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drees
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Re: DIY Solar PV Installation

Sat Sep 14, 2013 12:43 pm

QueenBee wrote:Engage cabling adds additional costs but it makes installation very easy. I'm not sure it's a huge improvement over their previous daisy chain method but I like it.

+1 (even though I haven't used the M215 and trunk cable).

Not crazy about the two different trunk cables depending on panel orientation, but I suspect it's the easiest way to avoid having to deal with tons of extra cable. I know that I have coils of cable under my M190 panels - both DC leads and inverter cable.
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

sitech
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Re: DIY Solar PV Installation

Mon Sep 16, 2013 10:39 am

Thanks for the positive comments. Still learning.

Here's some of my thoughts about some of the past questions/comments.

1) Anti-sieze compound. Yes, I did read that Unirac note. I referred to another Unirac note in Chapter 6.4. Unfortunately, all 3 Autozone's in my area ran out of the compound, would you believe it? I even did an online stock check first. Talked to a guy at Home Depot and he said with stainless steel fittings, you don't really need it. I lack experience here with exposed SS fasteners.

2) Engage Cable. I believe this is a must. I get my cables for $22-$25 a drop. I view this as part of the cost of going with Enphase. The thing to note is you will void a product's UL listing if you do not use it in the manner in which the manufacturer prescribes.

3) If cost takes precedence, I'd suggest going with microinverters from PowerOne or Renesola. Savings can be more than $500 for one array.

4) Cable Management. I view this as extremely important. Most solar PV fires are caused by poor cable management. See Chapter 2.2 for more info. My take is if the installation is supposed to last 25 years and is out of sight on my roof, I darn well do a good job upfront and try not to be cheap about it. At many sites, I see the pros cutting corners - $0.05 UV zip tie instead of $0.40 stainless steel cable clip, non rain-tight EMT fittings. Hard to see why you'd want to save $10 on a $10,000 bill.

QueenBee
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Re: DIY Solar PV Installation

Mon Sep 16, 2013 11:19 am

sitech wrote:4) Cable Management. I view this as extremely important. Most solar PV fires are caused by poor cable management. See Chapter 2.2 for more info. My take is if the installation is supposed to last 25 years and is out of sight on my roof, I darn well do a good job upfront and try not to be cheap about it. At many sites, I see the pros cutting corners - $0.05 UV zip tie instead of $0.40 stainless steel cable clip, non rain-tight EMT fittings. Hard to see why you'd want to save $10 on a $10,000 bill.


I'd be curious to see what your cable management looks like. I used SS cable clips but found that I also needed lots and lots of zip ties to keep things looking neat as there is so much extra cable. I think if the zip ties do fail the clips should be enough to keep the wires off the roof but we'll see :)

sitech
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Re: DIY Solar PV Installation

Mon Sep 16, 2013 1:37 pm

Hmm, sorry, didn't think to take pictures of how I tucked the cables in the clips - thought it seemed pretty straightforward.

With Enphase (M215), there shouldn't be lots of cables.

The Engage cable is laid out straight along the rack/rail and secured by the Enphase clips (see BOM chapter for full P/N). It only gets tricky when the cable needs to jump across to another rack/rail.

The cables from each PV panel are first connected to the M215, then tucked into the Enphase clips. Saw this in some Enphase training video. Those clips have 2 "pockets" - lift out the Engage cable, slip in the PV cables, tuck the Engage cable back on top.

So no unsecured cables, nothing lying on the roof.

Hope that made some sense.

QueenBee
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Re: DIY Solar PV Installation

Mon Sep 16, 2013 1:52 pm

sitech wrote:With Enphase (M215), there shouldn't be lots of cables.

The Engage cable is laid out straight along the rack/rail and secured by the Enphase clips (see BOM chapter for full P/N). It only gets tricky when the cable needs to jump across to another rack/rail.

The cables from each PV panel are first connected to the M215, then tucked into the Enphase clips. Saw this in some Enphase training video. Those clips have 2 "pockets" - lift out the Engage cable, slip in the PV cables, tuck the Engage cable back on top.


The engage cables are longer than the distance between each inverter, the enphase to engage cable was longer than needed, and the panel to microinverter cables are longer than needed as well so I had lots of slack to manage. I first used SS clips to get the engage cable off the roof and then used lots of zip ties to clean it it all up. Nothing touching the roof, nothing to get pinched by installing the panels, and no loops big enough to touch the underside of the panel.

I definitely missed that trick as that would help keep the smaller PV wires in place.

Did you see anywhere that required the extra bracing when spanning between rows? I was a bit sloppier and just used the SS clips on both sides. In one place where I had to span a foot and a half across the valley I used some conduit to provide extra protection.

sitech
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Re: DIY Solar PV Installation

Mon Sep 16, 2013 5:21 pm

Just did an install (for a friend who helped me did mine).

When the Engage cable hops from one rail to another, if it's close by (e.g. for 2 rows touching each other), then the cable can still be adequately secured using the clips.

In my case, my 2 rows of panels are separated due to the presence of rooftop vents. So the Engage cable sagged and laid on the surface. Chapter 6.4 documents how I worked around this.

Had another case where the Engage cable needed to run from a South-facing roof to a West-facing roof. I extended one rail from each roof side so that they nearly meet where the South and the West roof surfaces are joined together (alley). Then it was simple to keep the Engage on the rails using clips.

sparky
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Re: DIY Solar PV Installation

Tue Sep 17, 2013 5:51 pm

sitech wrote:...
2) Engage Cable. I believe this is a must. I get my cables for $22-$25 a drop. I view this as part of the cost of going with Enphase. The thing to note is you will void a product's UL listing if you do not use it in the manner in which the manufacturer prescribes.
4) Cable Management....Hard to see why you'd want to save $10 on a $10,000 bill.
I probably agree with Engage cables for the m215s. Where I was suggesting EMT and j-boxes was perhaps a special case. But one that comes up when you're not starting from a clean sheet.
I have expanded my system twice. The initial system was 2.8kW and a centralized inverter. I have a tile roof so, to help future proof, I re-roofed and added enough racking to double my array down the road when PV prices dropped. 18mos later I found 4 blem Sanyo panels and 2 m380 Enphase very cheap.
The panels had to be on a far corner of the roof away from the service panel so I ran EMT to a box near the panels' edge. Then I looked for Engage trunk cables for m380s. No dice. The m380s had been EOL'd (hence they were so cheap!!).
The 2 Engage cables I finally found were $95.
My thought process for using EMT was like this: Geez, I've got exterior EMT and boxes all over my property and there's been no issues for decades. I'm using these $95 cables to run <3.5 Amps of AC ~ 10 ft to the junction box where the fancy Engage end is going to get cut off (UL violation?) and spliced in the j-box. Who really knows how long this cable (that looks no better than a high-end extension cable) will last on my roof.

So, that was where my question arose. I bit the bullet and paid the $95. I've since installed some m215s and yeah, those cables aren't bad price-wise. I've have no sense that they'll outlast properly installed EMT and boxes though.

As for UL or warranty violations, funny you should ask. One half of one of my m380s failed the first week. It was a thermal issue.
Enphase said no problem to replace. I confessed to them that I had modified the unit by replacing the DC connectors with MC4s to match my panels. Not an issue they said and replaced the inverter within 2-days. All's been well since.

Lastly, I agree about not cutting corners, for the above example I was questioning the value of the Engage. Furthermore, I inspect my system closely once per year as added insurance and upgraded to WEEB clips after those became standard. Loosened panel fasteners has been my only issue.

viethoc
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Re: DIY Solar PV Installation

Sat Feb 01, 2014 5:57 pm

Hi all,

First, I want to thank sitech for his perfect write up. I read and followed up his instruction/explanation to the dot. Without his pictures and description I wouldn't dare to take on this huge project. I haven't done anything close to this magnitude. If I can do it, I think, anyone can.

I made mistakes as I progressed. For example, I mis-drilled few times and needed to seal them. I probably spent close to 40 hours to complete the whole project. I worked alone except got help from my wife to pull all the wirings thru EMT. And my brother helped out carrying all 16 panels onto the roof.

It took me 3 months to complete. The first month was to obtain a permit from my city's building division. I made one error and needed a second round of plan check. Every round was about 2 weeks. The second month was for installation. I worked mainly on weekends. I spent most of my time in marking on the roof and drilling holes. The rest came easier. The third month was to sign on with Southern California Edison (SCE) after the city's approval.

At the last minute, I found out that SCE wouldn't approve my project because according to their calculation my system would produce annually 800kWh more than my previous 12-month usage. However, I told them that my usage will definitely increase due to my recent lease of a Nissan Leaf. I would use additional 200kWh per month for charging it. They agreed with my argument.

I could have cut down the whole process to 2 months or so by having the correct & complete plan before submitting it. I also could have engaged with SCE early on instead of waiting until every thing was installed and signed off by the city before contacting them.

I started my plan submission on Nov. 8, 2013 and received SCE's approval on Jan. 31, 2014.

Overall, my system cost approximately $9,300. I had to pay $489.50 for City of Garden Grove's plan check and permit, and $392 for the main shipping. Therefore, my system of 4.08kW costs additional $700 more than sitech's system.

Again, I am very happy and want to express my gratitude to sitech's effort and helpful blog. Thank you.

cracovian
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Re: DIY Solar PV Installation

Fri Nov 21, 2014 9:29 am

Thank you so much for documenting everything so nicely. I looked at your parts list and it's amazing how you got it down to the last bolt and a can of grease :-)

However, even though it was done last year, I'm finding that you had gotten some of the best prices (even now) I could find for panels and all the enphase stuff... Who was your vendor if I may ask? Did you get it from different sources? Have the prices gone up and/or kept steady? EDIT: I just noticed that you had provided links to the suppliers on a page that I overlooked :-)

I just paid (a lot) to get my small 2.240 kW system running (8 x LG280S1C-B3 and M250) but all the cabling is there to accommodate another 8-24 panels. I realistically only have room for two more rows of eight and was planning to go cheap expanding it this time... I'm thinking about buying all the required hardware and paying an experienced (solar) electrician to get it installed. It shouldn't take more than one day or two, so $200-400 for labor maybe?

Either way, I'm trying to compile the list based on some of the items you've listed and so far GoGreenSolar with their $.74/watt Suntech STP-250s sounds appealing but the rest of their stuff is quite expensive compared to what you paid but still a lot less than other sources that I've come across...

I apologize for all this disconnected info but any comments on hardware, installation tips, pricing and sourcing would be greatly appreciated. Thanks again.

https://enlighten.enphaseenergy.com/pv/ ... PNjC497170
Last edited by cracovian on Fri Nov 21, 2014 11:39 am, edited 1 time in total.
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RegGuheert
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Re: DIY Solar PV Installation

Fri Nov 21, 2014 10:43 am

cracovian wrote:I apologize for all this disconnected info but any comments on hardware, installation tips, pricing and sourcing would be greatly appreciated. Thanks again.
Thanks for providing the details on your system! It looks very nice.

I guess I have to wonder if you REALLY need to use the M250 for 280Wp-rated modules in GA. While it is true that Enphase only recommends the M215 for modules rated up to 270Wp, I'm willing to bet that for your particular installation, you could use the M215 and almost NEVER limit the output power due to the microinverter limitation. You could likely save about $30/inverter by making this one change on future upgrades (although if you installed even-higher-wattage PV modules, then the M250 would likely be desirable).

Let me provide a bit more information in support of this idea:

- Since the beginning of August I have had both M190s and M215s mounted on my roof connected to identical 235Wp PV modules in virtually-identical conditions. Those are mounted on a nearly-south-facing 7/12-pitch roof at 39 degrees north latitude. The peak rating of the M190 (200W) is 85% of the PV rating while the peak rating of the M215 (225W) is 96%.
- Note that the peak power rating of the M250 matches its nameplate (250W), but the peak rating of the M215 is 10W higher than nameplate: 225W. (However, you typically pay for them per nameplate watt.) As a result, for your system, the peak rating of the M215 would be 80% of the PV rating while the peak rating of the M250 would be 89%.
- The difference in production for my M190s and M215s so far is zero. I won't know the year-round total differences until I get through about April, but I am surprised that with temperatures in the 20Fs, there is truly no difference in production so far in November. I expect small differences in January through March, but I doubt the year-round average will be over about 1%, if that.
- Your roof pitch is similar to mine, but you live in a climate that is 5% lower in latitude, so the sun is higher in the sky during all parts of the year, so the sun will be farther from the boresight of your array during the coldest months. Also, the temperature during those coldest months is quite a bit higher than here. As a result, conditions which cause the 85%-rated inverters in my system to limit will probably be more common than conditions which would cause 80%-rated inverters in your system to limit.

Bottom line: You could reduce the bill-of-materials cost for upgrades to your system by 7 to 10% while impacting production by less than about 0.5%.

If you purchase the materials and do the installation yourself, you will save the most money overall.
RegGuheert
2011 Leaf SL Demo vehicle
10K miles: Apr 14, 2013, 20K miles (55.7Ah): Aug 7, 2014, 30K miles (52.0Ah): Dec 30, 2015, 40K miles (49.8Ah): Feb 8, 2017, 50K miles (47.2Ah): Dec 7, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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