If you have a car like a Subaru you may already be driving around with this BCI battery size.
Or maybe you’re not going anywhere because your battery is dead and needs replacing…
Before you make a purchase and installation, be sure to read all the information below to ensure you select the correct battery. Plus you’ll find answers to all your biggest questions.
⚡BCI Group 35 Key Facts⚡
- Length: 9 1/16 inch
- Width: 6 ⅞ inch
- Height: 8 ⅞ inch
- Weight: 30 lbs
- 40Ah – 60Ah
- 750 – 900 CCA
- AGM, WET, SLA
- Starting, Marine
What is a Group 35 Battery?
BCI group 35 are most commonly built as starting batteries to crank medium to large combustion engines. You’ll find them in mid to large size cars and trucks.
You won’t come across them often these days but you’re most likely to see them in Japanese trucks and cars. Vehicle manufacturers including Toyota, Subaru, Nissan, Acura, and Mitsubishi are known to use this battery group. Additionally, older American made cars (before around 2003) used group 35.
The size of these batteries allows manufacturers to build in decent cranking capacity of between 750 – 900CCA. This gives you enough power to start engines in bigger cars and trucks.
You can also find dual purpose ‘marine’ group 35 batteries. These are similar to the starting batteries with strong cranking attributes. Plus it is also able to deep cycle with amp-hour capacities between 40Ah – 60Ah. These dual purposes are designed to be used on boats in order to start engines and run low key electronics.
It is rare to see a deep cycle group 35 for power backups or RVs. None of the major manufacturers or retailers stock this type. You’re better off checking otherBCI groups and types for this application.
BCI Group 35 Dimensions and Weight
The dimensions of a Group 35 battery are:
- Length: 9 1/16 inches (230mm)
- Width: 6 ⅞ inches (175mm)
- Height: 8 ⅞ inches (225mm)
The average group 35 battery weighs 30lbs (13kg). You can reduce this by 50% with a lithium phosphate equivalent.
Application and Chemistry Type
Group 35 are mainly built as starting batteries to start vehicle engines. Or as dual purpose marine used for a mix of starting and cyclical application. You won’t find deep cycle group 35.
AGM (Absorbent Glass Mat) is the frequent chemistry type for group 35. This gives you the benefit of added durability and reduced maintenance.
The electrolyte is absorbed by the material rather than remaining as a liquid. It requires no refills and can’t spill allowing you to mount it in any position. Plus it can deal with bumps and vibrations better. Overall this helps to increase lifespan. You need to be careful when charging as overcharging will quickly cause issues due to reduced venting for glasses. So don’t put AGM in a system built to charge flooded or sealed lead acid.
Flooded lead acid options are available too, in fact Subaru often uses these in vehicles.
Increasingly lithium ‘LifePo4’ products are entering the market. These offer higher energy density and are lightweight. They can be 70% lighter and have a longer life. Currently, they are far more expensive and can’t deal with such high currents for long periods of time.
Pros and Cons of Group 35 Batteries
Let’s look at the advantages and disadvantages of these batteries.
Pros:
- Commonly used as starting batteries
- High CCA for large cars and trucks
- AGM chemistry give long lifespan and less maintenance
- Marine dual purpose options
- Easy to find and purchase
Cons:
- Becoming less common in modern cars
- Few equivalents
- No deep cycle application
Group 35 vs Group 25 Batteries
Many people wonder if you can replace a group 35 with a group 25 battery?
Why is this? Well, they have similar dimensions and both tend to be built for cranking. Take a look at this size comparison, they appear identical… Even the polarity and position of the terminals are identical.
| BCI Group | Length (inches) | Width (inches) | Height (inches) |
| 25 | 9 1/16 | 6 7/8 | 8 7/8 |
| 35 | 9 1/16 | 6 7/8 | 8 7/8 |
Away from the physical dimensions, group 25 typically offers a lower Cold Cranking Amps (CCA) compared to group 35. This means if you try to use a 25 in place of a 35, it could struggle to start your engine. At least the reserve capacity will be affected.
You might be able to make the swap for a short period of time, but it’s best to stick to your original group.
Group 35 vs Group 34 Batteries
It’s only natural to compare group 34 and 35 batteries as they close together on a BCI size table. You should be aware of several subtle differences.
Starting with the dimensions. You can see on the table below that group 34 is longer in length by over 1 inch and taller by 1 inch. This means you’ll need to measure a battery compartment carefully to check it fits.
| Group | Length (inches) | Width (inches) | Height (inches) |
| 35 | 9 1/16 | 6 7/8 | 8 7/8 |
| 34 | 10 1/4 | 6 13/16 | 7 7/8 |
The application of the batteries is the same in certain cases. You’ll find both as starting and dual purpose marine. Group 35 deep cycle batteries are rare and more easy to find as group 34. So check the application carefully before making a replacement.
Finally, both are available in various chemistry types including AGM, but WET and SLA, plus LifePo4 are slowly entering the market.
FAQ
Japanese brands and older US made cars and trucks are known to use group 35 starting batteries. Car models include Toyota Avalon, Subaru Forester, Subaru WRX STI, and Toyota RAV4.
The energy storage capacity of group 35 is usually between 40Ah – 60Ah. BCI group sizes don’t specify Ah but you will see correlations between the sizes and capacities.
You can expect a normal lead acid battery to last for 6 to 8 years and produce 500 – 1000 charge cycles. If you switch to lithium the shelf life is far longer and 2000+ cycles.
Summary
I hope the information above helps you on your quest to investigate BCI group 35 batteries.
As you’ve discovered, these are mid sized batteries built for starting and cranking vehicle engines. Demand has reduced in recent years but you’ll still require them for brands like japanese brands or older models.
Additionally, there are a number of dual purpose options on the market to which can be used for starting and cycling on boats.
Manufacturers tend to produce a lot of AGM batteries for these purposes to improve durability and performance but flooded lead acid versions are still available.
