Group 31 Deep Cycle Batteries

A Group 31 deep cycle battery is a standardized battery size defined by the Battery Council International (BCI). It typically measures 13 x 6.8125 x 9.4375 inches, and is designed to deliver steady power over a long period of time. It is widely used in RVs, boat electronics, trolling motors, solar systems, off-grid applications, and other continuous loads.

The amp hour (Ah) capacity of Group 31 batteries varies by type and brand. Traditional lead-acid Group 31 batteries usually range from 95Ah to 125Ah, while lithium Group 31 batteries can offer 100Ah or more with higher capacity and longer lifespan. Redodo Group 31 batteries deliver up to 165Ah of capacity, making them among the highest-capacity options available in the Group 31 battery size.

Yes. In the same G31 size, lithium types generally have higher usable capacity (up to 100%) and longer lifespan than lead-acid batteries. What's more, lithium Group 31 batteries offer lighter weight, faster charging, and better performance in demanding applications.

Lead-acid Group 31 batteries usually weigh 60–75 lbs. In comparison, lithium Group 31 batteries are much lighter, weighing only around 22–30 lbs, making them easier to install and handle.

The main difference is size and capacity. Group 31 batteries are larger than Group 27 batteries and typically offer higher amp-hour (Ah) capacity. Both are common size for marine applications, but Group 31 batteries are preferred for boats with higher energy demands, and Group 27 batteries are more suitable for those small boats that focus on size and space. Ultimately, choose a battery size that fits your boat’s battery compartment.

Read more about Group 27 vs. 31 Battery

The main differences are size and capacity. Group 24 batteries are smaller and lighter, typically offering 70–85Ah (Redodo provide 100Ah Group 24 battery), while Group 31 batteries are larger with higher capacity, usually 95–125Ah or more. If your RV has limited space or lower power needs, a Group 24 battery may suffice. For longer run times and higher energy demands, a Group 31 battery is the better choice. Ultimately, choose a battery size that fits your RV battery compartment.

Read more about Group 24 vs. 31 Battery

It depends on your purpose. Group 31 deep cycle marine batteries are designed to provide a steady, long-lasting power output, making them ideal for running trolling motors, electronics, and other continuous loads. Dual-purpose marine batteries, on the other hand, are built to handle both starting engines and deep cycle use.

If you mainly need power for trolling motors and other electronics, a deep cycle marine battery is the better choice. If you want an all-in-one battery that can both start engine and power marine electronics & trolling motors, a dual-purpose marine battery is more suitable.

You can connect up to four Group 31 batteries in series for higher voltage (e.g., four 12V batteries for 48V) or in parallel for higher capacity (e.g., four 100Ah batteries for 400Ah). Just make sure they are the same type, brand, BMS, and were purchased within a month for best performance. However, if the batteries are used for both starting and deep cycle purposes, they can only be connected in parallel, not in series.