Mustang MonthlyHow To Engine
How-To Choose and Maintain a Battery
Here's how to extend the battery life for cars that aren't driven every day
Battery Maintenance Tips
We asked National Parts Depot's Rick Schmidt what he does with the batteries in the numerous vintage Mustangs and other collectible cars in NPD's collection, many of which are rarely driven. His advice applies to any battery and car, whether part of a large collection or--for like most of us--in a collection of one.
"If you're not driving the car regularly, it's best to completely remove the battery from the car," Rick said. "Batteries sometimes act like ticking time bombs, and you never know when a case is going to crack or vents are going to spew while a battery is not being used. From our experience, batteries will do funny things just sitting there, disconnected and motionless. So, get it onto a shelf or bench unless that's impractical because the car is driven more often than once or twice a month. Also try to store batteries in a cool and dry space.
"For a long time, we've done a scheduled regimen of slow-charging our batteries on a rotational basis, usually just a 2-amp charge until fully charged, about once a month. However, we're currently revamping equipment to utilize full-time Battery Tender trickle-chargers. Either way works well, but the Battery Tenders are less work and less to keep up with. You just hook them up and forget it.
"For old-style acid-wet batteries, keep up with the water level on a regular basis. Don't overfill, and it's good to loosen the caps while in storage rather than relying entirely on the pin-hole-sized vent, which can sometimes act as a high-pressure spray nozzle.
"Our experience is that batteries in general are fickle and inconsistent. Some batteries last 10 years and others only 10 months, for seemingly inexplicable reasons. Some batteries will slowly degrade, while others will just short-out and die. We've probably bought more batteries over the years than bottles of wax, despite our maintenance attempts. But then again, we didn't keep up with our batteries as well as we do today. Unless you're driving it, get it out of the car, and keep a low-amp charger on it or trickle-charge monthly in a dry and cool area. After that, the battery will decide how long it wants to stay with you.
"We've still got the original battery in our '97 Saleen S351, and with relatively light use and charging maintenance, it still cranks strong after nine years. We've had other batteries that were maintained religiously, and they flamed-out and sprayed acid all over a car's engine compartment within six months. In the final analysis, a slow maintenance-type trickle charger is the best way to extend battery life for a car that isn't driven on a daily or weekly basis."