Off-The-Grid Solar Power System

I have installed a medium-sized off-the-grid solar power system on our house.

Photovoltaic Panels

I collect solar energy using a Kyocera KD205GX-LP 205 watt photovoltaic (PV) panel purchased from Northern Arizona Wind & Sun and a Grape Solar GS-S-250-Fab5 250 watt PV panel purchased from Grape Solar through Costco.

Charge Controllers and Batteries

Each PV panel is wired to a Morningstar SunSaver 15 Amp MPPT solar charge controller. These MPPT charge controllers take the high voltage from the pv panels to provide up to 15 amps of charging current each to six golf cart batteries. These charge controllers also have a built-in system monitor that can be accessed using a Morningstar Meterbus to Serial Converter (MSC) and the MODBUS communication protocol. See Linux (and Mac OS X) Software to Read Data from the SunSaver MPPT Using MODBUS for details on developing MODBUS software to communicate with the SunSaver MPPT charge controller. Also see the Power System Status for this system's current status.

Main wiring and control systems

Charge controller

DC circuit breakers

IronRidge battery box

Six 6V golf cart batteries


This system runs a number of loads including this web server (Sheevaplug), a wireless access point, a router and hub, our outdoor lighting system, under-cabinet lighting in our kitchen, and a USB charging station for cell phones and iPods. The system also has a 300 watt sine wave inverter for basic AC loads and a 1000 watt inverter to provide AC power during a grid power outage.

Under cabinet LED lighting

Outdoor LED lighting

This USB switch and sets of relays are attached to the server and control the outdoor lighting and sprinkler system

I also built a DC power supply that has two USB ports on a wall plate. It will charge any device that can be charged from a USB port. We charge all our cell phones and iPods from it.

5 volt, 2 amp, 2 USB port charger - This is wired to our solar charged, 12 volt battery bank.

Charging an iPod and a Blackberry.

Morningstar SureSine-300, a 300 Watt sine wave inverter - This high efficiency sine wave inverter powers our cable modem and wireless phone system. In the summer, it also powers our sprinkler system. It has a built-in metering system, and its output can be seen at the bottom of the Power System Status page.

Xantrex XPower 1000 Watt modified sine wave inverter for back-up power during a grid power outage. This inverter can run our refrigerator from the batteries.


Last modified: February 20, 2014