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Chris Hobson

Axperts in parallel

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Ok lads a silly request from me.

I am busy planning the install of a 2nd Axpert to go in parallel with my 3 year old inverter. I have an inverter that is a month older than my current machine (the ideal partner).

I find the parallel cables untidy and would like to put them into trunking along with all the extra cabling. I am planning on using trunking with two channels to separate DC and AC cabling. My observation it that most of the cabling can be accommodated in trunking running horizontally below the inverter but the battery cables run vertically. My clients generally ask for GTIs or hybrids and a couple of single Axperts so this is not something I have thought through. Those of you who have multiple Axperts could I ask you please to post photos of your inverter installs.

Anyone used slotted trunking?

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1 hour ago, Chris Hobson said:

Anyone used slotted trunking?

I've used quite a bit of it. It works well. For heavy cables running vertically it's not as good, perhaps look at proper cable trays for that.

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Chris when @Mike installed my second inverter, all cables were routed through one piece of trunking. It is open at present awaiting the return of my faulty inverter so looks a bit of a mess and not fair to publish a photo. Nevertheless the important point is that I have not experienced any ill effects, at least not what I could observe. So I suppose its just a matter of personal preference of how you elect to do it. Looks like you are en route to major expense for more Pylontech batteries if you have a need for a second inverter. I miss mine because domestic peace is tested at times when the one inverter cannot cope with the load. Like a while ago when unusual kitchen activity tripped the load limiting 8 Kw breaker that Mike installed to protect the inverters. However @Coulomb advised that the bypass relays  are rated at 40A but suggested a maximum bypass load of 7 Kw depending on power factor of the load. So I suppose with two inverters in parallel they are capable of around 14 Kw in bypass mode since I am grid connected.

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5 hours ago, Chris Hobson said:

I am planning on using trunking with two channels to separate DC and AC cabling.

I think that this is a good idea. I believe that in Australia, it is mandatory.

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Posted (edited)
11 hours ago, Chris Hobson said:

Those of you who have multiple Axperts could I ask you please to post photos of your inverter installs.

20180627_070836.thumb.jpg.0dc72d831cf8bf381ab9f5057cc302cc.jpg

20180627_070931.thumb.jpg.7f7fa395c0a385d18739a410f6c33e7e.jpg

Posted not as a sample of perfection but so that you can gauge what you would do differently:D

Some notes:

I used 40x40 trunking and ran battery cables in the same trunking (because it is mine and I will break petty rules if I want to dammit:angry:), but I ran out of space hence the 2 exposed horizontal cables - so running a single 50x50 or 2 separate trunks of 40x40 should do it.

The bottom covers are removed to assist with airflow in summer when the inverters reach about 50C - I still have the original manufacturer layout of fans blowing out the bottom, but with 4 assist fans (2 each) blowing in the top.

The Battery Isol is 4 pole because it is 63amp, so I have paralleled 2 poles to make it 126amp 2 pole. The surge arrest that you see is DC arrest for the panels.

If I did this over (which I don't plan to) I would use 50x50 with AC and battery cabling in a single trunk (it is only running about 600mm to the right where AC turns up to the DB's and DC turns down to the batteries), and a single 15way DB below each inverter with AC on the left and DC on the right and a manufactured separator in the center (not really, I threw the separator in to keep the nannies happy:rolleyes:).

I am not sure how routing the parallel cabling could be changed - I guess I would just leave those as is. This install is in a small wasted space below a staircase that is kept closed and locked, so I am not too pedantic about the aesthetics.

Edited by pilotfish

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Chris,

you can actually make a very neat installation using wire mesh baskets or use the O-line 41x41 galvanized trunking with metal covers. The plastic one tend to look quickly 2nd hand when often fiddled with. I prefer to see and be able to feel the temp of the cables.

Regards

Ronnie

 

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Posted (edited)
1 hour ago, Ronnie_V said:

Looks more like a piece of art!

It is. ;) 

Carefully crafted over many many years ... as it used to be 2 separate systems, now it is one.

Completely unplugable in seconds, every single part of it, using 3 point plugs for AC and Brad Harrison for DC, DC color coded so I don't get it wrong putting it back together.

Even the battery bank/box is unplugable, on wheels.

And if there is lightning, the light bulb flashes we get compared to Jhb monsters, the array cables can be unplugged, left hanging lose where they can cause no damage.

To fit it into neat channeling... Not.A.Chance.

Re. the safety of it all ... has all the protections required, and then some.

Have not let a whiff of smoke out of any part in years. Nor have I shocked myself. :D

EDIT: And it is well ventilated. 

Edited by The Terrible Triplett

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2 hours ago, Ronnie_V said:

Looks more like a piece of art!

It's a candidate for a number of facebook pages dealing with this topic... like Crappy electrical, Shitty electrical. Crap Solar, I'm an electrician, and so forth.

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Just now, The Terrible Triplett said:

Trust me. Not a good idea.

Indeed... I think of those air conditioners duct-taped to car windows. Works, does the job... but man :-)

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Posted (edited)
8 minutes ago, plonkster said:

Works, does the job... but man :-)

Huge difference between crappy wires connected badly with no protections and a shitte load of (edit) over-sized top quality wires connected properly with protections.

Further to the above, a movable system has further complications vs a mounted one.

Give the guy a break. ;)

Edited by The Terrible Triplett

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2 hours ago, The Terrible Triplett said:

Give the guy a break. ;)

Fair enough. Truth be told, I suffer just a tad from OCD... but if you see some parts of my own system you would likely wonder why my OCD is so selective. That re-use of burglar-barring though... that is creative.

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Posted (edited)

One of my my motivations is the old English saying "The cobbler's children have no shoes!" There are three or four local solar installers at least two do not have solar in their own homes. If I cannot do a good job on my own install why should I be trusted to do anyone else's? I like @plonkster don't like wires festooned all over the place.

12 hours ago, Ronnie_V said:

you can actually make a very neat installation using wire mesh baskets or use the O-line 41x41 galvanized trunking with metal covers. The plastic one tend to look quickly 2nd hand when often fiddled with. I prefer to see and be able to feel the temp of the cables.

Thanks Ronnie

I had not considered galvanised trunking.

Addition: I like O-line's idea of that one can include a plug socket into the trunking. I plan to have two dedicated plugs for my use only which is not subject to as TTT calls them the "langhaar huisdier" overloading the system. With two Axperts I will have 8kW the house will be limited to 6kW and my man cave can have 1kW.

Edited by Chris Hobson
Addition

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Posted (edited)
1 hour ago, Chris Hobson said:

... wires festooned all over the place ...

I too have selective OCD and I absolutely deplore wires all over, like solar and computers cables.

I overcome the above idiosyncrasies by Googling wire mess, asking are they wire messes or wire art, like so, and I feel instantly better:

image.png.dd2153f3d96e3efe39d96d9d0eb21ddd.png

Edited by The Terrible Triplett

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So my local electrical wholesale shop cannot supply dual trunking where each compartment is of equal size. No problem I see that a 40x25mm trunking fits very nicely into a 100x40mm trunking.

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And what about power skirting , steel trunking in which they seperate electrics and usually IT or whatever. The nice thing is it is designed to take 4by2 plugs if you wanted and electrical point

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Thanks to @seant I investigated plugs and trunking  and ended up with very neat plug fittings. Today I have finished the AC side and communication cabling between the two inverters and installed 2 extra Pylontechs. BMS busy synchronising the modules. Next week I will install busbars and disconnects and PV for the new inverter.

818062989_parallel1.thumb.jpg.c9b0872148917c92b3149b66ba457428.jpg

I  hate cables that dangle and now have more dangling than when I started but it is a consolation to know it will look better when I am finished.

Pylons.thumb.jpg.85b86872bbb4efbf77f4aaa703168038.jpg

I inadvertently plugged Riaan's cable into RS485 port rather than the console port  but no harm done.

 

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12 hours ago, Chris Hobson said:

Thanks to @seant I investigated plugs and trunking  and ended up with very neat plug fittings. Today I have finished the AC side and communication cabling between the two inverters and installed 2 extra Pylontechs. BMS busy synchronising the modules. Next week I will install busbars and disconnects and PV for the new inverter.

818062989_parallel1.thumb.jpg.c9b0872148917c92b3149b66ba457428.jpg

I  hate cables that dangle and now have more dangling than when I started but it is a consolation to know it will look better when I am finished.

Pylons.thumb.jpg.85b86872bbb4efbf77f4aaa703168038.jpg

I inadvertently plugged Riaan's cable into RS485 port rather than the console port  but no harm done.

 

Love it when a plan comes together

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What I am interested in is how you handle the DC "distribution board". I would dearly love to do something like this (with DC breakers on the red side):

dc-distribution-box-500x500.jpg.eab4d48b6387becfa40fa6c8890a16d1.jpg

But have you seen the cost of a high-current switch like that?

I still like the idea of the bus bar though. In my system I have two big bus bars at the battery, but the box with the isolators for my charge controllers has no bus bars, so I have two cables entering for each, and two cables leaving to go to the bus bars. Two charge controllers, so 4 thick cables in that box. Now I want to add another charge controller... and it is getting crowded...

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2 minutes ago, plonkster said:

What I am interested in is how you handle the DC "distribution board". I would dearly love to do something like this (with DC breakers on the red side):

The DC side is a little less easy. My plan is to have a clear DB box with busbars roughly in the corner of the room. I then will run cables in trunking to below each inverter through a Mersen disconnect into the 100 x 40 mm trunking. On the PV side the cabling will have to go from the existing DC CB into the 100 x 40 and then through the lid of the 100 x 40 mm. The new PV homerun can neatly be accomodated in the 100 x 40 mm trunking.  Not ideal but should be neat enough. The  100 x 40 mm will have internal divisions for AC and DC just below the inverter where you end up having both classes. There is definitely scope for a twin channel 100 x 40mm trunking where each channel is 50 x 40 mm.

13 minutes ago, plonkster said:

But have you seen the cost of a high-current switch like that?

JIP they are pricey. I use DC circuit breakers - which are expensive but do add a 2nd line of safety over and above fuses. What I like about the Mersen disconnects is that is both a fuse and a switch.

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Posted (edited)

I have something similar, using a UT7 enclosure. I just need a second set closer to the isolators for the charge controllers. And at some point I want to put some cable glands on to make it even neater, and the cables going to the battery I want to beef up a bit, maybe make them 50 square.

busbars.thumb.jpg.769df33608834bc19b2bccbe0d258200.jpg

It also suffers a little from lack-of-my-own-crimper syndrome. I have since acquired a crimper :-)

Edited by plonkster

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