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Grid Connect with Battery Backup Power

Self-Consumption vs Energy Exports

Storm coming in, red clouds

With the demise of regulated feed-in tariffs (FIT) we started designing our grid connect solar systems with a focus on "self-consumption". Most electricity providers only offer 6-8 cents per kWh (if anything) while charging their customers 30+ cents for the same kWh. At this exchange rate it is obviously more economical to consume than to export.

Residential consumption usually peaks at 8am and 8pm but due to the nature of the technology, solar production is at its highest between 10am and 2pm.

Oversized Solar Systems

There are already thousands of potentially oversized solar systems in Australia. Habits and energy usage change over time; family members may have taken on day time jobs, started school or left the nest entirely.

Furthermore, solar systems designed under the now closed NSW Solar Bonus Scheme (60 cent per kWh) may have changed ownership resulting in an inferior FIT (and if ownership has changed, did the gross meter get changed to net metering?) The scheme will expire on 31.12.2016 and will leave many households with too big a solar system for anyone to profit but the electricity providers.

Last but not least, some of the more aggressive sales reps may also have omitted that working families do not benefit as much from a grid feed system as no-one would be home during peak production hours. Needless to say, our system designs have always considered individual needs over commercial gains. Have a look at our solar savings calculator that visualises energy usage and production.

Adding Batteries

A grid connect solar system can be taken to a whole new level by adding deep cycle batteries. These batteries can be much smaller than those used in stand-alone solar systems as the convenience of the electricity grid remains at your disposal. These batteries serve two purposes:

  1. Provide backup during grid failure
  2. Increase self-consumption

Backup Power

During a blackout a grid feed system disconnects from the grid - not producing any electricity either for the grid or for the supply of your house. Australia's ageing electricity grid with its above ground power lines will always be prone to failures - storm damage being the most common cause. A Grid-Feed Backup System supplies your house with power in the case of a blackout.


Wouldn't it be nice to have solar energy available around the clock – even after sunset? This is now possible with SMA Sunny Island systems.

A Sunny Island inverter automatically charges the connected batteries. When your solar panels produce more than you need, the Sunny Island prevents the (existing) inverter from feeding into the grid until the batteries are fully charged. In the evening (or during cloudy periods), electricity is drawn from the batteries hence maximising self-consumption. The grid will only be ever used as a last resort.

Upgrade your Grid Connect System

Most existing grid connect systems with an SMA inverter (e.g. Sunny Boy) are "battery ready" making the retrofitting of a SMA Sunny Island system seamless.

If your grid connect inverter is a Latronics PV Edge 1200 you can still upgrade to battery backup system.

Latronics automatic 3-way 25 amp transfer switch

Automatic Transfer Switch

Latronics 48V 1800W inverter

1800W Inverter

Plasmatronics PL60 regulator

60 Amp Regulator

Ritar 12V 120Ah battery

4 x 120Ah batteries

Sketch: Battery Box
Battery Box

Made to suit

Latronics Backup

A small 48V backup system for Latronics PV Edge 1200 Grid Feed Inverters.

Makes provisions to integrate an AC generator.

Price: $5,842 (for listed items only)

Sunny Island 6.0

Sunny Island 6.0

Leoch 390Ah AGM Batteries

390Ah AGM Batteries

Encosure for 48V battery bank
Battery Box

Custom made enclosure

SMA Backup

This 48V battery system with maintenance free batteries will provide a significant part of your night time energy needs (excluding heating, cooking and/or cooling).

If you have an SMA based grid connect (grid-feed) solar systems this upgrade kit is all you need to increase self-consumption and the next step in weaning yourself from the big energy retailers.

The upgrade kit includes a Sunny Island 6.0 Inverter/Charger, a 48V absorbed glass mat (AGM) battery bank, a stylish battery enclosure, all cables and required signage as well as installation (in Northern Rivers). Recommended for existing grid-feed systems ranging from 1.5kW to 6.0kW of solar.

Price: $13,800, installed*

*Any appliances that are to run off the batteries should be on a separate electrical circuit - which may require additional wiring depending on your circumstances.

We install solar systems in Northern NSW and Southern QLD.

Gold Coast (from Coolangatta to Southport), Nerang and Hinterland (Beaudesert) and out West (Warwick, Stanthorpe, Killarney)

Northern NSW (Tweed Heads to Yamba, including Evans Head, Byron Bay and Ballina); the Far North Coast Hinterland (Grafton via Lismore to Murwillumbah) and out West (Casino to Tenterfield, including Drake and Tabulam, as well as Woodenbong and Bonalbo)

For larger system we also go up to Brisbane or down to Coffs Harbour and even Glen Innes. Other places by arrangement.