My Actual Costs to Expand My DIY Rooftop Solar Array for MORE POWER!

In this video I review my planning, design and costs associated with expanding my rooftop solar array from 6.38 kW to 9.98 kW.

Advantage to over sizing your solar array over your inverter's rated capacity

Chapters
0:00 Introduction
1:57 Long Term Goal
3:12 Designing Phase 2
8:26 Costs of Phase 2

When I designed my rooftop solar array in 2017 I calculated that I’d need a 5 kW solar array to replace 100% of my electrical consumption average over the prior 22 months.

During my research for solar I realized that an electric car combined with solar is an awesome combination I should work towards, so in balancing roof space and my budget I settled on installing a 6.38 kW solar array (22 X 290 Watt REC Twin Peak 2 panels) as phase 1 and I’d get a Nissan LEAF to commute to work in.

With the money I got back from the federal and state tax rebates I was able to purchase a used Nissan LEAF in February 2018 and I loved driving electric!

My longer term goal was to install a phase 2 of additional panels once I got a second electric car. In May 2019 I was finally able to purchase our Used CPO 2015 Tesla Model S 85D! Those first few months owning our Tesla caused our net metering balance to dwindle faster than it ever had before because with a Tesla’s large battery and significantly longer range it’s a lot easier to use more energy. This isn’t a bad thing considering we’re no longer having to purchase gasoline as both our vehicles are now 100% powered by electricity!

In assessing the remaining roof space, current costs of solar panels I determined that I could mount 10 portrait panels or 12 landscape panels. 12 mounted landscape panels causes the racking to cost $325 more compared to 10 portrait panels, but I determined that the two extra panels produce about $76 in power per year so they'll pay off the difference in 4.27 years.

The design I settled on then was 12 NEA 300 Watt panels with power optimizers to pair with my existing SolarEdge string inverter bringing the total solar array to 9.98 kW!

I determined that the cost difference between 10 panels mounted in portrait, and 12 mounted landscape is that the racking costs $325 more for 12 landscape panels, but that the two extra panels produce about $76 in power per year so they'll pay off the difference in 4.27 years.

$3,630.51 - Panels and most of the Mounting Hardware
$24.55 - Additional Mounts (I broke 1, and mis-calculated by 4)
$696 - SolarEdge Power Optimizers
$5.63 - Solid Bare Copper Grounding Wire

This brings my total system size to $4,356.69 before tax rebates
The federal tax rebate was 30% in 2019 so I got $1,307 back and the $2,000 Utah state tax rebate was already used up from phase 1.

That brings the final system cost to $3,049.69 or $0.85 per Watt.

[rrr]

So, you installed the panels on the roof yourself?
Did it require approval or inspection from you city?

[kyleshirk]

Where do you go to buy the panels and hardware? I'd like to add additional panels to out system as well. We have solor edge too.

[Whitlow]

Kind of confusing how you have a 9.98kw system and 7.5 kw inverter, you Saud it would be more efficient but from that power generated graph it peaked at 7.5kw for may, so correct if im wrong but you're losing out on almost 2.4kw at peak power output

[pedrogarces]

Excellent background of your system! Have you thought about adding consumption monitoring? I added that to my solaredge system and it’s great to track real-time

[Lawiah]

Note: Solar Panel Specs - account for cold temperatures at your location
the "NEC 300W solar panel spec sheet", *see temperature coefficient of Voc, * which measures the change in voltage per degree Celsius away from the Normal Operating Cell Temperature (NOCT).
...
The panels NOCT is 45° C @ 39.82 Voc *(478V);* take the difference of NOCT and the coldest day on record for your location (−34.4 °C + 45) for a value of *79.4° C* below the standard conditions. example location is Salt Lake City (year 1933)
...
The temperature coefficient on these panels is 0.280%/°C. This means that for each degree Celsius away from the NOCT, the panel will *produce .33% more voltage.*
Multiply the Voc of the panel (39.82) by the temperature coefficient of Voc (.0033%) = 0.131406V
...
Multiply voltage change per degree Celsius (0.131406) by the temperature difference (79.4°C) = 10.434
...
As shown, each panel will produce about 10.434 volts above its rated Voc of 39.82 or 39.82 + 10.434 = 50.254V, true panel voltage
...
Multiply the true panel voltage by the max number of panels in the Phase Two string (12), 50.254 * 12 = *603V*
The total voltage of the array can peak at 603V on a record cold day!
*Note: we did not calculate the temperature coefficient of Voc for the Phase One string.*
Best regards

[fancyIOP]

Thanks for this, much love from South Africa 🇿🇦... I’m watching such videos because I’m also considering solar and battery 🔋 storage.

[saratdev]

Hello Anthony,
Did you add to an existing inverter? I currently have a 4.35 kw with e phase iq7+ inverter with 14 panels. I wanted to add an additional 8 panels. Do you think this can be done?

[waydweber]

Do you think you will install a battery wall in the future?

[javediqbal]

Very useful idea you video watch Pakistan

[ywan]

Did you need to get a permit from the city or your utility provider for solar expansion? I have a 6.8 kWh and interest in expanding as well. Right now, I bought 1000 watts 12V panels with a 1000 W grid-tied inverter from Amazon, yet the output less than 2.0 kWh. I am unsatisfied with it.

[jaymbhalodia]

So I have 5kw invertor but just 2.4 kw system thinking to add more panel so wanted to know if I can add more panel on my own

[jaymbhalodia]

How are these panel connected in series or parallel ? Can u share circuit diagram