How to install a DC-DC Battery Charger

How to install a DC-DC Battery Charger

Wagan Tech8/21/23

by Justin Gray

Installing a DC-to-DC battery charger involves connecting a secondary battery (typically an "auxiliary" or "house" battery) to your main battery or alternator system in a vehicle or a standalone power setup. This type of charger allows the secondary battery to be charged from the primary battery or alternator while you're driving, ensuring that both batteries remain charged and functional.

Note: Before you start, make sure to read the manufacturer's instructions that come with the specific DC-to-DC charger you're using, as installation steps and requirements may vary between manufacturers. Also, if you're not comfortable working with electrical systems, it's recommended to seek professional help to ensure a safe and correct installation.

Tools and Stuff You'll Need:
- Wagan Tech DC-to-DC battery charger
- Cables (positive and negative) with appropriate connectors
- Wire crimping tools
- Wire strippers
- Cable ties and mounting hardware
- Multimeter
- Drill (if necessary)
- Fuses and fuse holders
- Protective gear (gloves, safety glasses)

Installation Steps:

1. Choose the Mounting Location:
Decide where you want to install the DC-to-DC battery charger. It should be placed in a well-ventilated area away from excessive heat, water, and other potential hazards.

2. Disconnect the Batteries:
Disconnect the negative terminal of both the primary (starter) battery and the secondary battery to prevent accidental short circuits during installation.

3. Mount the DC-to-DC Battery Charger:
Securely mount the DC-to-DC charger in the chosen location using appropriate hardware. Ensure that the charger is positioned in a way that allows for proper airflow and cooling.

4. Connect to Primary Battery:
Connect the positive cable from the DC-to-DC charger's input terminal to the positive terminal of the primary battery. Use appropriate connectors and secure them tightly.

5. Connect to Secondary Battery:
Connect the positive cable from the DC-to-DC charger's output terminal to the positive terminal of the secondary (auxiliary) battery.

6. Grounding Connection:
Connect the negative cable from the DC-to-DC charger's input or output terminal to a suitable grounding point on the vehicle's chassis. Ensure a clean and secure connection. Do not reconnect battery negative cables at this time.

7. Alternator Connection:
If your vehicle has a fixed voltage or temperature compensating alternator (standard alternators) installed, leave the Ignition Override cable (BLUE color) open. If your vehicle has a smart (variable voltage) alternator installed, the Ignition Override cable must be connected to the vehicle’s ignition. The Battery Charger will only operate when the vehicle’s ignition is turned on.

8. Monitoring and Control (if applicable):
Some DC-to-DC chargers come with monitoring and control features. If yours does, follow the manufacturer's instructions to set up any monitoring displays, remote controls, or other functionalities. We offer the Digital Remote Interface for use with both of our DC-DC Battery Chargers.

9. Fuse Protection:
Depending on the charger and battery setup, you might need to install fuses in the positive cables for protection against overcurrent. We recommend installing fuses in-line with all positive (+) power cables: Bolt down fuses (ANL fuse, etc.) are preferred because they ensure a low resistance connection. Blade-type fuses are not recommended as they can result in a high resistance connection which causes excess heat and may damage the fuse holder and/or the wiring. Self resetting circuit breakers are not recommended as they may trip prematurely due to the heat generated by the current flowing through the wires.

10. Test and Verify:
Now reconnect the negative terminals of both batteries. Double-check all connections for tightness and correctness. Use a multimeter to verify that the charger is operational and providing the correct voltage output.

11. Secure Cables:
Route and secure all cables neatly to prevent them from getting damaged and to maintain a tidy installation. Use cable ties or clips to secure the cables along their path. I prefer to enclose all wires in a wire loom. It is very important that all wire extensions are well connected, to ensure the stable and reliable operation of the product. After a secure connection is made, use heat shrinkable tubing to completely cover any exposed wiring to prevent a short circuit or debris intrusion.

12. Test the System:
Start your vehicle and let it run. Monitor the voltage on both batteries using a multimeter or the charger's monitoring system. The voltage on the secondary battery should increase as it charges.

Regular Maintenance:
Periodically check the connections and overall functionality of the DC-to-DC charger. Clean the charger and the area around the charger to ensure proper ventilation/cooling.

Always follow the manufacturer's guidelines and instructions for your specific DC-to-DC charger model. If you're uncertain about any step of the installation process, consult a professional or someone experienced in electrical systems to ensure a safe and effective installation.

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DC - DC Battery Charger 25A

DC - DC Battery Charger 40A

Digital Remote Interface

ANL Fuses (assorted capacities)

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