Saturday, February 16, 2013

Off Grid Solar

This post is long overdue, but after we moved into our stone cottage on the prairie after 2.5 years of hard work; we sort of took a break. Alas, there are things that need to be shared, some of them major. For starters, we are living completely off the grid with the use of our self installed PV system. Our only outside source of energy is our 1000 gallon propane tank (I use the term ‘only’ loosely). Here is a rundown of our system. It starts outside with 8 REC 235w solar panels. They are wired in 4 series strings of 2 panels each and mounted to our homemade tilt-able solar mount. It is constructed out of what is called telespar (stop sign post) with no welding. It has been strong and sturdy even in our heavy winds, although if I had to do it all over again I might use uni-strut instead of telespar. It is better suited for bolting together and they make all kinds of connectors for it.
From the mount, the panels are wired into an MNPV6 combiner box. The combined output travels underground via #4 copper up to our loft. We bought a pre-wired E-panel from Midnite Solar which I would highly recommend to anyone who is a novice in producing their own energy. Our system includes the 240v E-panel, 4000w Magnum inverter/charger, the Midnite Solar Classic 150 charge controller and all the NEC required breakers and disconnects. It wasn’t cheap, but very very worth it. I don’t know that I would have been able to figure out the hook up without the components pre-wired to each other. Plus, inside the E-panel every bus and breaker is labeled so figuring out where to connect the wires to and from the system is a lot easier.
So, speaking of wires – this is how our system works.
DC power from the panels combined and sent to the E-panel via Classic charge controller
DC power is sent to 24v 500 amp hour battery bank (seen without finished enclosure) and inverter
  • Batteries are Interstate Batteries DCM0100 sealed AGMs
E-panel sends 120/240v AC power to our house breaker panel via inverter
Generac standby generator is plumbed into our propane tank and AC output goes up to the E-panel
  • From there we are either charging the batteries or running the house or both

The system comes with a remote panel that I have wired into my utility room so we can monitor /control the system from the main floor. We are constantly checking the SOC (state of charge). You can also monitor the input of the PV panels via the charger controller. I haven’t set it up yet, but I have an app downloaded to my computer that allows you to check the charge controller using a local area network (LAN). After spending some time with our system, we couldn’t be happier. We appreciate the sunshine even more than we did before.

So, that is the basics. Any questions?

On a side note. We also couldn’t be happier with our masonry heater. The constant radiant heat is awesome. And we are slowly but surely learning how to cook in the bake oven – including pizzas and rustic artisan loaves.