Coast Custom 12 Volt

Coast Custom 12 Volt, Warwick & Toowoomba

Custom Off Grid Power Systems, Warwick & Toowoomba

From a weekend-ready 100Ah lithium setup through to full-time off-grid systems with Cerbo GX monitoring and large solar capacity, we design and install complete power systems sized around how you actually travel. Not from a catalogue.

Ideal for reliable off-grid power and extended touring.

Small off-grid Victron setup on Millard caravan, Warwick QLD
Victron Energy Authorised Installer
200+ Solar Installations
10+ Years Experience
50+Off-Grid Systems Built
VictronAuthorised Installer

What's Included in Your Off-Grid System

Every off-grid system is engineered from your actual power requirements. Genuine Victron components, correct wiring, no catalogue packages.

Full System Design

Each system is built around your real power needs: what you run, how long you run it, and how you recharge on the road. Every component is sized to your setup. You get a full design with itemised components before any work starts.

Lithium Battery Bank

100Ah to 1000Ah lithium iron phosphate (LiFePO4) battery banks in 12V & 24V configurations. Lighter than AGM, deeper usable discharge (80–100% vs 50% for AGM), 3,000–5,000 cycle lifespan, and charges significantly faster. The correct choice for serious off-grid and full-time travel.

Victron Inverter/Charger

Victron MultiPlus or MultiPlus-II for clean 240V power from your 12V & 24V battery bank. True sine wave output, safe for laptops, CPAP machines, induction cooktops, and sensitive electronics. Also charges the battery bank from 240V shore power when available.

MPPT Solar Regulator

Victron SmartSolar MPPT controller. Extracts maximum power from your solar panels at all times, regardless of battery state. Bluetooth monitoring via the VictronConnect app. Works with 12V, 24V, and 48V solar arrays depending on your system configuration.

DC-DC Charger (Alternator)

REDARC or Victron Orion DC-DC charger. Charges the lithium battery bank from your vehicle's alternator while you drive. Unlike a basic VSR relay, a DC-DC charger provides the multi-stage charge profile that lithium batteries require and handles smart alternators found in modern vehicles.

Battery Management System

A BMS (Battery Management System) protects the lithium bank from overcharge, over-discharge, short circuit, and temperature extremes. It also keeps cells balanced across the bank so capacity is maximised over the life of the battery. Every lithium install includes a BMS matched to the battery bank.

Distribution & Fusing

Victron SmartShunt, sized busbar, and individual fusing on every circuit throughout the system. Every cable run is sized to handle the full load it's expected to carry. Every fuse is rated and positioned within 300mm of the battery. Every connection is labelled and accessible for future troubleshooting.

System Monitoring

Victron Cerbo GX or REDARC Manager30 for full system visibility: battery state of charge, solar input, load draw, and charging source, on your phone, tablet, or a dedicated display. Know exactly what your system is doing at all times. The Victron VRM portal also lets you review historical data remotely.

Why We Use Victron Energy

Why We Use Victron MPPT Controllers

Victron Energy is the industry standard for off-grid power management. Dutch-engineered and manufactured to the highest tolerance, Victron products are used in superyachts, telecom towers, remote scientific stations, and emergency backup systems, environments where failure is not an option. The MultiPlus and MultiPlus-II inverter/charger, SmartSolar MPPT controller, SmartShunt battery monitor, and Cerbo GX communication hub work together as a complete, integrated ecosystem rather than a collection of compatible-but-separate products. When every component speaks the same language, the system can prioritise charging sources intelligently, protect the battery from every angle, and give you complete visibility of every watt flowing in or out.

Victron Energy Authorised Installer

As a Victron authorised installer, Nathan supplies the full Victron range and installs to Victron's installation standards. Systems are commissioned via the VRM portal so you can monitor performance remotely from your phone at any time. Victron's product warranty is among the strongest in the industry, and their support network is genuinely accessible if you ever need it years down the track.

Australian Standards Compliant

Every Install is AS/NZS 3001.2 Compliant

We follow all relevant Australian Standards on every install. Every job, every time.

Service Areas

Based in Warwick, We Travel

Based in Warwick, we travel across Southeast Queensland for off-grid power system builds. Mobile service available. We come to you.

Warwick Toowoomba Stanthorpe Goondiwindi Dalby Inglewood Tenterfield Southern Downs
Common Questions

Off Grid Power System FAQ

Honest answers to the questions we get asked before every job.

Off-grid systems vary depending on your power requirements and how long you need to run self-sufficient. Get in touch and Nathan will work through your exact needs and provide a tailored quote.

Lithium iron phosphate (LiFePO4) batteries are lighter, discharge deeper (80–100% of rated capacity vs 50% for AGM before damage occurs), charge significantly faster, and last 3–5 times longer, typically 3,000–5,000 cycles vs 500–1,000 for AGM. The upfront cost is higher, but over the life of the battery the cost per usable watt-hour is considerably lower. For a simple weekend setup where weight isn't critical and the system is small, AGM can still work. For any serious off-grid use (full-time travel, extended trips, or where weight matters in a 4WD), lithium is the correct choice and the one we recommend for almost every application. We'll talk through both options with you and give you an honest comparison for your situation.
A standard VSR (voltage-sensitive relay) dual battery system was designed for lead-acid chemistry. It connects the two batteries in parallel when the voltage reaches a set threshold, allowing the alternator to charge both. Lithium batteries have a different charge profile. They need a regulated to spec multi-stage charge with specific voltage and current limits. A VSR doesn't provide this and can either damage the lithium battery by overcharging it, or fail to charge it effectively because the voltage profile doesn't match. Additionally, modern Euro 6 and smart alternators reduce their output voltage as a fuel-saving measure, so a VSR won't open at all in these vehicles, so the secondary battery never charges. A DC-DC charger solves both problems: it provides a correct lithium charge profile regardless of the alternator type and works effectively even at reduced alternator voltages.
Yes. Nathan is a Victron authorised installer and stocks and installs the full Victron range. That includes the MultiPlus and MultiPlus-II inverter/chargers, SmartSolar MPPT controllers (in all available current ratings), SmartShunt battery monitors, Cerbo GX communication hubs with GX Touch display, Orion DC-DC chargers, and all associated cabling and accessories. Systems are commissioned to spec via the Victron VRM portal so you can monitor your system remotely from your phone. We don't just plug Victron components together. We configure them as an integrated system with the correct charge parameters, transfer switch settings, and alarm thresholds for your specific installation.
That's exactly what a well-designed off-grid system does. The battery bank sits at the centre of the system. Multiple charging sources feed into it: solar via the MPPT controller, the alternator via the DC-DC charger, and 240V shore power via the inverter/charger when you're plugged in at a caravan park. Nathan configures the system so all three sources work together and prioritise to spec. If shore power is available, it charges the battery and powers the 240V loads directly. When you're driving, the DC-DC charger tops up the battery from the alternator. When you're parked in the sun, the solar does the work. Everything is automated. You don't need to switch anything manually. The Victron Cerbo GX (or REDARC Manager30) gives you real-time visibility of what every source is doing, and the system protects itself from overcharge and over-discharge automatically.
If your system includes any 240V work (an inverter/charger, 240V GPOs, a shore power inlet, or a transfer switch), then yes, an AS/NZS 3001.2:2022 compliance certificate is legally required. This applies to caravans, camper trailers, motorhomes, and campervans. The certificate covers the design, installation, and testing of the electrical installation and is a legal requirement in most states for 240V recreational vehicle work. It's also commonly required by insurance companies when making a claim related to electrical faults or fire. We include the compliance certificate with every 240V installation. For pure 12V & 24V systems (DC-DC charger, solar, lithium battery bank), a certificate isn't legally required, but we install to the same wiring standard regardless, because a wired to spec 12V & 24V system is a safer one.

What Our Customers Say

★★★★★

Nathan installed 2 x 12 volts systems, one in our Motorhome and one in the trailer. Not only is the system fantastic and we never have to worry about our power, but he also fixed faults we had with our old system. The batteries have 7 years warranty, the upgrade to our panels keep the batteries topped up which really helps on cloudy and rainy days. We recommend Nathan to everyone, and he is so easy to deal with.

Jenni & Steve K

✓ VERIFIED GOOGLE REVIEW

★★★★★

10/10 for everything! Nathan drove to woop woop to install our bushman fridge, new battery system & fans. Last week in 42 degrees our fridge was lovely and cold and the fans were a godsend! We will use Coast Custom 12 Volt for anything we need in our offgrid set up!

Glynis C

✓ VERIFIED GOOGLE REVIEW

★★★★★

Nathan is a wonderful source of knowledge and Ideas. There is no pressure and helped Improve the efficiency of our stock caravans solar charging system. Work and components are 1st class. He is happy to do the smallest job at a sensible price. It's a relief to have a 5 star technician serviceing the Warwick and Toowoomba regions.

John M

✓ VERIFIED GOOGLE REVIEW

Ready to Go Off-Grid?

Ready to Design Your Off-Grid Power System?

We'll work out your load requirements and build a system for the way you travel. No catalogue packages, no guesswork.

0421 214 111
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