Service
Marine 24V and 48V DC Battery Systems, Gold Coast
DC and ELV electrical work for vessels at the client's home, driveway, dry storage, or on-trailer. LiFePO4 battery bank upgrades from AGM or lead-acid, Victron MultiPlus II and Cerbo GX commissioning, Lynx distribution and DC bus design, BMV-712 and SmartShunt monitoring, Orion-Tr Smart bidirectional DC-DC chargers between house and start banks, and full integration into VRM for remote oversight. Most install work scheduled outside business hours to suit owners' schedules.
Why owners come to us
Marine DC work is a specialised corner of electrical practice and the customer base is narrow. The five common reasons vessel owners book us:
- Existing AGM or lead-acid bank is at end of life and the replacement decision is whether to like-for-like or step up to LiFePO4
- Existing LiFePO4 install is on a budget BMS and you want to swap it for a managed Victron system with proper Cerbo GX integration
- House loads have grown (induction cooktop, watermaker, larger inverter, second fridge) and the existing 12V system can't keep up, meaning a 24V or 48V conversion
- The boat already runs Victron components but they were never properly commissioned, so VRM doesn't show what it should and the BMS doesn't talk to the inverter
- You bought the vessel with an existing electrical system that nobody fully documented, and you want it audited and improved before a long trip
If your needs are different (small day boat, simple 12V install, no monitoring requirement) you're probably better served by a marine specialist who works dockside in volume. Our scope is mid-to-large vessels at the owner's home, where the work justifies the time and travel.
What the Combined Estate Audit covers on the marine side
Marine DC work is quoted from a Combined Estate Audit, $900, which covers both the home electrical and the vessel. If you only want the vessel side, that's a quoted-as-scope conversation rather than a fixed audit fee. Either way, the on-vessel portion of the assessment is the same:
1. Existing battery bank inventory and condition
Chemistry (LiFePO4, AGM, gel, flooded lead-acid), nominal capacity, age, manufacturer, cell or block configuration, and current state. We measure resting voltage, surface charge after a load test, and capacity if access allows. Older lead-acid banks usually test below their rated capacity by 30 to 50 percent, sometimes much worse. The audit confirms whether the existing bank is recoverable, end-of-life, or borderline.
2. Existing inverter, charger, and converter inventory
Make, model, age, configuration, and commissioning state of every Victron, Mastervolt, Magnum, or generic component on the boat. We pull current configuration via VictronConnect or VRM where possible, document the as-installed state, and identify any units running outdated firmware or non-default settings that don't match the documented bank.
3. DC distribution and busbar architecture
Where the main positive and negative busbars are, what's connected to them, what fuses or breakers protect each branch, what the battery cable sizing actually is, and whether the distribution is consolidated (Lynx Power In, Lynx Distributor) or scattered (random terminal blocks across multiple lockers). Scattered distribution is the most common finding on older installs and the most worthwhile thing to fix.
4. BMS configuration and integration
If LiFePO4 is already installed, the BMS make and model, whether it has Victron-compatible CAN or VE.Bus integration, whether it's actively talking to the Cerbo GX or MultiPlus, and whether it's configured to manage charge sources properly. A BMS that isn't talking to the inverter is one of the most common, and most dangerous, findings.
5. Charge sources and shore power configuration
Solar array (panel count, controllers, MPPT make/model), alternator and DC-DC charger setup, shore power inlet and any galvanic isolator, generator if fitted. We trace each charge source through to the bank and confirm settings match the chemistry.
6. Loads and consumption profile
What's running off the bank, peak draw, daily consumption in amp-hours, what's switched and what's hard-wired, what's on its own protection. Critical for sizing recommendations on any upgrade.
7. Safety and standards compliance
Cable sizing to AS/NZS 3004.2, fusing within recommended distance of the bank, isolation switches, ventilation around lead-acid banks if still present, earth bonding where applicable. Documented and photographed.
The on-vessel portion typically runs three to four hours. Findings go into the same written report as the home audit, with a separate marine section. The report is yours regardless of whether you proceed.
The five most common findings on marine audits
Marine DC systems share predictable failure patterns. These five repeat across nearly every audit.
1. Existing LiFePO4 bank with a budget BMS that isn't talking to the inverter
Common on five-year-old upgrades where the previous installer fitted Battle Born, Renogy, or similar drop-in batteries with internal BMSes, but didn't connect those BMSes to the Victron inverter. Result: the inverter doesn't know when the BMS has tripped, doesn't get accurate state-of-charge from the bank, and can't manage charge profiles properly. Fix is either a system-level Victron BMS upgrade or careful integration of the existing battery BMS into the Victron ecosystem.
2. Lead-acid bank well past its useful life
AGM rated for ten years, found at twelve. Resting voltage looks fine, capacity test shows 35 percent of nameplate. Owner has been topping up shore power weekly to compensate. Replacement is the only path. Decision is then like-for-like AGM (cheaper, simpler, shorter life) or LiFePO4 (more expensive, longer life, more capable, requires BMS integration work).
3. DC distribution that grew organically and now needs consolidation
Battery positive feeds three terminal blocks across two lockers, each with its own ad-hoc fusing. Negative is similar. Cable runs are different lengths to similar loads, causing voltage drop imbalance. Fix is consolidation onto Lynx Power In and Lynx Distributor with proper fusing per branch. Cleans up the engine room significantly and fixes long-standing voltage drop issues.
4. Inverter sized for the original 12V system, struggling on the upgraded bank
Original 12V MultiPlus 2000VA installed when the boat ran a smaller load profile. Owner has since added induction cooktop, watermaker, or larger fridge. Inverter is now thermal-cycling under load. Upgrade path is either matching MultiPlus II at higher rating, or stepping the whole system up to 24V or 48V which lets a same-rated MultiPlus II handle the load comfortably.
5. Cerbo GX present but never properly commissioned
Found on roughly half of vessels with a Cerbo. Either VRM is set up but the device list is incomplete, or VRM was never connected at all and the Cerbo is local-only. Either way, the owner doesn't have remote oversight despite paying for the hardware. Commissioning fix is usually a four-to-six-hour job.
What an upgrade or new install actually involves
Marine DC work is custom-quoted from the audit findings, but most jobs fall into one of four shapes. Indicative scope and timeline below. Actual quote depends on vessel size, access, existing equipment, and whether you're staying at 12V or stepping up.
Drop-in LiFePO4 swap, same voltage
Existing AGM or lead-acid bank replaced with LiFePO4 at the same nominal voltage. New bank, integrated BMS, charge source settings updated for LiFePO4 profile, BMS connected to the Cerbo GX so it talks properly to the MultiPlus. Two to three days on site. Indicative cost $6,000 to $14,000 depending on capacity and whether existing distribution is reused.
Voltage step-up (12V to 24V, or 24V to 48V)
Larger job. New bank at higher voltage, new MultiPlus II at matching voltage, new MPPT controllers, Orion-Tr Smart DC-DC chargers between the new house bank and any retained 12V circuits or the start bank. Cabling resized throughout, Lynx distribution installed, system fully recommissioned. Five to seven days on site. Indicative cost $18,000 to $35,000.
Cerbo GX commissioning and integration only
Existing hardware is fine, the integration is the problem. Cerbo configured for VRM, BMS comms verified, alarm thresholds set, dashboards configured, monitoring tied into the home Home Assistant if applicable. One to two days on site. Indicative cost $1,500 to $3,500.
Full electrical refit
Older vessel, original wiring, multiple legacy systems, owner wants the whole thing brought to current standards with documentation. Includes everything above plus DC distribution rebuild, switchpanel work, possibly shore power inlet replacement and galvanic isolator install. Two to four weeks on site, scheduled in evening and weekend blocks. Indicative cost $40,000 and up.
Every job ends with a documented handover pack: bank specifications, charge profile settings, BMS configuration, VRM access, wiring diagrams as installed, and a written maintenance schedule. You own the system documentation, not us.
Available packages
Combined Estate Audit, from $900 (Zone 1)
For owners with both a home and a vessel. Single combined report covering home electrical and vessel DC systems, with an integration roadmap if you want vessel-to-villa work down the line. Three to four hours on the vessel, two to three hours at the home, written report within five business days.
Vessel-only audit
If you only want the vessel side assessed and don't need the home covered, custom-quoted from the scope. Usually $600 to $1,200 depending on vessel size and access.
Final scope and pricing for installation work land after the audit. Audit findings credit 50 percent against installation when you proceed within 90 days. See /pricing/ for the full pricing structure.
What every vessel owner should understand about their DC system
Marine DC is more demanding than residential power. Constant vibration, salt air, intermittent charging, deep cycles, no grid backup. Component choices and installation discipline matter more than they do at home. Here's the technical context most owners never get from the original installer.
Voltage choice is about cable size and current, not about "more voltage = better"
Power equals voltage times current. Doubling the voltage halves the current for the same power. Halving the current means smaller cables, lower resistive losses, less heat, lower fuse ratings. On a vessel running a 3000W inverter, a 12V system draws 250A continuous. The same load at 48V draws 62.5A. The 48V cabling is dramatically smaller, the busbar can be physically smaller, and voltage drop becomes manageable. For vessels with serious house loads, 24V or 48V is engineering, not preference. For small day boats with minimal house loads, 12V remains correct.
LiFePO4 is mostly better than lead-acid, but not always
LiFePO4 advantages: 80 percent usable capacity (versus 50 percent for lead-acid before damage), 3000–5000+ cycle life (versus 500–1500 for lead-acid), constant voltage under load, half the weight for the same usable capacity, no off-gassing. LiFePO4 disadvantages: 2 to 3x the upfront cost per usable amp-hour, requires a BMS that has to be integrated properly, sensitive to temperature extremes (charge below 0°C kills cells), more expensive cells if individual cells fail. Most modern installs justify LiFePO4. Some don't.
The BMS is the single most important component
A LiFePO4 bank without a working BMS is a fire risk. The BMS protects against overcharge (cells venting at high voltage), overdischarge (permanent capacity loss), cell imbalance, over-temperature, and over-current. A BMS that isn't talking to the inverter has no way to tell the inverter to stop drawing current when a cell goes out of range. The cheapest way a LiFePO4 install fails is "the BMS tripped because of an imbalance the inverter didn't know about, the bank disconnected, the inverter cut out, and the owner couldn't run the fridge for the next three days." Proper integration prevents this.
Why Victron, specifically
Strong warranty support in Australia. The broadest managed-system ecosystem (VRM remote monitoring, Cerbo GX as the system controller, full Modbus and CAN integration, MultiPlus inverter/chargers that work as the system core). Excellent local distribution that engages well with installers (Energy Solutions Australia, Solar Online, and similar). Open enough to integrate with Home Assistant, Node-RED, MQTT brokers, and third-party BMSes when needed. The hardware is competitively priced against equivalent marine-grade alternatives once you factor in the integrated ecosystem.
Charge sources need configuration, not just connection
Solar MPPT controllers, alternator DC-DC chargers, shore power chargers, generator chargers. Each one has charge profile settings: absorption voltage, float voltage, equalisation, temperature compensation, low-voltage cutoff. For LiFePO4, the right profile is dramatically different from the lead-acid defaults most equipment ships with. An installer who fits the hardware but doesn't reconfigure the charge profiles has shortened the life of the new bank from day one.
VRM is genuinely useful, but requires internet at the boat
Victron Remote Management gives you remote oversight: state-of-charge, solar input, AC input, alarms, historical graphs. Worth having on any vessel that's left unattended for weeks at a time. Requires a continuous internet path back to the VRM portal, which means either a marine 4G/5G router or a Starlink Mini. Without internet at the boat, the Cerbo logs locally and the data doesn't leave the vessel.
For deeper reading, see our guides on LiFePO4 vs AGM, 12V vs 24V vs 48V, and Marine System Design.
Frequently asked
▸ Where do you do the work?
▸ Why won't you work at marina berths?
▸ Why 24V or 48V instead of 12V?
▸ How long does a LiFePO4 battery last?
▸ Can I use my existing AGM bank with a new LiFePO4 bank?
▸ Do I need a Cerbo GX if I just want better batteries?
▸ What if I already have non-Victron components?
▸ How do I monitor the boat when I'm not on it?
▸ Can the boat data feed into my home dashboard too?
Book the audit
Marine work starts with the Combined Estate Audit if you want both home and vessel covered, or a vessel-only scoped audit if you don't. Bring the vessel make and model, year, the existing inverter and battery details if you have them, and your VRM login if it exists. Most enquiries get a response within four business hours.