BCI stands for Battery Council International. Now you can forget that bit of information because the industry just uses the term BCI when referring to a type of battery cataloging system for cars. What the BCI or battery group number allows you to do is to determine the length, width, height as well as the terminal configuration of your car’s battery.
This is helpful when confirming that the replacement battery that you have selected is a direct match to the one you are replacing. Here’s what you do. Find the catalog number for your existing battery. It will say something like 8475 if it’s sold by NAPA. What this is telling you is that this battery is in the 75 BCI group and carries an 84 month warranty. Now measure your battery and record the dimensions. Next google “BCI Group” and find a chart (batteryweb.com works for me) to confirm your de-coding of the catalog number. Always move the battery so that the terminals are closest to you to correctly determine the position of the positive and negative terminals. So you will find that 8475 ends up being a side terminal battery with the positive terminal on the left.
Now that you know that the battery will fit and the cables will reach and tighten properly, let’s make sure that your battery selection is going to start the car. Look for CCA or CA on the battery--these stand for cold cranking amps and cranking amps respectively. These ratings indicate the battery’s ability to turn over your car’s engine in stressful conditions--the higher the rating the better. CCA is just a higher standard than CA. We’re looking for a battery with a rating that equals the one you’re replacing or fulfills the requirement as listed in your owner’s manual.
The final rating that appears on the battery is RC which stands for reserve capacity. The battery manufacturers have thought of everything including the hapless possibility that your vehicle might have to run all of its accessories solely off the battery. So reserve capacity is a rating in minutes of how long the battery could sustain that condition if the alternator or its belt failed.
Even though cold weather is associated with car battery replacement, probably because of the visceral reaction of seeing the service truck in your driveway during a snow storm, heat related issues are just as destructive to batteries. So whether you’re trying to replace your battery wearing a winter coat or a tee shirt, start first with the numbers that you find on the battery to make the job easier.