Battery and Electrical Systems

In many ways the components of the automotive electrical system appear to have changed the least over the years of any required for basic vehicle function. And that is often where the trouble starts.

The fact is that while the function of these components is the same as their ancestors, the control systems in play and the demands on them are vastly different.

Alternators, for example, are dramatically smaller than they used to be, yet output has risen to keep step with the proliferation of power accessories. Starters are also no exception, with smaller, more powerful units required to turn modern high-compression engines.

Even batteries have been called upon to have greater capacity, yet still fit into the confines of an increasingly crowded underhood environment. And all components have to withstand the greater heat generated by modern systems.

Control Systems

“Soft start” alternators are a method of protecting the unit from the sudden spike in load when a car is started with a good portion of its accessories turned on. That sudden spike could damage an alternator, but could also cause a technician to misdiagnose a new unit.

Taking an output reading before the system has stabilized could cause the unit to appear faulty, when it is really just protecting itself. Honda units, for example, have regularly been flagged as defective, when they were in fact quite properly delaying the delivery of full output.

There are quirky failures, too. Using Honda as an example again, some of the make’s cars are equipped with a one-way clutch to allow the engine to spin faster than the starter. These have been the subject of multiple failures due to the starter motor remaining engaged after the engine has started. This is not, apparently, the fault of the starter, but is instead a fault in the ignition lock cylinder, which can get hung up in the “start” position, energizing the starter and keeping it engaged. This overheats the starter and can drain the battery.

A damaged battery can also cause air conditioning to stop working. A fuse behind the CD player can cause a no-start. A loose connection can cause myriad intermittent problems.

Which is all to say that the solution to the problem may not be as simple as replacing an alternator, starter, or battery.

Heat can also cause a unit to produce as little as 70% of its rated capacity, possibly putting it into deficit if accessory loads are higher. It should be considered a normal condition, though a performance check will determine if there is a problem.

The Battery: the Heart of the System

Which brings us to the component that does the heavy lifting in the system: the battery.

If a customer asks you why one battery costs this much and another costs less, you would probably know to begin talking about Cold Cranking Amp ratings, but do you know what these are and how they differ from Cranking Amps? How about Reserve Capacity?

The CCA number stands for Cold Cranking Amps. This number, which can range from the 500s to more than 900, is how much power the battery can deliver at minus 18C. This is what gets you started on those cold winter nights. The number below this one, CA or Cranking Amps, is the power delivered at 0C. This number will always be higher than the CCA rating, so don’t confuse the two. A battery’s ability to supply power is halved by every 10 drop in temperature. Of course, at colder temperatures you need more power to turn that engine over. When those two demands intersect–the battery’s reduced ability to supply power becomes less than the starter needs to turn the engine over quickly enough–a no-start results.

The third number is Reserve Capacity (RC). This may not be labelled on the battery, but it should be in your supplier’s catalogue. This number is particularly important for anyone who may have a large accessory power drain on his vehicle, such as extra lighting or a large stereo.

You should also know what battery sizes manufacturers are focusing on, in order to maintain the right inventory:

* GM continues to standardize on Group 75 and 78.

* Ford continues to use group 65 with 650 to 850 CCA, though some global Ford vehicles are using a DIN-style battery with recessed posts and lower CCA.

* DaimlerChrysler uses Group 34 in passenger cars, but Group 65 in Ram trucks.

* Honda is using Groups 51, 51R, 35, 24F.

* Toyota’s standard is 35 and 24F.

* Lexus uses Group 24F and 27F.

And, while popularity can vary by province, city, and even neighbourhood, top North American group sizes rank Group 75, 34/78DT (Dual Terminal), 35/75DT (Dual Terminal), 65, and 58 as the top five.

The Warranty Issue

Historically, the starting and charging system has seen more than its fair share of warranty woes. In some cases, one in three units have been returned as faulty. This, however, does not mean they really were faulty, at least not to begin with.

Recently, an article in a trade magazine advised consumers to follow a jumper-cable boosting with a good run on the highway to charge up the battery. Treating an alternator as a battery charger will fry said alternator very quickly. A weak or dead battery will do the same.

It may surprise you that more than one in four alternators returned as cores are in fact perfectly serviceable, meaning they are operating within specifications. While that fact may lead you to believe that you are benefiting from extra alternator sales, it also means you’re probably going to get the one you just sold back soon, as it is unlikely to fix the problem.

Dos and Don’ts: Battery and Electrical

Do determine why the first unit failed. Try to eliminate the guesswork replacements.

Don’t forget to read the instructions or tips in the box, and remind your customers to do the same.

Do insist that replacement batteries meet or exceed the CCA rating of the original.

Don’t forget to discuss warranty issues with a high-claims client.

Do take time to understand modern electrical units and systems.

Don’t forget the important role that connectors and good electrical contacts can play in ensuring a satisfactory repair.

Do schedule a clinic; customers will appreciate learning what’s new and any quirky failures.

Special thanks go out to all those contributing to the content of the preceding counterperson-focused articles, either through providing content specifically for them, or contributing to our files over recent months. In case where reference materials were supplied we have listed only the company. So thanks go to (alphabetically by company): Soren Sorensen, ACP, Bill Coles, Brian Fleming, and Ron Strain at Affinia Canada Corp., ArvinMeritor Light Vehicle Systems, Robert Bosch, Cadna Automotive, Canamotive, Dennis Sullivan, Cliplight Mfg., Dayco Canada, Bob Sinclair and Greg MacDonald at Dixie Electric, East Penn/Power Battery Sales, Exide Technologies, Mark Baker and Peter Murnen, Federal-Mogul, Fenwick Automotive Products, Frost and Sullivan, Rinaldo Sardella, GE Lighting, Sandy Wallace, Gates Canada, Bob Stanbury, Grant Brothers Sales, Hella Inc., Honeywell CPG, “Mac” McGovern, KYB America LLC, and Bill Dennie, Tenneco.