Outback FX-series vs FXR-Series?

2twisty · August 2018

I just ordered a VFXR3648 to replace the VFX3648 that suddenly stopped working saturday. I plan to repair the VFX, but in the interest of getting the power back online right away, I ordered a replacement.

I consoled myself by saying, "once I repair this, I will be able to stack them and make 240 split phase."

Today I find out that the FXR manual says that I can't stack with FX!

Is there an upgrade path for the FX to FXR so that I can stack them?

I can't find anything useful on Outback's web site, nor can I find any documentation that details the differences between the FX and FXR series units.

Please advise.

Estragon · August 2018

Reading the sell sheet and manual, it's not entirely clear to me the fxr does split phase at all, even with another fxr. It mentions using up to none for 3-phase, but I didn't see anything explicitly about stacking for split phase.

Maybe ask them directly?

2twisty · August 2018

I've got a call into them and a support ticket. No response yet.

Since the chassis of the FX and the FXR are identical, I am hoping that I might be able to purchase the parts to convert my FX to an FXR so I can stack them. Selling the FX and buying another FXR might cost me about the same, too.

Oh, and today I discovered that the FXR is incompatible with the MATE, so I had to drop another $430 on a Mate3.

bill von novak · August 2018

Estragon said:

Reading the sell sheet and manual, it's not entirely clear to me the fxr does split phase at all, even with another fxr. It mentions using up to none for 3-phase, but I didn't see anything explicitly about stacking for split phase.

From a blurb from AltE:
============
Multiple FXR inverter/chargers can be stacked for split and 3-phase systems. Up to nine inverters can be wired together for a 3-phase system with all voltage models, three inverters per phase. Split phase 240V can be created with the 24V and 48V models, to create up to a 36kW inverter (120V A) or 30kW (230V E).
============

2twisty · August 2018

From reading in some manuals, it appears that the control and FET boards are different between FX and FXR. Now, to find out if the AC board is different, and what are the costs of the boards vs selling the FX and buying another FXR.

Outback seems to think that resale on FX is decent since there may be people out there with existing FX infrastructure that want another FX and don't want to pay to replace all their inverters.

Estragon · August 2018

Good to know. I though it would be pretty weird to not support stacking for split phase.

2twisty · August 2018

Estragon said:

Off-grid.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter

Can you send me pics or a diagram of how you have the autotransformer wired up to make the 120v output of your inverter into 240 split phase? I've looked at some diagrams but it's not abundantly clear. Maybe seeing how someone actually implemented it will help.

If I can't get into abother FXR to go split phase, I'll do it with a transformer.

mike95490 · August 2018

2twisty said:

Can you send me pics or a diagram of how you have the autotransformer wired up to make the 120v output of your inverter into 240 split phase? I've looked at some diagrams but it's not abundantly clear. Maybe seeing how someone actually implemented it will help.
If I can't get into abother FXR to go split phase, I'll do it with a transformer.

What are the loads you are trying to power ? It might be a cheap transformer (2000VA) or expensive (8000VA) and will the heavy load be intermittent, or 10+ minutes at a time ? (time % at high power influences the transformer requirement)

2twisty · August 2018

Wanting to power a dual-zone mini-split.

https://www.highseer.com/multi-split-dual-zone-outdoor-unit.html?gclid=CjwKCAjwtvnbBRA5EiwAcRvnpomVB3Nbn15d3T3XeOd7ZshRQVoCZSg8tbrPUUbylL_69-LrKVvQiRoCs7oQAvD_BwE

My math says about 2500 watts at peak.

Estragon · August 2018

Mine powers a 240v submersible pump, my only 240v load.

I have a pair of Outbacks stacked for parallel 120v. One spends the vast majority of its existence sleeping, mainly there just in case multiple big loads come on at once (visitors do dumb things at inconvenient times). They feed a panel with bigger/non-essential loads, and optionally a smaller/essential loads panel.

IIRC, the wiring was fairly straightforward. (fairly heavy, 8 or 10ga, I think) 120v hot/neutral/ground in from the big load panel, and 240v L1/L2/ground out to the pump switch. If you end up going that route and aren't sure hooking it up, I can open it up to confirm connections.

bill von novak · August 2018

2twisty said:

Estragon said:

Off-grid.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter

Can you send me pics or a diagram of how you have the autotransformer wired up to make the 120v output of your inverter into 240 split phase? I've looked at some diagrams but it's not abundantly clear. Maybe seeing how someone actually implemented it will help.

If I can't get into abother FXR to go split phase, I'll do it with a transformer.

A "true" autotransformer has three wires coming out - 120V, common or neutral, and 240 volts. Most ones for sale out there have two windings and thus you get four wires. One winding goes to 120V and neutral, the other winding goes to neutral and gives you one free end. The free end is the opposite-phase 120 volts (so that to the other 120V gives you 240V.)

In two-winding transformers (most of them) it's possible to get the winding direction backwards. If that happens, you will measure 0 volts between the two 120 volt windings. In that case reverse one winding.

2twisty · August 2018

I plan to buy the Outback transformer that's not in a case and mount it to a wall.

https://www.solar-electric.com/x-240.html

JRHill · December 2020

My VFX3648 recently begin to malfunction related to the AGS for my generator. Its most likely the relay on the AC board (BTW, $345 from Zonnaenergy.com and it was a NEW board not a salvage). I bought the AC board but I also bought a new VFXR3648-A from NAW&S as I really need a backup in an emergency. The old, obsolete VFX3648 will become my backup. The other reason I upgraded the inverter is I went with SimpliPhi batteries and really need the LVCO which the new inverter supports.

But what really has been on my mind is exactly what this post speaks of: the possibility of self upgrading the old VFX3648 to the "R" by replacing the circuit boards. I can't tear my production inverter down for inspection/comparison. At least now I know the cases are identical. Hmmmm.

JRHill · December 2020

2twisty said:

I plan to buy the Outback transformer that's not in a case and mount it to a wall.

https://www.solar-electric.com/x-240.html

BTW, I use the X-240 not to make 240vac but to bring it 125' from the shop where I have a welder/generator that is a backup to the primary genset. I didn't like the X-240 and its breakers mounted in the open so I used a cheap plastic fishing tackle box to house everything - mounted vertically to the wall. Obviously, the lid should be open for venting when using it for charging/power but that is an extremely rare occurrence. It works great and I can charge at the full 20aac with our standard, small house loads and it barely gets warm to the touch.

JRHill · June 2021

JRHill said:

My VFX3648 recently begin to malfunction related to the AGS for my generator. Its most likely the relay on the AC board (BTW, $345 from Zonnaenergy.com and it was a NEW board not a salvage). I bought the AC board but I also bought a new VFXR3648-A from NAW&S as I really need a backup in an emergency. The old, obsolete VFX3648 will become my backup.

BTW, I sold the old VFX with the new board (if needed) instead of saving it for a backup. It just didn't make sense to have that unit sitting around when someone who needed it could use it immediately. I still ponder having spares on hand but to date there is no trend as to what to have on hand.

Outback FX-series vs FXR-Series?

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