The Difference In Non-Vented Lithium Batteries vs. Vented Lead-Acid Batteries

Posted July 10, 2023

When selecting and upgrading batteries within your vehicle or boat, it’s important to know the key distinctions between vented lead-acid batteries and non-vented lithium batteries in order to maintain proper safety and system performance. While it is possible to replace lead-acid batteries with lithium batteries in general, there are nuances to be aware of, particularly when it comes to installations in smaller spaces like RVs. This is primarily due to the fact that lead acid batteries often require off-gassing and can pose a serious threat to health and safety compared to non-toxic, non-vented lithium batteries. Below we cover the differences between these two key categories of batteries, why they are not interchangeable, as well as provide an update on related recent RV industry standards.

What are Vented Lead-Acid Batteries?

Vented lead acid batteries have openings to allow gasses that are formed to escape. Flooded and absorbent glass mat (AGM) batteries are examples of lead-acid batteries that require ventilation. In these types of batteries, the exterior case contains the actual components and chemicals and will vent hydrogen gas. Proper ventilation for these batteries prevents the buildup of hydrogen gas, which can be explosive when allowed to accumulate within a vehicle or vessel especially. Ventilation for these types of batteries also keeps the air around the battery and your vehicle clean and breathable.

insight 12v lithium rv battery installation

What are Non-Vented Lithium Batteries?

Lithium batteries, on the other hand, do not require ventilation because they do not produce hydrogen or any other gas. Non-vented, cobalt-free lithium batteries - particularly lithium iron phosphate (LFP or LiFePo4) batteries, are inherently non-toxic, resulting in greater safety as well as significantly less required maintenance time. Whether they are installed indoors, in small compartments, or on their sides, LFP batteries like those designed and manufactured by RELiON, are not prone to thermal runaway or fire due to their strong covalent bonds. This makes them the safest possible batteries to use in any application, but especially in small, enclosed spaces, such as within RVs and vessels.

While Lithium batteries are all non-vented, the cases are vented in order to equalize the pressure in the chassis. Unlike flooded batteries, the exterior case you see is just a container to hold the actual battery cells which contain all the battery components and chemicals inside individual, sealed cells.

Are These Two Battery Types Interchangeable?

Placing a lead-acid battery that requires ventilation for off-gassing into a space that is designed for a closed, non-vented lithium battery will lead to damage like poisonous gas in the air and the potential for fires. This is due to the fact that the wide variety of compartments and locations that are able to house lithium batteries, which don’t require any kind of ventilation for off-gassing, are not well suited for lead-acid batteries that require ventilation for harmful gasses.

lightweight non-vented lithium rv battery

Updated RV Industry Standards

Recent updates to the RV industry’s standards regarding the use of batteries in RVs further underscore exactly why these two types of batteries are not interchangeable. In context, due to the rise in demand for lithium batteries in RV applications, the RV industry initially added lithium batteries to the American National Standards Institute (ANSI) Low-Voltage Standard in 2020. However, in doing so, lithium batteries were lumped together with lead-acid batteries when it came to safety and hazard guidelines, despite their inherently unique attributes and risk factors. Several months later, the RV Industry Association Board of Directors addressed this discrepancy by approving a recommendation from the Standards Steering Committee that permitted non-vented (lithium) batteries to be located inside the living space of the RV without the ventilation that is required for flooded and AGM lead-acid batteries. The RV industry’s clarification about this key difference between these two types of batteries is essential, though many RV users remain unaware of this change, assuming that these batteries are in fact interchangeable. However, this new RV standard clearly outlines why this is not possible, namely, that there would be no way for the harmful gasses created in a lead-acid battery to be released from the non-vented compartment that the lithium battery was located in.

Now that you have an understanding of why non-vented lithium batteries should not be treated as equivalent to vented lead-acid batteries, you have a better idea of how to go about selecting and replacing batteries within your RV or vessel. However, if you still have any questions about which batteries to use, get in touch with an expert at RELiON today.