Click & Clack : Battery Life, Decoded

Sunday, November 11, 2007

Q Dear Tom and Ray:

Summing up my Saturday,

Me (the boyfriend) to Her (the girlfriend): "Your car's not starting right; your battery may be going out."

Her: "When you have time, can you maybe fix it, please?" (Translation: "Before you even think about doing anything fun this weekend . . .")

Clerk (at auto-parts store): "Yep, your battery's almost shot."

Me: "But I put it in new just two years ago. Doesn't the big '84' on the battery mean '84 months' . . . as in '84-month (seven-year) warranty'?"

Clerk: "Sure, but car batteries never last more than two or three years; that's why the manufacturer prorates them so heavily."

Why do battery manufacturers promote batteries as being "84-month batteries" if they seldom last more than 24 to 36 months? And if car batteries aren't going to last more than 24 to 36 months, what am I paying extra for when I buy "84-month" batteries rather than cheaper "72-month," "60-month" or "48-month" batteries? -- Gary

A RAY: Well, the numbers on the batteries relate to their warranties, Gary. So an "84-month battery" is warranted for 84 months. If it fails before 84 months, it'll be replaced.

TOM: There's a "free replacement period," during the first one to three years (depending on how good your particular battery's warranty is). After that, they'll prorate it, giving you some money back, depending on how old the battery is when it dies and how much time is left on the warranty.

RAY: While batteries vary, batteries sold by reputable retailers generally last about as long as their warranties suggest.

TOM: Almost all replacement batteries sold in the United States are made by three big companies: Johnson Controls, Exide and East Penn. Retailers like Sears or NAPA specify exactly what they want in a battery, and one of those three manufacturers makes the batteries to those specifications.

CONTINUED     1        >

© 2007 The Washington Post Company