A dual battery system that is designed around what you actually run, and wired so it holds up on corrugations — installed at our Malaga workshop.
Most dual battery disappointments are design problems, not product problems. Before recommending anything we want to know what you are running and for how long.
| Voltage-sensitive isolator | DC-DC charger | |
|---|---|---|
| How it works | Connects the auxiliary battery to the alternator once the start battery is charged | Takes the vehicle's supply and produces a proper multi-stage charge for the auxiliary battery |
| Suits | Older vehicles with a conventional fixed-voltage alternator | Modern vehicles with smart or variable-voltage alternators, and lithium or AGM auxiliaries |
| Charges the auxiliary fully? | Often not, particularly on newer vehicles | Yes, and to the correct profile for the battery chemistry |
| Solar | Separate controller needed | Many units accept solar input directly |
On most vehicles sold in the last decade or so, a DC-DC charger is the right answer. If someone quotes you a simple isolator for a modern vehicle, ask how the auxiliary battery will reach full charge.
The components in a dual battery system are the easy part. What determines whether it works in three years is the installation.
This is auto electrical work, and it is the half of the trade this workshop is named for. A tidy install is not cosmetic — it is the difference between a system that works out past Kalbarri and one that fails there.
We quote after we have looked at the vehicle, because an honest number needs the actual fault rather than a description of it. What moves the price on this kind of work:
You get the number before the work starts, and nothing extra happens without you approving it first.
Workmanship and parts are covered. The specific period depends on the job and on the part supplier's own warranty, so the terms that apply to your repair are set out on your invoice — ask us to walk you through them before you approve the work if you would like it clear up front.
This sits alongside your rights under Australian Consumer Law, which apply regardless of what any warranty document says.
Working out your power needs, choosing the battery and charging method to suit your vehicle's alternator type, finding a safe and secure mounting location, then running correctly sized and fused cable with proper terminations, protection and earthing. The design conversation comes before any parts are chosen.
If your vehicle has a smart or variable-voltage alternator — most vehicles from the last decade or so — you need a DC-DC charger, because an isolator will not fully charge the auxiliary battery. Older fixed-voltage alternators can work with an isolator.
Yes, and it is worth doing even if you are adding panels later. Many DC-DC chargers accept solar input directly, which keeps the system simpler than adding a separate controller afterwards.
It depends on the vehicle and the battery. Under-bonnet, in a tray, in a canopy or in a cargo area are all options, and each has ventilation, heat and mounting considerations. We will talk through what suits your setup.
Yes. Bring it in and we will tell you honestly whether it suits your vehicle's charging system and your power needs before fitting it — better to hear that first than after.
Areas we service: Malaga · Morley · Ballajura · Wangara · Bayswater · Midland · Guildford · Ellenbrook · Bassendean · Perth and the wider Perth metropolitan area.
Tell us what the vehicle is doing and we will diagnose it properly. You get the price before the work starts.