PS2 System Basics

Discussion about OutBacks "PS" enclosures

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jazzer
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Posts: 51
Joined: Tue Jun 06, 2006 7:23 pm
My RE system: PS2 with GVFX3648, MX60, Mate (v4.2.1), FN-DC, 327AH AGM 48V battery banks [234AH EV185A-A, 93AH UPS12-350MR], 3470W mixed modules composed of 6 strings in 56-60V nominal (83Vmp) configuration
Location: Exeter NH

PS2 System Basics

Post by jazzer »

I am relatively new to this forum and about to make a go of putting together a grid-tied system. I live in NH where it is pretty cold and snowy in the winter but we do not have a salt air problem. Please excuse the "newbie" nature of my questions -- I'm not an NEC-knowledgeable electrician.

1) Can a PS2 system be mounted outside, on the side of the home next to the service entrance? Also I don't have an area at eye-level that is 50" wide for the PS2 mounting plate, at least not next to the service entrance. Does it need to be at eye-level or could it be mounted above a garage door?

2) Can the PSPV box be mounted directly on the roof or to a mast on the roof?

3) In a system with a single GVFX3648 & MX60, no hub is required but the MATE is recommended. Why do the MX60 & GFX both require RTS sensors? If this is for sensing battery temperature to effect safe-charging, shouldn't the MX60 be responsible for that? And therefore, why would that information be needed by the GFX?

4) In a system with a single GVFX3648, why do you recommend an OBDC-175 breaker to be used with PS2DC? Is this to protect the GFX in the case of battery discharging to the loads? Is there any reason you cannot use a 100A breaker instead of 175A?

5) I already have a sealed 2 kVA 480/240 to 240/120 transformer I intend to use in reverse as a step up transformer to bump the 120V output of the GFX for my well pump -- the only thing that requires 240V for me. Is there any reason I cannot either mount this where the X-240 would go, or connect it similarly if it is nearby?

6) Overall for a system with about 2.4 kW of panels, where only a single GFX is required, what else can be eliminated in the interests of a fiscally-conscious installer such as myself? At the moment, I think the only thing I eliminated from the standard PS2 system was the HUB-4.

Thank you for your patience!

Jake
Kent Osterberg
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Post by Kent Osterberg »

1) Can a PS2 system be mounted outside, on the side of the home next to the service entrance? Also I don't have an area at eye-level that is 50" wide for the PS2 mounting plate, at least not next to the service entrance. Does it need to be at eye-level or could it be mounted above a garage door?
The PS2 is not an outdoor rated enclosure. For an outdoor installation, consider using the PS1, it'll take less horizontal space too. Either way, the breakers in the PS2 or PS1 must not be higher than 6.5 feet.
2) Can the PSPV box be mounted directly on the roof or to a mast on the roof?
The PSPV is NEMA 3R rated for mounting directly to the roof provided that the pitch is 3:12 or steeper. It is a good idea to mount it a few inches above the roof so that water runs freely under it. Since you are talking about a roof mount, you must include a GFP/2 in your system.
3) In a system with a single GVFX3648 & MX60, no hub is required but the MATE is recommended. Why do the MX60 & GFX both require RTS sensors? If this is for sensing battery temperature to effect safe-charging, shouldn't the MX60 be responsible for that? And therefore, why would that information be needed by the GFX?
Only one RTS is required if the hub is used and the RTS is connected to the inverter on port 1. Both the GFX and the MX 60 use temperature information to properly manage the battery bank, so two RTSs are required with no hub.
4) In a system with a single GVFX3648, why do you recommend an OBDC-175 breaker to be used with PS2DC? Is this to protect the GFX in the case of battery discharging to the loads? Is there any reason you cannot use a 100A breaker instead of 175A?

The breaker serves as a disconnect and provides fault protection. The OBDC-100 breaker may be used, but you may experience nuisance trips.
5) I already have a sealed 2 kVA 480/240 to 240/120 transformer I intend to use in reverse as a step up transformer to bump the 120V output of the GFX for my well pump -- the only thing that requires 240V for me. Is there any reason I cannot either mount this where the X-240 would go, or connect it similarly if it is nearby?

If 2kva is sufficient for your pump, go for it. You'll need a 15-amp breaker to protect the transfomer.
6) Overall for a system with about 2.4 kW of panels, where only a single GFX is required, what else can be eliminated in the interests of a fiscally-conscious installer such as myself? At the moment, I think the only thing I eliminated from the standard PS2 system was the HUB-4.
In a grid-tied system, the hub allows the MX 60 to receive instructions from the FX. I wouldn't consider it to be superfluous. Take a look at the PS1, it might be a better fit for your needs.
jazzer
Forum Expert
Posts: 51
Joined: Tue Jun 06, 2006 7:23 pm
My RE system: PS2 with GVFX3648, MX60, Mate (v4.2.1), FN-DC, 327AH AGM 48V battery banks [234AH EV185A-A, 93AH UPS12-350MR], 3470W mixed modules composed of 6 strings in 56-60V nominal (83Vmp) configuration
Location: Exeter NH

Post by jazzer »

The PS2 is not an outdoor rated enclosure. For an outdoor installation, consider using the PS1, it'll take less horizontal space too. Either way, the breakers in the PS2 or PS1 must not be higher than 6.5 feet.
Ok, I think I'd rather stick with the indoor enclosure. If I can mount this thing next to my breaker box in my basement that'd be perfect. So do you have to intercept the two 120V feeds coming in, run them through the PS2AC, and then out and back into the AC breaker box?

Also, would you need any more than the two 50A breakers for bypass/normal if you did it this way?

The PS2 FX wiring diagram on your website at www.outbackpower.com/pdfs_wiring_diagrams/PS2AC-DCSYSTEM.pdf shows a bunch of house load relays. It seems those would not be necessary if you patched directly into the breaker box. Am I right or confused about something?

If 2kva is sufficient for your pump, go for it. You'll need a 15-amp breaker to protect the transfomer.
Yes it should be fine because the max current is 8.3A but the continuous is only around 6A. Thanks for the breaker advice. I am confused though because I have been referencing the X-240 drawings and it looks like that transformer is not actually stepping up but inverting the phase so you would get 240V across the input and output, not from the output to neutral. Is that how X-240 works? The link www.outbackpower.com/pdfs_wiring_diagrams/900-0009-1sht1.pdf on page 3 shows how to connect it but it is confusing me. Note how the DPST 20A breaker supplying the well pump has two 120V feeds, not a 240V & a neutral. Please clarify how this is supposed to work.

In a grid-tied system, the hub allows the MX 60 to receive instructions from the FX.
What kind of instructions? Only temperature related or are there other messages passed, and what nature are they? Two RTS cost less than 1 RTS & 1 HUB. I'd like to know why the hub is not superfluous in the case of 1 GFX and 1 MX60.

Thanks for your quick reply.
Kent Osterberg
Forum Emperor
Posts: 1523
Joined: Mon Jun 09, 2003 11:01 pm
My RE system: SMA Sunny Boy 2500 with eight Mobil Solar Ra 180 modules
Location: Cove, Oregon
Contact:

Post by Kent Osterberg »

So do you have to intercept the two 120V feeds coming in, run them through the PS2AC, and then out and back into the AC breaker box? Also, would you need any more than the two 50A breakers for bypass/normal if you did it this way?
Do not power the PS2AC directly from your utility service. You must have a service disconnect and overcurrent protection prior to the PS2AC.

The PS2AC has input/output/bypass breakers sufficient for a grid-tied inverter and backup power system. You'll need a 30-amp to 50-amp breaker in your service panel, connected with appropiate wire, to feed the input of the PS2AC. That will consist of two hot legs, one neutral (same size as the hot legs), and usually a #10 ground.

Unless your service panel is set up for an auxiliary (generator) input, you'll need a separate load center for the loads that will be backed up. This is usually a major undertaking that is most easily accomplished if the backup load center is adjacent to the main panel. In many cases, the PS2AC can be the backup load center. That's why the PS2AC diagram shows many ac breakers. It comes with two: one for a 15-amp outlet on the side of the PS2AC and one uncommitted 20-amp breaker.
I am confused though because I have been referencing the X-240 drawings and it looks like that transformer is not actually stepping up but inverting the phase so you would get 240V across the input and output, not from the output to neutral. Is that how X-240 works? The link http://www.outbackpower.com/pdfs_wiring ... -1sht1.pdf on page 3 shows how to connect it but it is confusing me. Note how the DPST 20A breaker supplying the well pump has two 120V feeds, not a 240V & a neutral. Please clarify how this is supposed to work.
In the U.S., a 120/240 vac system consist of two 120-volt legs, measured to neutral, that are opposite in phase such that the voltage between the two hot legs is 240 volts.
What kind of instructions? Only temperature related or are there other messages passed, and what nature are they? Two RTS cost less than 1 RTS & 1 HUB. I'd like to know why the hub is not superfluous in the case of 1 GFX and 1 MX60.
With a hub in the system, the FX can change the MX 60's operating voltage to force it to deliver the maximum charge current. Your system will work without a hub, however there probably will be occasions that it doesn't deliver as much power as possible. Considering the cost of a PV system, the cost of a hub is justified.
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