We recently completed a large residential off grid system in Walkamin FNQ.
The customers statement of “ I want to utilise whatever I want, whenever I want”, definitely put our stand-alone design principles to the test.
The Lead Carbon battery bank weighing in at 3.6 tonnes was the ultimate solution.
Lead carbon batteries are the latest, most advanced technology for off-grid solar systems. They include highly conductive carbon material with high capacitance into the negative electrode, combining the advantages of lead acid batteries and super capacitors. The Lead carbon battery also known as Ultra-battery provides high energy density AND high power with rapid charge and discharge, all with longer cycle life. The design life of these 2V batteries is 20 years and at 30% DOD will provide 7000 cycles.
We have over designed the solar PV to compensate for days of low irradiance, which is allowing the battery bank to charge fully by 9-10am, even on a cloudy day.
It is AC coupled system which is ideal for larger usage patterns through the day. This method utilises the energy produced daily directly from the Fronius grid tied inverters, minimising unnecessary energy through-put to the battery bank, which in turn maximises battery life.
The Fronius and Selectronic Inverters installed are considered to be the rolls Royce of off-grid system inverters. These components have been labelled “unbreakable” in our harsh Australian climate and as a result of this backed by a 10 year warranty.
Additionally we have installed a Fronius wind monitor into our system, given the onsite wind performance. The online portal collaborates the data received from the anemometer and delivers the information onto a usable platform. This functionality allows us to determine whether it is a viable option for a future wind generator.