My Off-Grid Home Power system

       We have an independent off-grid system at home used for supplying power during blackouts in our area.

       Since the page was becoming too long, I will just post the latest system configuration and updates here.

This is the main 3.18kW system diagram as of 20160906.

Full build details and more pics can be seen here: 3.18kW Hybrid Off Grid / Grid tie system.

full size image

This is the secondary system diagram as of 20160906.

Full build details and more pics can be seen here: Off grid System (full).

full size image

We are using twelve Hanwha Q-Cells Q.PRO BFR-G4.1 265 panels on the South-East slope of the roof as primary source for the entire system.

A pair of chinese 160W panels as a secondary source.

Total PV on the roof = 3.5kW

This is the main "power center". The hybrid off grid / grid tie power goes in and out of this panel board.

This is the workshop "power center". The off grid power is distributed from this panel board.

Secondary system metering is done by an Arduino based battery metering system I designed and wrote code for.

Main system metering uses the same but which has been modified for the higher voltage operation, uses a larger LCD screen and has a case.
It is also modified to have the control lines wired out to control relays for the grid tie inverter and external AC charger (not used yet).

Each system metering uses one 75mV/100A shunt.

Batteries used are twenty Northstar NSB170 Blue+ AGM batts wired in 4S5P
for a total bank capacity of 850Ah at 48V for a bank capacity of 40.8kWh or 20.4kWh useable.

The batteries are paralleled via copper busbars with equal lenght cables.

Secondary system uses two C&D Technologies Deep Cycle Series DCS-100HIT 12V 100Ah AGM cells wired in parallel for a total bank capacity of 200Ah at 12V.

The main system uses a 3kW inverter/charger for off grid use during blackouts.

A grid tie inverter above it runs 24/7 as long as there is grid and sufficient battery charge.

We have two 12V inverters. A 2000W 220V unit and an older 600W 115V unit. These were used in the old system but now only for portable use.

All rooms have dual switches. The top switch is for the mains powered lighting and the bottom for 12V solar powered LED lighting.

The rooms have DIY LED lighting made from commonly available COB LED strips mounted near the original mains powered flou lighting.


Since the master's bedroom receives the full afternoon sun, it gets pretty hot in the summer so we have installed a 200mm PC fan in the ceiling controlled by a thermostat to vent hot air.


       14 Dec 2017:

Running an Ametek motor to the ground.
Visit this page towards the end for more details and pictures.

Page created and copyright R.Quan © 23 Sept 2014.