's 3.6 kVA - and in GenSupport mode the XW demands every last amp from the generator. So make sure to set that to what the gen can actually put out continuous and maintain voltage and freq.

200+ lbs of flywheel @ 650 rpm should prevent short term frequency glitches.)

Nope - not as good as you might think. You don't have enough power strokes per minute to maintain perfectly smooth output with no torsional vibration, even with your 200 lb flywheels. Those flywheels are constantly speeding up and slowing down. They get one short "bang" and then the whole device sits there huffin' and puffin' and suckin' and blowin', just on stored energy in the flywheel, for the next 650 degrees of rotation so it can finally deliver another big "bang" to keep it going. Generator heads are very sensitive to this. What you need is a lot of smaller "bangs" at higher frequency to make it smooth.

Basic rule of thumb in engineering regarding engine design; if you want smooth power delivery with minimal torsional vibration you add cylinders and/or run it faster.
--
Chris

NorthGuy

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

If gen support is enabled it will still only use 80% of the gen support amps setting for the charger. But when loads comes on during charging with gen support, now the XW will dial the charger back accordingly and continue applying more load to the generator right up to the gen support amps setting where the charger in it finally reverses direction and starts assisting the generator to prevent overload.

In my testing I found this to be a little bit different. There's a limit, which is AC2Size*0.8 when GenSupp is disabled and min(GenSuppAmp, AC2SIze*0.8) when it is enabled. XW tries to keep the charging current low enough so that combined load on the generator does not exceed this limit. Other than setting the limit, enabling or disabling GenSupp has absolutely no effect on the XW behavour during charging. GenSupp only makes difference when your loads exceed the above limit. Then, if GenSupp is enabled, inverter provides energy from batteries to support loads together with the generator. If it is disabled, XW overloads generator, possibly to the point of death.

inetdog

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

Basic rule of thumb in engineering regarding engine design; if you want smooth power delivery with minimal torsional vibration you add cylinders and/or run it faster.

Is there any value in adding a torsionally elastic coupling of some sort between engine and flywheel? (Assuming that you carefully avoid resonance problems, of course. Which you can do if the design shaft speed and firing rate are fixed.)

mike95490

Re: 240 vs 120 volt inverters

Sets the percentage of the maximum DC output current that is available to the charger.
The maximum DC output current for different models is:
• Xantrex XW6048 120/240 60—100 ADC

So, 30A would be 30% of the 100A max of the charger ?

15A on Gen Support for the generator you got is too much. That's 3.6 kVA - and in GenSupport mode the XW demands every last amp from the generator. So make sure to set that to what the gen can actually put out continuous and maintain voltage and freq.

So that does not work the same as AC2. And it's in 240V, not the 120v leg
So if I want to limit my 6hp genset to 2200watts (VA) I'd set for 9 A. ?

I'm glad I'm asking twice before I plug the numbers in.

And I think if my generator waveform is irregular enough, that it would disqualify and then try to re-qualify it, [blinking LED @ inverter] and I don't see this happening except at startup.

final ? iteration :
• charger 30 [% of 100A = 30A] does bank capacity alter this value?
• Gensupport 9A [limits total genset load & charge to 9A @ 240V and throttles back charging first, then supports loads]
• Gensupport + enabled
• AC2 60A

And the last question, I've been using AC2 to slowly ramp up the load on the genset, instead of slamming 2200 w of load onto a cold diesel, will the Charger setting let me change this on the fly too ? 5%, 15% 30% as it runs and warms up ?

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

So if I want to limit my 6hp genset to 2200watts (VA) I'd set for 9 A. ?

That is correct. And you will not see that load on the generator with just the charger. It will limit the charger load to about 1,700 VA. And it will cut the charger back if loads are added, and further keep the load from 1,700-2,200 VA. Only when it goes into gen support mode will you see the load on the generator go to the full 2,200 VA continuous, and only if the legs are balanced. It will limit it based on the highest loaded leg at all times. That's why I use the PSX-240 on ours - it helps squeeze every last watt out of the generator.

And I think if my generator waveform is irregular enough, that it would disqualify and then try to re-qualify it, [blinking LED @ inverter] and I don't see this happening except at startup.

The Listers I've seen driving ST5 heads have a problem with the freq constantly varying +/-1 Hz all the time due to the flywheel effect and the fact that you only have 5.4 power strokes/second. In that same second the gen head has already completed 60 AC cycles. So for about 12 AC cycles the freq varies because the flywheels slow down slightly under the load of the driving the generator and scavenging and recharging the cylinder, then suddenly speed up when the power stroke "hits" it. That won't necessarily cause the generator to be disqualified. But the inverter does have to match this type of output waveform to sync with it. And the heavier you load it, the worse it gets. So be aware of that with a Lister.

The easiest illustration I can think of to explain what happens is like the difference between the old chain drive Harleys and the Japanese four-cylinder inline bikes. The drive chain on the old Harleys (they all got belts now) used to whip like a wild snake due to the uneven power delivery of the engine. The Rice Bike's drive chains run smooth as silk. That's the effect of more cylinders and higher rpm vs just one or two running at low speed. Your gen head "sees" that same pulsing power delivery and the smoothness of its output suffers because of it.

• charger 30 [% of 100A = 30A] does bank capacity alter this value?
• Gensupport 9A [limits total genset load & charge to 9A @ 240V and throttles back charging first, then supports loads]
• Gensupport + enabled
• AC2 60A

And the last question, I've been using AC2 to slowly ramp up the load on the genset, instead of slamming 2200 w of load onto a cold diesel, will the Charger setting let me change this on the fly too ? 5%, 15% 30% as it runs and warms up ?

Bank capacity setting only affects the end amps for absorb. It does not affect the max charge rate setting. I think 9 amps is a reasonable setting for Gen Support for your generator. It might handle 10 amps - you could try it. If the freq and voltage drop too far out of range for Gen Support it will just drop the generator and requalify it. If it does that, set it back to 9 amps.

Yes, I'd set AC2 at the max of 60. I use the 60 amp setting for the AC2 Breaker Size even with our little Robin diesel and our Champion, and it works fine as long as you have the Gen Support Amps set correctly for the generator's capability. I've never yet had it trip the breaker on either the Robin or the Champion, and it lets the generator deliver surge without getting disqualified because it runs up against a "hard stop" of limiting the amps to the inverter's input. Most generators will hold in surge on the electrical side good enough to lug them down to just about stalling the engine without popping the breaker. So the "hard" limit is going to be how low you set the freq and voltage limits to the AC2 input, which is going to determine if the inverter is going to unload the gen or not during a heavy surge event.

Typically, the inverter requires the generator to deliver the surge power for a big load for about 1-2 seconds before it will start assisting it. If the inverter is in the process of assisting the generator already, then the inverter handles the big surge part. But in the initial stage of gen support, where the gen is carrying all the load and the inverter is standing by because gen support amps haven't been reached - when the load comes on it's going to make the generator grunt pretty good. Then a second or two later the inverter "kicks in" and supplies the overload power, bringing the gen back to its rated load (or whatever you got the amps set at). This is where the autotransformer makes all the difference in the world on a split phase inverter - it will squeeze every last possible watt out of the generator during that initial overload event so the gen stays online until the inverter starts helping it.

You can manually change the max charge rate "on-the-fly" if you want to ramp up the load on your diesel. But I don't do that with our Robin diesel. It smokes and complains a little about being heavily loaded when it's not yet fully warmed up. But it's not going to hurt the engine as long as it's got oil pressure. A liquid cooled engine is going to warm up slower, so it may be a more desirable thing to do for the Lister. But the air-cooled Robin comes up to temp within about a minute and then the exhaust smoke cleans up and it's fine. You have to tune that for the type of generator you got.
--
Chris

mike95490

Re: 240 vs 120 volt inverters

And you will not see that load on the generator with just the charger. It will limit the charger load to about 1,700 VA. And it will cut the charger back if loads are added, and further keep the load from 1,700-2,200 VA. Only when it goes into gen support mode will you see the load on the generator go to the full 2,200 VA continuous, and only if the legs are balanced.

ouch. I want to put a 2000 - 2200 watt load on the generator, because the listers "wet stack" if they are not loaded enough (thermosiphon cooling and all that) My base household loads run 50 - 350 watts, unless the pump or hairdryer are on. what would you tweak, to keep the generator at full load of 2200w ? Am I better off sticking with my scheme of no gen support and using AC2 to ramp up the load on the generator ?

ChrisOlson

Re: 240 vs 120 volt inverters

mike95490 wrote: »

ouch. I want to put a 2000 - 2200 watt load on the generator, because the listers "wet stack" if they are not loaded enough (thermosiphon cooling and all that) My base household loads run 50 - 350 watts, unless the pump or hairdryer are on. what would you tweak, to keep the generator at full load of 2200w ? Am I better off sticking with my scheme of no gen support and using AC2 to ramp up the load on the generator ?

Well, you'd have to set the gen support amps at 11 amps to get a continuous 2100 watt load on the generator with the charger and loads. When it goes into gen support mode that means the generator is going to have to be able to deliver 2,640 watts and still stay within reasonable voltage and freq range. The Lister clone can do that, but I don't know how much governor droop you get to maintain the frequency. The heavier you load a Lister driving a generator, the more wild the frequency swing gets and the inverter has to be able to track that to help the generator out.

It's better to run your stuff a Hz or two over than it is to run a Hz or two under when you don't have a generator that will maintain perfect 60 Hz.

I guess I'd try that first and see if it handles it ok - 11 amps.
--
Chris

ChrisOlson

Re: 240 vs 120 volt inverters

NorthGuy wrote: »

In my testing I found this to be a little bit different.

NorthGuy, I either misunderstand what you are trying to say, or you are not explaining it right. I took these photos for both you and Mike to see what happens when you use Gen Support. I have to do this in two posts because the software is limiting the number of photos in one post. But I can't show it without the pictures, and hopefully this will help folks gain a better understanding of how the XW dials power up and down with Gen Support, and why I believe the XW to be The Best There Is when you need split phase power and want to run big stuff with Gen Support. And why it's superior to 120V stacked units - I already BTDT with some of the best 120V inverters designed with Gen Support in stacked configuration. And it don't work as well as the XW, because the XW is smart (I wish Outback could've answered these questions for me when we were looking at the Radian, but they couldn't tell me how it works in the Radian).

This is the photos I took - in this photo this is the Gen Support settings I'm using for the Honda generator. I reduced it from the normal 17 amps to 16 amps because it's quite hot and muggy here and with the moisture in the air the power output of the engine is reduced some, and it's 107 degrees in the powerhouse with the generator running.



This is the output of the Honda in this photo:



And this is the present loads:



The Honda generator maintains virtually perfect frequency and voltage (+/- 1 Hz and 1V) no matter what the load on it up to 5.0 kVA. So the 16 amp Gen Support setting means peak 3,840 VA continuous load for it. The XW is charging batteries here so theoretically it could load it to the max. But it doesn't. The percentage at this particular loading is 89.7% of the Gen Support setting.

More Load:
Ok, now I increased the load so this is the output of the Honda - right dead up against the Gen Support setting with almost perfect leg balance (with the PSX-240):



And this is the load after I threw some more wood on the fire:



XW is STILL charging the batteries - it hasn't entered Gen Support Mode yet. But notice that as the load gets closer to the Gen Support setting that what it does is using an increasing percentage of the Gen Support Amps for loading on the generator. This is so it can make a silk smooth transition into Gen Support when yet another load comes on.

Now I have to move on to another post to show what it does in Gen Support Mode.
--
Chris

ChrisOlson

Re: 240 vs 120 volt inverters

NorthGuy wrote: »

In my testing I found this to be a little bit different.

Ok, here we are in Gen Support and this is the load:



And this is the output of the Honda when I snapped the photo, but I'll explain below:



When the new load comes on that forces the system into Gen Support, the inverter initially allowed the Honda to go up to about 4,400 watt load. I tried to catch that in the photo but wasn't fast enough and what I snapped was after about 1 second when it was dialing the load back down to 3840 VA on the generator. For the first two seconds the inverter shares the surge with the generator when it first enters Gen Support. Do you see the significance of that? When you combine the surge capacity of both the generator and the inverter there is virtually nothing that you can't start. This lasts for two seconds and then it adjusts the generator load back to the Gen Support setting.

The XW is smart - real smart, when it comes to Gen Support. It beats the SW Plus hands down and the SW Plus was really, really good.
--
Chris

NorthGuy

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

NorthGuy, I either misunderstand what you are trying to say, or you are not explaining it right.

Sorry, I'll try to explain it better.

Generator support only works when XW is inverting and doesn't work when it's charging.

If you disable GenSupp on your first screen, but then set "AC2 Breaker Size" to 20A (your number for "GenSupp Amps" divided by 0.8), then the screens on your first post will be exactly the same.

Only when you cross over (as with the screens on your second post), GenSupp kicks in and provides smooth regulation.

On the charging side, GenSupp doesn't make any difference (except for modifying the limit set by "AC2 Breaker Size"). The regulation is not as smooth. There could be oscillations, huge changes in charging current in response to the changing loads, reaction on strating motors is not that smooth etc. In some cases it can even drop the charger completely and abruptly.

Of course, if charger is only 30% of the overall load, that's Ok, but things get jumpy if charger is the most of the load. For example, in my situation, where charger is 6kW and other loads is no more than 1.5kW. Or Mike, charger is 2kW and load is 200W. Some of the jumping can be relieved with PSX-240 (which I haven't installed yet), but not all of it.

ChrisOlson

Re: 240 vs 120 volt inverters

NorthGuy wrote: »

On the charging side, GenSupp doesn't make any difference (except for modifying the limit set by "AC2 Breaker Size"). The regulation is not as smooth. There could be oscillations, huge changes in charging current in response to the changing loads, reaction on strating motors is not that smooth etc. In some cases it can even drop the charger completely and abruptly.

I guess I haven't seen that. With Gen Support enabled it does instantly react to load changes by varying the charger amp requirement to prevent overloading the generator. But assuming it doesn't enter Gen Support mode I've never seen it drop the charger here, even with the diesel. I'm thinking the difference might be the PSX-240 that we're using to balance things out. Schneider told me, before we even bought the system, that keeping the transformer and using it would enhance the performance of the whole outfit with our little generators. It could be that you are overloading one leg of your generator during charging when a unbalanced load "hits", so the XW has to take more drastic action to keep the generator qualified, and the only option it has is to drop the charger when the actual full load or surge limit of the generator has not actually been reached. That's the only thing I can think of.

With Gen Support enabled the XW determines surge loading on the generator by how you got the freq and voltage limits set. It will load the generator in surge right up to where you got those limits adjusted to (if you set the AC2 Breaker Size high enough).

And there could be a difference in generators too. Both our Honda (computer controlled engine and voltage regulation) and the Robin (raw diesel torque and I got the smoke screw set so it leans on the fuel rate pretty heavy and belches black smoke during surge so it don't lose rpm) have tremendous surge capability. Our Champion generator is pretty weak in comparison and it can't handle charging so I disable the charger when I run that generator, otherwise the inverter will just spit it off.
--
Chris

mike95490

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

That is correct. And you will not see that load on the generator with just the charger. It will limit the charger load to about 1,700 VA. And it will cut the charger back if loads are added, and further keep the load from 1,700-2,200 VA. Only when it goes into gen support mode will you see the load on the generator go to the full 2,200 VA continuous, and only if the legs are balanced. It will limit it based on the highest loaded leg at all times. That's why I use the PSX-240 on ours - it helps squeeze every last watt out of the generator.
//////
Bank capacity setting only affects the end amps for absorb. It does not affect the max charge rate setting. I think 9 amps is a reasonable setting for Gen Support for your generator. It might handle 10 amps - you could try it. If the freq and voltage drop too far out of range for Gen Support it will just drop the generator and requalify it. If it does that, set it back to 9 amps.
/////
Yes, I'd set AC2 at the max of 60. I use the 60 amp setting for the AC2 Breaker Size even with our little Robin diesel and our Champion, and it works fine as long as you have the Gen Support Amps set correctly for the generator's capability. I've never yet had it trip the breaker on either the Robin or the Champion, and it lets the generator deliver surge without getting disqualified because it runs up against a "hard stop" of limiting the amps to the inverter's input. Most generators will hold in surge on the electrical side good enough to lug them down to just about stalling the engine without popping the breaker. So the "hard" limit is going to be how low you set the freq and voltage limits to the AC2 input, which is going to determine if the inverter is going to unload the gen or not during a heavy surge event.
////
Typically, the inverter requires the generator to deliver the surge power for a big load for about 1-2 seconds before it will start assisting it.
////
This is where the autotransformer makes all the difference in the world on a split phase inverter - it will squeeze every last possible watt out of the generator during that initial overload event so the gen stays online until the inverter starts helping it.
//////
Chris

Well, you'd have to set the gen support amps at 11 amps to get a continuous 2100 watt load on the generator with the charger and loads. When it goes into gen support mode that means the generator is going to have to be able to deliver 2,640 watts and still stay within reasonable voltage and freq range.

Chris,
I appreciate the heck out of your detailed explanations about how this works. (and your stuff at the LEF & cogen forums ) So maybe one more round of questions to fine tune my brain today.


So, the 1700VA charger load is set by the % of Max Charger Capacity ?
And I could tweak that on the fly as the engine warms up?

The Gen Suport amps is the most combined (loads & charging) for continuous load, but genset has to have enough "grunt" left to supply a 2 second surge load till the inverter goes into Assist Mode?


If GenSupport = 9A it will "limit the charger load to about 1,700 VA"
and then

11 amps to get a continuous 2100 watt load on the generator with the charger and loads. ... When it goes into gen support mode that means the generator is going to have to be able to deliver 2,640 watts

Is that 2640w a 2 sec surge, or what the generator will have to carry steady ?
I've got some elevation here, and don't want to stress the Indian Iron to it's breaking point (which varies from fiberboard to aluminum)

Except for the blow dryer, my loads are pretty low, and I'm thinking about just sticking with my varying of AC2 for simple charging.

The 2100 / 2640 ratio is now the part I'm not following. What set that ratio ?

And the auto-transformer, I thought the GenSup+ added the inverter windings into load balancing, does the external auto-transformer help that significantly?

bmet

Re: 240 vs 120 volt inverters

Thank you for statement about the Champion generator. I see those units at some of the national retail chains, and wondered why they are much cheaper.

NorthGuy

Re: 240 vs 120 volt inverters

ChrisOlson wrote: »

I guess I haven't seen that. With Gen Support enabled it does instantly react to load changes by varying the charger amp requirement to prevent overloading the generator. But assuming it doesn't enter Gen Support mode I've never seen it drop the charger here, even with the diesel. I'm thinking the difference might be the PSX-240 that we're using to balance things out. Schneider told me, before we even bought the system, that keeping the transformer and using it would enhance the performance of the whole outfit with our little generators. It could be that you are overloading one leg of your generator during charging when a unbalanced load "hits", so the XW has to take more drastic action to keep the generator qualified, and the only option it has is to drop the charger when the actual full load or surge limit of the generator has not actually been reached. That's the only thing I can think of.

I guess PSX-240 makes a huge difference in reaction to loads, because without it any change in one-sided load cause twice as much change in charging current. I wish they would have an option to regulate average of L1 or L2 insted of the highest. I don't have a good space for PSX-240 because I never thought that I would need it.

You need a heck of a load for it to drop the charger when I charge at 6kW, but starting a table saw (30A surge) does it. However, smaller motors starting may drop charging current from 80A to almost 10-20A. Generac does not take it very well, so I had to increase voltage/frequency tolerances to avoid disqualification. Motors don't start every minute, so I can leave with that.

ChrisOlson wrote: »

And there could be a difference in generators too. Both our Honda (computer controlled engine and voltage regulation) and the Robin (raw diesel torque and I got the smoke screw set so it leans on the fuel rate pretty heavy and belches black smoke during surge so it don't lose rpm) have tremendous surge capability. Our Champion generator is pretty weak in comparison and it can't handle charging so I disable the charger when I run that generator, otherwise the inverter will just spit it off.

When I was experimenting with grid (that is I set all the settings as for generator, but connect grid), it still had the same problems - hunting and rapid changes in charging current. But different generators react differently. When XW hunts, Generac starts hunting between 59 and 61 Hz, but my Champion keeps much steadier at 61 Hz, rarely drops to 60Hz. I can hear a little bit of a hunting with Champion too. I guess Honda would be steady even when load oscillates.