How Do I Replace the Battery in My Generac Fuel Monitor?

This article explains how to identify Gen 4 vs. Gen 5 fuel monitors and provides step-by-step instructions to replace the batteries in Gen 4 devices, including required tools, safety notes, and post-replacement activation. Gen 5 devices are sealed and contain a non-replaceable battery (10–15 year life).

Apr 10, 2026
Knowledge

Title

How Do I Replace the Battery in My Generac Fuel Monitor?

URL Name

How-Do-I-Replace-the-Battery-in-My-Tank-Utility-Device

Public Answer

How do I replace the battery in my Generac fuel monitor device?

Environment

Applies to: Gen 4 fuel monitors only.

Note: Do not use this guide for Gen 5 devices — Gen 5 fuel monitors do not use replaceable batteries. They contain a built-in battery with an estimated lifespan of 10–15 years and should not be opened or tampered with.

For help with your Gen 5 monitor, please contact TU.support@anova.com as these devices are owned and supported by Anova.

Identifying your Generac fuel monitor

How to tell the difference between Gen 4 and Gen 5 devices:

Gen 4 Monitor	Gen 5 Monitor
Replaceable AA lithium batteries	No replaceable battery
Flat and rectangular with 3 LEDs	Sleeker, slanted case design
Label includes “TU102” or “TU104”	Label may show “Gen 5” or unique SKU
Screw-secured back panel	Sealed unit (no screws)

Gen 4 device

Gen 4 fuel monitor example

Gen 5 device

Gen 5 fuel monitor example

Need more help identifying your device? Contact Support.

Battery information

Gen 4 Generac fuel monitors come with four (4) Energizer L91 AA long-life lithium batteries pre-installed. Typical battery life is 3–5 years depending on conditions. When replacement is needed, follow the steps below.

Required tools & materials

Phillips head screwdriver
4 × AA Energizer L91 lithium batteries (using other battery types may reduce device lifespan)

Battery replacement instructions

Important: Always remove the monitor from the propane tank before servicing.

Remove the monitor from the tank for safety and easier access.
Place the monitor face down (feet up) on a flat surface.
Unscrew the back panel using a Phillips screwdriver (4 screws).
Tip: Use the magnetic feet to hold the screws during removal so they don't get lost.
Lift off the back panel carefully.
Remove the old batteries.
Insert new AA lithium batteries, matching the polarity symbols in the battery compartment.
Note: Do not mix old and new batteries or different battery chemistries.
Reinstall the back panel.
Reinsert and tighten all screws.
Prompt a new reading by holding the activation magnet on the activation pad for ~3 seconds, then remove it.