Quick review of first timer off grid / emergency backup system

audiodave1audiodave1 Registered Users Posts: 10
I was good this year so Santa said I could pull the trigger on a small off grid starter system. I am in the Philadelphia region.
This will be a ground based system (likely always as my house faces 55 degrees off north) built around (2) ET Solar 245W panels (8A/30v) I bought off CL for .82/w.

I will rack these on a home brew unistrut frame that will accommodate easy seasonal tilting. Sandbag it down for now.
Panels paralleled and sent down 40' of 10AWG, might put in earth grounded conduit to reduce RFI. CC will be a MidNight KID. 24v in, 12v out to a "starter" 12v 100-some Ah battery. Move up to some paralleled 6v GC (Costco etc...) batt's this summer if all is stable.

I'm 95% 120v in our suburban domicile so I chose a small GOPower 300w SW inverter that would run small loads and a larger GOPower 1500w SW inverter to (at worst) run forced air, small fridge/freezer, 2 sump pumps that run 4x a day for :45 seconds ea.
The Go's seem to be a decent balance between durability and cost for a backup system. Eyes are blurry from reading reviews on all this stuff.

Holding all this together will be 1awg, I will cut and crimp. May do fuses to start and upgrade to breakers later...or get the KID breakers. Will have a disconnect for the PV's. DC breakers aren't cheap nor are the boxes! Bussman makes some surface mount marine grade CB's that may work.

My calculations show I should be able to produce/store about 90Ah a clear day after system inefficiencies.

I am still determining usage but not a big deal right now. Moved into a place that is 3x more efficient all around. Old house I had calculated about 3kW a day usage, might be 1.5 here if the Honda eu2000 ran out of fuel.

Putting in a basic 6 circuit transfer switch to run the basement and critical circuits if need be (and for knowledge development). Manual patching of PV/Gas power for now.

Putting in a few shunts to measure the V/A. Found some "cost effective" digital meters on amazon I will try to calibrate and make work...I hope. Any other suggestions for cost effective/accurate monitoring aside from CC displays? Love to see info at a glance from a distance.

I suppose a batt temp sensor would not be a bad idea.

System will be in a storage room in the basement. Batteries on the floor. Going to push a little air around with a 4-6" computer fan. The room is not airtight.

I will document the process the next few months...

I think I have it right...or at worst conservative on the available power.
Dave

Comments

  • AuricTechAuricTech Solar Expert Posts: 140 ✭✭
    Re: Quick review of first timer off grid / emergency backup system

    Given the size of your PV array, I would go with a battery bank at least twice the size you mentioned.
  • audiodave1audiodave1 Registered Users Posts: 10
    Re: Quick review of first timer off grid / emergency backup system
    AuricTech wrote: »
    Given the size of your PV array, I would go with a battery bank at least twice the size you mentioned.

    Thank you,
    I tried to leave the system a bit open ended to grow the storage over time with the additional panels.

    I feel a couple 6v220Ah is big enough to be useful but certainly not the ending point.

    Dave
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