When your truck won’t start, the batteries usually take the rap. While there may not be enough juice there to turn the engine over fast enough to start it, the batteries probably didn’t get that way on their own.

Batteries are part of a system that includes the alternator, starter, and all the cables and terminals that connect everything together. If there’s some weakness in that system, it will eventually manifest as a weak or dead battery. More likely, four weak or dead batteries.

For modern sophisticated fleets with well-equipped shops and trained technicians, dead batteries are little more than an inconvenience. For single truck owner-operators, dead batteries mean at least a day’s downtime, possibly a service call for a jump-start, and the expense of replacing at least one and possibly all four batteries.

How does and single-truck owner-op stay on top of his or her batteries? Start with making a point to do a starting/charging system health check at least twice a year. It’s best done just before winter sets in and again before the heat of summer can cripple the batteries.

Also, regularly clean and tighten your battery terminal post connections and inspect the heavy cabling between the batteries, the alternator and the starter for looseness and corrosion. And make sure the restraints in the battery box fit tightly on the battery. Batteries that rattle around the battery box can be easily damaged.

By some margin, vibration, loose connections, and corrosion are the biggest killers of batteries.

Battery basics

You’ll hear this a lot when it comes to spec’ing trucks and buying parts: start with the right battery for the job.

Your application will dictate the type of battery that would serve you best. For example, a low-mileage P&D operation with dozens of engine starts each day will require a different battery than an over-the-road truck. Such a truck might start five or six times a day with lots of drive time (recharge time) in between starts.

Each time the battery starts the truck, a certain amount of capacity will be used up. The cumulative effect of multiple starts with little recharge opportunity is a battery that is partially discharged most of the time.

“You can only discharge the battery so deep so many times before it fails,” says Joe Puff, vice-president of truck technology and maintenance at NationaLease. “For example, on a truck with a liftgate that’s not used very often, that battery may never get below 80% state of charge. It may last four years. But in a scenario with more liftgate cycles and shorter drive times, it might allow the depth of discharge to get to 50%. That deeper discharge could take a year off its life.”

Lead acid batteries don’t respond as well to deep discharging because of the construction of the lead plates in the battery. To get a high cranking amp battery, you need a lot of surface area where the lead is exposed to the electrolyte (acid) in the battery.

“To get the higher cranking amp rating, you either make very porous plates, or you put a lot of thin plates just to get that surface area,” says

Larry Rambeaux, a sales application engineer at Purkeys Electric in Lowell, Ark. “There’s just not enough material there to handle that deep discharge/recharge cycling over and over.”

The CCA myth

The prevailing thinking is that Canadian trucks need batteries with a high CCA rating (cold cranking amps). A high CCA rating ensures there’s enough juice there to turn the engine over on a cold winter morning.

And that’s true to some extent. But as Rambeaux points out, to get that high rating — 950 to 1,150 CCA maybe — but keep the battery within the Group 31 form factor, manufacturers use thinner plates which will degrade faster than the thicker plates on a lower-CCA battery, like 750 or 825.

“If you could look at a battery cycling test, you’d see, generally speaking, that a 700-750 CCA battery will usually run somewhere around 400 cycles,” Rambeaux says. “Meanwhile, a 950 CCA battery might do less than 200 cycles. It can be a huge difference. And the worst thing is, you pay more for the 950 than for the 700-750.”

Starting concerns notwithstanding, if you run high CCA lead-acid batteries and use an inverter to support hotel loads, you’re going to see reduced battery life. There are always trade-offs.

Deep discharge & hotel loads

And there are options too. AGM (absorbed glass-mat) batteries can handle deep-discharge conditions much more readily than standard lead-acid batteries. They also do just fine with normal starting demands, even after cooking dinner in the truck and watching a Godzilla double feature before bed. This makes them ideal for over the road trucks.

There are also dual-purpose AGM batteries that deliver high current for starting.

While AGM batteries won’t suffer as much as lead-acid batteries from deep discharging, they still need adequate driving time to sufficiently recharge. Again, the over-the-road truck is a good candidate for AGMs. But as any refrigerated hauler who has spent a few days in Phoenix or Laredo waiting on a load will tell you, even the AGMs won’t have enough reserve to run the hotel loads and start the truck without some driving time to recharge them.

The perceived problem with AGM batteries is the cost. They can be really expensive — like three to four times the price of standard battery. Can you make a business case for AGMs? Probably, but it depends on the application.

“With all the additional technology on trucks today, the telematics, always-on systems, cheap, inefficient inverters, etc., there’s a lot of drain on the batteries. It’s not just the hotel loads,” says Puff. “You need batteries capable of deeply discharging when you have high accessory loads. On the other hand, trucks in frequent stop/start applications with low mileage might not be the ideal candidate.”

Regardless of the type of battery you choose, lead-acid or AGM, cheap or premium, you’ll only get out of it what you put into it.

“People always ask me whether or not buying a premium battery is worth it,” Rambeaux says. “And I always tell them, if you don’t fix your maintenance practices, the only thing you’re gonna be doing is throwing away $400 batteries instead of $100 batteries.”

Battery Maintenance: A systems approach

Technically, batteries do not need a lot of tender loving care. They typically no longer require periodic electrolyte top-ups as the containers are mostly sealed. It’s the rest of the electrical ecosystem on the truck that needs your attention — especially cables and connections.

Corrosion in cables (usually seen as a green or yellow powder on exposed wire) chokes the flow of electrons through the cable. This is called voltage drop, and it happens in both directions. It affects the flow of current from the alternator to the battery, and from the battery to the starter and other systems.

“You can buy the best batteries in the world and the most powerful alternator, but if you have crappy, damaged, or corroded cables, you won’t get the energy needed to recharge your batteries,” Rambeaux explains.

Brian Thompson, national fleet manager at Delco Remy, warns corrosion is a battery killer. “We see more of it in the northern regions where de-icing chemicals are used extensively. Catch it early, before it has a chance to do some real damage.”

You can check for voltage drop if you have the equipment and skill to do it, but visual inspections are almost as effective, if they are diligent.

“Watch for any exposed wire or connections that are not coated with anti-corrosion compound or at least, dielectric grease,” he suggests, adding, “Wire chaffing allows moisture and corrosive compounds to get into the cable itself. Make sure the wire harnesses are tight tucked up out of harm’s way and not rubbing against the chassis or anything else.”

Obviously, the battery terminals need to be cleaned periodically and the corrosion removed from the posts, but that’s just the first steps.

“I strongly recommend coating the battery terminals with some kind of a corrosion inhibitor,” says Puff. “The locations that tend to get overlooked most often are the ground cables and connection points going from the engine to the frame. Also, the cabling and connections at the starter.”

And while it’s painful to think about, corroded or even chaffed cables should be replaced. It’s dirty work and the cables are expensive, especially the big “00” cables carrying all the current. If they continue to degrade, they will eventually take down the batteries too.

Your initial repair bill will easily double or quadruple if require new batteries along with the cables. Pay me now or pay me later…

When you’re finished your battery inspection and clean-up, make sure you tighten the battery hold-downs. Vibration is as big a killer of batteries as corrosion or undercharging. You don’t want four expensive batteries rattling around in the battery box. 

And finally, consider that if you have one bad battery in a group of four, the three remaining batteries will do what they can to pick up the slack. This places additional stress on the good batteries. You probably won’t notice it at first, but over time, one dead battery will irreparably damage the others due to the deeper discharge cycles.

If you discover a dead battery, check the condition of the others before bolting in the new one. Three weak batteries will quickly take down the new one. Before you scrap the bad battery, try to find out what caused the failure. You do not want the same thing to happen to the replacement battery.