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**araghava** · 02-08-2015, 01:47 PM

You might want to analyze if a time of use plan works for you. If you are not at home during peak demand hours, you can probably get by with a smaller system.

**venvis2001** · 02-08-2015, 05:41 PM

Time of Use plan

Thanks. I earlier analyzed & also had couple of installers give me quote based on my usage. I am already on TOU (E6). My usage is roughly 80% off peak & 20% part-peak/peak. Based on that the recommendation from installers were 4.8K or 4.5K system (covers close to 85% of my usage). So, I thought going with 5K system will cover 100% of my cost.

**Basslakerider** · 02-09-2015, 06:11 PM

Originally posted by venvis2001

All,
I am in the process of planning & designing my solar system for my home. Based on my usage over the last 3 plus years, I have decided to go with 20 panel system (5.1 KW if I use 255W panels) which will produce approximately 7500KwH per year (my usage is around 7600 to 7700KwH). Planning to install it myself, but may get the design/permit service done by someone (online I saw some for $300 to $500). Have a licensed electrician for connection/inspection part.
My system will be: 20 255W panels (thinking of renesola) + M215 enphase. Will have 3 circuits (roof 1, 2, 3 areas) with 8+10+2 panels. I have to learn a few more details before going for the design. I plan to run the conduit in the attic.
Have couple of questions regarding the wiring of the three circuits.
1. The roof 1 area (8 panels) is about 15 to 20 feet away from roof 2 area (10 panels) & roof 2 area (2 panels) is about 6 or 8 feet away. Should I bring the three circuits to the attic separately & then use a AC combiner box in the attic? This will literally make no conduit visible on the roof. I can put the three 'junction boxes' just under the panel/run the conduit into the attic. OR should I run some conduit on the roof (from roof 1 area to roof 2 area, then roof 2 to roof 3 area & then put a combiner near roof 3 area/then go to the attic)? I have hard time deciding on this. OR will the design/permit service provide diagrams that will show the details? (I will check with them but I want to know/learn myself first!)
2. I assume the three circuits will be connected in parallel? (240V AC coming out of each circuit). is that correct. Using a SOLADeck AC/DC combiner box for 2 or 3 branches.
Suggestions on places to buy the panels/inverters will be great.
Thanks for your suggestions.

I'm doing the same, no suggestions from anyone here yet on design services, I just googled solar design services and not sure who I will use yet. But get your panels inverters, etc. stuff at Renvu in Mountain View, several good recs here, and prices there are very good for DIYers.

**Amy@altE** · 02-09-2015, 06:39 PM

What kind of roof shingles or tiles do you have?

**sdold** · 02-09-2015, 09:02 PM

Originally posted by venvis2001

Suggestions on places to buy the panels/inverters will be great.
Thanks for your suggestions.

I sent you a PM a couple of weeks ago recommending Renvu, a friend and I both had a good experience dealing with them. The customer service is good and they were happy to take back things that that I turned out not to need. You can also drive over there and pick up will-call items.

I did my own calcs and drawings for the permit, $500 sounds like a fair price, it was a lot of work!

**venvis2001** · 02-09-2015, 09:39 PM

Design and drawings

Originally posted by sdold

I sent you a PM a couple of weeks ago recommending Renvu, a friend and I both had a good experience dealing with them. The customer service is good and they were happy to take back things that that I turned out not to need. You can also drive over there and pick up will-call items.

I did my own calcs and drawings for the permit, $500 sounds like a fair price, it was a lot of work!

Thanks sdold. Yes I have been checking them out for the panels/inverters, etc. I agree that design & drawings take time (especially for someone who does not use sketchup or other autocad type tools regularly). I am going to give it a shot & see how difficult it is. I have an approved plan from my neighbor who installed Supower systems using solarcity & I can just follow the same set of sheets.
I also checked with 3 different designers (talked to them & asked for a quote) - ACO solar quoted $1000 for design services, renvu for $550 & another designer quoted 1200. One of them asked me whether I need PE stamp (not sure if that is required?). If required, I think they will add extra $$. the 1200 quote included PE stamp.

When I compared renvu prices to aco solar, aco came out a bit cheaper but I don't have any reference/recommendations on them. At least a few forum members have had very good experience with moutainview supplier!

I will keep posting my thoughts, plans, etc. as I work through the details. Appreciate everyone's help in guiding me!

**venvis2001** · 02-09-2015, 09:42 PM

My roof type

Originally posted by Amy@altE

What kind of roof shingles or tiles do you have?

OK. My roof is a two story, concrete tile roof. I have been up on my roof several times, but not to the edges much. I called couple of roofers to just quote me on setting up just the mounts (QV tile hook mounts with flashing). One of them quoted a reasonable amount for a day's effort (give or take). I might go with that idea. Once the roof mounts are in, plus I will have a few 'safety hooks' setup near the ridges, I can use safety harness & feel comfortable in mounting my panels & doing the wiring. That is my plan so far.
If it were shingles, I could do it myself since I have volunteered several solar installations through Grid Alternatives in Bay Area. I plan to go for one or more installations before I do mine!

**venvis2001** · 02-09-2015, 09:44 PM

Originally posted by Basslakerider

I'm doing the same, no suggestions from anyone here yet on design services, I just googled solar design services and not sure who I will use yet. But get your panels inverters, etc. stuff at Renvu in Mountain View, several good recs here, and prices there are very good for DIYers.

Hi Basslakerider, I downloaded google sketchup last week & have been playing around with it. It may take a while to do the design/drawing myself. I checked couple of online design services.. i can email you my thoughts since I can't mention names in the forum.
First I have to firm up my decision on 'what panels' to get before jumping into design. I hope to decide by end of this month.. my day job is keeping me busy during weekdays.

**Amy@altE** · 02-09-2015, 10:00 PM

I'm a New England gal, not too familiar with the concrete shingle flashings for conduit. My gut says that the SolarDeck won't work with them, you'd be better off with a Midnite MNPV6-DISCO AC MICRO http://www.midnitesolar.com/productP...tOrder=4&act=p

And yes, this would wire them in parallel.

**Amy@altE** · 02-09-2015, 10:01 PM

Also check which edition of the fire safety code you have to comply with, you likely can't go within 3' of the edge or ridge line with panels.

**venvis2001** · 02-10-2015, 08:35 PM

Firecode in my city

Originally posted by Amy@altE

Also check which edition of the fire safety code you have to comply with, you likely can't go within 3' of the edge or ridge line with panels.

You are correct. I checked with our FD in the city & they gave me a nice hand out. Edge/Eve/Ridges - should leave 3 ft, which I have planned to leave.

**venvis2001** · 02-10-2015, 08:39 PM

Question on Time of Use

Originally posted by araghava

You might want to analyze if a time of use plan works for you. If you are not at home during peak demand hours, you can probably get by with a smaller system.

If I use approx 25KwH per day, 18 of which is in off-peak; I produce 20KwH during the day, 15 in peak, how does PG&E calculate net metering? Is it purely consumed-produced KwH (on a yearly basis) or there is a complex formula here? or is it based on $/W for produced & $/W consumed used in the calculation?
I am trying to understand how a smaller system with TOU will offset the usage.

**foo1bar** · 02-10-2015, 11:00 PM

Originally posted by venvis2001

If I use approx 25KwH per day, 18 of which is in off-peak; I produce 20KwH during the day, 15 in peak, how does PG&E calculate net metering? Is it purely consumed-produced KwH (on a yearly basis) or there is a complex formula here? or is it based on $/W for produced & $/W consumed used in the calculation?
I am trying to understand how a smaller system with TOU will offset the usage.

My understanding from talking with people in PG&E area is that if you earn $15 of credits during peak you can use $15 of energy (peak or non-peak).
SO best situation is if you produce completely during peak and consume completely during non-peak.
You're estimating that your consumption is 18kwh nonpeak and 7kwh peak.
And production is 5kwh nonpeak and 15kwh peak.
Without looking at the $/kwh to confirm, I'd beleive that the 8kwh (beyond consumpiton) during peak will more than pay for the 13kwh nonpeak.

One thing to note - if you have the above scenario all year long, and you have extra $ of credit, AND have generated fewer kwh than consumed, then at that 1 year mark your credits are zeroed out. (with no check cut to you)
ONLY if you produce more kwh than you consume will you potentially get a check from PG&E. BUT that check is going to be ~$.04/kwh for your excess production. And $.04/kwh is not a lot - very likely less than cost_to_install/total_energy_generated. SO often your best choice is to size it so that you're definitely smaller than total # of kwh consumed - but that you'll generate enough (or almost enough) dollars in credits to pay for your use.

If you size it a little bigger and you have credits that get zeroed out at your yearly anniversary, you could consider it a "gift" to PG&E - that's one of my friends attitudes... He thinks they've got enough problems, so he's OK with giving them that little "gift" since he's getting to use their grid for cheap.

**venvis2001** · 02-11-2015, 11:28 AM

Originally posted by foo1bar

My understanding from talking with people in PG&E area is that if you earn $15 of credits during peak you can use $15 of energy (peak or non-peak).
SO best situation is if you produce completely during peak and consume completely during non-peak.
You're estimating that your consumption is 18kwh nonpeak and 7kwh peak.
And production is 5kwh nonpeak and 15kwh peak.
Without looking at the $/kwh to confirm, I'd beleive that the 8kwh (beyond consumpiton) during peak will more than pay for the 13kwh nonpeak.

One thing to note - if you have the above scenario all year long, and you have extra $ of credit, AND have generated fewer kwh than consumed, then at that 1 year mark your credits are zeroed out. (with no check cut to you)
ONLY if you produce more kwh than you consume will you potentially get a check from PG&E. BUT that check is going to be ~$.04/kwh for your excess production. And $.04/kwh is not a lot - very likely less than cost_to_install/total_energy_generated. SO often your best choice is to size it so that you're definitely smaller than total # of kwh consumed - but that you'll generate enough (or almost enough) dollars in credits to pay for your use.

If you size it a little bigger and you have credits that get zeroed out at your yearly anniversary, you could consider it a "gift" to PG&E - that's one of my friends attitudes... He thinks they've got enough problems, so he's OK with giving them that little "gift" since he's getting to use their grid for cheap.

Thanks for the explanation. This makes sense - I should probably go with a smaller system (not with 20 panels, but with 18). I am fairly confident that my usages is 75% to 80% off peak & 50% to 60% of the power produced from my panels will be during peak.

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