Changing the Battery in a 2010 Toyota 4Runner
© Copyright Chuck Kopelson 09/21/2016
Updated September 26, 2016
The original battery in my 4runner was a Panasonic EP-34R. The spec says it has 575 CCA (cold cranking amps) and a reserve of 130 amps. I really liked this battery because it gave me over 6 years of life. I wanted to get another one but they aren't available anymore.
When looking for a new battery I wanted to zero in on the size. It's not as easy as you would think. Battery sizes are standardized by the Battery Council International (BCI). Here's a copy of their battery data book which has all the sizes and specs for just about any automotive battery. You need to know the length, width, height (not as important), terminal type and which side the + terminal is on.
When I was looking for a battery I went to many different websites where you would enter the vehicle description and year and get a BCI group code or size. Many of the sizes and codes didn't match up. It turns out that a group 34R battery measures 10.3" long, 6.8" wide and 7.9" tall which was what the original Panasonic battery measured. This battery has a top post (A, A2) that is on the right side which is why it is called a group 34R. Some battery companies listed group 24 batteries as compatible. They are because they measure the same length and width but are 1" taller. The battery below has A terminals and has the + terminal on the right when viewed from the front. When you install this battery in your 4runner it will be turned around so the + is on the left when you view it standing in front of the truck looking down at the battery..
What the companies are doing is making a battery that has the correct length, width and terminal but they very the height so they can use one size battery for a number of group numbers. Most of the time the height of the battery doesn't matter, as long as the capacity is correct, because there's enough clearance under the hood. If the battery is shorter they supply a plastic shim that goes under the battery so it's high enough for the battery clamps to work (see above).
There are a number of different battery technologies. Unless you have installed something that uses lots of power like a big stereo system or a winch (that gets used) you don't need a deep cycle battery. These batteries are usually used in boats where you are using the battery to run all the amenities in the cabin with the engine off. The battery is designed so it won't go bad if it's deeply discharged.
Next there are standard wet lead acid batteries, some that are maintenance free sealed and some have caps on the top to occasionally top off the cells with distilled water. Another newer battery which is in the mainstream is an AGM (absorbent Glass Mat) battery. Instead of having liquid acid between the plates these batteries have a very thin fiberglass mat between the plates that is saturated with acid. I like these batteries because they are much more vibration resistant which is a good thing for off roading. I went with a maintenance free AGM.
There are also a number of new lighter weight exotic batteries I've seen in use in airplanes.
You can search around for information on all of these technologies and decide what's best for you. You will probably come up with a number of batteries that fit the bill. I like to look at the Consumer Report battery tests to see what they came up with. You need to be a subscriber to get these tests. You can also go to your local library if they get Consumer Report magazine. Realize that trying to choose a battery is like shooting at a moving target. There are only a handful of companies that really make batteries and they make them to the spec of the retailer. The retailer can change the spec from year to year so it's very difficult to know what you're getting. I looked at the April 2015 Consumer report car battery buying guide. I bought my battery over a year later.
I chose the Sears DieHard Advanced Gold battery part number 50733. This battery got high ratings on Consumer Reports and is a maintenance free AGM. It's 1" shorter than the 34R spec. The stock battery is rated at 575 CCA. This DieHard is rated at 775. The stock battery is rated at 130 amps reserve capacity. The DieHard is rated at 120. You can usually find the DieHard on sale for a good price. I paid 120.00 for mine in August of 2016.