A Dual Battery System is a second battery in your 4×4 that allows you to power 12V accessories, such as a camping fridge, without the risk of draining your vehicle’s main cranking battery. There are various types of Dual Battery Systems on the market. Some are standalone units not hardwired to your vehicle, while others are connected to the engine’s alternator.
Dual battery systems connected to the alternator require an isolator switch. This switch allows the second battery to recharge while you drive, but it automatically disconnects once the engine is switched off. This prevents the second battery from draining your 4×4’s main starter battery – which could leave you stranded in a remote area.
The isolating mechanism can vary in design and function, but generally, there are two options:
Both setups have pros and cons. Solenoid systems are robust, simple, and low-cost solutions. However, they may underperform in some vehicles, especially modern cars with low-voltage intelligent alternators. When the alternator’s output is above 13.9 volts, solenoid-based dual battery systems generally perform at their best. In contrast, DC-to-DC chargers can boost low-voltage alternators, optimising the charging process for your Dual Battery System. However, DC-to-DC chargers are typically more costly and require more installation knowledge.
On that note, most issues with Dual Battery Systems stem from inexperienced installers or poor electrical knowledge.
Fortunately, Safari Centre Cape Town is a leading supplier, retailer, and installer of dual battery systems. Whether you need a DIY kit, National Luna battery box, or a highly customised C-Tek or Victron system, give us a call on (021) 595 3910 to chat with a dual battery expert.
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