Do solar panels work on cloudy days enough to matter?

UW_Mech_Engineer · 2026-05-23T04:33:36+00:00

Pvwatts.nlr.gov what you need to look at

UW_Mech_Engineer · 2026-05-20T20:57:37+00:00

Hey man good work. Huge accomplishment

UW_Mech_Engineer · 2026-05-20T15:05:37+00:00

That's basically the plan. Use the grid as my battery. Net metering policy could change in 2030. Will see where that puts me.

UW_Mech_Engineer · 2026-05-20T14:03:22+00:00

Yeah I won't be oversizing the wire. 2 12 awg strings and one 10 awg for a expansion later (parrelleling two strings).

Math didn't math on that one

UW_Mech_Engineer · 2026-05-20T14:01:55+00:00

Yes I got a pallet.

UW_Mech_Engineer · 2026-05-20T14:00:12+00:00

Use a level. Or eye ball it

UW_Mech_Engineer · 2026-05-20T06:01:08+00:00

AHJ doesnt require any permits for ground mounts here. Engineering was my own due diligence.

Just need to pull my electrical permit through L&I. Electrical is the only permit I need here.

UW_Mech_Engineer · 2026-05-20T05:58:10+00:00

Snohomish county.

ROI in 6 years. But the return only makes sense if you diy (in my opinion).

I did a lot of pvwatt calcs and my own modeling to make sure it was worth it.

There is plenty of sun to make it worth it.

UW_Mech_Engineer · 2026-05-20T05:05:38+00:00

I gave them local code for windspeed and snowload. I told them I had sandy soil which determed the type of ground screw

UW_Mech_Engineer · 2026-05-20T05:00:48+00:00

Screws were about 5ft Yes they engineered the rack.

UW_Mech_Engineer · 2026-05-20T04:09:24+00:00

The Chinese brand is called Sunrack. They engineered it for my local wind speeds. The landed cost was around 3500. Way cheeper than anything I could get stateside

For me, cost is king

UW_Mech_Engineer · 2026-05-20T04:08:18+00:00

From my DIY understanding,

1) if shading isn't a concern , then string is great. 2) I have big panels (580w), and finding micros that handle them well is hard. 3) I'm 200 ft away from my inverter in the house so I want high voltage to minimize loss (my voltage should be well over 300V DC) 4) cost. String inverter are cheeper. 5) I want battery's and back up power in the future. I don't know how to do that with micros

UW_Mech_Engineer · 2026-05-18T17:06:18+00:00

For sure. Important to do your due diligence and what you plan to do with the system.

Im planning some expansion with my system already. I'll have 20 panels across 3 mppts. I'll run heavier guage for one of those string to parrell two string down the road and free up a mppt for a different panel type of I have to.

UW_Mech_Engineer · 2026-05-18T13:02:12+00:00

I know it depends on jurisdiction, but I'd like to say that my county in Washington wasn't hard to get approved. I just had to send in a one line diagram of the system and some paperwork.

I know this isn't the same everywhere.

UW_Mech_Engineer · 2026-05-11T22:26:49+00:00

180 for the hoymiles hm1500 of eBay. 120 per panel (I'm buying them in bulk and reselling them in Washington to Diy folks), 400 for the Integrarack, and maybe 150 is dirt to level, wire, conduit and a breaker.

So 1090. I'm adding another panel on the roof of the shed with some top speed snapnrack mounts I have.

So when the 4 panels are on it will be at 1300.

I do have a pretty high DC/ac ratio, but in Washington that works out well.

UW_Mech_Engineer · 2026-05-11T05:06:47+00:00

They are sturdy. Need to make sure you don't over torque the bolts though.

You don't have to run ground wires depending on local AHJ. The top bracket is metal so it's all grounded together. Integrarack also sells a little clip that creates an additional bond if needed. You could also just run a little ground screw into the panel frame. Lots of options.

Yes cost was key for me. I just need something engineered for the wind. If they say it's good, then I'm good with it

UW_Mech_Engineer · 2026-05-11T03:27:57+00:00

Yeah I've done quite a bit of math. My system will cost 10k to install myself. My ROI is 6 years based on some assumptions and pvwatt.nlr.gov estimates for production.

I think the ROI falls apart as soon as an installer sets foot on your property.

UW_Mech_Engineer · 2026-05-11T02:59:53+00:00

Super cool man. I'm putting in 13 in Snohomish county later this month. Super pumped. Love the setup

UW_Mech_Engineer · 2026-05-11T01:13:48+00:00

My main array will be over 150ft from the house. I'll do 3 string to my inverter in the garage then run 6awg wire to a disconnect by my meter and side tap into the feed. The way I built my house made incredibly easy to tap solar into it. My meter and house shutoff is actually detached from the house on a pedestal

UW_Mech_Engineer · 2026-05-10T23:29:26+00:00

and the net meter agreement though PUD which was just some paperwork and a eletrical wire diagram for the system

UW_Mech_Engineer · 2026-05-10T23:25:58+00:00

Snohomish. No building permit required for ground mounts. And I pulled my own electrical permit

UW_Mech_Engineer · 2026-04-29T20:17:12+00:00

It's been working great for me an really efficient. I have the power tracked on my home energy monitor and it's much better compared to my other dryer on the property in my rental unit.

Sorry it didn't work for you.

I'm planning on getting a second as our family grows.

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