National Luna Distribution Boxes

A previous blog post covered the pros and cons of a portable dual-battery system versus an installed unit. Aside from portability being the most apparent advantage, one of the main benefits of a battery-box system is its feature-filled control panel, boasting:

  • USB ports
  • Power sockets
  • Solar input (model dependant)
  • A quick-connect coupling for our 220V Intelligent Battery Charger

Fortunately, if you don’t have the space for a portable system – or your auxiliary battery is mounted in a unique location – you can still enjoy the features of the battery box’s control panel by installing a National Luna Distribution Box.

Available in three models, our Distribution Boxes are ideally suited to fixed installations such as trailers, caravans, campers, and other custom setups where the battery is located separately from the charging system. In addition, the Distribution Box allows you to connect the control panel and charging system to more than one auxiliary battery.

In terms of features, the three Distribution Box models are identical to their portable alternatives, with the most notable difference being that a mounting panel replaces the box itself.

On that note, it’s important to note that the Distribution Box does require some installation work, and only competent DIYers should attempt the fitment.

See below for a brief breakdown of each model’s application and features.



The 12V Auxiliary Distribution Box is an entry-level solution that offers all the benefits and features of a well-specced control panel ­– without needing to wire the unit to the vehicle’s charging system.

From that perspective, the 12V Auxiliary Distribution Box is the most straightforward unit to install and is easily recharged by plugging a 220V Intelligent Battery Charger directly into the control panel’s recharge port.

Moreover, the 12V Auxiliary Distribution Box features a comprehensive range of plug points to power your camping fridge, LED lights, or recharge your cellphone/camera gear. Many of these ports can be swapped out and customised to your needs.



The primary feature of the DC25 Distribution Box is its built-in 25 Amp DC to DC charging unit that allows you to recharge your auxiliary battery – via your vehicle’s alternator – while driving.

The DC to DC charger also isolates the auxiliary battery from your vehicle’s charging system once the engine is switched off, thereby protecting the vehicle’s cranking battery from accidental discharge.

However, aside from recharging the auxiliary battery from the vehicle’s alternator, you can also plug a solar panel directly into the Distribution Box’s 375W MPPT solar regulator.

Best of all, the DC25 Distribution Box supports 12V lead-acid batteries (wet, calcium, Gel, AGM), as well as lithium.



In contrast to the DC25 Distribution Box, the flagship DC40 unit sports a 40A DC to DC charger and 600W MPPT solar regulator – allowing you to use a significantly larger panel array.

What’s more, because the unit boasts a 40A DC-DC charger, it reduces the bulk charging time of your auxiliary battery, particularly during the first 3-hours of driving. These results are more noticeable if you’re using a lithium-based battery.

You should consider the 40A charger instead of the 25A unit if:

  • You have a large-capacity battery.
  • You want the extra solar capabilities.
  • You’re powering a load (a fridge or another appliance) while simultaneously charging the battery.
  • You have an alternative power source such as a wind generator or AC-DC power supply typically found in campers etc.



The DC25 and DC40 Distribution Boxes can be connected to National Luna’s optional Remote Monitor. Aside from displaying the battery’s state of charge, the monitor also shows:

  • DC input voltage.
  • Solar input voltage.
  • Alternator input voltage.
  • Auxiliary battery voltage.
  • Charge current, temperature, battery type, and error warnings if something is wrong.

In addition, all three Distribution Box models feature a quick-connect recharge port for the National Luna 5 Amp Intelligent Battery Charger. The charger offers a multi-stage recharge cycle that can be left unattended or permanently connected to your lead-acid battery.

The charger also features additional attachments that allow you to use the unit for other applications, such as maintaining your vehicle, caravan, trailer, boat, motorcycle, or quad-bike battery.

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