How to Easily Add a Second Battery to a Micro Minnie FLX

How to Easily Add a Second Battery to a Micro Minnie FLX
Steps to installing an additional battery for double capacity.

By: Becca & Brian Roy

Straight from the lot, the Winnebago Micro Minnie FLX is a great turn-key travel trailer for off-grid adventures. The 3,000-watt Xantrex inverter is fed from the 320Ah Lithium-ion battery powering the many amenities - from the Truma air conditioner, the 12v refrigerator, convection microwave oven, and anything else you can plug into it. 

But what happens when you find that your power needs exceed the battery’s capabilities for your adventuring? With the summer heat here in south Florida, we’ve relied heavily on our A/C which is quite the draw on our current setup. Luckily there is an answer: double your capacity by adding a second Lithionics battery! 

An Easy Step-By-Step Guide for Lithionics Battery Install

With tracking showing that our delivery date was approaching, we eagerly set aside a few hours for the installation of the additional Lithionics 320Ah battery. It turned out we really overestimated the time needed as the project was easily completed in under an hour. 

Note: If you want to add a second battery as well, you can start the process by calling the Winnebago Parts department at (574) 825-8052 or emailing them at [email protected] to get yours on order.

Here’s our step-by-step guide from unboxing to powering up for the first time:

1. Unbox: The battery comes well-packaged and is accompanied by a pair of battery cables, a 14” red 2/0 and a matching black 2/0 cable as well as the metric hardware required to attach the battery cables to the terminals to install the new battery in parallel with the existing one. 

Safety precautions are included in the installation guide from Lithionics with the battery, be sure to read these before you start as well.

The only tools you’ll need for the install are a drill with a Phillip’s head attachment, a 13mm socket, and a torque wrench. 

2. Disconnect Power: After the unboxing, we made sure to disconnect all power to the area we’d be working in by unplugging from shore power, turning off the breaker, and shutting down the inverter.  

3. Prepare Area: We then opened up the battery compartment by removing the pair of screws from each side, allowing us to slide it out and gain full access to the system. Once this was accomplished, we removed the existing wooden brackets to stage the new battery next to the existing one. 

4. Install Battery: We then installed the new battery in parallel with the other by connecting the red cable positive to positive and the black cable negative to negative. Under no circumstances would you want to install these batteries in series (positive to negative) as this would double the voltage output, damaging your system.

(Note: Parallel doubles the battery capacity while keeping the voltage the same, whereas the series doubles the voltage output which would cause system damage.)

5. Secure Batteries: Next, we simply cut the existing wood brackets in half and repurposed them to secure both batteries next to one another. After turning on both batteries, we immediately saw the second battery show up in our Lithionics App. 

6. Update Battery Capacity in Xantrex App: We then closed the box up and went into our Xantrex app and updated the battery capacity to 640Ah in the settings. 

Installing an additional battery in a Micro Minnie FLX is as close to plug and play as you can get, enabling you to immediately extend those boondocking sessions. To see a video of the install, check out this post on our Instagram account! 

Happy camping!