goldbrick
Posts: 574
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Dumbest excuses people have given for NOT installing PV

Mon Apr 01, 2019 2:50 pm

goldbrick wrote:
RegGuheert wrote:The roof where I installed my PV panels has a fake gable. I left it there because I was unwilling to tackle the project and because it looks kinda purdy. But it takes the space of about 5 PV panels that could have been up there producing for the past 8 years.
Mine are really fugly and the soffit is rotting because of them. They don't take up a lot of space but it will be much easier to remove them before installing the panels rather than the other way around.

BTW, I've learned a lot from your posts here. Thanks for the info. I'm still undecided whether to use micro-inverters or power-optimizers. The roof is only so big and I think when it's full I could get by with 1 string inverter so that is still an option I'm considering.

User avatar
RegGuheert
Posts: 6419
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Dumbest excuses people have given for NOT installing PV

Mon Apr 01, 2019 4:25 pm

goldbrick wrote:BTW, I've learned a lot from your posts here. Thanks for the info.
You're welcome!
goldbrick wrote:BI'm still undecided whether to use micro-inverters or power-optimizers. The roof is only so big and I think when it's full I could get by with 1 string inverter so that is still an option I'm considering.
They are both good options, IMO. A good friend of mine just chose to install the PowerEdge system for his house over the objections of his installer who was pushing microinverters, partly because of my recommendations. While he didn't purchase the PowerEdge central inverter that works with a battery, he wanted to have the option to switch to one of those later in case batteries became affordable. Enphase is claiming they are developing an off-grid microinverter-based approach, but I get the impression they are still about 18 months out (and no one seems to know what the theory of operation, cost, etc. are for their new stuff).
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

Lothsahn
Posts: 435
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: Dumbest excuses people have given for NOT installing PV

Mon Apr 01, 2019 6:22 pm

goldbrick wrote: BTW, I've learned a lot from your posts here. Thanks for the info. I'm still undecided whether to use micro-inverters or power-optimizers. The roof is only so big and I think when it's full I could get by with 1 string inverter so that is still an option I'm considering.
I just went through the micro vs power optimizers for my home. I just installed StorEdge (battery compatible) Inverters with my system with Power optimizers. This should make it easier to plug on a battery in the future when I want to, although I'll likely still have to run a subpanel when I go to do that.

If you're not planning to do batteries anytime soon, go with micro inverters. They have a longer warranty than string inverters and should have a lower cost of ownership. Also, they make wiring simpler and if one fails, you only lose the output of one panel, not a whole string. Finally, for whatever reason, codes are way more restrictive on HV DC than AC (you'd think that'd be backwards), so you're limited on where and how you can conduit the DC cabling.

Unless you have specific needs, go Micro. I've heard good things about Enphase and APS, although APS apparently has some issues with their monitoring software.
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
Battery swap 2019/04/24 (87% SOH, 12 bar)

Lothsahn
Posts: 435
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: Dumbest excuses people have given for NOT installing PV

Mon Apr 01, 2019 6:24 pm

RegGuheert wrote:A good friend of mine just chose to install the PowerEdge system for his house over the objections of his installer who was pushing microinverters, partly because of my recommendations. While he didn't purchase the PowerEdge central inverter that works with a battery, he wanted to have the option to switch to one of those later in case batteries became affordable.
This is exactly why I did what I did. That said, I believe the powerwall and Sonnen battery both support AC coupled battery backup, including with Micro Inverters. Sonnen batteries are very expensive, though.
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
Battery swap 2019/04/24 (87% SOH, 12 bar)

goldbrick
Posts: 574
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Dumbest excuses people have given for NOT installing PV

Mon Apr 01, 2019 7:11 pm

Lothsahn wrote:If you're not planning to do batteries anytime soon, go with micro inverters. They have a longer warranty than string inverters and should have a lower cost of ownership. Also, they make wiring simpler and if one fails, you only lose the output of one panel, not a whole string. Finally, for whatever reason, codes are way more restrictive on HV DC than AC (you'd think that'd be backwards), so you're limited on where and how you can conduit the DC cabling.
I have no plans to go with batteries anytime soon and my breaker box is on the North side of the house so the wire routing seems like the biggest potential issue with the installation. I may be adding more panels later as well and now that I think of it, adding more AC wires seems much easier than adding more DC wires. I guess I'll ask the local inspector about the code requirements but the micro inverters are starting to sound better.

User avatar
RegGuheert
Posts: 6419
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Dumbest excuses people have given for NOT installing PV

Tue Apr 02, 2019 4:15 am

Lothsahn wrote:Finally, for whatever reason, codes are way more restrictive on HV DC than AC (you'd think that'd be backwards), so you're limited on where and how you can conduit the DC cabling.
Simply put, DC is much more dangerous than AC, both in terms of a shock hazard and as a fire hazard. SolarEdge has done a lot to make it safe in their system, but the regulations had already been put in place due to issue with prior technologies.
goldbrick wrote:I have no plans to go with batteries anytime soon and my breaker box is on the North side of the house so the wire routing seems like the biggest potential issue with the installation. I may be adding more panels later as well and now that I think of it, adding more AC wires seems much easier than adding more DC wires. I guess I'll ask the local inspector about the code requirements but the micro inverters are starting to sound better.
I agree that microinverters are the better choice in your case.
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

Lothsahn
Posts: 435
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: Dumbest excuses people have given for NOT installing PV

Tue Apr 02, 2019 8:00 am

RegGuheert wrote:Simply put, DC is much more dangerous than AC, both in terms of a shock hazard and as a fire hazard. SolarEdge has done a lot to make it safe in their system, but the regulations had already been put in place due to issue with prior technologies.
Safety: Can you explain why this is? If you do a quick google search DC vs AC safety, you'll get a bunch of answers saying DC is safer.
https://www.brighthubengineering.com/po ... omparison/
https://www.electronicproducts.com/Powe ... ltage.aspx

Fire Hazard: I would expect heat to be current*resistance... roughly proportional to the power flowing through them, given equivalent sized cables. Why is DC solar more likely to catch fire, or be a hazard during a fire?

I tried to find both answers on my own, but haven't been able to do so.
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
Battery swap 2019/04/24 (87% SOH, 12 bar)

SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Dumbest excuses people have given for NOT installing PV

Tue Apr 02, 2019 8:35 am

Reliability aside, I would avoid micro-inverters due to the high i^2 losses. I personally also find the parallel wiring scheme to more difficult to work with and my impression from a few projects is that a lot more cabling is used.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

User avatar
mwalsh
Posts: 9640
Joined: Thu Apr 22, 2010 10:10 am
Delivery Date: 05 Jan 2011
Leaf Number: 0213
Location: Garden Grove, CA

Re: Dumbest excuses people have given for NOT installing PV

Tue Apr 02, 2019 8:38 am

goldbrick wrote: I'm even thinking of buying a new Leaf so that I can claim the additional power consumption. Right now I'll be limited to a 3-4 kW system but I'm pretty sure the roof can handle more than that.
That can be a challenge. I went through the same thing trying to convince the utility that I had the additional consumption in the pipeline, in that I had to send them a copy of my LEAF reservation info.

I ended up with 27 panels for 6.2kW worth, all south facing on one roof face (which also required a variance from the fire department over fire ventilation access).
2011 Blue Ocean SL with 83,000 miles
2015 pack on 12/30/15
Tinted windows
Bosch AGM 12v
Ecopia 422+ tires
L1 EVSE upgrade
FIAMM horns
Superbright LED lighting
2013 sun visors
LED shifter
Heated seats
GT-R map lamp lenses
Altima illuminated door switches

goldbrick
Posts: 574
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Dumbest excuses people have given for NOT installing PV

Tue Apr 02, 2019 9:09 am

Lothsahn wrote:Fire Hazard: I would expect heat to be current*resistance... roughly proportional to the power flowing through them, given equivalent sized cables. Why is DC solar more likely to catch fire, or be a hazard during a fire?
SageBrush wrote:Reliability aside, I would avoid micro-inverters due to the high i^2 losses. I personally also find the parallel wiring scheme
to more difficult to work with and my impression from a few projects is that a lot more cabling is used.
I'd think micro-inverters would require smaller cables and generate less heat in the cables (i^2*R losses). The power through the wires = V*I and with micro-inverters the voltage is much higher so the current is much less. That is the reason long distance power lines are such high voltage; it reduces the transmission losses.

I'll probably sketch out the design with both configurations before I decide. I am a bit worried about the reliability factor (more active parts means more chances of failure to me...) but the reliability is supposedly good and they are covered by a warranty. And if one or two fails, I'd still be generating power from the remainder of the panels. I think the deciding factor will be the cabling concerns since it will be a fairly long run from the panels back to the box.

Return to “Solar”