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Solar for Tiny Homes, Granny Flats and Off-Grid Cabins in the Northern Rivers: Grid-Connected or Off-Grid, Sizing, Battery Chemistry, Rules and Rebates

Checked and updated by our licensed electricians: October 2026

The Northern Rivers has more granny flats, studios, tiny houses and bush cabins per head than almost anywhere in Australia, and the power question comes up with every one of them: run a cable from the house, plug in like a caravan, or go off-grid? This guide, written by local electricians who install grid-connected solar and batteries and design stand-alone systems, sets out which route fits which dwelling, how a granny flat is fed and metered (and when a tenant can have their own bill), what a tiny house on wheels needs at a powered site, what goes into an off-grid system and how to size it for our winter and our hinterland shade, why lithium iron phosphate is the chemistry, the planning and electrical rules in plain English, and the federal rebates that off-grid systems can claim. The sizer at the top gives you a first answer in six taps. Councils decide what you may build; we size the power.

On this page: The sizer: what your small dwelling needs · Grid-connected or off-grid: which one are you? · Granny flats: sub-main, meter and the tenant question · Tiny houses on wheels: the 15 A outlet and the caravan rules · Off-grid cabins and tiny homes: what is in a stand-alone system · Sizing: daily energy, days of autonomy, winter sun · Battery chemistry: LFP, lead acid and the rest · Planning and electrical rules · Rebates for small and off-grid systems · Our off-grid service · Questions we get asked

Tiny home and granny flat solar sizer

Six taps: the dwelling, people, full time or weekends, what runs in it, hot water and (for off-grid) the days without sun to cover. The result shows on screen straight away; sending it to your phone is optional.

Grid-connected or off-grid: which one are you?

Dwelling Usual power route Solar and battery Watch out for
Granny flat or studio beside a powered house Sub-main from the main switchboard to a small switchboard in the flat; one meter Extend the main house system: a few more panels and a battery module Separate tenant billing needs separate metering; council zoning and the 60 m2 rule
Tiny house on wheels at a powered house 15 A caravan outlet on its own protected circuit (about 3.4 kW) The house’s solar does the work; panels on the tiny house only if it will move off-grid later One big draw at a time on 15 A; the caravan rules on where it may sit
Cabin or tiny home with no grid nearby Stand-alone system: panels, lithium battery, inverter-charger, generator input Sized from the daily energy, two to three days of autonomy, winter sun with a margin Shade, frost on the battery, the generator still needs fuel
Tiny house on wheels going to a block with no power Off-grid kit: roof and ground-frame panels, lithium battery, inverter-charger As above, limited by roof area; a ground frame fixes that A tiny house cannot be the only dwelling on a vacant lot without approval; check the council first

Granny flats: sub-main, meter and the tenant question

A granny flat (a secondary dwelling in planning language) sits on the same lot as the main house, so electrically it is an extension of it. The electrician runs a sub-main (commonly 32 to 63 A, sized for the flat’s loads) from the main switchboard to a small switchboard in the flat with a safety switch on every circuit, and the whole lot sits behind the one meter and the one bill. The main house’s solar and battery then cover the flat, which is why the right answer is usually “a few more panels and another battery module” rather than a second system. A heat pump for the flat’s hot water on a midday timer, and induction rather than bottled gas, keep its load small and inside the solar window.

The tenant question. NSW tenancy law stops a landlord charging a tenant for electricity unless the rented premises is separately metered. A private check meter on the sub-main lets you see the flat’s use and apportion the bill by agreement, but to put the tenant on their own retail account you need a separate connection point and meter, which is a connection application to Essential Energy through a retailer; the network and the council both have to allow it, it carries its own daily network and retail charges, and the 2015 national study of the question costed the network side of a typical granny flat connection in the low thousands. Ask through the application before you promise a tenant a separate bill. If the flat does get its own connection, it can also have its own solar and battery, and the federal rebate applies to it as a separate premises.

Planning: most councils limit a secondary dwelling to about 60 square metres (or a quarter of the main house, whichever is greater), it cannot be subdivided off, and the zones where it is allowed differ: Lismore allows them with consent in residential zones and villages, Ballina does not allow them on rural land, Tweed and Byron have their own rules. A complying development certificate is possible where the state rules are met; otherwise a development application. Our Suffolk Park page covers the granny-flat-heavy streets there.

Tiny houses on wheels: the 15 A outlet and the caravan rules

A tiny house built on a registrable trailer is, in law and in wiring, a caravan. Parked at a house with power, the simplest supply is a 15 A caravan outlet on its own RCD-protected circuit from the house switchboard, installed by a licensed electrician, giving about 3.4 kW: enough for a fridge, lights, a laptop, a small split-system and a kettle one at a time, but not an electric hot water tank and the kettle together. The wiring inside the tiny house, the inlet and the lead are done and certified to the transportable-structures standard (AS/NZS 3001) by a licensed electrician, as for any caravan; a home-wired tiny house with a 10 A plug and a piggyback lead is the most common fault we see.

Panels on the tiny house itself only earn their keep if it will later move to a block without power; while it sits beside a powered house, the house’s solar and battery already cover it. Planning: NSW rules allow a registered caravan (and so a tiny house on wheels) to sit on land with an existing house for use by the household without development approval, subject to conditions on number, location and use, and the council decides the detail; it cannot be the only dwelling on a vacant lot. Lachlan Shire’s tiny house fact sheet is the clearest NSW statement of the position; check your own council.

Off-grid cabins and tiny homes: what is in a stand-alone system

With no grid, the system has to make, store and manage every kWh itself. The parts: solar panels on the roof or a ground frame (a ground frame is often better in the hinterland, where you can chase the sun past the trees); a lithium battery sized for two or three days; an inverter-charger that turns battery DC into 230 V AC, charges the battery from the panels and the generator, and manages the lot; a generator input with automatic start for long grey spells; and the protection, isolation and earthing the stand-alone standard requires. A Sigenergy system can be configured fully off-grid with its generator input, which is what we used on our hinterland job; smaller tiny-house kits use dedicated off-grid inverter-chargers.

Our off-grid solar: how it works and what is in a system and off-grid solar approvals in NSW pages go deeper; the real example is the off-grid Mullumbimby hinterland home with a Sigenergy battery and a backup generator, and the generator question on its own is in generator or home battery for Northern Rivers blackouts.

Sizing: daily energy, days of autonomy, winter sun

  1. Daily energy. Add up what actually runs. A light-use tiny house (fridge, lights, laptop, phones, fans, a small pump, gas or outdoor cooking) uses about 1 to 2 kWh a day. A normal small home with induction, a washing machine, screens and a small split-system uses 3 to 5. Electric hot water is the load that breaks small systems: an element tank adds 3 kWh a day or more, a heat pump about a third of that on a midday timer, bottled gas none. Weekend-only use is sized a little under full-time, because the battery sits full between visits.
  2. Days of autonomy. How many days without useful sun the battery must cover. Two is the common starting point on the coast; three in the hinterland, in winter, or where there is no generator. Battery kWh = daily energy x days, divided by the usable share (90 per cent for lithium iron phosphate).
  3. Winter sun. Each kW of panels makes about 3.8 kWh on an average Northern Rivers day and about 30 per cent less in June (about 2.7 kWh), before shade; a valley floor or tall eucalypts can halve that again. Size the solar to refill the battery on a June day with a 20 to 30 per cent margin, and let a generator cover the rare fortnight of rain rather than doubling the battery for it.
  4. Peak power. The inverter’s kW decides what runs at once: a kettle, an induction zone and a split-system together is about 5 kW. Size the inverter to the loads, not the battery.

Detail in off-grid batteries: days of autonomy.

Battery chemistry: LFP, lead acid and the rest

Chemistry Usable share Life Notes for small and off-grid homes
Lithium iron phosphate (LiFePO4, LFP) 80 to 90 per cent Thousands of cycles; 10-year warranties common The standard: no gassing, light, heat-tolerant, modular. Do not charge below 0 C without a heater (rare here, possible on frosty hinterland mornings in an unheated structure). Sigenergy and GoodWe are LFP.
Lead acid (AGM, gel, flooded) About 50 per cent A few years; shorter if cycled deep Only for very small or very cheap builds; needs about twice the nameplate for the same usable energy; flooded cells gas and need ventilation and topping up.
Lithium NMC 80 to 90 per cent Good Common in cars and some wall batteries; LFP is preferred for stationary storage here for thermal stability and cycle life.
Portable power stations (LFP in a box) 80 to 90 per cent Good Fine for a weekender or a shed; not a dwelling supply, and not eligible for the rebate as a stand-alone unit.

Planning and electrical rules

  • Planning: councils decide what may be built and lived in: secondary dwellings need consent or a complying development certificate and are zone-limited; a registered tiny house on wheels follows the caravan rules and cannot be the only dwelling on a vacant lot; a fixed tiny home is a manufactured home and needs a development application including the service connections. Check your council’s page before you buy anything.
  • Grid-connected wiring: AS/NZS 3000 (Wiring Rules): sub-mains sized to the load, RCBO protection on every circuit, a 15 A caravan outlet on its own protected circuit.
  • Transportable structures: AS/NZS 3001 covers the wiring of caravans and tiny houses on wheels and their site supplies; licensed electrician, certificate of compliance.
  • Stand-alone systems: AS/NZS 4509 (stand-alone power systems: safety and design), AS/NZS 5033 for the solar array, AS/NZS 5139 for the battery position (not in a habitable room, clearances from exits and windows, protection from vehicles, suitable wall), installed by SAA-accredited electricians with the stand-alone endorsement so the STCs can be claimed.
  • Metering: one meter per connection point; a tenant may only be charged for power on a separately metered premises; a second connection is Essential Energy’s and the council’s call.

Rebates for small and off-grid systems

Off-grid is not left out. Under the federal Cheaper Home Batteries Program, one battery per off-grid dwelling that is lived in (sheds, bore pumps and the like are not eligible) earns the rebate when installed with a new or existing solar system of up to 100 kW: nominal capacity 5 to 100 kWh, STCs on the first 50 kWh of usable capacity. A property more than 1 km from the grid does not need a VPP-capable battery; within 1 km you either use a VPP-capable battery or supply written evidence from the network that a connection would cost more than $30,000. A second off-grid dwelling on the same land (a tiny house beside the cabin, say) can claim too if it has its own solar, is separate from a dwelling that has already claimed and stays installed to the end of 2030 or the end of its warranty, with photos, a site map and the VIN for a caravan or tiny house on wheels. Solar STCs apply to off-grid solar as to any other. The battery factor steps down for installs from 1 January 2027 and again from 1 July 2027, set by the install date. A grid-connected granny flat fed from the main house shares the main house’s one-battery-per-premises rebate rather than earning its own.

How the rebate is claimed and who qualifies: Cheaper Home Batteries: who qualifies and how to claim.

Our off-grid service

Sun Connect Solar installs grid-connected solar and batteries across the Northern Rivers and designs and installs stand-alone systems for homes with no grid, from tiny houses to hinterland homesteads. For a granny flat we run the sub-main and the switchboard and extend the main house’s solar and battery to cover it. For a tiny house on wheels at a powered site we install the 15 A outlet to the caravan rules, or design the off-grid kit if it is heading for the bush. For a cabin or tiny home with no grid we do the full stand-alone design (loads, autonomy, winter sun, shade), install it to the stand-alone standard with lithium iron phosphate storage and a generator input, and claim the STCs and the battery rebate. Every design starts with a site visit, because shade and roof area decide more than any calculator.

Towns where this comes up most: Byron Bay and the hinterland, Murwillumbah and the Tweed Valley, Mullumbimby and Main Arm.

Want to know what this means for your home?

Start with the free tools (no details needed to see a result): solar and battery price calculator, is my solar battery-ready? checker or the 60-second battery quiz.

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Questions we get asked

Does a granny flat need its own solar system?

Usually not. A granny flat on the same lot as a house with power is normally fed from the main switchboard by a sub-main to a small switchboard in the flat, so the main house’s solar and battery already cover it; a bigger battery or a few more panels on the main roof is cheaper than a second system. A separate system makes sense when the owner wants separate bills for a tenant (which also needs separate metering), when the flat is a long way from the house, or when the main roof is full. A separate connection and meter is a connection application to Essential Energy through your retailer, and the network and the council both have to allow it.

Can a tiny house on wheels run on solar?

Yes, two ways. Parked at a house with power, it plugs into a 15 A caravan outlet on its own safety-switch-protected circuit (about 3.4 kW), installed by a licensed electrician, and the house’s solar does the work. On a block with no power it runs as a small off-grid system: panels on the roof or a ground frame, a lithium battery, an inverter-charger, and often a small generator for a run of grey days. The wiring inside a tiny house on wheels is done to the transportable-structures standard (AS/NZS 3001) by a licensed electrician, the same as a caravan.

Is a tiny home or granny flat legal in the Northern Rivers?

It depends on what it is and where. A fixed granny flat (secondary dwelling) needs council consent or a complying development certificate, is generally limited to about 60 square metres or a quarter of the main house, and is allowed in some zones and not others (Lismore allows them with consent in residential zones and villages; Ballina does not allow them on rural land; Tweed and Byron have their own rules). A tiny house on wheels registered as a trailer is treated as a caravan: NSW rules allow it on land with an existing house for use by the household without approval, subject to conditions, but it cannot be the only dwelling on a vacant lot. Check your council before you buy or build anything; we size the power, the planners decide the rest.

What size off-grid system does a tiny house or cabin need?

Work from the daily energy. A light-use tiny house (fridge, lights, laptop, fans, gas cooking) uses about 1 to 2 kWh a day; a normal small home with induction, a washing machine and a small split system 3 to 5 kWh; add electric hot water and it climbs fast. The battery holds two or three days of that; the solar is sized to refill it on a winter day (about 2.7 kWh per kW of panels here in June) with a margin. The sizer on this page does the arithmetic; the firm design follows a site visit, because shade in the hinterland changes everything.

Which battery chemistry is best for off-grid?

Lithium iron phosphate (LiFePO4, or LFP). It gives 80 to 90 per cent of its nameplate as usable energy, lasts thousands of cycles, does not gas, weighs a fraction of lead acid and tolerates our heat well; it should not be charged below freezing without a heater, which matters on the odd frosty hinterland morning in an unheated structure. Lead acid (AGM or gel) only makes sense for a very small or very cheap build: about half its capacity is usable and it lives a few years. The Sigenergy and GoodWe batteries we install are LFP, and a Sigenergy system can run fully off-grid with a generator input.

Do off-grid systems get the battery rebate?

Yes. The federal Cheaper Home Batteries rebate covers one battery per off-grid dwelling that is lived in (sheds and bore pumps are not eligible), installed with a solar system, 5 to 100 kWh nominal with STCs on the first 50 kWh usable. A property more than 1 km from the grid does not need a VPP-capable battery; within 1 km you either use a VPP-capable battery or show written evidence from the network that connecting would cost more than $30,000. A second off-grid dwelling on the same land can claim too if it has its own solar and is separate from a dwelling that already claimed, with photos, a map and the VIN for a caravan or tiny house on wheels. Solar STCs apply as usual. The factor steps down for installs from 1 January 2027.

Can my granny flat tenant have their own power bill?

Only with separate metering. NSW tenancy law stops a landlord charging a tenant for electricity unless the premises is separately metered. The clean way is a separate connection point and meter through Essential Energy and a retailer, which the network and the council must allow and which carries its own daily charges; the simpler way is a private check meter on the sub-main so you can apportion the bill by agreement. Ask Essential Energy through the connection application before promising a tenant a separate account.

How does Sun Connect Solar help with a tiny home or granny flat?

We are Northern Rivers electricians who install grid-connected solar and batteries and design and install off-grid systems. For a granny flat we run the sub-main and the flat’s switchboard and size the main house’s solar and battery to cover it. For a tiny house on wheels we install the 15 A outlet or design the off-grid kit. For a cabin or tiny house with no grid we design and install the full stand-alone system (panels, lithium battery, inverter-charger, generator input, protection) to the stand-alone standard, and claim the STCs and the battery rebate for you. Our off-grid Mullumbimby hinterland job with a Sigenergy battery and a backup generator shows what that looks like.

Sources

Lismore City Council secondary dwelling brochure; Lachlan Shire Council “Tiny houses” fact sheet (NSW position on fixed and mobile tiny homes); Ballina, Tweed and Byron Shire council secondary dwelling pages; NSW Fair Trading tenancy rules on utility charges as summarised in NSW property press; Australian Energy Market Commission / Energeia second connection point report (2015); Clean Energy Regulator Cheaper Home Batteries Program and solar battery pages (off-grid rules, read 24 October 2026); AS/NZS 3000, AS/NZS 3001, AS/NZS 4509, AS/NZS 5033 and AS/NZS 5139 as applied by licensed electricians; Solar Accreditation Australia stand-alone endorsement; SolarQuotes battery guides on chemistry; off-grid sizing practice (lifepo4.com.au autonomy guidance, tiny house load notes); Essential Energy connection process. Load and yield figures from our own calculators. Full list in our research note. Checked October 2026.

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