This article first appeared in the November, 2015 edition of SportsCar Magazine. SCCA members can read the current and past editions of SportCar digitally here after logging into their account; To become an SCCA member and get SportsCar mailed to your home address monthly in addition to the digital editions, click here.

Avoiding the dreaded flatto batto takes a minimal amount of effort, yet many of us still ignore battery maintenance

When it’s time to go, it’s time to go, and a dead battery in your competition car can mean your day ends before it begins. No go, no compete, no win – it’s as simple as that. But while we all know a dead car battery is one of the worst avoidable nightmares on race day, surprisingly few of us make the effort to ensure our battery is up to snuff.

Over the last year, Battery Tender has become more involved with the SCCA, but while selling battery chargers and their lightweight lithium ion batteries is a priority, their goal is also one of education. You see, the company’s CEO, Mike Prelec Sr., is also a racer competing in his third-generation MX-5, and he hates to see anyone miss a race because of battery woes; and, as he points out, the steps to keeping a battery healthy are simple.

“If you don’t move the vehicle, the battery’s going to go dead,” Prelec explains. “There’s a certain amount of parasitic loss that will kill the battery.” That loss also applies to competition cars with kill switches.

“With a kill switch, you still have the self discharge of the battery itself,” says Battery Tender’s Vice President of Engineering Larry Gordon. “Even with a kill switch, if the battery’s going to be sitting long enough you should still have a charger on it.”

How long is long? “Any time you’re not driving the car for any length of time,” says Gordon, “even for a couple of days. The battery should be connected to a charger if you want to keep the battery in top condition.”

“Your battery has a certain number of cycles in its life, and if you let it completely discharge when sitting, then when you recharge it you just used up one of its cycles,” Prelec says. “If you keep it topped off then you’re not using up those cycles.”

For competitors utilizing a total loss system where the alternator has been removed, minimizing discharge cycles is of vital importance. “Any time you get the opportunity, throw a charger on the battery,” says Gordon. “And, if you notice it’s getting discharged quicker or if you’re not getting as much power out of it, then the battery’s probably getting toward the end of its life.”

So what kind of charger should you use? Obviously, Battery Tender recommends its own, but Gordon notes that most chargers will get the job done. “Look for a maintenance-type charger if you’re going to leave your battery charging for a couple of weeks or a month – 99 percent of modern chargers switch down to a lower voltage when the battery reaches capacity.” However, Gordon warns, “Some of the shop chargers still don’t have a maintenance mode.”

A good weight-saving option, and one that’s becoming very affordable, are lithium ion batteries. With Li-ion, a sub-four-pound battery can do the job of a conventional 20 pounder, but there are advantages beyond that. “A lithium ion should get about double the life of a lead acid battery,” Prelec says. “If your car has a kill switch, lithium ion batteries don’t have the parasitic loss of lead acids, so you could leave the lithium battery without charging it for a year and it should still be at 80-percent charge.”

The flipside is Li-ion batteries are very temperature sensitive. “If it gets down to about 40 degrees F or less, then you’re going to start having a problem with lithium – they don’t like cold weather,” explains Prelec, noting that simply keeping the Li-ion battery warm and then connecting it to the racecar in the morning can minimize that problem. Prelec also notes that Battery Tender’s Li-ion batteries can be treated like any standard battery, even using the standard Battery Tender charger on them.

So, before you close the garage door on your racecar for a month, take that extra minute to hook your racecar’s battery to the charger – it could be the key to winning (or even making) your next race.

Words by Philip Royle
Image by iStockPhoto.com/Jorgenmac
Product Images courtesy of Battery Tender