Outback Power GTFX2524 Inverter question for a mobile application.

TucsonAZ · March 2018

**The story of how I got it**

Four years ago I went to check out one the guy had listed on Craigslist for $500, I offered him $350 and he turned me down. Fast forward to today and a couple dogs were in the road while I was driving so when I stopped to get them off the road I happened to be in front of his house (very rural setting) so I asked if they were his (they weren't but we did get them home). I ended up asking if he still had the solar stuff and they'd been just sitting in the same spot in his shed since the last time I was there. When I asked how much he says "well I was asking $500 but I'll take $140" so needless to say that was a done deal. Also included a Xantrex C35 which I have no use for but I'm sure I can figure something out.

**My actual question**

My question is, I'm building a little enclosed trailer/camper right now and was planning on using two Cotek 1,500 PSW inverters but would love to have a singe 2,500 watt instead to allow for surges. What I'm wondering is can I hook this up so that when I have shore power I'm running on shore power and when I unplug the shore power it automatically switches to my battery bank essentially giving me uninterrupted continuous power? Clearly I'm not going to be feeding power back to the grid but having the ability to always have power when I'm plugged into the grid or not would be an added bonus.

Thanks a lot!

1,200 watts of solar
6,000 watt 24v battery bank
Midnite Classic 150

ScoobyMike · March 2018

An AC transfer switch would work. You would run the shore power and the inverter power as inputs to the transfer switch, with shore power as the priority. The output would be inverter power unless there is shore power. Check out Go Power or Xantrex transfer switches on Amazon.

TucsonAZ · March 2018

ScoobyMike said:

An AC transfer switch would work. You would run the shore power and the inverter power as inputs to the transfer switch, with shore power as the priority. The output would be inverter power unless there is shore power. Check out Go Power or Xantrex transfer switches on Amazon.

I thought the GTFX2524 had one built into it, am I wrong? In fact I thought it had a transfer switch and a battery charger for when I'm plugged into shore power.

TucsonAZ · March 2018

Anyone?

mike95490 · March 2018

whats the link to the manual ?

westbranch · March 2018

well if you search for GTFX you get to http://www.outbackpower.com/products/inverter-chargers/gtfx-gvfx-120v and see:
.

OutBack Power’s true sinewave grid-interactive inverter/chargers incorporate a DC to AC sinewave inverter, battery charger and AC transfer switch housed within a die-cast aluminum chassis.

A built-in transfer switch automatically disconnects your loads from the utility grid and powers them from the inverter in the event of an outage, allowing you to continue using your solar and battery backup power, unlike traditional grid-tied systems.

Intelligent multi-stage battery charging prolongs the life of your batteries and built-in networked communications enables you to stack up to two units while simultaneously communicating with other OutBack Power components. The modular system architecture means that increased power output is just an additional inverter/charger away.

TucsonAZ · March 2018

westbranch said:

well if you search for GTFX you get to http://www.outbackpower.com/products/inverter-chargers/gtfx-gvfx-120v and see:
.

OutBack Power’s true sinewave grid-interactive inverter/chargers incorporate a DC to AC sinewave inverter, battery charger and AC transfer switch housed within a die-cast aluminum chassis.

A built-in transfer switch automatically disconnects your loads from the utility grid and powers them from the inverter in the event of an outage, allowing you to continue using your solar and battery backup power, unlike traditional grid-tied systems.

Intelligent multi-stage battery charging prolongs the life of your batteries and built-in networked communications enables you to stack up to two units while simultaneously communicating with other OutBack Power components. The modular system architecture means that increased power output is just an additional inverter/charger away.

Okay, that's why I mentioned my desired use for this unit just to make certain I wasn't missing something. I was kinda hoping somebody maybe had one and could just tell me that when I'm plugged into shore power the system will run on shore power and when I unplug it will seamlessly switch to the battery back without interruption. I also didn't know how the charging system functioned and if it would negate my need for the other charger I was intending on using.

mike95490 · March 2018

there is the install manual and the programming manual. Have those been read ?

http://www.outbackpower.com/resources/documents/product-documentation/item/gtfx-gvfx-series-120v-technical-documentation

I don't have any outback gear, and not up on their programming

TucsonAZ · March 2018

mike95490 said:

there is the install manual and the programming manual. Have those been read ?
http://www.outbackpower.com/resources/documents/product-documentation/item/gtfx-gvfx-series-120v-technical-documentation

I don't have any outback gear, and not up on their programming

Yep read both but not clear on programming perimeters and if it can be used as I'd like as it is or if there are other things needed. Seems like a common unit so I figured somebody with hands on experience might be able to chime in.

Raj174 · March 2018

@TucsonAZ
I believe all Outback inverters need a Mate to program the settings. I think the one in the link below will work with a FX unit. You might give the NAWS store a call for confirmation.

https://www.solar-electric.com/outback-power-mate-systems-display-controller-black.html

Rick

Estragon · March 2018

I have two vfx inverters, which I think are similar to the gtfx.

My inverters are normally powered by battery, and will supply 120vac to any ac loads greater than a settable search mode value. In search mode, it pulses at a settable interval to see if there is a load demanding power. Mine are set up as a master/slave parallel stack, but the general idea is the same.

If it sees a qualifying voltage (from a generator in my case) on the ac-in terminals, an internal transfer switch activates to bypass the battery circuit and supply loads with the ac-in power. There are a number of settings related to qualifying ac-in (voltage and frequency ranges), and limits (max ac-in, etc).

Using this in a mobile application does potentially have an issue with neutral/ground bonding. A mobile version would switch the neutral as well as line, as the n/g bond is assumed to be made on the shore power side when on shore power. You'll want to consider how the gtfx works in the context of your trailer ac wiring.

I assume there will be additional settings for interacting with grid, which you'll need to review carefully. My understanding is a gtfx is designed only for grid interactivity, not generator input, so there will be differences in qualification parameters etc.

I think an OB mate display capable of running appropriate firmware will be needed, at least for initial setup. Personally, I'd want one for ongoing monitoring and adjustments, but you might be able to get away with borrowing one to set up. With a mate, you're stuck with default values for battery charging values etc., which are unlikely to work well.

With multiple stacked inverters I need a hub for networking with the mate as well, but IIRC a hub isn't needed for a single inverter.

Aside from the mate, you'll need assorted breakers, wire, etc., which should be specified in the install manual.

TucsonAZ · March 2018

Estragon said:

I have two vfx inverters, which I think are similar to the gtfx.

My inverters are normally powered by battery, and will supply 120vac to any ac loads greater than a settable search mode value. In search mode, it pulses at a settable interval to see if there is a load demanding power. Mine are set up as a master/slave parallel stack, but the general idea is the same.

If it sees a qualifying voltage (from a generator in my case) on the ac-in terminals, an internal transfer switch activates to bypass the battery circuit and supply loads with the ac-in power. There are a number of settings related to qualifying ac-in (voltage and frequency ranges), and limits (max ac-in, etc).

Using this in a mobile application does potentially have an issue with neutral/ground bonding. A mobile version would switch the neutral as well as line, as the n/g bond is assumed to be made on the shore power side when on shore power. You'll want to consider how the gtfx works in the context of your trailer ac wiring.

I assume there will be additional settings for interacting with grid, which you'll need to review carefully. My understanding is a gtfx is designed only for grid interactivity, not generator input, so there will be differences in qualification parameters etc.

I think an OB mate display capable of running appropriate firmware will be needed, at least for initial setup. Personally, I'd want one for ongoing monitoring and adjustments, but you might be able to get away with borrowing one to set up. With a mate, you're stuck with default values for battery charging values etc., which are unlikely to work well.

With multiple stacked inverters I need a hub for networking with the mate as well, but IIRC a hub isn't needed for a single inverter.

Aside from the mate, you'll need assorted breakers, wire, etc., which should be specified in the install manual.

Awesome stuff thank you so much for the first hand insight on your units. It sounds like I'm going to need the mate as part of my system so I will confirm and work on finding a deal on one of those. I didn't totally get your concern over the common, are you meaning because when I'm actually off grid I won't actually be grounded?

Are you thinking I should maybe not use this in the situation I'm thinking of using it in? I don't actually "need" to as I have two other 1,500 watt inverters and was planning on going with those so I have two and some level of redundancy if there's an issue. I also already have a three stage 24v charger so at the end of the day I can just move forward with my original plan I just liked the idea of not having any loss of power.

Estragon · March 2018

Not really saying you shouldn't use it, just pointing out the issue.

It isn't a matter of not being "grounded". In a mobile application "ground" is usually the frame, which may or may not be at close to actual local earth potential.

The issue is that neutral likely isn't switched in the inverter. Your AC neutral may be bonded to (so at the same potential as) the frame. In a mobile inverter, when connected to shore power, this bond is lifted by switching the neutral so it's (presumably) at the same potential as local earth. When on battery power, the neutral will (likely) be at frame potential. With the gtfx, you could have the neutral bonded to both the local earth potential via shore bond and to frame potential via trailer bond.

It's just something to be aware of, and an extra reason to be careful with shore power (which you should be anyway). Imagine some donkey wires the shore power you plug into with reversed polarity. With "neutral" bonded to frame, your frame is now live with respect to ground, and bad things could happen.

TucsonAZ · March 2018

Hmmmmm, so I wouldn't use the frame for grounding anything actually beyond the trailer lights being grounded to it and even that I normally avoid. It's my understanding that grounding to chassis would not be wise or safe. I will admit that I often have to really think about electrical systems but overall I'm pretty good with them. In this case I would firstly leave everything isolated and with no potential of grounding out on anything within the trailer. My AC power runs will be confined to a very small area with short wiring spans and few outlets.

The inverter has a hot/neutral/earth in and out so it would be shore power plug to breaker to inverter, inverter to breaker box and off to two/three outlets.

Estragon · March 2018

I don't think it's a question of not grounding anything to chassis, more that you want to check shore power connections. My boat panel has a light to indicate reversed shore power polarity, for example, and I assume this would be fairly common on trailers as well. If not, I'd use a simple, cheap tester that plugs into an ac outlet and shows wiring status.

TucsonAZ · March 2018

Estragon said:

I don't think it's a question of not grounding anything to chassis, more that you want to check shore power connections. My boat panel has a light to indicate reversed shore power polarity, for example, and I assume this would be fairly common on trailers as well. If not, I'd use a simple, cheap tester that plugs into an ac outlet and shows wiring status.

Ahhhh and finally we've got power to the light lol. You're saying if I plug into an outlet with reversed polarity accidentally I'll fry the GTFX and be out of luck correct? Yeah I guess I didn't factor that in and would need to figure out a way to address that. Maybe by making an extension cord that has an indicator built in or by having a disconnect to the shore power inside and an reverse polarity light next to it so I have to turn the shore power on via a switch.

TucsonAZ · March 2018

Something like this:

https://www.amazon.com/Blue-Sea-Systems-8077-Main/dp/B0000AXNVA/ref=sr_1_18?ie=UTF8&qid=1521697799&sr=8-18&keywords=reverse+polarity

Estragon · March 2018

Yup, that's similar to what I have on my boat.

Something like this is handy too.

https://www.amazon.com/dp/B002LZTKIU/?tag=theboagal0a-20

Outback Power GTFX2524 Inverter question for a mobile application.

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