If you have an older Ford or Lincoln you’re likely to be looking at this battery group. If you’re reading this then your current battery is probably dead, I’m sorry for your loss!
Before you make a new purchase and installation it’s important to double check your getting it right. Lead acid and car batteries can be downright confusing.
Below you’ll find all the important advice relating to group 36R batteries and clear answers to your biggest questions.
⚡BCI Group 36 Key Facts⚡
- Length: 10 ⅜ inch
- Width: 7 ¼ inch
- Height: 8 ⅛ inch
- Weight: 35 lbs
- 12V
- 650 CCA
- AGM, WET, SLA
- Starting
What is a Group 36R Battery?
BCI group 36R batteries are built as starting batteries for cars and small trucks. In recent years, since 2010, they have become uncommon in newer cars, but many older models still use them. Automobile manufacturers including Ford, Lincoln, Mercury, and Mazda are known to use this battery size.
A group 36R is 12 Volts and has 650CCA to start cars with mid to large sized engines.
One anomaly of this battery group is the addition of an ‘R’. You will not find a standard group 36, only 36R. The ‘R’ denotes that the polarity is reversed. This means that the positive and negative terminals are in the opposite location. In this case, the positive terminal is on the right and negative on the left. Vehicles using these batteries have cables and connections to complement this. It means you might have trouble fitting this battery in a vehicle designed for another group size.
You won’t find any group 36R designed for deep cycle or marine use. You should only use them for cranking and not running electronics. For its relative size, it produces a higher Cold Cranking Amps (CCA). Manufacturers won’t even specify the Amp-hour (Ah) capacity as it’s not relevant.
BCI Group 36R Dimensions and Weight
The dimensions of a group 36R battery are:
- Length: 10 ⅜ (263mm)
- Width: 7 ¼ (183mm)
- Height: 8 ⅛ (206mm)
- Average Weight: 35lbs (16kg)
Chemistry Type and Application
Group 36R are available in all major lead acid battery types including flooded, sealed lead acid (SLA), and absorbent glass mat (AGM).
Each of these offer different properties and attributes. When replacing a battery you should check your current chemistry type and make sure it matches. Flooded and SLA are interchangeable. An SLA is very similar to a flooded battery but is maintenance free. It is sealed so there is no need to refill the water for the battery acid. Although, this can slightly reduce lifespan.
Be careful when picking an AGM battery. They can’t be used in all systems as you must charge them carefully. Reduced venting means they deteriorate quickly when overcharged. If used correctly, they enjoy a longer lifespan, zero maintenance, eliminate risk of spills, and cope with vibrations better.
Manufacturers don’t make lithium equivalents of 36R starting batteries. This is because modern cars rarely use this group so demand is low.
The application of group 36R is limited to starting and cranking. You won’t find any deep cycle or marine versions. So don’t try to use one in your boat or RV.
Pros and Cons of Group 36R Batteries
Let’s look at the advantages and disadvantages of these batteries.
Pros:
- Easy to buy online or in store
- Fits older US made cars
- Available in all chemistry types
Cons:
- Not used in modern vehicles
- Not for deep cycle or dual purpose
- No lithium options
- Only in reverse polarity
- Very few equivalents or replacements
Replacing a 36R Battery
Battery Group 36R vs 65
A selection of car owners have asked if you can replace a group 36R with a group 65.
The answer is no, a group 65 battery does not fit a 36r group car.
In this case, you should stick to your current battery group.
Why? Because the two groups are fundamentally different. Firstly, if you check the table below you’ll see the dimensions are completely different. A group 65 is much longer and wider. This means it is unlikely to fit in your battery compartment.
| Group Size | L (inches) | W (inches) | H (inches) |
| 65 | 12 1/16 | 7 1/2 | 7 9/16 |
| 36R | 10 3/8 | 7 1/4 | 8 1/8 |
Adding to this, group 36R is reverse polarity. This means the terminals are on the opposite side so you’ll have a hard time connecting a group 65 to your vehicle.
Aside from the physical dimensions, a group 65 is more expensive and has a higher CCA. You’ll be adding unnecessary power at added cost.
FAQ
Cars that use group 36R batteries include:
Ford Taurus 1996 – 2007
Ford Five Hundred 2005 – 2007
Ford Edge 2007 – 2010
Ford Freestyle 2005 – 2007
Lincoln MKX 2007 – 2010
Mercury Sable 1996 – 2005
Mercury Montego 2005 – 2007
Mercury Sable 2008 – 2009
Mazda 626 1998 – 2002
They can deliver 650CCA and 800CA.
This stands for reverse polarity. It means the positive and negative terminals are in the reverse position. In this case, the positive is on the right and the negative is on the left.
A 36R battery costs between $100 and $200. Prices vary depending on the brand and retailer.
Summary
I hope this page clears up your queries about group 36R group batteries.
As you have discovered, these are built as starting batteries with reverse polarity. A select number of cars produced prior to 2010 most commonly use this BCI group. There are few equivalent replacements or equivalents.
Happily, many retailers still stock these products so you should find suitable options at a reasonable price. Just be sure to check and match the current chemistry type on your battery. For example, it’s not good to accidentally replace a flooded lead acid with an AGM. Other than this you shouldn’t have a problem as you won’t find them for other applications like deep cycle or marine.
