Also, if you get the ones with MC4 or 2->1 connectors like the diagram, you are limited to 30A (MC4 spec) for any one connector.
Its usually more flexible to get the SISO-40 without MC4 connectors (just terminals), and it also saves you paying for extra pairs of MC4 at the iso end of the solar cable.
Makes sense, Iāll stick to the one you suggested then as I noticed they way cheaper indeed.
My bad just realised you suggested the siso40 in a previous post already, sorry about the confusionā¦ lots to take in for a noob lol.
Youāre doing great - you have your electrical layout and isolation for the panels sorted, now you need your physical layout.
The cheapest is one row of 12 - that uses 4 end clamps and 22 mid clamps - 26 parts in total.
2 rows of 6 use 8 end clamps and 20 mid clamps - 28 parts in total.
If you are ground mounting on your own wooden frame, look at the Chiko corrugate mounts - throw away/use somewhere else the corrugate part, just screw the mini rail to your timber (they come with 3/8" head roofing wood screws) and as long as your timber is solid, you panels wonāt move.
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Still alive, didnāt zap myself lol
I managed a cheap panel tester but canāt tell if thatās a valid under load read or not.
Iāve drop them on the ground next to each other, waited 15 mins to get to temp and after tested them all as quick as possible.
They averaged 190w even if they 250w but they old and also wasnāt an ideal angle but at least the number will give an idea right?
Iāve got some poles for the rail, the breaker in picture (have another in use as well on my current system) and fusesā¦ plus a 17kwh lifepo4 battery coming in a couple months 
Iām getting VERY excited now, especially to know that the multi be very happy about the better response of the batteries under stress.
I will reread your suggestions on wiring and come up with another diagram to double check over the next days champ, hope you well and will have some days off over holidays 
Back at it, no rails yet but should get them this weekend.
Iāve put down this diagram (I hope is not too messy) and wondering what you reckon @RoarPowerNZ ?
I have some poles Im about to put on the ground and 2 rails of 6 panels will be fixed to them in parallel with 8 rails.
Iām going with 2 isolators to keep things nice and cool as I have a spare one, that wouldnāt hurt right?
I think I nailed the wiring? Sparky will do that anyways but Iām keen learning nonetheless.
I know I could pair the parallels at the panels and have a long single cable to isolator/mppt but I have found a ton of quality cable for cheapish and have plenty of it tooā¦ that would limit the power loss too right?
Once again thank you for your help, I will reward your time somehow at the end of this.
Hey Gab, great to see you back.
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Check those terminal numbers carefully - most of the solar isolators iāve used are numbered 1,3,5,7 on the top, 2,4,6,8 on the bottom, and 1 connects to 2, 3 connects to 4 etc
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Your diagram through the isolators looks good - you will be reducing the current on your run from panels to iso down to one times Isc (~8A) which is great, and at your Isc those isolators will be switching 8A per contact so no where near their rated max current which is probably 30A or 40A or so.
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I would do the run from iso to 150/70 in as large a cable as possible, but its a short run so 4mm will handle 16A no problem. 6mm would be better, and busbars with 25mm or 35mm coming from it would be better still, but 35mm is very stiff, expensive, and overkill for what will probably max out at about 15 to 18 amps realistically, so i would say that 25mm would be best.
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You have drawn the 150/70 as if it has two pairs of solar input terminals - it only has one pair, the left pair are the battery terminals, so maybe you were just simplifying the diagram, but you have a dilemma here - put two wires in each solar terminal, or use busbars. I would probably go with two pairs in each, but busbars do have some advantages;
- the loops from terminal 8 to 2 canāt be a different cable size from the run from iso to mppt, or the smaller one (the loop) will fall out (no pressure on it from the terminal) - busbars resolve this as the cable size change happens via ring terminals
- barbars eliminates the short loop wire in each iso
- reduces the current on each wire - the only combining is done at the busbars which are usually 100A rated
- enables the cable from the busbar to the mppt to be up to 35mm^2 (but 25 is probably sufficient)
- gives you a place to bring in even more arrays later (if they are the same voltage, but as time goes on it will be harder to find matching panels, so probably not a big benefit here )
Ive drawn a diagram for you of the busbar solution - iāve used my isolators, but as above, your terminal numbering might be different. The disadvantage of busbars is that they will be about $20 each, plus you need 8 x 4mm M6 rings, and 2 x 25mm M6 rings to make it really tidy.
Some sparkies will frown on the non-busbar solution where you have two wires going into one terminal if they have ferrules on them - the argument being that you can get lots of pressure on one ferrule, and almost none on the other, creating a bad connection.
I like that you will have your isolators inside - but if your panel-to-isolator runs are not in conduit, you should still run a drip-loop before your isolator so that if water does track down the cable, it drips off and doesnāt track into the isolator.
Exciting times!
Gab.drawio.pdf (2.8 MB)
The isolators I have are Beny BYH-32 and have indeed the 1357 on top and 2468 at bottom, so what I am connecting will be 1 to 2 and 7 to 8 for positives, 3 to 4 and 5 to 6 for negatives (specular wiring on the second breaker). Am I missing something?
I am using 6mm cable everywhere, the run from iso to mppt will be about half a meter max.
My mppt does have 2 inputs indeed, it has 2 line with integrated MC4 connections (30A each line if I recall correct from our previous discussion?).
And realizing that I imagine I would have double the busbars too, as everything is split between 2 inputs?
The old ferrule dilemma yeā¦ Iāll see what the sparky reckons but I have nude cable on my existing breaker and is been good to me for the last couple years (unit is indoors in a dry spot).
Would you have 1 to 2 and 7 to 2 or 1 to 2 and 7 to 8, bridging 8 to 2?
Otherwise I could just go the busbar way having 2 tiny bars for negative and 2 for positive on each iso, still tho I would have to use a cable that fits into my MC4 connection at the mppt.
I like the idea of having different solutions to a problem tho, makes it fun!
Ahh, ok, its the MC version not the TR (terminals) version.
Cool, so you are set 
With two mc4 inputs you are prob best to go with your original diagram.
Once you get the array and controller part done, you are onto the battery cabling next.
Something to think about for the future;
From the mppt down to the battery, you need a breaker, so that the inverter, and all mppt controllers can be de-powered. With just the one mppt controller that you currently have, you can just go straight down to the batteries via the breaker - simple and clean. The inverter would be cabled off the breaker too - for 125A or 250A breakers we usually go with MCCB type breakers, and usually the MCCB breakers have bolts that can easily fit two lugs per bolt, so one for the controller, one for the inverter.
The typical future expansion path of a system like yours is to add additional controllers, each with their own array. With separate controllers, the newer array(s) can have drastically different panel specs, and be facing in different directions (i.e be optimised for morning vs afternoon) or even be a different power source such as micro hydro. The typical way to bring in the power from these additional controller is via busbars, and in some systems (particularly boats where the panels are easily shaded, or houses where there are lots of smaller roof faces that have different orientations) you might have 3, 4, 5, 6 controllers. In these cases all the controllers connect the same pair of busbars, and then one thicker cable goes down to the battery breaker. Another thick cable goes to the inverter. In this way, you donāt end up with more than 2 lugs on a single breaker bolt - instead the busbars take that role, and their capacity is high. For a 4-stud busbar, its typical to be able to fit at least a pair of lugs going upwards from each stud, and a pair downwards, and sometimes lugs on the end studs going sideways, so possibly up to 20 lugs per busbar, versus a max of 2 on the breaker bolts.
If you want a really slick setup, Victron make really nice busbars with built in features such as fuses, shunts, and sensors.
Looks like Iām set indeed, just need to get the last bits and itās party time!
You couldnāt have made it more clear, would be a breeze from now to get everything ready for the sparky and that will save some money that will go instead on the new battery.
I would be really happy to send some beer money your way for the time and knowledge shared, if you send me a way to?
I am all sorted on the battery/ inverter side as I am actually upgrade my old system.
I have at the moment 2s4p lead acid battery bank that goes, via overkill thick cable, to a power in victron busbar modified with fuses for each string. The bank is isolated from the easysolar via a DC Solutions 160 Amp 3 Pole Fuse Switch Disconnector NH00 Type Fuse with 2 160 Amp fuses in it, also have a smartshunt on the negative between bus bar and fuse breaker.
When I get the new lifepo4 I will remove the busbar as there is no point having it (battery comes in a box with wheels and just the 2 lugs) and will connect it to the fused breaker directly (with in between the shunt).
Everything is earthed on a long rod on the ground tagged by my old sparky, I might need another for the panels?
Getting there!
No need Just walk your neighbours and anyone interested through your system, point out what each component does, and educate as many people as you can. It wonāt benefit me, but maybe we can move the needle for the future
This depends on your sparkie - iāve seen sparkies want an additional earth rod at the panel end when the panels are a long way from the inverters so that you are not relying on a single 6mm cable that is going a long way, but iāve also had discussions where the conclusion was that only one rod was appropriate.
Once you are finished your system, consider posting some pics on the āShow Us Your Systemā topic. When people see pictures of systems, especially systems that are in the same country/region, it gives people confidence to tackle their own system.
Oh man @RoarPowerNZ , legend.
I am inspiring a few friends already indeed as they see my journey and start to ask questions about solar and off grid living.
I will share my system once done for sure!
I have today installed the first raw of 6 panels on the new rail supports Iāve made this week (tornado proof lol), tomorrow will finish with the other and Iāll be nearly ready for the sparky.
Itās about 20 meters from the panels to the mppt, as I acquired a full 100mt roll of 6mm cable Iām thinking to go with individual cabling from each rail to the isolators indoorsā¦ it will be 8 20mt cables to deal with but isolators be nice and dry in the room with the easysolar and batteries (hoping they donāt start a fire lol).
Can I direct bury the cables or a conduit be better? I could even leave the cables sitting on the ground (grass) if, as there is only foot traffic and sporadic.
Whatās your suggestion?
Cheers champ
ASNZS (the Aus and NZ safety spec) says that the cable must be buried at least 600mm deep, in solar conduit (that is conduit marked SOLAR, which is higher impact resistance than thinner non-solar conduit) with a protection layer and alert tape. The protection is usually a roll of hard plastic about 200mm wide that gets put just above the conduit - this means spades, diggers etc have a good chance of hitting the protection first and realising that something is there. Above that you put some fill, then lay the alert tape. Alert tape is not physical protection, just a long-lived plastic material that will be dug up by an excavator bucket. The operators are always looking at the spoil they tip from their buckets, and they should see this first and stop digging.
Talk to your sparkie - the rules for you might be different.
For 8 cores of 6mm you will need about 32mm conduit - chop up 8 pieces about 10cm long each and tape them together to get a measure of your required conduit. Each brand of solar cable has different physical insulation diameter, and corners make a big difference (lots of corners means you need a larger conduit to carry the same number of cores than if it were a straight pull) so I canāt say what your conduit needs to be. You should only have 2 corners, one at each end, because your trench should be straight (nothing is worse for a digger driver later than knowing where a cable trench is, only to find later it has an unexplained bend in it). Remember you might also need an earth wire in that conduit, and you might want to leave a paracord draw string in the conduit for future pulls.
There is a tradeoff between the cost of cable and conduit, and the losses, but remember that you only suffer the cable losses at max yield, so a cable loss that is unacceptable according to general ārule of thumbā (which is 3%) might only occur for a few hours per day on maybe 25 days of the year, and on these days you will easily meet your energy goal. The same cable might only drop 1% on an overcast day, and this is the day you need lowest losses, so the payoff for building in super low design losses might never be realised.
You might also want to pre-pull cables you donāt yet need. The cost of cable is about $1/mm^2/m - so $4/m for a 4mm^2 core, $6/m for a 6mm^2 core , compared to your labor or the value of your time and effort, or the risk of not being able to successfully pull additional cable later, this might be very small. Also, its many times easier to bundle 6,8,10 cores, tape into a bundle every 2m, and pull through in one effort than to pull 2, then try to pull 2 more, then try to pull 2 more. Corners are a nightmare in this situation, so if you can afford it, and you pull more cores than you need, your future self will thank your current self.
Also consider that if a future pull is unsuccessful (broken draw string for example), you are up for digging another 600mm trench and installing another set of conduit. It might make upgrading to the next conduit size worthwhile.
You often donāt know what the expansion path of your system will be, and there is a good chance that the panels you can get in future, if they are added to the system instead of replacing the current panels, will be best on their own controller, so this means a dedicated pair of cores, so another good reason to pull as many cores as will fit, and pull now rather than later.
20m is a short run, so thatās good. Having your iso inside is also excellent.
Weāre all excited to see your system running, good luck.
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@RoarPowerNZ I canāt thank you enough for the help and the inspiration, the system is up and running and thereās a big grin on my face!
Here a couple of sh1tty pictures for now but they give the idea, I want to cover cables and make things a bit prettier around the system slowly slowly but for now itās working (wonderfully too I must say).
The solar is been cranking happily 1600/1700W (maxing at 110/111v, way below the 150v max, as expected) and running nice and cool even in very hot days.
Literally 2 hours ago the new lifepo4 battery arrived and Iāve connected the lot, configured the shunt and multiplus and will test it over the next days.
Iāve learned a lot of things and I am absolutely stoked I could made this very needed upgrade happen, wouldnāt have been possible without the time you spent explaining in detail every step.
I am already sitting here looking at how to connect in parallel 2 multis LOLā¦ or maybe upgrade to a multi 2 5000ā¦ will see, Iām in love with the brand thatās for sure.
What a time to be aliveā¦
Thank you!
Well done Gab.
Your eye for detail in the panel alignment is impressive - its very easy (and ugly) to get panels out of alignment, and although it makes absolutely no difference to performance or safety, a perfectly aligned array is beautiful and implies a master installer, or at least one with an eye for detail.
Your new battery certainly tidied up the battery cabling - you probably canāt justify cable trays with only one positive and one negative - attaching them to the wall might be the appropriate finishing.
One thing you really need to do is watch the system at full noise and write down the panel performance in a notebook that you keep tied to the wall or such. The voltage wonāt change much, but its good that you are familiar with how high the voltage has got to compared to your controller max Voc. The current will change a lot, and with any system where you have strings in parallel, you absolutely need to know the current at full sun, so that you can spot when you have full sun but only half or 1/3rd of that current (which implies one or more sub-arrays are broken/disconnected).
Iām impressed with how much new info you have digested, and youāve implemented a great system.
RP.
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Appreciated bud, thatās the cabinet maker eye for detail that comes out (the posts are not so squared between them, i cheated using that angle for the pic LOL).
I am keen to clean the panel the easysolar is on from the old holes and make the whole corner visually pleasing, first comes fine tuning of the system.
One last question as we here and might not be worth to open a new topicā¦
Seller gave me the specs for battery, 28.4v bulk and 27.4 float.
I have set up the multi to those specs but for the shunt, as manual, put the charged value at .2 points less than float (27.2v).
Now watching the battery charged at 100% floating at 27.23v.
Is that ok or should it float at 27.4v as specs?
Should I set the shunt at 27.4v so it allows for more amps to get in, or should I donāt worry as the bms will do the job regardless?
Any other setting I should touch in the shunt/multi?
I might upload some screenshots if needed but I am confident everything else is right, just this small detail Iām not sureā¦
Cheers
Nope, 0.2 less then bulk 
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That makes sense indeed! Cheers bud
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