# Spare parts for an off-grid PV system?



## K.B. (Sep 7, 2012)

My PV system has been up and running for about 4 months now, and all seems to be going well (knock on wood).

Since the PV system is our main power supply, I would like to try and be proactive in ordering a few parts to keep on hand in the event of a malfunction by one of the system components. 

I have a spare 150V Din Rail breaker for the combiner box. I probably should order a couple extra since I have 3 strings of panels. 

I ordered an extra 12V ventilation fan for the battery box, to make sure we can continue to actively remove any hydrogen gas build-up. The fan is controlled by the Outback FlexPower panel and is set to come on for 1 minute out of every 5 minutes while the batteries are charging (above 52.8V on the 48V battery bank). 

The other main components are all part of the FlexPower panel. I spoke with one of the reps at Outback and his suggestion was to consider getting a replacement fan for the FM80 charge controller. He stressed that they try very hard to get any necessary replacement parts out right away, so any down time for the system is minimized - which I appreciated.
http://www.solar-electric.com/outback-power-replacement-fan-fm80.html

I looked around for a replacement fan for the VFX3648 inverter that is part of the panel and have not found one yet.

The breakers that are built in to the panel for the battery, PV, and AC disconnects all seem pretty robust.

I have a surge/lightning arrestor on the PV combiner box.

I keep a good supply of distilled water on hand for maintaining the batteries. The amount required so far has been pretty minimal. I have not let the batteries get below 78% state of charge, yet.

I still have my cheapo 5000W generator that I used during construction. I will be getting a honda eu2000i or eu3000is in the near term to use for supplemental charging through the winter months. 

Are there any other parts, spares, or items that you would recommend having on hand?

Thank you very much!
KB


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## Steve_S (Feb 25, 2015)

Whatever gen-set you use, have an extra spark plug (Gapped), air filter and can of oil always at hand.

Should you ever blow a Breaker to the point that it needs a replacement, you have other bigger problems that need to be dealt with first & foremost.

Lightning Arrestors can go poof, which is their purpose so an extra one is not a bad idea.

On a side note regarding the Genny. I'm a bit of a stickler when it comes to things like oil... I break in new motors with regular oil as recommended and then switch to Synthetic 0w40. You would be surprised what a difference that makes on any motor but especially on ones that run intermittently.


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## TnAndy (Sep 15, 2005)

Well, you probably don't want to hear this, but I bought a spare set of inverters (GTFX2524)(2), three FM80 charge controllers, and a Hub(the electronics of my system) and have them in Faraday containers.....sealed 55gal drums lined with cardboard.


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## K.B. (Sep 7, 2012)

Steve_S said:


> Whatever gen-set you use, have an extra spark plug (Gapped), air filter and can of oil always at hand.
> 
> Should you ever blow a Breaker to the point that it needs a replacement, you have other bigger problems that need to be dealt with first & foremost.
> 
> ...


Thank you for the tips and reminders on the generator maintenance. I am in decent shape, but a few extra parts would be good to pick up. I have not tried the synthetic oil in the generator. May be something to think about once I pick up the Honda unit.


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## K.B. (Sep 7, 2012)

TnAndy said:


> Well, you probably don't want to hear this, but I bought a spare set of inverters (GTFX2524)(2), three FM80 charge controllers, and a Hub(the electronics of my system) and have them in Faraday containers.....sealed 55gal drums lined with cardboard.


Not that I don't want to hear it, I think it sounds like a great spot to be in. Unfortunately, it will likely be at least a few years before I can factor full spare units into my priority list. 

The shielded storage is an interesting topic... I am curious how effective a metal roof may be in preventing/reducing damage to electronics inside the house from a solar flare or EMP. The roof certainly stops all cell signals from getting through. My power/battery room is surrounded by 8" concrete walls within the insulated envelope of the house to help with maintaining a stable temp since we don't use any air conditioning. The concrete walls may offer some additional benefit to blocking a pulse, but I am not sure. Storing spare parts that contain sensitive electronics in a Faraday cage of some form makes sense.


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## Steve_S (Feb 25, 2015)

There is one thing I did not put in my previous post but one which you may wish to consider as well. A backup heat source (no flame) that can be used to keep your "battery room" area warm in case of emergency. 

I have my Powerhouse / Pumphouse (14' x 6') separate from my cabin so I have to think 3 backups. Being in Ontario Canada it get's chilly in winter so "be prepared" goes with living up here. I built the structure on a FPSF Slab with Radiant PEX (1/2") and Hyper Insulated (4" thick ISO Foam in-walls, 2" ISO + OSB Sheathing outside, roof 6" ISO +sheathing+air-space+tin).

Heat-1:
PEX will be heated with a Solar Propylene-Glycol panel (5'x3') that will heat store in an old recycled hot water tank. Majority of this came from BuildItSolar.com.
Heat-2: 
12V Automotive style air heater. This will run IF Glycol Temp is not up. THIS IS A BACKUP.
Heat-3: 
Battery Charging generates "some" heat but not enough... I have a Buddy Heater (Propane Ceramic Heater) if absolutely necessary.

NB: This 12V System is Separate from my Solar System which is 24V 980aHr. The 12V system has it's own small panel, charge controller & BIG AGM. This makes it isolated from my other systems while benefit from being there with it. It also allows me to have 2 12V LED Lights in my Pump/Powerhouse which is quite plenty as I painted everything inside with a Pearl White HD Porch Paint... WOW Does it ever reflect light!

Not sure about where you are as far as building codes and electrical codes etc... but as I am installing Tin Roofs, I am grounding them using chase lines.

On Grounding... My Pump/Powerhouse is grounded to the 6" Well casing situated inside which is 30' deep (bottom 10 of that in granite). My actual well is 240' deep. Cabin has 2 Ground Points, 1 @ Entry point / panel that goes to a Grounding Plate 30" from slab 24" deep, 2nd on opposite side of the cabin. My Solar Panels (8x 260w) are 40' from Powerhouse mounted to a 20' Sea Container (pivoting panel mount) are grounded separately there along with the Sea Can itself. (Big Steel box on top of a Granite Ridge = Lightning Potential ! )

All I can say, do NOT skimp on grounding properly !

PS: I have been using Synthetic Oils for 20+ years now and never had any issues whatsoever. From my Generators to my 355HP SBC & 560HP 402-BBC and it really is amazing. I put 40,000km on my 355hp/350 SBC and tore it down to refresh it.... Still looked as good & clean as it did when I first put it together. Yes it costs a bit more and there is a bit of feldercarb phooey out there about Synthetics but extreme duty equipment including military all use Synth for good reason.

Sorry for the long rattle, hope it helps.


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## K.B. (Sep 7, 2012)

Thanks again - I appreciate the additional thoughts.

I think the radiant floor heating systems can work really well, especially in cold climates. I did not go that route, but still wonder if I should probably have installed the pex tubing while the slab was being poured, for down the road or just in case. 

Well-insulated and high thermal mass were two of the primary design features of our new house. Our climate is pretty mild, but still can swing 50F over the course of a day. Designing the house to take advantage of passive solar and having thick concrete core walls and floor are good ways to moderate indoor temperature swings. 

This will be our first winter in the house, but based on the slow changes in indoor temps to outdoor extremes, I am optimistic that we will stay in a safe zone even without supplemental heating beyond the passive solar. Wood heat is the primary active heat source after the solar, and I have a couple of individual thermostat regulated propane wall heaters hooked up to the house supply to serve as backup if we need additional heat or to make sure the house doesn't get too cold while we are traveling. 

My battery room also contains all my solar-PV components, and it is in the most temperature "protected" part of the house.

Regarding codes, all of our construction process was inspected and approved by the county. As the owner-builder, I felt fortunate that our inspectors were generally pleasant and very helpful. If one of them wasn't familiar with something, they made sure to send an inspector who was the next time. We got lots of tips along the way.

I think the pre-assembled Outback FlexPower panel was a great help in making the PV inspection go smoothly.


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## JeepHammer (May 12, 2015)

I back up all primary production parts as I can afford them.
Inverter rack with redundant inverters installed keeps me cooking when an inverter fails,
And the inverters can load share, when more power is needed, another inverter comes on line to supply demand.

The old Sunny Boy, my first large capacity inverter, sits ready with quick connects to supply basic power if the rack/high dollar inverters fail... Like from a software issue.

I'm not a software genius, and I have no control over the internal workings of inverters, ect.

What I can control is the EXTERNAL connections, conductors, ect. and I don't do things like most people would... 
Or like the 'Factory' recommends.

I don't hold with the idea of 'Battery Box' for one thing,
4" separations between batteries allow heat to escape,
The same is true with racking batteries with open bottom racks and air space under the batteries.

I don't 'String' batteries like most places recommend,
I use 6 volt batteries, 4 batteries to a rack,
And roller (wheels) casters on the racks.
24 volts per rack, with quick connectors,
This allows me to move batteries quickly, without breaking my back,
To ROTATE batteries in '_In Banc_' to maximize longevity and storage capacity.

Battery connectors I pay particular attention to,
To prevent corrosion and to keep RESISTANCE to a minimum.
Corrosion is self explanatory,
Resistance isn't so obvious, but resistance wastes your panel power TWICE,
Once when the battery charges, once when you draw from the battery.
You can EASILY loose 10% production going to the batteries with high resistance!
That means 10% more panels, and 10% more batteries to get the same results,
Panels & batteries are expensive, doing proper connections is time consuming, but not that much more money...
And your cables/terminals last longer! Again reducing expense over time.

I didn't go with a traditional 'Battery Box' with panels/inverters mounted remotely.
I went with a 'Power House' that also serves as the well pump cover/well head.
Its simply a 'Yard Barn' with a hole cut in the floor for the well head to stick up through,

Direct Current (DC) doesn't push through wires very well, not like Alternating Current (AC) does.
To cut down on wire/cable losses, the Power House/Well House is directly adjacent to the panels.
This gives MUCH shorter runs of DC wiring, reducing losses,
And once the power goes through the inverter, coming out as AC power, then its run to the house/shop.

The power house is heavily insulated, has a sheet metal interior (helps with lightening potential and reduces RF noise)
The sheet metal is also fire resistant, allows for fire prevention/control.

The building has lightening rods!
I've been nailed by lightening 3 times, and the last time I lost nothing but lightening arresters and a ground cable clamp!

I also keep extra lightening arresters handy, with a solar array on a hill you just never know!

By using high quality (Anderson) connectors,
Using a mechanical crimp on terminals,
Then SOLDERING terminals for a high quality ELECTRICAL connection,
Then using heat shrink tubing and boots on the connectors/terminals for environmental protection,
And Dielectric grease or contact grease on the contact surfaces of the terminals,
I reduce the electrical losses, and get terminals that last for years & years.

For ventilation, both passive and active...
'Whirley-Bird' vent on the roof over the batteries,
Vents in the ends of the buildings,
Small solar panel drives fans,
And a switch on the outside door kicks on a fan driven by the battery banks.

Hanging my face protection, safety glasses (Both, not one or the other) on the door to the battery compartment reminds me NOT to deal with batteries without protection.

I also hang installed connectors for the battery strings over the batteries,
Along with automatic watering system.

The hanging connectors is where I install charge controllers,
So the smaller wires are crimped in, and sealed with, the cables feeding the inverters.
The battery connections are terminals and large cables only, no small wires to corrode through unnoticed or small, unknown material terminals in battery connections that sometimes cause corrosion problems...

I'm trying a 'Wet Tray' for the batteries to keep the operating temps down in summer.
Batteries live MUCH longer if you can keep the battery under 75*F.
A 'Spring House' would be perfect, a water bath that is constant flowing to keep temperature down...
I don't have one.

I have the well pump running between 10:00am and 2:00pm,
Peak Sun hours.
The pump fills pressure tanks (also in the 'Power House') and a temp switch changes water when it reaches 75*F.

The power house hasn't needed heat but two times in 15 years,
Provided by a propane heater.
Between the batteries, inverters, charge controllers, water tanks, and insulation,
The room simply doesn't unless it gets to -10*F. and stays there for a while.
Too much going on in the heavily insulated room...

Another 'Trick' was to bury about 100 yards of plastic 10" corrugated plastic pipe at 7',
Screen vent on one end, the other end comes up in the power house,
The earth brings the incoming air up to above freezing,
And supplies cool air in the summer.

It makes no sense to pump hot air into the building in the summer,
Cold air in the winter...
Earth moderated temp air makes more sense, and costs nothing but the pipe/labor to install.

Just some ideas from a guy looking for a 'Better' way,
Take what you can use...


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## K.B. (Sep 7, 2012)

JeepHammer said:


> I don't 'String' batteries like most places recommend,
> I use 6 volt batteries, 4 batteries to a rack,
> And roller (wheels) casters on the racks.
> 24 volts per rack, with quick connectors,
> ...


Thank you very much for your time and tips. 

I would be interested in any pictures you may be willing to share regarding the battery racks/quick connectors.

I may need to expand my amp-hour capacity in the future, once I get some experience with these lower end L16's and I may change around my battery housing at that point. 

Thanks again!


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## JeepHammer (May 12, 2015)

I understand this site lays claim/copyright to anything you post up,
And I do technical writing on this subject, I don't want my pictures copyrighted by someone else.

The principal is simple,
There are two main cables tacked to a 2"x6" board that runs a comfortable height above the batteries.
These are the primary feed lines from batteries to inverter, heavy gauge,
In my case, 2/0 ga fine strand welding cables.

Welding cable is designed to carry high amperage, so its normally 'Virgin' copper, no alloys.
This reduces resistance losses in the cables.
They are also oversized for the application, again, to reduce resistance losses at peak draw on the batteries.

Welding cable has an insulation that is seriously tough!
Designed to NOT arc through at high amperages,
Designed to resist oil, corrosives, and abrasion, since welding cable is designed to be dragged across shop floors with who knows what on the floor,
And over sharp edges...

Its also the ONLY commonly available, reasonably priced pure copper conductor designed specifically for high DC amperage.

The inbound lines from the panels also run along that same 2"x6" board over the batteries.
This gives me access to the lines for charge controllers.
I can charge different battery strings off different panel strings.

If one panel string goes down, bad connection, bad panel,
I don't lose ALL battery charging.
Designed in redundancy.

Main lines have Anderson connectors spliced into them hanging down over the battery strings,
And since the charge controllers are mounted above the battery strings also,
I just crimped/soldered/sealed their leads into the Anderson connectors that hang down.
This means no small wires connected to the batteries directly,
So no corroded small wires down at battery level that eats small wires/terminals for lunch.

The batteries are four to a roller rack, 24 volts/Series wired,
With an Anderson connector also.
One yank on a connector and the roller rack can be serviced,
Or moved in the bank (rotated) so the batteries age gracefully.

Just keep in mind a couple of things when you are working with DC,
A 'Crimp' is a MECHANICAL connection, not an electrical connection.

Solder is an electrical connection.

Anything around your batteries MUST be environmentally sealed or the gasses/acid will attack/destroy it over time,
Some faster than others...

Terminals/Connectors have a circular 'Mills' rating.
Just because a 'Fat' wire will fit in the socket end, DOES NOT mean it will conduct amperage like the cable will!
The cable can be as big as your thumb, but if the terminal ends can't conduct as much as the cable you are wasting time & money...

All you are going to do is heat up that restrictive terminal end,
And that's not only a bad thing, but it can be dangerous.

Solid, thick neck (neck, part between socket and contact surface area) are best.

Also when you pick terminal ends, consider the contact patch area on the 'Eye' or 'Ring'.
A thicker terminal will deliver more amperage,
But if its real thin walled, that's a restriction also.
The terminal contact face should ideally be larger than the contact patch of the battery or inverter terminal you are putting it on...

I can link you to some pictures of different terminals/cables if you like...


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## K.B. (Sep 7, 2012)

Well, even though the spare parts that I ordered arrived, they were not much help with the problem I had with the PV system last week.

The inverter suddenly stopped working altogether. No error messages or events logged with the Mate controller... just dead.

Fortunately, the new Honda eu2000i generator had arrived and was able to see us through the weekend and next day until the inverter boards arrived from Outback. 

To their credit, Outback shipped the parts the same day and have a walkthrough video posted on replacing the boards:
[ame]https://www.youtube.com/watch?v=KtEw8ijqHpU[/ame]

Using the video as a guide, the board replacement was mostly straightforward. It took way more time to disconnect and dismount the inverter from within the Flexpower panel (which is not covered in their video).

Hopefully that issue is behind us for awhile. 

It looks like TnAndy's level of preparedness (spare inverters stashed away) for the win!


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