Want to DIY a 6000w system - Where to start? Parts list?

[Expat]

Yes, I'm still here. I just didn't see the point in responding. It's my impression that this site is geared towards people in the industry, rather than the DIY crowd. I was insulted/attacked right from the beginning, why bother? I've been compiling a materials/parts list through various sources, including a very helpful local installer who is very supportive of the DIY crowd (I was beginning to think this didn't exist in this industry). Although, there does seem to be a few like minded individuals here so perhaps I'll keep at it.

As to my friends part list, he is busy tidying up the complete list for me and will pass it along when he is finished. I've been using him for pointers in the mean time. I have no idea about the 1st set of panels he got or where he received them, but no - he is not in the solar power industry.

So far, I've come up with about $12k for LG panels, enphase microinverters, and ballasted racks for my flat roof. $11k using a Sunny Boy centralized inverter. By the time I add up all the odds and ends (Wiring, boxes, etc) and some associated fees (inspection, sign off on my roof, etc), I assume I will be right around/under the $10k I was expecting after rebate. I need to decide how cheap/expensive I want to go regarding the inverter and racks (unirac rapidrac isn't terribly cheap) - there's definitely a little money to be saved there.

[russ]

Yes, I'm still here. I just didn't see the point in responding. It's my impression that this site is geared towards people in the industry, rather than the DIY crowd. I was insulted/attacked right from the beginning, why bother?

Bother or don't bother makes no difference to us - however the guys will help all you want as long as the requests are real

The costs vary from area to area - depending on state and local requirements and local labor costs.

Blanket statements as regards costs across the US are generally not correct.

[UCF]

Impressive system. I am not sure about the fuse holders and fuses for that price but the rest seems in line.

How long did you take to compile your parts list and what was the availability of the 33 Canadian panels?

Cooper Bussman CHMDIU - 3.09 each
Cooper Bussman PVM-15 fuse 2.79 each

Google: PV Cables

It took me few days to compile it and find the best prices, as far as the modules I bought them couple months ago from a big west coast distributor and as far as I know they are still listed as available on their website.

[t5800512]

Hi Expat and Knsolar. Do you have any specific questions? I believe both of you are on the right track. Start by defining your requirements. Lay out your roof design, and then start selecting which brands you want to use. I went with LG panels, Enphase microinverters, and Unirac for the racking system. Unirac has a website that will help you design your rack system. I found it to be very useful. Do a search for Unirac and design tool. It gave me parts counts right down to the last WEEB clip.

Keep in mind if you use microinverters, they (as well and panels and racks) have to be earth grounded. Rather than running a continuous number 6 copper wire to each one, I elected to use a WEEB clip to ground them to the rack, which in turn is grounded.

[Expat]

Hi Expat and Knsolar. Do you have any specific questions? I believe both of you are on the right track. Start by defining your requirements. Lay out your roof design, and then start selecting which brands you want to use. I went with LG panels, Enphase microinverters, and Unirac for the racking system. Unirac has a website that will help you design your rack system. I found it to be very useful. Do a search for Unirac and design tool. It gave me parts counts right down to the last WEEB clip.

Keep in mind if you use microinverters, they (as well and panels and racks) have to be earth grounded. Rather than running a continuous number 6 copper wire to each one, I elected to use a WEEB clip to ground them to the rack, which in turn is grounded.

Thanks for the reply.

My questions will likely arise as I start the install process. I think the bulk of my questions have been answered already. Given the vendor sponsor, I don't think I can get 'best price' info here...which is fair.

Right now, I think my biggest choice will be trying to decide between centralized or micro inverters. I'm leaning towards the microinverters based upon individual monitoring capability and the slightly easier install. Also, it may be nice to not have a large inverter hanging on the wall, as my meter is easily visible from the street (not really a big issue, tho). Garage mounting isn't desirable for my setup/wants. I should mention that I will have zero shading issues, so I wont receive any of that benefit that they claim microinverters provide in that scenario.

[Sunking]

My questions will likely arise as I start the install process.

That will be too late. Before you can apply for a permit, you have to have a complete design and material list or else NO PERMIT. You will not even be able to apply for a permit. .

[Expat]

System installed using Unirac, a single Sunny Boy 10000TL inverter and 33 Canadian Solar CS6P-300 Modules all attached to the roof with 72 attachment points ( wind load up to 130mph) by Snapnrack . All the parts are available on the internet and I will be happy to provide any documentation to show for it and prices paid if questioned .

Awesome, exactly what I was looking for.

Those modules seem to be a bit more efficient (16% vs 15%) than the LG's I'm looking at and I found 7200w worth (24 panels) of those Canadian Solar panels for a bit cheaper than 6000w worth of the LG's. After doing more calculations and using the PVWatts utility, I was considering going to a bit larger than a 6000w system anyways. Looks like I'll be pushing the idea of '$0 electric bills' with just a 6000w system would likely need a slightly larger array.

[Expat]

Okay, one question I do have is sizing of the inverter. I see many people undersize the inverter, while others match? If going with 7200w worth of panels, would the SMA 7000w inverter work well, even if I later decided to add a few panels? Should I consider the 8000w?

It might be worth mentioning that I am in the very sunny southwest.

EDIT - I see it may be common to use a 1.15 ratio, all the way up to a 1.3 ratio? If this is the case, it sounds as if the 7000w inverter would be the better choice?

[UCF]

Okay, one question I do have is sizing of the inverter. I see many people undersize the inverter, while others match? If going with 7200w worth of panels, would the SMA 7000w inverter work well, even if I later decided to add a few panels? Should I consider the 8000w?

Use their string tool (on the web) , I can tell you one thing, my 9900 DC rated system flat lines at 10200 Watts AC on a good day for a little bit ( talk about the derating factor we all have been hearing from the pros . Now, my panels are only positive tolerances ) . You will not see this with enphase and if you have no shading sma is the way to go . Even with little shading you can go with their dual MPPT inverters .

[SunEagle]

Cooper Bussman CHMDIU - 3.09 each
Cooper Bussman PVM-15 fuse 2.79 each

Google: PV Cables

It took me few days to compile it and find the best prices, as far as the modules I bought them couple months ago from a big west coast distributor and as far as I know they are still listed as available on their website.

Those are great prices for both fuse holder and fuse. I spent about $10 each for my single pole Bussmann fuse holders and close to $8 each for my 10 amp fuses. Although mine were Class CC made by Littlefuse.

I should have gone to "PV Cables" for my purchase instead of Amazon. Thanks for the tip.

[UCF]

Okay, one question I do have is sizing of the inverter. I see many people undersize the inverter, while others match? If going with 7200w worth of panels, would the SMA 7000w inverter work well, even if I later decided to add a few panels? Should I consider the 8000w?

It might be worth mentioning that I am in the very sunny southwest.

EDIT - I see it may be common to use a 1.15 ratio, all the way up to a 1.3 ratio? If this is the case, it sounds as if the 7000w inverter would be the better choice?

I'm not pro and I'm sure people will pipe in but I would go with a single 8000TL for 7200W panels worth , if you are planning on expanding, two dual MPPT sma inverters are way to go. Lower start voltages , you can miss match panels between strings and a lot more flexibility for the future expansion all due to huge voltage window. those inverters only come as 3000, 4000 and 5000 .

[t5800512]

I agree with SunKing, you should really have all your questions answered and a firm plan in mind before you move forward. You will want a to scale drawing for your own planning purposes. Besides the building permit, I also had to have drawings to get my interconnect agreement signed. I created my drawings using a cad package, but I believe you can get by with graph paper and a pencil.

I'm really sold on micro inverters. They are a little more expensive, but it's great to be able to monitor the output of each panel. Say your using a string inverter and the output of one of your strings drops, what do you do? Test every panel? I also believe the added cost of micro inverters can be justified considering the life span (warrantee period) of Micro vs. String Inverters. String inverters will likely need to be replaced over the life span of your panels. Micro inverters may also need replacement, but it won't be on your dime.

I also really like the high efficiency LG panels. Mine are producing higher than their rated output. But the reason I chose them was because I have limited south facing roof, and wanted to squeeze every watt I could from it. If you don't have space limitations, you can save some money on the panels. But keep in mind that the enphase micro's will not work with 72 cell panels.

As for prices go. Prices are constantly changing, so it makes little since posting them on a forum. Do an internet search for your specific items and find the best price that way. That is exactly what I did, and I put it into a spread sheet for comparison purposes. I then went out for bids so I did not have to peace mill my system all across the country. I pinged at least a dozen of the largest internet distributors. After narrowing it down, I went for second and third best offers. I got the best pricing from Civic Solar. But you will need to do your own homework.

Unirac makes a quality product, but the best thing is that almost everyone sells them. As a result, you can get some heavy discounts on it. If I remember correctly, I paid about half of list price.

[Expat]

I'm really sold on micro inverters. They are a little more expensive, but it's great to be able to monitor the output of each panel. Say your using a string inverter and the output of one of your strings drops, what do you do? Test every panel? I also believe the added cost of micro inverters can be justified considering the life span (warrantee period) of Micro vs. String Inverters. String inverters will likely need to be replaced over the life span of your panels. Micro inverters may also need replacement, but it won't be on your dime.

I also really like the high efficiency LG panels. Mine are producing higher than their rated output. But the reason I chose them was because I have limited south facing roof, and wanted to squeeze every watt I could from it. If you don't have space limitations, you can save some money on the panels. But keep in mind that the enphase micro's will not work with 72 cell panels.

From the little I know/have researched, I really like the idea of microinverters as well.

The last bit is some good info, I did not know that. So, the Enphase M250's will also not work with 72 cell panels as well?

[t5800512]

Yep, that is according to Enphase; no 72 cell panels. I believe it is because of the possible max voltage the 72 watt panels can produce. Even then, there are some 72 cell panels that would be fine for the voltage perspective. But if it voids the warranty, who cares. Best to play by the Enphase rules.

What size panels are you considering? You may be able to save yourself some money and go with the M215 microinverters if you are going to stay in the 250 to 270 watt range. I used the M215 inverters with 280 watt panels. I did so knowing that my azimuth was about 16 degrees from ideal. I used PVWatts, and it has been right on the money.

[silversaver]

He also gets 2 spares for just in case
And these panels are extremely generic meaning finding one with the same specs is not difficult if it becomes necessary.

Thank you. I figured the same and saved 1 spare for raining day