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The Straight Skinny on Battery Service

A 3D render of an extreme closeup of an illuminated check battery dashboard light on an dashboard panel background

When we do a survey article, we typically group them by content, gathering several resources related to a specific service challenge. This month’s article is a grouping of another sort. This month, we are featuring several resources that could be said to be grouped under the heading, “We love to see knowledge pieces in the trade media that emphasize topics we have been (politely) screaming about for years.” Often, we feel like the boy who cried wolf, providing direction to the market that isn’t always corroborated by the various trade publications that cover our industry. So, imagine our surprise (and glee!) when we encountered a rash of resources that almost seemed to have sprung from our own content team. Awesome! So, here goes.

AGM Batteries – Dos and Don’ts

For those of you who have been with us for some time, seeing us focus on an AGM-related resource probably comes as no surprise. It is likely our number one topic for coverage. Why? Because, even though AGM batteries are nearing their 20 year anniversary as an OE-installed battery in the North American carpark, there is still an enormous amount of misinformation out there related to them. This article, by Andrew Markel from Underhood Service Magazine, is a great primer on AGM battery service. In it, he addresses four common myths related to AGM batteries, starting with our favorite, “You can use your regular battery charger on AGM or gel cell batteries.” Hint – this is totally false. Check the article out here:

Diagnostic Strategies for Stop/Start Systems

If we have a second most popular article topic from our years of publishing this blog, it is probably a tie between Stop/Start systems and parasitic drains. Similar to the AGM battery, Stop/Start systems present a variety of service challenges, including the fact that many utilize a different design than traditional systems (use of two batteries working in conjunction, for example) and the fact that many Stop/Start systems incorporate new battery types (Start/Stop AGM batteries and Enhanced Flooded batteries, to name a few). This primer, again, by Andrew Markel from Underhood Service Magazine, provides an excellent overview of these systems and the things to keep in mind when tasked with servicing them. There is so much to love about this article, but this quote really sums it up for us: “When trying to resolve a complaint, code or no-start/no-crank condition on a stop/start vehicle, it is essential to know how the system operates. The problem may not have a complicated reason – something simple may cause the stop/start system not to work.” We cannot recommend this article enough.

But, What’s an EFB Battery?

Toyota Highlanders
Photo courtesy of

We have been talking about EFB (enhanced flooded batteries) since 2015, when we incorporated them as a battery type option in all of our electronic battery tester models. At the time, most of the market asked what this was and noted that they weren’t seeing these batteries in the wild. That all changed in the 2017-2018 model years, when these batteries started making their way into new vehicle production, within Stop/Start system architectures. This service bulletin, from Toyota as referenced on, addresses this new battery type as used in 2017-2019 Toyota Highlander models.

Vehicle Connection Best Practices

If we get crushed in blog comments and on social media, often it is because we suggest (or admonish, depending on your reading of our pleas) to always connect to a vehicle electrical system in the following manner: positive clamp to the battery’s positive post and negative clamp to vehicle ground (unpainted part of the engine or chassis). This is a safety best practice, the goal of which is to ensure you make your second connection (negative clamp) away from the battery, such that if a spark is thrown when the circuit is completed, it is as far away from the battery (and its potential to expel flammable gasses) as possible. Many users have reminded us that they have done it otherwise (clamps to both positive and negative posts) a hundred, even a thousand, times without incidence. New system designs, which incorporate sensors into the vehicle battery connections to monitor battery charge, provide new reasons why the right way is the only way to connect to vehicle electrical systems, whether charging or jump starting. This article, by Mark DeKoster in the February 2020 issue of Motor Age, is ostensibly about vehicle load shedding strategies and how to service vehicle equipped with this technology. But the part we love the most is where Mark gets into the realities of making a vehicle connection on late model vehicles.

To connect power from an outside source to any of these vehicles requires that you connect the hot lead to battery positive. The ground lead is connected to a good underhood ground. Jump starting a vehicle with this system also requires that you do not attach the jumper cable to the negative battery post or connection. What happens when you don’t follow this protocol? You confuse the battery state of charge calibration and monitoring. The load shedding may not work correctly until the system has a chance to recalibrate itself.”

Couldn’t have said it better ourselves. In this case, Mark is addressing the service implications of the Ford load shedding system, but he could easily have been referencing GM or any other manufacturer. Check this great article out for tons of really useful information.

We really love it when we see the professionals emphasizing the same topics and specific points that we believe are critical for the success of today’s technicians and shops. Vehicle electrical systems are changing, and changing rapidly. Some of these changes are subtle and others are very significant. It is a safe bet that the pace of change will not slow anytime soon. Staying current on system design and best-practice service strategies are key to ensuring that you can keep delivering high customer satisfaction while also running a profitable operation.

What electrical system changes have caused you the most difficult or do you think aren’t focused on enough? Please leave a comment below. We’d love to hear from you

2 Responses

  1. In the section about EFB batteries, there is a link for, “This service bulletin, from Toyota as referenced on”

    That link is bad.

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