Off-grid minimal garage. Am I on track?

[rivarola]

I have an off-grid garage about 50 feet from my house. I've added a garage door opener recently that I'm powering with a Ecoflow DELTA 2 + battery for 2kwh. Works great, and now I want to take the next step of installing 2 400w panels on the 35 degree shingle roof. Right now, the garage door opener is all that needs power, and I don't expect any further need beyond that.

I'm located in Long Island, NY.

Is there anything wrong with the following plan?

I've studied how to properly mount the panels with proper flashings. I'll also send the leads into through the roof with a conduit flashing, which I'll locate under one of the two panels.

My plan is to wire the two panels (400w max, 12.9 amp max, 31 V max) in parallel, resulting in preserving that max of 31v. The ecoflow has a 500W max/60v/15A max solar charging envelope. So if I understand correctly, voltage will be fine even in cold weather, and the ecoflow will draw nor more than 15A. I will be "overpaneled" for peaks output days, but I figure if on the worst days I get 10% of max (80W) for 5 hours, that's 400Wh, which is enough to keep the unit charged enough to service the door (based on the current drain rates I'm seeing).

Roof faces SW. Surface wont' get direct sun until a few hours after sunrise, but will get a lot of late sun.

I don't have a ground rod anywhere near the garage. I presume I need to drive one, and I'll rent equipment if feasible and DIYable.

• Am I right to assume that I don't need an MPPT? My ecoflow has that taken care of already?
• Is it OK to penetrate the roof via a conduit flashing, located underneath one of the two panels? (I don't fear leaks as this is just a garage and I have clear visibility to the roof.)
• Is my grounding plan OK? Any tips to share?

 

[Jet]

Shouldn't be 10% that often at all. Do you mean 2 400 watt solar panels or 2 200 watt panels. With 800watts of solar you are definitely "over paneled" for a 2000 kwH battery. If your battery is 12 volts it's ok to charge with 15 amps. If 24V 15A would be a little high for lead/AGM but ok for lithium (80aH battery) and charging at 48V (500/50 = 10A) would be 0.25C charge rate (2000 kwH battery/50 = 40aH charged at 10 amps = 0.25C). That is still doable for many lithium batteries but not optimal for long battery life. You could probably run some lights and a fan intermittently in your garage with that set up. These numbers are approximate.