Nissan Leaf 48v Off-Grid Solar Project

[OffGridInTheCity]

Your Midnite Classic 150 does have some extra protection, though I'm not sure it would be considered surge protection. When I searched it said it has HyperVOC that allows for temporaty excess to 198V. (but they still recommended a separate surge protector, like you've done! )

Yes on HyperVOC but with 3s and my panels and my weather region this was never a concern. However, we get significant lightning during summers... spectacular events.... and thus the reason for Surge Protection.

On the other hand, I've not had any kind of lightning event with my home the 16yrs I've lived here and it did cost me an extra $500 (I use 5 of them). No judgement here!

 

[Fukuokian]

Yes on HyperVOC but with 3s and my panels and my weather region this was never a concern. However, we get significant lightning during summers... spectacular events.... and thus the reason for Surge Protection.
View attachment 33579

On the other hand, I've not had any kind of lightning event with my home the 16yrs I've lived here and it did cost me an extra $500 (I use 5 of them). No judgement here!

Yep, it's better to have insurance and not need it, than to need it and not have it. For now I have to choose a cheaper insurance, that doesn't have the best coverage possible. I do respect and admire what you've done!

 

[Fukuokian]

https://secondlifestorage.com/index...rcuit-breakers-yellow-vs-blue.8350/post-71688. Funny how you can randomly come across some info you're interested in. I was searching the forum to see any info on Nanque (for DC breakers) and came across your post Korishan

Note to myself... Check if the breakers I buy are bidirectional or not.

 

[Fukuokian]

Purchased these items to make my PV combiner box:

SPD: NanQue 2p DC250V (1314 yen) definitely not a schneider, but NanQue has a good reputation in the Asian market.
80A Din Rail Distr Box (Blue) x2: (726 yen)
Master DC MCB: TOMZN 600V 2P 63A (confirmed Bidirectional) (845 yen) TOMZN also seems to have a good rep. in the asian market
Edit: need to reorder 90a-100a master breaker, as I decided to add the extra string of panels.
PV MCB x 4: TOMZN 500V 20A (confirmed Bidirectional) (1789 yen) EDIT: NEC Section 690.8(A)(1) and NEC Section 690.8(B)(1)(a). says 1.56
times the Isc. So my ISC is 14.25a x 1.56 = 22.23 breaker per string... so 25a rounded up. It shouldn't hurt anything using 20a breakers... just the possibility of nuisance breaks. I'll upgrade anyway to the 25a breakers.
Aluminim Din Rail 40cm: (309 yen)
Mc4 10 pairs (721 yen)
SN-2546B Crimping Pliers for MC4 (1286 yen) Not the cheapest, but still cheap... reviews commented that the quality was good... will have to update you after I use them
Outdoor Waterproof Enclosure/Box (1371 yen)

Total Payment (so far): 8361 yen (about $56 usd)
The combiner parts are really $47 (I consider the crimper a tool I'll use for other things too.)
I think I already have bits of wire to do the internal connections so hopefully that's free, in my case. (I'll make sure to use properly rated wire for the current at each stage.)

Oh, I need to scrounge up a backplate to mount the din rails inside the plastic enclosure box. (not wood)

I'll update things and probably show my assembly process after everything arrives, and I get to it!

 

[Fukuokian]

I found this an interesting video about a NanQue (DZ47Z) breaker that failed. He had several breakers fail, but he tears apart this one and does some CSI (crime scene investigating) There's some interesting info is in the comments. If you don't want to read through them all, check the last one for his final? opinion.

Note to self: Do regular monitoring of components for heat issues!

 

[kje]

Purchased these items to make my PV combiner box:

SPD: NanQue 2p DC250V (1314 yen) definitely not a schneider, but NanQue has a good reputation in the Asian market.
80A Din Rail Distr Box (Blue) x2: (726 yen)
Master DC MCB: TOMZN 600V 2P 63A (confirmed Bidirectional) (845 yen) TOMZN also seems to have a good rep. in the asian market
PV MCB x 4: TOMZN 500V 20A (confirmed Bidirectional) (1789 yen)
Aluminim Din Rail 40cm: (309 yen)
Mc4 10 pairs (721 yen)
SN-2546B Crimping Pliers for MC4 (1286 yen) Not the cheapest, but still cheap... reviews commented that the quality was good... will have to update you after I use them
Outdoor Waterproof Enclosure/Box (1371 yen)

Total Payment (so far): 8361 yen (about $56 usd)
The combiner parts are really $47 (I consider the crimper a tool I'll use for other things too.)
I think I already have bits of wire to do the internal connections so hopefully that's free, in my case. (I'll make sure to use properly rated wire for the current at each stage.)

Oh, I need to scrounge up a backplate to mount the din rails inside the plastic enclosure box. (not wood)

I'll update things and probably show my assembly process after everything arrives, and I get to it!

Nice list with links. Seems like this will be successful. Very excited about updates from your setup and when you connect the battery.

I bought this SPD but haven't installed it yet:

 

[Fukuokian]

I pulled the trigger and bought my solar panels from https://www.solar-off.com. I've purchased from them before, so no worries there. Plus, they are a Japanese Company (started in 2014), so I don't have to import/deal with customs.

Decided to go with 4 strings right away, so 12 panels total. Price (with shipping included) worked out to $117 usd each. AIKO-A460-MAH54Mb (460W each - 5520W total) $0.254 per W. If you're in Japan, they discount 550yen per panel if you pick them up from a Seino Transport branch.

Happy, but no vacation for a while.

 

[Korishan]

That's really good pricing. Here in the US it's still hard to get lower than $0.50/W on decent panels.

 

[kje]

I pulled the trigger and bought my solar panels from https://www.solar-off.com. I've purchased from them before, so no worries there. Plus, they are a Japanese Company (started in 2014), so I don't have to import/deal with customs.

Decided to go with 4 strings right away, so 12 panels total. Price (with shipping included) worked out to $117 usd each. AIKO-A460-MAH54Mb (460W each - 5520W total) $0.254 per W. If you're in Japan, they discount 550yen per panel if you pick them up from a Seino Transport branch.

Happy, but no vacation for a while.

Congratulations
Pictures would be nice

 

[Fukuokian]

Parts are trickling in...

Bought the enclosure on the left from Amazon... cheap plastic. $10.61usd.
Soon after I found the metal heavy-duty enclosure on the right for $13.50 usd. Guess what I'll be using. ; )

The metal one has a grounding screw on the main body, but I'll probably add a grounding wire between the door and the box for safety; like the second picture below.

Will add some sealing foam tape to make it more bug-proof.

---------Edited addition-----------
Caution: I just noticed that the front door is very close to the master circuit breaker. So close, it could potentially not allow it to trip... The back plate is glued and bolted in place, so I can't exchange it for something thinner. However, I can shim the front door away from the box. It's connected by the four bolts you can see in the picture. Another update: It's really close, but a shim won't be needed.

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Also, bought some 14SQ (6awg) 600v wire - 10m for $34 usd (free shipping). (I'll use it for running from the combiner box to the inverter/charger, once I decide where they'll be located.

 

[OffGridInTheCity]

Personally, I *love* it when parts trickle in... and sometimes I wish they'd arrive faster.... but then, one has to actually 'do the work' to use them! I enjoy a lot of the solar installation tasks but when it comes time to crawl in tight spaces under the house I'm less enthusiastic.

Do you have any "crawl under the house" type tasks needed for you're install?

However, the end result / working system can be very satisfying

 

[Fukuokian]

Personally, I *love* it when parts trickle in... and sometimes I wish they'd arrive faster.... but then, one has to actually 'do the work' to use them! I enjoy a lot of the solar installation tasks but when it comes time to crawl in tight spaces under the house I'm less enthusiastic.

Do you have any "crawl under the house" type tasks needed for you're install?

However, the end result / working system can be very satisfying

I don't have any 'under the house' solar tasks, but I've braced a saggy floor before; it was surprisingly easy. Pop up a tatami mat, and pry up some planks, then fond memories of 'The Great Escape (1963)' but along a concrete, surprisingly clean, crawlspace, instead of a dirt tunnel.

My nemisis is in the other direction, a.k.a attic. Push up a ceiling panel in a closet, balance on something, while reverse giving birth to myself into a space filled with dust, at sauna temperatures. Then balance, contort and make my way through knee bracing and giant beams, but don't step on the floor/lower room's ceiling, which is a thin panel of wood that would teleport me forthwith to my doom if any of my weight is applied to it. In the future I dread that I must make a repeat journey there, to run new wire from my new inverter's planned location to the house's distribution panel.

Start is in the far right closest to the camera, and make your way to that vertical support in the back that supports the ridge beam.

 

[Fukuokian]

Have to reorder some parts for the combiner box... see the edits here: https://secondlifestorage.com/index...f-48v-off-grid-solar-project.12890/post-94067

 

[Korishan]

I have 20A per string on mine as well. Rarely do they go above 12-13A though just because of MPPT. Altho, if there was ever a short circuit, I want them to pop fast, no waiting if possible.
TOMZN are definitely up there in quality and common in installations. I've seen professional installs with those brand, so I feel safe using those as well. Another one I've had no issues with is Chtaixi. Most of my breakers are these. I've even had problems with Dihool breakers.

 

[Fukuokian]

I have 20A per string on mine as well. Rarely do they go above 12-13A though just because of MPPT. Altho, if there was ever a short circuit, I want them to pop fast, no waiting if possible.
TOMZN are definitely up there in quality and common in installations. I've seen professional installs with those brand, so I feel safe using those as well. Another one I've had no issues with is Chtaixi. Most of my breakers are these. I've even had problems with Dihool breakers.

Thank you for this info...

I also checked the Japanese Electrical Code, and supposedly they technically allow it but recommend the 25a ones. I'm gonna go with the 20a ones for now, and if there are any problems (tripping) then I'll switch to 25a breakers.

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I did find a big problem with the 14mm2 wiring I bought; I was gonna use it after the combiner box and to the inverter/charger. However, it's only rated to 60deg. Celsius and doesn't have UV protection. (UV not a big deal in my case, as I was planning to route from the combiner box and through the attic), but regardless the temperature rating is too low. (A big no-no under the code here.) *sigh*

[I'm adding a caveat that the following information is just what I found, and may or may not be true,] Japanese code seems to require meeting international standards ( IEC 62930) ...which explicitly outlines the -40 deg C to +90deg C temperature rating as a performance requirement. There's another possible requirement that cable ampacity must be (at least) 125% of total Isc.

Finally, if you're trying to work between AWG and mm2 like me, be careful as a lot of sites give approximate values between the two measurement systems. (ex. 6awg doesn't equal 14mm2) Make sure you're looking at the specific wire specifications.

Anyone buying PV wiring, make sure it's rated correctly to your local code. I'm sharing my mistake, so you don't repeat it.

 

[OffGridInTheCity]

Heat can add up and in my experience wire rated for >60C would be good and it's worth paying attention to actuals when the system is operating. Metal conduit and connection boxs don't help dissipate heat but conduit is required in my jurisdiction for DC 48v+ and I've had 2 incidences of arcing connections and have come to firmly believe in metal connection boxes.

It's about 150ft from my arrays to my charge controllers and the original electrician ran 2 x sets of 6awg in 1" conduit - e.g. 4 x individual wires. Originally I overplanneled and neared 4000w / 45a per pair of wires quite often in summer and... neared 60C as measured in a connection box about 10ft from the charge controllers. When I expanded, I went with just 1 pair of 6awg per 1" conduit - partly to keep things cooler.

What was interesting to me, the heat increased as one got further from the PV and closer to the charge controllers. You could feel it by wrapping you're hand around the conduit as various places along the way - the heat noticeably increased. I still don't understand this - I was thinking the heat would be steady the whole length. Maybe I'm off base?

Here's a snap of the last 14 days. The 1st number after the word "Wire:" is the PV -> Charge Controller connection box temps in "C" about 140ft from the array combiner boxes.

9 days ago I hit a 51.3C max for that day and a few 50.0C, 50.6C numbers but things tends to stay <50C for the most part on hot summer days / max PV since I stopped overpanelling.

The 2nd number is the temp at the main + and - buss of the system - also in a metal control box. The 3rd and 4th numbers are the temps in the wiring troughs under the Midnite Classic 150s.

 

[Fukuokian]

Heat can add up and in my experience wire rated for >60C would be good and it's worth paying attention to actuals when the system is operating. Metal conduit and connection boxs don't help dissipate heat but conduit is required in my jurisdiction for DC 48v+ and I've had 2 incidences of arcing connections and have come to firmly believe in metal connection boxes.

It's about 150ft from my arrays to my charge controllers and the original electrician ran 2 x sets of 6awg in 1" conduit - e.g. 4 x individual wires. Originally I overplanneled and neared 4000w / 45a per pair of wires quite often in summer and... neared 60C as measured in a connection box about 10ft from the charge controllers. When I expanded, I went with just 1 pair of 6awg per 1" conduit - partly to keep things cooler.

What was interesting to me, the heat increased as one got further from the PV and closer to the charge controllers. You could feel it by wrapping you're hand around the conduit as various places along the way - the heat noticeably increased. I still don't understand this - I was thinking the heat would be steady the whole length. Maybe I'm off base?

Here's a snap of the last 14 days. The 1st number after the word "Wire:" is the PV -> Charge Controller connection box temps in "C" about 140ft from the array combiner boxes.

9 days ago I hit a 51.3C max for that day and a few 50.0C, 50.6C numbers but things tends to stay <50C for the most part on hot summer days / max PV since I stopped overpanelling.
View attachment 33610
The 2nd number is the temp at the main + and - buss of the system - also in a metal control box. The 3rd and 4th numbers are the temps in the wiring troughs under the Midnite Classic 150s.

I ran your general conditions through an AI (grok) and it said your wire's average operating temperature will likely be approx 50-55 degrees in a 30deg ambient. I really like that it explains it's 'thinking/calculations'.... here is some of what it said when I asked about temperature variations.

• Heat Dissipation:
  • In a conduit, heat dissipation depends on the surrounding environment (e.g., air gaps, conduit material, and external conditions).
  • If the conduit is uniformly installed (e.g., same material, no tight bends, consistent contact with surrounding air or surfaces), heat dissipation is relatively consistent along the length.
  • Variations occur if parts of the conduit are exposed to different conditions, such as:
    • Localized Hot Spots: Sections near heat sources (e.g., equipment, sunlight) or with poor ventilation (e.g., buried or tightly packed conduit) may be warmer.
    • Conduit Transitions: Changes in conduit type (e.g., from PVC to metal) or areas with more conductors can affect heat dissipation.
    • Ends vs. Middle: The ends of the run, near terminations or junctions, may be slightly cooler due to better heat sinking into connected equipment or air exposure.
• Ambient Temperature Variations:
  • If the 150-foot run spans different environments (e.g., indoor to outdoor, or through areas with varying airflow), the ambient temperature may differ, affecting the wire temperature.
  • For example, a section exposed to direct sunlight (ambient >40°C) will be warmer than a shaded or indoor section (ambient 30°C).

-------

Typical Temperature Uniformity​

• Uniform Conditions: If the conduit is installed in a consistent environment (e.g., same ambient temperature, same number of conductors, no external heat sources), the wire temperature will be nearly uniform, varying by ±1–3°C along the 150-foot run due to minor differences in convection or conduit contact.
• Non-Uniform Conditions: If the run includes environmental changes (e.g., part indoors, part outdoors in sunlight), temperature differences could be 5–10°C between sections, with hotter areas where heat dissipation is poorer or ambient temperature is higher.
• Hot Spots: Localized hot spots (e.g., near tight bends, junctions, or equipment) could increase the temperature by 5–15°C in those areas, but this is uncommon in a well-installed conduit.

---------

 

[Fukuokian]

Here's my combiner box layout... though I may move the SPD to the lower DIN as there's room..

 

[OffGridInTheCity]

Interesting AI comments and I'm not 'anti-AI' but it's not what I experience. The main point I would like to make is that it's good to measure or even monitor the actual situation once you have things in operation because 'advice of what to expect' does not always one's personal situation

Typical Temperature Uniformity​

• Uniform Conditions: If the conduit is installed in a consistent environment (e.g., same ambient temperature, same number of conductors, no external heat sources), the wire temperature will be nearly uniform, varying by ±1–3°C along the 150-foot run due to minor differences in convection or conduit contact.

The last 100ft is under the house (75F max in summer), clamped to the bottom of the floor joists (reasonable air flow) but is not uniform. You can feel the heat increase from mid-way to junction box.

Some pics.
This is the mid-way point (about 100ft from PV array) where the heat starts to increase. This pic is looing back towards the PV array where the conduit enters the house.

Then turning the other way it goes 40ft (from pic above) and makes a right hand 90deg for another 20ft to connection box (square box in pic) where the 1st wire: heat measurement is....

The heat at the bend is noticeably higher than the mid-point and then again at the metal box. Here's a pic of the inside of the connection box where I have a temp probe (Midnite Classic battery temp probe) on the wires coming out of the conduit from the array into the control box.

I don't experience uniform temps.

• Non-Uniform Conditions: If the run includes environmental changes (e.g., part indoors, part outdoors in sunlight), temperature differences could be 5–10°C between sections, with hotter areas where heat dissipation is poorer or ambient temperature is higher.

This doesn't apply in my case.

 

[Fukuokian]

Interesting AI comments and I'm not 'anti-AI' but it's not what I experience. The main point I would like to make is that it's good to measure or even monitor the actual situation once you have things in operation because 'advice of what to expect' does not always one's personal situation

I am actually anti-AI in the sense that I won't/don't trust it ... just like I don't trust driverless cars in their current form. It's only as good as the programming/tech it uses; with a proven track record/history, I may adjust my opinion. (I also don't like the term AI, as it's--at least now--really just pattern recognition, and not a form of actual intelligence. However, I digress.) Where I do like 'AI' is using it as a tool to help me think/learn, and to verify your own work. I like situations where it can lead me to explore and learn on my own.

I totally agree with measuring and monitoring IRL.

In the case of your temperature variances, are they within an acceptable range? "...heat at the bend is noticeably higher than the mid-point." If it feels significant, i'd quantify it by getting an accurate measurement--attaching a probe or use a thermal imaging tool. Maybe there's damage, or a manufacturing defect within the wire/conductor?