240v split phase inverter/chargers with 120v generators?

Audiomaker

Hey all,

Some of us have inverter/chargers which are designed for use with regular 120/240v split phase power input from the grid.

I am wondering how people go about things when only a small 120v single phase generator or other AC source is available?

In my case, the XW6048 specifies that it will not work with 120v only generators. What if 120v was all I had to work with?

Ideas?
Sean
P.S. Not knowing any better, my plan at the moment is to add a separate 120v charger to the battery bank for any times when 240 split might not be available.

Blackcherry04

Transformer 120 V to 240 V

http://www.solar-electric.com/catalo...sformers&cat=0

BB.

I believe that some of the Magnum AC inverters will take 120 VAC in and give you 120/240 split phase output. There is are some details (as I recall) on power limitations (120 VAC limited charging power because 1/2 leg).

http://www.solar-electric.com/invert...nsiwainac.html

--I think (if I recall correctly--I have to head out right now).

-Bill

Audiomaker

Well I'm not 100% on if mine will take 240v single phase across L1 and L2 and work or not without the neutral? I also wasn't aware that autotransformers could produce split phase 240v from 120v input...is that correct?

BB.

Outback power has a very good Auto Transformer Manual:

http://legacy.outbackpower.com/pdf/manuals/fw-x240.pdf

It is amazing all of the things they do with the transformer.

-Bill

jonr

There is no problem producing split phase 240V from any AC source with a center tapped transformer.

solorone

Xantrex XW 4024 can be switched to 120 V input. Sadly it did not come with the jumpers need to convert it. I need t get a set, as the OP notes, there could be a problem with the genset output being limited to 120 V.

Audiomaker

Well one of the main reasons I asked this question is because I see a lot a folks here running pretty big (read 240 split phase) inverter/charger systems, but who have small 120v portable generators as backups.

My own situation is that my installation is in an RV, and while many RV parks have 50amp 240v service, some do not, not to mention that I'd like to be able to charge from a regular 115v outlet in a pinch (or from my 2.3kw Honda portable).

The Honda is a backup to my diesel genset (240v split phase).

Again, I don't know if the XW6048 is using two legs of 115v to the neutral, or 240v across L1/L2 for it's charge source. The meters imply that it's 115v X 2 since there is no 230v meter per say, just L1 and L2 @ 115v.

I figured I'd get around this by purchasing an additional 115v-48vdc battery charger for those rare times when I don't have 240v available, but if an autotransformer will give me 240v split phase from 120v single, then I could theoretically power the 6048 from a small generator or someone's extension cord (yes, with a derating).

Blackcherry04

If your talking about using a Honda EU 2000 with a Outback 240 v transformer, I think you can forget it. The generator just doesn't have enough power to saturate the windings with out faulting, so I have read.

http://www.solarpaneltalk.com/showthread.php?14777-Honda-EU2000-Transformer-Problem&highlight=transformer

Hill_Country

If it helps at all, BB is correct about the Magnum Energy MS-PAE inverters being able to take 120v AC input and output 120v/240. As per Pg. 25 of the Magnum Energy MS-PAE manual (link: http://magnumenergy.com/wp-content/uploads/2012/08/64-0032-Rev-A-MS-PAE-Series.pdf )

"2.4.5 Wiring the AC Input and Output

The MS-PAE series provides 120/240VAC on the output, but the input may be wired either as a
120/240VAC input or a 120VAC input (to one input only) depending on your AC source. The AC output
will continue to produce 120/240VAC with either the 120/240VAC or 120VAC input configuration.

WARNING: DO NOT connect 120VAC (same phase) to both AC HOT 1 IN and AC HOT 2
IN inputs. These inputs must be 180° out-of-phase (i.e. 120/240VAC). If you only have a
120VAC source, you may connect to either the AC HOT 1 IN or AC HOT 2 IN, but NOT to
both or damage may occur." (Pg. 25 of teh Magnum Energy MS-PAE Manual, Magnum Energy.

Also, I have a 120v Yamaha EF2000is 120v only small-ish gas generator and will be utilizing it to charge the batteries. However, I do not have any 240v loads right now...but may in the future.

Audiomaker

I’m really having trouble figuring out the best route at this point.

Let me ask this as a “what would you do?” question.

First, this is an RV and being mobile has to be able to accept multiple forms of energy input.

The question is addressing the times when only 120vac is available.

Secondly, I intend to “front end” this with a 12v to 120v inverter so that this 120vac can also be produced by the alternator of the engine (and the starter bank).

Thirdly, let’s just assume that the XW6048 requires split 120/240v input (I think it does).

Here are some options…

1. Purchase a separate 12vdc inverter in the 2kw range and install that as the vehicle system (as opposed to the separate “house* system).

Purchase a 120vac to 48vdc charger which autonomously charges the house bank. The vehicle inverter powers this charger. The XW6048 “sees” no AC input.

One particular model of inverter (Xantrex Prowatt 2000) has an ignition lockout which prevents the inverter from producing power (and hence draining the bank) when the engine isn’t running. As as accessory, there is a rudimentary transfer switch which can be purchased which is put inline with the inverter to automatically run from “shore power”.

You (I) would run this transfer switch to an external 115v shore power connection (meaning run an extension cord to a gas station’s 15a outlet, or to a small portable generator….etc.

So… the connection looks like this:

Alternator > starter bank > 120vac inverter > 120vac to 48vdc charger > House bank

When the 120v extension cord going to someone’s house or from the small generator is used, it looks like this because of the transfer switch:

120vac generator or shore > transfer switch > 120vac to 48vdc charger > House bank.

Fundamentally this should work, but of course bypasses all of the bells and whistles of the XW6048 (load sharing type stuff). It also may introduce anomalies from having multiple chargers in the system that aren’t accounted for by the Xanbus system.

Ok, on to # 2…

2. Run the same setup but replace the 120vac to 48vdc charger with a transformer who’s output is seen by the XW as “the grid”.

This looks like this:

Alternator > Prowatt 2000 > transformer > transfer switch between transformer power and actual 50amp 240v RV shore power > AC1 input to XW.

OR

120vac from generator or extension cord > Prowatt 2000 in bypass > transformer > transfer switch between transformer power and actual 50amp 240v RV shore power > AC1 input to XW.


Obviously the XW6048 would need it’s parameters set not to overload the ratings of what’s in front of it (i.e….derate the AC1 input current setting).

The advantage to this method is that the XW6048 is once again doing the charging if the prior electronics can both provide enough “umph” to get it going, and that they can provide the required 120v/240v split phase input to the XW.

In this case, the XW sees the input power as the grid and features like grid support are enabled where the XW can provide additional power from the bank to overcome startup loads the little 120v generator or 15a circuit can’t handle.

Of course this doesn’t work if the XW runs in “bypass” when it’s sees grid power. I think that might be part of how the grid support option functions?
For example, if you enable grid support the XW no longer bypasses but inverts all the time? Not sure about that.

BB.

Audiomaker wrote: »

Here are some options…

1. Purchase a separate 12vdc inverter in the 2kw range and install that as the vehicle system (as opposed to the separate “house* system).

Purchase a 120vac to 48vdc charger which autonomously charges the house bank. The vehicle inverter powers this charger. The XW6048 “sees” no AC input.

One particular model of inverter (Xantrex Prowatt 2000) has an ignition lockout which prevents the inverter from producing power (and hence draining the bank) when the engine isn’t running. As as accessory, there is a rudimentary transfer switch which can be purchased which is put inline with the inverter to automatically run from “shore power”.

You (I) would run this transfer switch to an external 115v shore power connection (meaning run an extension cord to a gas station’s 15a outlet, or to a small portable generator….etc.

So… the connection looks like this:

Alternator > starter bank > 120vac inverter > 120vac to 48vdc charger > House bank

When the 120v extension cord going to someone’s house or from the small generator is used, it looks like this because of the transfer switch:

120vac generator or shore > transfer switch > 120vac to 48vdc charger > House bank.

That is probably the simplest and most straight forward.. And if something "breaks", you have backups and work arounds until you can fix the original problem.

Cost is an additional AC to DC conversion for extra battery charger (from AC power) instead of the "pass through" capabilities of the very nice Hybrid inverter system (call it 10-20% "extra" conversion losses).

Fundamentally this should work, but of course bypasses all of the bells and whistles of the XW6048 (load sharing type stuff). It also may introduce anomalies from having multiple chargers in the system that aren’t accounted for by the Xanbus system.

Ok, on to # 2…

2. Run the same setup but replace the 120vac to 48vdc charger with a transformer who’s output is seen by the XW as “the grid”.

This looks like this:

Alternator > Prowatt 2000 > transformer > transfer switch between transformer power and actual 50amp 240v RV shore power > AC1 input to XW.

OR

120vac from generator or extension cord > Prowatt 2000 in bypass > transformer > transfer switch between transformer power and actual 50amp 240v RV shore power > AC1 input to XW.

The extra cost/losses of a transformer/weight of a transformer has its "own charms"... I am not sure I see a clear improvement over option one--Possibly a bit more efficient...

A very programmable AC to DC battery charger (the Xantrex TrueCharge 2 series looks very nice--the TC-1's were well liked--The TC-2's were very difficult to find for months/year+ after the planned introduction date--So I cannot really point to very many people here who have use them (a couple of posters--maybe?).

Obviously the XW6048 would need it’s parameters set not to overload the ratings of what’s in front of it (i.e….derate the AC1 input current setting).

The advantage to this method is that the XW6048 is once again doing the charging if the prior electronics can both provide enough “umph” to get it going, and that they can provide the required 120v/240v split phase input to the XW.

If your AC utility/generator power usage is a small part of your daily life (mostly dry camping)--I probably would not worry too much about the "extra conversion losses). The ability to make use of both 120 and 240 VAC power, utility/genset/vehicle power is probably well worth the costs.

If however, you do spend lots of time on utility (or generator power)--Then losses could be larger factor (something like $0.10 to $0.20 per kWH of generator fuel--As an example--Or 10-20% more utility kWH billed.

\In this case, the XW sees the input power as the grid and features like grid support are enabled where the XW can provide additional power from the bank to overcome startup loads the little 120v generator or 15a circuit can’t handle.

Of course this doesn’t work if the XW runs in “bypass” when it’s sees grid power. I think that might be part of how the grid support option functions?
For example, if you enable grid support the XW no longer bypasses but inverts all the time? Not sure about that.

More or less as I understand the original XW Hybrid inverter (I am not a Xantrex/Schneider support person--take with a grain of salt)--The "as shipped" unit is really a 240 VAC (or 230 VAC 50 Hz) unit with split phase out put capabilties. It can/does use the neutral (from genset/utility power), but you cannot run as 120 single leg power.

There is the capability to change a couple of jumper inside the XW to put the split phase 120/240 VAC transformers into parallel for pure 120 VAC at 2x the current (same wattage)--And you have download a new 120 VAC only firmware package to the inverter.

If you never need 240 VAC, and can use lots of 120 VAC power--It may be "the way" to go. Not sure how many people (if any) are running 120 VAC XW configurations.

Note that some battery chargers (like the Xantrex TC-2) will run on anything from ~100 VAC to ~240 VAC 50/60 Hz--So from a battery charging perspective, it does give you a lot of options too (TC-2's are not that large of charger--The XW is much high current capabilities for charging--In general, as I recall)

-Bill

Audiomaker

Bill, keep in mind that my charger needs to be 48v. I only know of the Iota and PowerMax offerings.

The "charms" of the transformer based system are that since the XW remains the primary charger, there is no electrical "crosstalk" or influence on the rest of the system (such as the MPPT60), and the charge profiles I set using the SCP remain in effect. All of the system's toys and meters would continue to work, and once I add a Conext Combox, I'd be able to monitor input from the portable/extension cord aspect of the input.
As mentioned, I would have to derate the charger depending on if I were using 15a, 30a, or 50a service and also set up additional cascading transfer switches.

Push come to shove, having an Iota (or other ) backup charger on standby in a addition is just a matter of the wallet. The 48v chargers run just shy of $400.... not sure what the proper transformer will cost in contrast. Since an RV can also take 30a 120v, I'd need a transformer sized to take advantage of that. When going 50a 240, it goes directly to the AC1 (no transformer).

The fact is that I didn't know transformers could create 120/240 split phase output (L1-N-L2) from 120v (L1-N). That's still a foreign concept to me that I'm trying to absorb, and I'm trying to find diagrams of one that actually shows that configuration because ultimately that would be a fancier solution.

BB.

Yea--Getting to 48 volts, the "smart battery charger" selection gets rather thin.

In this manual:

http://legacy.outbackpower.com/pdf/manuals/fw-x240.pdf

Page 9 shows an auto transformer as a 120 VAC genset + 120/240 VAC split phase AC main power and a pair of "sync'd" or "stacked" inverters--Should work just fine with a 120/240 VAC XW hybrid inverter--Which is what (I think) you want to do.

A standard (isolated) transformer with input windings and separate output windings "Isolates" the input to output voltages. I.e., you can have different neutral bonding, floating input vs output voltages, local ground/neutral bonding, etc.

Auto transformers do not (necessarily) have isolated windings. For example, you can have 1/2 the windings on the 120 VAC input, (L1+Neutral) and the second winding sort "reversed" from the first winding share a common ground/neutral point, and the opposite terminal gives you a 180 degree out of phase 120 to neutral terminal (L2+Neutral). Auto transformers are typically smaller/lighter than full isolated transformers because the same winding is sort "shared" between input and output power (I am not really good at describing this--Sorry).

Note, you will see some transformer diagrams with a Dot next to a lead--That is so you can get the "correct phase relationship between input and outputs--Sort of like the +/- polarity of a battery bank.

Now--A draw back may be that a smaller Honda eu2000i (1,600 watt 120 VAC) type genset may not be able to drive the above Outback Auto-transformer--I don't know anything about. But I would take what BC04 says to heart.

-Bill

Audiomaker

Copy that Bill.

I was looking at that diagram earlier and wondering. Some stacked inverter arrangements I've seen require the twin inverters to achieve 120/240 split.

This .pdf has what I'm looking for http://www.victronenergy.com/upload/documents/Datasheet-Autotransformer-32A-and-100A-EN.pdf Split phase: 120VAC to 120/240VAC , and yes, that's to go right into the AC1 of the 6048




I don't see any reason why a inverter/transformer/inverter setup wouldn't work with XW except for the inrush current.... which I suppose could be dealt with. The XW does allow you to limit the "ac breaker size", to which it will limit it's draw accordingly.

Audiomaker

Blackcherry04 wrote: »

If your talking about using a Honda EU 2000 with a Outback 240 v transformer, I think you can forget it. The generator just doesn't have enough power to saturate the windings with out faulting, so I have read.

http://www.solarpaneltalk.com/showthread.php?14777-Honda-EU2000-Transformer-Problem&highlight=transformer

Thanks BC04. I don't have an inverter generator, but I am considering fronting this with an actual inverter so inrush might be an issue. I figure if it is, that I'll find a suitable soft-start on eBay to help it out. Yet another can of worms....and another..

mike95490

I got a 3KVA center tap transformer ( about 90 pounds shipping weight, it broke the pallet it was strapped on) from ebay, and use it with a honeywell 2Kw inverter generator, and it works fine with my XW Don't have a honda to try it with. I know Chris O was unable to get a PXS transformer to run from a honda, Your mileage may differ !

Audiomaker

mike95490 wrote: »

I got a 3KVA center tap transformer ( about 90 pounds shipping weight, it broke the pallet it was strapped on) from ebay, and use it with a honeywell 2Kw inverter generator, and it works fine with my XW Don't have a honda to try it with. I know Chris O was unable to get a PXS transformer to run from a honda, Your mileage may differ !

Good to hear from someone actually running an XW this way.

While not the most simple option, being able to power an XW (or other larger split phase inverter) from a 120vac source seems like an invaluable addition to the tool kit and it's a short jump from there to 12v.

I can see all sorts of possibilities to this route, and it will be interesting to see what it takes to get it to work when fronted by an inverter.

In my application I'd like to include the charging system of the truck as a power source... meaning that if had a long drive at night, the 48v house bank would be charged when I arrived (it's bad form to run a generator while going down the road although it is sometimes done).

To add to my kookiness, I should mention that the hydraulic systems on my rig are 230v 3Ph that I have adapted with phase converters (static) and VFD's. There are actually multiple 3ph systems in this truck that are being powered at the moment by the 6048. For the record, that is working without issues.

It's kind of fun to consider powering industrial motors via solar, or 12v alternator power.

mike95490

Audiomaker wrote: »

.....It's kind of fun to consider powering industrial motors via solar, or 12v alternator power.

When my house floors were being installed and finished, I noticed the batteries were getting lower every day (late summer, clear skies) Then I discovered the floor dude had pulled the panel off the breaker panel, and clipped his 3hp floor sander in, and was running off the 3Kw PV array & batteries. The contractors 5Kw genset could not run it, and they had to rent a trailer genset to run the sander. XW was happy as a clam sucking the batteries down all day.

wkobe88822

mike95490 said:

I got a 3KVA center tap transformer ( about 90 pounds shipping weight, it broke the pallet it was strapped on) from ebay, and use it with a honeywell 2Kw inverter generator, and it works fine with my XW Don't have a honda to try it with. I know Chris O was unable to get a PXS transformer to run from a honda, Your mileage may differ !

do you have a model number for that transformer?

mike95490

This is the Transformer label.  Ya gotta know what they are and how to wire 'em up to do what you want.  It's a big hunk of enclosed and epoxy potted boat anchor.   It's a pretty beefy thing for only 3KVA rating.  does not get warm after several hours at 1,500 watts

Here it is to the right of the little worthless yellow diesel generator:

wkobe88822

So this gives you split phase 240? I got a few part. Numbers for square d transformers that so also .

mike95490

Any transformer with a center tap, and is rated for enough voltage and amps, will do, as a Autotransformer

I am only using the 240v winding pair, the 120v genset connects to one winding, the 240v is picked off of
the 2 series windings and I don't use the 480v winding set at all.

wkobe88822

Ok thanks I'm looking to float my system on my eu2000 on crappy days rather than. Running my 12 kw diesel.

wkobe88822

I work at a power plant and our electricians will help me. But could you tell me how you wired yours so I can get a understanding of it?

mike95490

Your system and mine will be very different.  Enlist the help of your power plant friend. here's a couple links to get you started

https://www.electronics-tutorials.ws/transformer/auto-transformer.html
http://www.outbackpower.com/downloads/documents/Hardware_Accessories/autotransformer/PSX-240_Relay_Manual.pdf

Ability to run from a small inverter gen was my driver to get the transformer, found on fleabay, price included shipping, but I knew how to make many sorts of transformers work for this application.

wkobe88822

What kind of system are you running? I'm off grid 7.8 kw of panels VFX 3648 fp2 12 kw diesel and Honda eu 2000 that I want to run on shitty days to float system.

mcgivor

It is my understanding that the split phase XW inverter charger will accept a 120V input from a generator without the need for a transformer, simply by connecting between L1 and N on AC 2 input. This is something I read as a feature that allows the use of a smaller generator, not something I've personally done, since I use strictly 230V. The wording was something to the effect of, allows the use of a 120V input to produce 120/240V without the need for an external transformer.

wkobe88822

What's the xw inverter? I have outback VFX 3648 fp2 most likely different.

Estragon

The OP in this thread had XW.

I run stacked VFXs in master/slave parallel for 7kw 120v out, and an autotransformer to run 240v pump. I assume yours are series stacked?

mcgivor

My mistake, too many X's got me mixed up, never mind. Tagging onto an old thread leads to confusion, always best to start a new discussion, yes/no?