Size of Cables for connecting Solar Panels -> Inverter -> Fusebox

[MJCM]

The following

 

1- We want our Solar Panels in a Field in the back of our property as my Wife definitely doesn't want them on the house!

2- We want the Inverter and Batteries in a shed that is approx 20-40m (depending on the location of the panels) from the panels

3- The (intended location of the inverters) Shed is approx 10-20m away from the other side of the wall where our Fusebox is located. (on the other side of the wall it's no suitable place for the Inverters or Batteries

 

My question is.

 

I still have NYY 25mm² available from our House build (And always can order more)

Would that be suitable to connect A) The panels to the Inverters B) the Inverters from the shed to the HOUSE?

 

If Not? What kind of cable to use (Edit: I don't want high power loss because of using thin cables)

 

It seems the installers ALL want to install the panels ON the house and the INVERTER / Battery right at the FUSE BOX ????

 

Edited January 4, 2022 by MJCM

[BritManToo]

1 hour ago, MJCM said:

It seems the installers ALL want to install the panels ON the house and the INVERTER / Battery right at the FUSE BOX ????

Running 240V AC over any distance is not really a problem.

Running DC cables IS a problem.

 

Solar panels (and batteries) should be close to the inverter.

My solar panels are 5m max from the GTI, using normal 2.5mm twin insulated.

3 panels, each producing up to 4A (even though the 330W panels are supposed to deliver 9A).

So 12A going down the 2.5mm cables (my panels are in parallel, different if you have them in series). Standard 2.5mm cable should be good for 16A/500V, anything higher and you're taking a chance.

 

No reason to have the inverter/battery/panels near the house fuse box. 

Edited January 4, 2022 by BritManToo

[Crossy]

@BritManToo is correct.

 

BUT

 

With the correct cable sizes there's no reason not to go against the trend although personally I'd still be putting the inverters near the panels even if it means building them a shed to live in (with good shading [under the panels?] and ventilation).

 

The Growatt inverters which I believe you are considering are "string" inverters with 550V max solar input voltage and 15A max string current. They have two MPPT trackers.

 

You need to get 2 x 2-core from your array to your inverter. 

 

Using 10mm2 (you will need 4 cores per inverter) you'll drop about 1% of your solar when everything is running at max power. Note that your arrays run at up to 550V DC so mains practices and cables are required. 4 x 10mm2 is about 20mm in diameter!

 

DC cable costs could become significant, particularly if you want to run underground!!

 

I'm not surprised at the attitude of the installers, they want to do what they know. I'd build the ground mount framework and an inverter house then TELL installer what you want, you are after all, the client. If they don't want the $$ ...

 

 

[MJCM]

Thank you @Crossy & @BritManToo

 

I have been looking at DC cables but I only can find 6mm²  anyone has a link?

 

Edit 2: Found it I think

 

https://www.lazada.co.th/products/photovoltaic-cable-pv1-f-10-sqmm-solar-cable-pv1f-10-red-i1406688465-s3605222387.html

 

Edit: No need to put the cables underground, but would put them in HDPE Conduit!

 

If we put the Place for the Inverters and Batteries in the area where we want the Panels it floods, not significant approx 40-50cm but still it floods. It poses no danger to the panels because they stand approx 150cm above the ground. So water will not reach the panels.

 

The reason it floods is A) Run off from the Surrounding Rice fields to the BIG lake in front of the house B) Run off from our own Fish lake (water for my wife's garden) in the back of the Property!

 

And that area also has NO shade because of the flooding my wife doesn't do anything with it, we were intending to have truckloads of soil come in, but then the Solar Plan came along!

 

 

Edited January 5, 2022 by MJCM

[Crossy]

You can use regular mains rated cables (they're usually 750V), so THW or VCT  if you run it in conduit that's not buried. But do ensure that it can't fill with water.

 

I would still use "solar" cables for the panel connections as the MC4 connectors seal to it properly.

 

[MJCM]

Someone wrote me this about my remark of using NYY 25mm²

 

Quote

Cannot use it for DC cables maximum is 6mm to fit MC4 and inverter housing connection

So apparently I can't use 10mm DC Cable!

[Crossy]

You run the big stuff to a box and have a suitable connector inside the box to link to stuff that fits the MC-4.

 

You could even put your safety disconnect in the box and use that to link the two sizes.

[MJCM]

6 hours ago, Crossy said:

You run the big stuff to a box and have a suitable connector inside the box to link to stuff that fits the MC-4.

 

You could even put your safety disconnect in the box and use that to link the two sizes.

Thx DC.

 

But I hope the installers (again) will know what they are doing.

 

I hope it doesn't work out the same as my simple Question (I thought ???? ) can you make Solar Pump automatic

 

But that said, they are from a total different company

 

Edited January 5, 2022 by MJCM

[Crossy]

It's always a problem when you want something outside their comfort zone.

 

Alternatively inform them where the kit is going and let them design it. 

[MJCM]

18 minutes ago, Crossy said:

It's always a problem when you want something outside their comfort zone.

 

Alternatively inform them where the kit is going and let them design it. 

I b....dy well did. I composed an email approx 3 pages long explaining what is going on, where we want the panels, where our fuse box is, where we want the inverters etc etc.

 

We even include Pictures, drawing, measurements!!

 

(Ps: That email took 2 weeks to compose with lots of changes!!!!)

[Crossy]

15 minutes ago, MJCM said:

I b....dy well did. I composed an email approx 3 pages long explaining what is going on, where we want the panels, where our fuse box is, where we want the inverters etc etc.

We even include Pictures, drawing, measurements!!

(Ps: That email took 2 weeks to compose with lots of changes!!!!)

 

Ignored of course ???? 

 

I have the same problem at work, I'm just the "stupid farang consultant", then when it all goes pear-shaped whose fault is it  ...

 

Welcome to my world, at least I get paid $$$ to be ignored.

[BritManToo]

Just now, Crossy said:

Ignored of course ???? 

 

I have the same problem at work, I'm just the "stupid farang consultant", then when it all goes pear-shaped whose fault is it  ...

Not yours because you detailed every concern and sent copies to everyone.

And if they point the finger at you, you just pull out the memo.

[MJCM]

4 minutes ago, Crossy said:

 

Ignored of course ???? 

 

I have the same problem at work, I'm just the "stupid farang consultant", then when it all goes pear-shaped whose fault is it  ...

 

Welcome to my world, at least I get paid $$$ to be ignored.

Jealous that you get paid for that!

 

Personally I am ........ this close to pull the plug on us spending xxxK THB on this!!

Edited January 5, 2022 by MJCM

[Crossy]

1 minute ago, BritManToo said:

Not yours because you detailed every concern and sent copies to everyone.

And if they point the finger at you, you just pull out the memo.

 

Nah, even with the doc trail it's still "blame the consultant" time.

 

Amazingly I'm having this exact conversation (over IP address allocation) right now over Line. Three docs, all different, none right

[MJCM]

Just now, Crossy said:

 

Nah, even with the doc trail it's still "blame the consultant" time.

 

Amazingly I'm having this exact conversation (over IP address allocation) right now over Line. Three docs, all different, none right

S..t show none the less!!

[Crossy]

2 minutes ago, MJCM said:

Jealous that you get paid for that!

 

Personally I am ........ this close to pull the plug on us spending xxxK THB on this!!

 

You could pay someone to help you DIY it ????

 

Sadly we're too far away and I'm already snows under ???? 

[MJCM]

Just now, Crossy said:

 

You could pay someone to help you DIY it ????

@BritManToo already said he is very expensive ????

[Crossy]

On the plus side I did get a couple of bottles of decent red from one of the contractors ????

 

The MD himself delivered it

[MJCM]

I think my wife already here made her mind up

 

400k (money I am willing to spend on solar (approx) / 2500 THB electric bill per month = 160 / 12 (month in a years) = 13+ years!!

 

I am thinking of going of over the "Dark Force" (read: Solar is too expensive ???? (but my thought is more of Solar is too difficult ????)!

[Crossy]

3 minutes ago, MJCM said:

I am thinking of going of over the "Dark Force" (read: Solar is too expensive ???? (but my thought is more of Solar is too difficult ????)!

 

It would be a real shame for the environment.

[BritManToo]

6 minutes ago, MJCM said:

I think my wife already here made her mind up

 

400k (money I am willing to spend on solar (approx) / 2500 THB electric bill per month = 160 / 12 (month in a years) = 13+ years!!

 

I am thinking of going of over the "Dark Force" (read: Solar is too expensive ???? (but my thought is more of Solar is too difficult ????)!

Did you decide what panels (total watts), inverter (total watts), battery (total KWhrs) you wanted? 

I did price up, 5500W hybrid inverter, 10x 330w panels, 110KWhrs of storage at 90Kbht of parts on another thread.

Price of the system should be based on Max current used at any moment and max units of electricity used/day.

Edited January 5, 2022 by BritManToo

[MJCM]

1 minute ago, BritManToo said:

Did you decide what panels (total watts), inverter (total watts), battery (total KWhrs) you wanted? 

Yes!!!!

 

5kW+ Panels plus 10kW+ of Batteries (10kW+ of Batteries could be expanded to 15kW because I found out that I don't have a Meter that is capable of running negative)

[Crossy]

What's your monthly power bill ??

[MJCM]

^^^^^^That

 

would make our PEA bill really low and would help us prepare for the future!

[BritManToo]

9 minutes ago, MJCM said:

Yes!!!!

 

5kW+ Panels plus 10kW+ of Batteries (10kW+ of Batteries could be expanded to 15kW because I found out that I don't have a Meter that is capable of running negative)

And your max power required at a moment in the day.

5Kw panels (220 x 330w), cost 60Kbht, 10KWhr of battery (48V 200AH smart), cost 50Kbht, 2x 5500w inverter, cost 33Kbht (parallel wifi x2).

https://shopee.co.th/อินเวอร์เตอร์ไฮบริดนอกกริด-5.5KW-MPPT-48V-Inverter-off-grid-hybrid-สามารถทำงานได้โดยไม่ต้องใช้แบตเตอรี่-รองรับ-WIFI-i.428988356.12724725647

 

I'd forget about having the ability to export as your meter doesn't run backwards.

So around 150Kbht + installation, which would generate around 20 units/day, 10 of which you would store in the battery for the night.

Edited January 5, 2022 by BritManToo

[MJCM]

3 minutes ago, Crossy said:

What's your monthly power bill ??

 

[MJCM]

1 minute ago, BritManToo said:

And your max power required at a moment in the day.

5Kw panels (220 x 330w), cost 60Kbht, 10KWhr of battery (48V 200AH smart), cost 50Kbht, 2x 5500w inverter, cost 40Kbht.

I'd forget about having the ability to export as your meter doesn't run backwards.

So around 150Kbht + installation, which would generate around 20 units/day, 10 of which you would store in the battery for the night.

If I am going solar I am going all in. I want to prepared!!

[Crossy]

2 minutes ago, MJCM said:

If I am going solar I am going all in. I want to prepared!!

 

Beware the Zombie Apocalypse!

[MJCM]

Just now, Crossy said:

 

Beware the Zombie Apocalypse!

No DC I am not the one for TEOTWAWKI but I just want to do it RIGHT the first time!!!!!!!!!!!!!!!!!!!!!!!!

[BritManToo]

6 minutes ago, MJCM said:

If I am going solar I am going all in. I want to prepared!!

I specified a 600 unit/month install (20 units/day).

Based on Crossy and my experience of panels producing 1 unit/day/panel.

And as the inverters will work up to 6 in parallel, should be able to upgrade if required.

Edited January 5, 2022 by BritManToo