Assistance Designing Whole Home Grid Tied System

[bedpan]

Hey Folks,

I have got a couple quotes for Grid tied system at my house. Price wise I feel they are competitive to the market, it just feels like to much to pay though. With my payback being well over 10 years I cannot make the leap. That said however If I do a self install it looks like it would cut the price to close to in half bring my payback down to 5-10 years or a number I can live with.

I am wondering if you can suggest any services around that will help me design the system. I am quite comfortable working with electricity and have a background in electronics. I just want to make sure what I buy meets my needs and comes close to code compliance (close in the sense that if your close enough the inspector can point you in the right direction). I have been through a number of ESA inspections over the years including a Panel replacement, Knob and tube upgrades and full basement finishing.

Is there any companies around that do this? Ideally somewhere in Canada, or more specific in Ontario! I would love to have a discussion with this person/company have them spec out the whole system with a complete build list. I order and assemble. I know its never that easy and there will be parts missing and changes required as reality kicks in but as long as it gets me close.

Further it would be great to get some help with all the other paperwork. My building Dept. tells me they need an Engineers report for the roof and weights. I need to contact the ESA and get a permit pulled, I need to contact Ontario Hydro for a meter upgrade and approval and I need a home energy audit so I can take advantage of a $5k rebate.

Maybe I am just dream.. But anyone have any suggestions?

Thanks kindly for your feedback!

 

[Hedges]

I certainly recommend DIY, if you are comfortable working with 120/240VAC.
Anything commercial installed needs a lot of markup, and they may have to cut corners to be profitablle.

Places like Alt Energy Store will design and sell a complete bundle.
I started that way (Real Goods, which Alt Energy since acquired), but now I shop A la Carte mostly on eBay.

You need to determine code requirements. Here in some markets of the US, we now need grid support features like UL 1741 SA, which means latest model inverters. If not applicable, you can pick up new in the box old-stock equipment. I like earlier model SMA Sunny Boy inverters.

Also, decide if you might want battery backup in the future. Some brands/models support that with batteries optional. Some GT inverters do "frequency-watts", which is an optional part of UL 1741 SA, also what SMA has done for years. This lets a separate battery inverter control GT inverter by shifting frequency slightly above 60 Hz while off grid, to match production with loads.


I think PV panels + inverters can be had in the $0.50 to $0.70/W range. With rack mounting hardware and electrical stuff, around $1/watt.

Installed on the roof, you may need Rapid Shutdown, and additional box per panel (or not needed with micro inverters.)
Any modern GT inverter will include GFCI and AFCI, also needed for rooftop mount.

 

[bedpan]

I certainly recommend DIY, if you are comfortable working with 120/240VAC.
Anything commercial installed needs a lot of markup, and they may have to cut corners to be profitablle.

Places like Alt Energy Store will design and sell a complete bundle.
I started that way (Real Goods, which Alt Energy since acquired), but now I shop A la Carte mostly on eBay.

You need to determine code requirements. Here in some markets of the US, we now need grid support features like UL 1741 SA, which means latest model inverters. If not applicable, you can pick up new in the box old-stock equipment. I like earlier model SMA Sunny Boy inverters.

Also, decide if you might want battery backup in the future. Some brands/models support that with batteries optional. Some GT inverters do "frequency-watts", which is an optional part of UL 1741 SA, also what SMA has done for years. This lets a separate battery inverter control GT inverter by shifting frequency slightly above 60 Hz while off grid, to match production with loads.


I think PV panels + inverters can be had in the $0.50 to $0.70/W range. With rack mounting hardware and electrical stuff, around $1/watt.

Installed on the roof, you may need Rapid Shutdown, and additional box per panel (or not needed with micro inverters.)
Any modern GT inverter will include GFCI and AFCI, also needed for rooftop mount.

Thanks for the Reply Hedges..

I have no major concerns about working on/in the panel other then meeting code compliance. Common sense will get me 80% of the way there but there are rules that exist (usually for a good reason) that a DIY'er just would not understand without working full time in the industry. Having been through several code inspections I find our inspectors up here very friendly and helpful to DIY'ers.

I will have a look at the Alt Energy store. Do you know if they will design for someone knowing they cannot buy from them (US to Canada shipping can be quite cost prohibitive)?

Without our current $5k federal grant for home energy consumption improvements their is a stipulation that good installed must be CSA approved. This will limit some of the kit that can be installed. Generally anything sold and approved in the USA will also be CSA approved.

Regarding design. The long term plan is to buy/build my own battery system to go along with this install. I will need a hybrid inverter that will accept DIY battery packs. It seems most hybrid inverters are tied to proprietary system batteries. I have done a pile of research but everything keeps leading me back to the Sol-ark 12k. If I stay under 10K inverter capacity I don't have to get full approval from our hydro company (Ontario Hydro). So I will likely be looking at 12-14k of panels on the roof. Based on the initial quotes I have this will be close to getting me to net zero consumption using Net Metering. This goes back to the design aspect though an many of the questions I have to insure what I build will in fact get me to where I want to be.

Cheers and thanks again!

 

[bedpan]

I have just reached out to one of the local vendors I got a quote from to see if they would be interested in helping a DIY'er. I guess it really depends on how busy they are. If they are not super busy then I guess some money is better then none. If they are already pushing 100% capacity I am guessing I am going to get a good luck from them.

We will see.

 

[Hedges]

Used to be Solar Queen with Alt Energy Store would do a design for free, sell nice hardcopy plans for a modest price. She passed away, but you could check what services they can offer now.

An inverter with its specs will define the minimum wiring/breaker requirements, and range of PV array voltage/current. Take a first cut at it, and we can review and give feedback.

Some of the hybrids use custom high-voltage batteries. Several are compatible with BMS that are also available to do-it-yourselfers.

I use SMA Sunny Boy GT PV inverters, and added on Sunny Island battery inverters. These are a very nice system.
I don't think they have time-shifting feature, but they do support grid-backup.
Because power failure is infrequent, I use AGM batteries. For DIY lithium, REC makes a compatible BMS.

If your roof has multiple orientations, you can put in more PV watts than inverters would appear to support, because power will be spread out over more hours.

There are a few rules (at least by US NEC) regarding system size. In particular, breaker panel main breaker + backfed PV breaker can't exceed 120% of busbar rating. PV breaker goes at far end of busbar. There are some way around that, especially if you have a main breaker at the meter, and wires to the breaker panel.

I was able to get a pallet of 9, 140 lb inverters shipped from Canada to San Jose for a few $hundred. Because they were manufactured in Canada, no duty and I served as my own importer, just paperwork I sent to the shipping company.

The biggest part of the work is physically handling and mounting all the panels.
In San Jose, rooftop permit is expedited and no mechanical permit if < 40 lbs. per footing. I guess they assume lag screws into sheathing. I would rather find and screw into joists, anyway. But mine is ground-mount (due to old shake roof), and I kept each array under the size that would require a building permit.

 

[bedpan]

Thanks again Hedges!

As mentioned I have reached out to a local company to see what they are willing to do. I suspect they are not interested but they seemed like the best quote and best people to talk with of the 3 quotes I got.

I will reach out to Alt Energy and see what they have to say.

Until I get a little further along I was not going to put pen to paper on a design. Buying localish I will see what the "best" panels are I can get. Using the Sol-Ark inverter play with numbers and see what I can come up with. I was trying to find today, can I use DC Optimizer with the Sol-Ark (sound like some are compatible)? I have a Good Southern Exposure but I would guess I will only get about 6kW on that side. Then my West roof is unobstructed but peaks will limit me to about 5kW there. The East roof has some shade for a good piece of the morning but is quite large and would take probably 16kW or more of panels. From an aesthetic purpose the South and east would look best but for production South and West would be best. This is part of the design side that I would like some help with. I know there are some great simulators. How much difference would this make, would DC Optimizers help (on the east) and if so how much?

Does anyone have any good resources for code in Canada specific to solar? Things like do I need rapid shut down or what shut downs are acceptable? Again just starting to look at the code side. I understand the the basics of the wiring but there is a lot more then basics to learn.

There use to be a great Dummies Guide to Canadian Electrical Code. I wonder if they have updated to include solar.

Thanks!

 

[Hedges]

I think optimizers are primarily to allow series connection of panels with different current output, like of different orientation or wattage (e.g. poorly matched.) Because optimizers are MPPT which respond over time, they could interfere with MPPT of inverter.

PV strings of different lengths need to go to different MPPT. Probably SolArk has multiple. Sunny Boy recent models have 2 or 3.
You can parallel two string of same length but different orientation. The penalty is only about 2% (assuming no shading), and lets one MPPT support more watts of panels.

East vs. West - do you have time of use pricing? For us, West facing makes kWh when they are more valuable.

PV panels can be found new and used from liquidators. Quantity of new panels tends to be more limited, extras bought for a specific job. Prices can range from as lows as $0.12 or $0.20/kW for panels of questionable degraded condition to $0.50 for new. Probably not a good deal to pay higher prices than that. Avoid some used panels which have UL labels stripped off; wouldn't meet code requirements.

Panels do vary in quality/durability. They ought to last 25 to 40 years. Some degraded fast, and test reports from previous years can show which brands fared better in accelerated testing.

Some older ones were 12% efficient (120W/m^2) but newer ones can be 20%, 200W/m^2.

When you DIY batteries, realize that even LiFePO4 have caused fires. I think they belong in a bunker away from the house. Same for commercial models, which although UL listed have also caused fires. With lithium, you also can charge only when warm enough, so some combination of heating, low-temperature disconnect, and current limiting is required. With lead-acid, just needs voltage vs. temperature compensation.


PV panels are cheap, so over-paneling on the East face could deliver a good amount of power. Is West street-facing, so you want to keep it more attractive? Obviously being in Canada, South has a better chance of sun exposure most of the year. Limited area there, so most efficient panels are what you want.

I mostly read good things here from users of SolArk. Some people complain about price vs. very similar Deye, not available here for licensing reasons. Some are disappointed 12k SolArk doesn't produce 12kW AC. Apparently it can handle 12kW of PV, charging batteries and making up to 9000 VA of AC (split 4500 VA between each phase.) Whether you get 4500W per phase depends on power factor of your loads.

SolArk also supports GT inverters on its output.

Have any motors to start? They need a surge about 5x nameplate rating. Top-name low frequency transformer type inverters will perform better for that. SMA Sunny Island, Schneider, Outback, Midnight, Victron, etc.

Your building permit office would be the source of most requirements. Here, states differ in which version of NEC they follow. Rapid Shutdown and walkways on the roof are for fireman safety. AFCI is to avoid fires. UL-1741 SA is for grid stability with higher levels of GT PV installation.

 

[bedpan]

Thanks again...

My reading on DC Optimizers says beyond helping with mismatched panels, they also help with shading of individual panels and capturing light earlier and later in the day. I have not see anything specific to the SolArk that says they will take Optimizers but I did see one post saying Tigo optimizers were ok. I know nothing about them yet... Another topic to look at...

The SolArk has 4 PV inputs, but they are labels 1A, 1B, 2A and 2B. I am not sure how they are broke up. I am guessing 1's are linked some how so have to be similar input and same with 2's.

I will likely go with new gear for this project. As mentioned to take advantage of the $5k rebate things have to be CSA approved and I also imagine new from a Canadian Vendor. Sucks but I have to play by there rules. Unless the savings are so strong as to make the 5k not worth the effort. I am guessing but I would think that the ESA (Electrical Inspectors would possible look for the CSA approval as well) but I am not sure about that.

My electrical Panel is in my garage. it is attached. This should make routing of cabling from the roof a lot easier. I also feel a little better with Lithium batteries in the garage rather then the basement. Yes it is attached but safer as there is a firewall between the two. The likely hood of a fire spreading that fire before help arrives is small enough that I can live with it.

I have seen that the SolArk is just a rebranded Deye/Sunsynk. It seem SolArk has cornered the market for the split phase so there is no opportunity to grey market import one. It seems that SolArk has a great rep for support though so they need to pay for that somehow. I am aware that it is limited to 9k inversion. If I go over 10 it apparently gets much more complicated so its likely a good fit.

I had not thought about the east/West generating really at different times of day. From an over paneling perspective this makes sense. Also as you mention time of use. My ultimate goal is net zero regardless of the time of day. Ontario Hydro, my power provider supports net metering and banking of excess generation up to 1 year. So I am hoping the time of day becomes moot.

I have looked at some of the low frequency inverters. Makes sense that they would have better support for motors. One of the critcal loads I would designate would be my 240V well pump. It peaks at about 1.2kW on start up but runs for about 2-3 minutes at about .9kW. Beyond the well would be the furnace, 2 fridges, a freezer and probable a couple lighting circuits. I believe the SolArk should be up to task. Long term I would love to be able liven up the whole panel and selectively turn on and off loads. It won't be code but it should be doable by backfeeding the main panel and killing the main breaker.

I did some digging last night and I have not found much yet on our local code requirements. I will have to make some calls in the coming weeks to try and get some answers.

I should add. I am not dead set on the Sol-Ark either. Its just the one that seems the best documented online. If I can go SMA or any other CSA approved provider, get the most of the same features for less money I would absolutely consider it.

Cheers and thanks.

I think optimizers are primarily to allow series connection of panels with different current output, like of different orientation or wattage (e.g. poorly matched.) Because optimizers are MPPT which respond over time, they could interfere with MPPT of inverter.

PV strings of different lengths need to go to different MPPT. Probably SolArk has multiple. Sunny Boy recent models have 2 or 3.
You can parallel two string of same length but different orientation. The penalty is only about 2% (assuming no shading), and lets one MPPT support more watts of panels.

East vs. West - do you have time of use pricing? For us, West facing makes kWh when they are more valuable.

PV panels can be found new and used from liquidators. Quantity of new panels tends to be more limited, extras bought for a specific job. Prices can range from as lows as $0.12 or $0.20/kW for panels of questionable degraded condition to $0.50 for new. Probably not a good deal to pay higher prices than that. Avoid some used panels which have UL labels stripped off; wouldn't meet code requirements.

Panels do vary in quality/durability. They ought to last 25 to 40 years. Some degraded fast, and test reports from previous years can show which brands fared better in accelerated testing.

Some older ones were 12% efficient (120W/m^2) but newer ones can be 20%, 200W/m^2.

When you DIY batteries, realize that even LiFePO4 have caused fires. I think they belong in a bunker away from the house. Same for commercial models, which although UL listed have also caused fires. With lithium, you also can charge only when warm enough, so some combination of heating, low-temperature disconnect, and current limiting is required. With lead-acid, just needs voltage vs. temperature compensation.


PV panels are cheap, so over-paneling on the East face could deliver a good amount of power. Is West street-facing, so you want to keep it more attractive? Obviously being in Canada, South has a better chance of sun exposure most of the year. Limited area there, so most efficient panels are what you want.

I mostly read good things here from users of SolArk. Some people complain about price vs. very similar Deye, not available here for licensing reasons. Some are disappointed 12k SolArk doesn't produce 12kW AC. Apparently it can handle 12kW of PV, charging batteries and making up to 9000 VA of AC (split 4500 VA between each phase.) Whether you get 4500W per phase depends on power factor of your loads.

SolArk also supports GT inverters on its output.

Have any motors to start? They need a surge about 5x nameplate rating. Top-name low frequency transformer type inverters will perform better for that. SMA Sunny Island, Schneider, Outback, Midnight, Victron, etc.

Your building permit office would be the source of most requirements. Here, states differ in which version of NEC they follow. Rapid Shutdown and walkways on the roof are for fireman safety. AFCI is to avoid fires. UL-1741 SA is for grid stability with higher levels of GT PV installation.

 

[Hedges]

Sol-Ark 12k has 2 MPPT. Says 2 PV strings each w/o fuses, 3 with fuses. Of course, any number could be paralleled externally with fuses.

https://ironedison.com/images/products/Sol-Ark/Sol-Ark-12k-Inverter%20SPEC%20SHEET-IronEdison.pdf

New overstock/excess PV panels should quality for the rebates. Quantities tend to be limited, when many are purchased for a large job and the leftovers are liquidated.

If well pump draws 900W running, for an induction motor probably 4500W surge. Only some meters are fast enough to capture that. I now have a Harbor Freight clamp ammeter with inrush. I've used an oscilloscope with current transformer to measure some devices. If that's your only big motor, seems like any 5kW or larger inverter works, even if not high frequency.

An optimizer may implement "ideal diode" to avoid the 3 diodes drop of a shaded panel.
There are some situations of partial shade, especially for half-cut panels (which are two strings in parallel) that poor MPPT algorithm might not bypass, and optimizer could help with.

I haven't used optimizers, but I suspect they're over-hyped. Probably are good with SolarEdge/StoreEdge where they allow longer single PV string as well. Current adjustment is limited, so doesn't fix everything.

If you need RSD, the extra cost for optimizer could be OK. If ground mount and no need for RSD I would skip the optimizer and keep it simple, spend the extra money on more panels.


For battery backup, Enphase, StoreEdge, Sunny Boy Storage, Tesla PowerWall all use expensive proprietary batteries. SolArk, Sunny Island, Schneider, Outback, MPP, and others would support DIY 48V battery banks.

 

[bedpan]

Side'ish note... I had an ad come up (On facebook, I rarely use it....) for an inverter.. So I clicked on it.

There is a Canadian Supplier of the Deye 7.6kW hybrid inverter..

7.6 KW 48V Hybrid Inverter

This Hybrid Inverter has all-in-one most needed functions for a hybrid system. It supports inputs from battery storage, solar PV, generator, and grid; outputs to DC battery storage, AC loads, as well as grid feedback. The smart multiple modes control can direct power flow between different...

shop.amray.solar

Claiming CSA approval.
Attached are the documents they have sent me..

 

[Xhumeka]

How are you making out @bedpan ? I'm going through the same process here in Toronto, and would be interested to hear an update from your side and hear any advice you have for others. Particularly interested if you have found a grid-tied inverter that operates at 48v and supports DIY battery banks (I don't want to be forced to buy an expensive Growatt battery if possible). Also curious to hear if you were able to work with a local installer that is DIY friendly (ie allows you to do some of the easy stuff, while they take care of engineer reports, permits, wiring to code, etc)

Cheers!

 

[bedpan]

How are you making out @bedpan ? I'm going through the same process here in Toronto, and would be interested to hear an update from your side and hear any advice you have for others. Particularly interested if you have found a grid-tied inverter that operates at 48v and supports DIY battery banks (I don't want to be forced to buy an expensive Growatt battery if possible). Also curious to hear if you were able to work with a local installer that is DIY friendly (ie allows you to do some of the easy stuff, while they take care of engineer reports, permits, wiring to code, etc)

Cheers!

Hey Xhu..

I have back burnered the project for right now...

I do still plan on doing it sometime in the next few years. It just pending funding I can put together and hopefully some government incentives to make it worth while. I love the idea of being more self sufficient.