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.
 Unless you're going for the...  Unless you're going for the restored look of a vintage-Mustang battery like those available from Antique Auto Battery, this Group 24 Autolite 84 battery purchased at a California Kragen Auto Parts store is ideal for 99 percent of all vintage Mustangs. It has enough strength to easily turn over a 428 Cobra Jet big-block and has an 84-month (seven-year) pro-rated warranty. We picked this battery up for our 351W-powered '69 Mustang project car at a local Kragen for 60 bucks. |  The Autolite 84 battery in...  The Autolite 84 battery in a Group 24 size certainly has enough cranking amperage to get any Mustang started, including '67-'73 big-block 390, 428, and 429 cars. At a typical auto parts store, the recommendation for most vintage Mustangs, including big-block cars, will be a Group 24-sized battery. The Autolite 84 has 835 cranking amps at 32 degrees F. At 0 degrees F, cold-cranking amperage (CCA) is still an impressive 675. |  NPD also has a full line of...  NPD also has a full line of battery accessories available, including the hold-down clamp and hold-down kit shown here for '67-'73 Mustangs. |
"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."