On this page you’ll find out about group 25 batteries including common uses, dimensions, and replacement options.
The term ‘group 25’ refers to the BCI size categorization of the battery’s exterior dimensions. It does not define the exact cell type, application, or capacity.
That being said, most of these batteries share very similar characteristics and uses which we will discuss below. Adding to this, you can find comparisons with equivalent replacement choices.
⚡BCI Group 25 Key Facts⚡
- Length: 9 1/16 inch
- Width: 6 7/8 inch
- Height: 8 7/8 inch
- Weight: 35 lbs
- 40 – 60Ah
- 500 – 850 CCA
- AGM, WET, SLA
- Starting / Cranking
What is a Group 25 Battery?
These batteries are used as starting batteries in a limited number of vehicles. These days you will rarely see a group 25 battery and only a select number of manufacturers continue to build them.
More often, people will replace the manufacturer starting battery with a group 25 aftermarket. This is because they are usually built with AGM (Absorbent Glass Mat) internal structure. This provides an increased durability when faced with bumpy roads and heavy vibration. Plus they can perform better in extreme cold.
With this target market for the battery you can find aftermarket group 25 batteries installed in 4×4 vehicles like Toyota 4Runner, Tundra, FJ, Subaru Outback.
You will not find any group 25 batteries designed for deep cycle or marine. It’s not impossible, but during our extensive search we found no manufacturers or retailers.
BCI Group 25 Dimensions and Weight
Standard group 25 battery dimensions are:
- Length: 9 1/16 inches (230mm)
- Width: 6 7/8 inches (175mm)
- Height: 8 7/8 inches (225mm)
These are mid-sized batteries which weigh about 35lbs or 16kg.
Application and Cell Type
Group 25 batteries are generally used as starting batteries. They have a CCA (Cold Cranking Amps) of between 500 and 850 so they can deliver a high current for a few seconds.
As the application for this battery group is almost exclusively for starting, you won’t easily find any deep cycle or marine options. This shouldn’t be an issue as you can use similar groups such as 24 or 35 for this purpose.
The internal cells are usually lead acid AGM technology but you will also find flooded WET on the market. You won’t see GEL chemistry in this size anymore.
The BCI group size only applies to lead acid batteries, although lithium manufacturers attempt to use the equivalent dimensions. You won’t find many lithium batteries marked as group 25 (if any) and even with similar dimensions they won’t be suitable for starting your vehicle engine. Lithium batteries often struggle to deliver a strong enough current.
Pros and Cons of Group 25 Batteries
Let’s look at the advantages and disadvantages of these batteries.
- Used for off-road vehicle
- Focus on AGM cells to deal with vibration and bumps
- Decent CCA
- Expensive (over $150)
- Limited availability with few manufacturers
- Only for starting so there’s limited applications
Group 25 vs Group 24 Batteries
To be honest group 24 batteries are much more common than group 25 but they often serve different purposes.
You will only find group 25 as a starting battery for a limited number of vehicles. Contrastingly, group 24 tend to be universal general purpose batteries for deep cycle and marine uses. Plus there is a small selection of group 24 starting batteries.
They are both available in flooded WET cells and AGM.
The dimensions are very similar but a group 25 is nearly 1 inch shorter in length. It is 9.1 inches long compared to 10 inch length of group 24.
This means you could replace a group 25 with a group 24, just measure the length of your battery compartment to check. Plus ensure the application (starting) and cell type matches.
Group 25 vs Group 35 Batteries
Group 35 batteries can often fit the same requirements as a group 25. This is because the application and size is similar.
In fact, the only difference in dimension is that a group 25 is shorter in length. It measures 9.1 inches long compared to 9.6 inch length of a group 35. That’s only ½ an inch. So it will likely fit in your battery compartment.
Adding to this, group 35 are regularly manufactured as starting batteries for cars, which is the same use as group 25. Plus you can find both as flooded WET or AGM cells.
If you’re looking at group 35 batteries then you’ll find a much wider choice of designs, retailers, and manufacturers. They are much more common.
Finally, you will also find marine and hybrid group 35 which are used on boats for a mix of engine starting and deep cycling. This is not the case for group 25.
Only a small number of vehicles use a group 25 battery, most of these are fitted aftermarket to off road vehicles like a Dodge, Toyota 4Runner, Tundra, FJ, or Subaru Outback.
Yes, it is possible to put a different group size in your car to start the engine. You should closely check the specification to make sure it fits your battery compartment and has the required capacity for your vehicle.
They have a fairly low total capacity of between 40Ah and 60Ah but the starting CCA (Cold Cranking Amps) is ample, often between 500 and 850 CCA.
It can be tricky to find a wide selection of these product manufacturers including Odyssey, Full Throttle, and Duracell. Adding to this, Walmart stock some of these brands.
I hope you’ve learned all you need to know about group 25 battery dimensions, uses, and comparisons.
As you have discovered, 99% of them are used as starting batteries for vehicles. Usually they have AGM internal cells for durability and reliability, even on bumpy terrain.
If you’re considering a group 25 for marine or deep cycle use, then you’re best looking at other options with a better choice. For example, a group 24 will better serve your needs with similar dimensions.
Hi, I’m Michael, the editor here at Watt A Lot.
After years of experience with off-grid power like solar panels, inverters, and batteries I decided I should share my hands-on knowledge with you. In my professional and personal life, I’ve needed to find electrical solutions for remote situations from owning a food truck, to running events at the top of mountains, to my converted campervan. So whether you’re looking for the best products or fixing an electrical problem, you can rest assured my advice comes from real hands-on experience.