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Car battery types

Car battery types and why they’re changing

What’s causing the change in car battery types?

Carmakers are trending toward absorbed glass mat batteries (AGM. Why? Because late model vehicles have more computers and power draining accessories than ever before and that’s stressing out the electrical systems in newer cars. Just look at these startling stats:

• Modern vehicles have more than 150 electrical devices, compared to 20 electrical devices in cars from 20 years ago.

• More computers — car makers are computerizing everything in the car. There can be as many as 100 computers in a single vehicle: All these systems run with a computer

Engine control (PCM/ECU/ECM)
Transmission control (TCM)
Body control module (BCM) to run turn signals and headlights, brake lights and daytime running lights
HVAC head to run blower motor control module for variable speed blower motors, heater control module to control heat and AC,
TPMS — tire pressure monitoring to monitor and report low tire pressure
ABS — anti-lock brake module to operate ABS, traction control module to maximum traction on slippery surfaces, vehicle stability module to prevent losing control, accident avoidance module to slow the car if you’re approaching another vehicle too fast
Lane departure — to warn you if you’re about to leave your lane or if another car is in your blind spot Backup backup module to run the backup camera and calculate reverse angle of attach
Remote keyless entry
Push button start
Seat module to remember your preferred seat preference
Heated seat module to maintain proper seat heating
Rear defogger module to monitor and turn off the rear defogger
Power window module to provide auto-up and anti-pinch features,
Radio/Bluetooth systems that automatically vary volume based on vehicle speed and microphones in the vehicle,
Vehicle comfort modules to adjust ride height and vary stiffness based on road conditions, auto dimming mirror to prevent glare, and more power ports (as many as 8 in some vehicles).

Start/stop systems require a different battery

Start/stop technology system REQUIRE an AGM battery and these systems track the recharging needs of the battery as it ages. When you replace an AGM battery on a vehicle with a start/stop system, you MUST reset the computer to tell it the vehicle has a new battery. If you skip this step, the computer will assume you still have the old battery and will charge it as if it’s an older battery. That will shorten its life!

Car batteries are the most commonly replaced part

Car batteries never made the top ten list 10 years ago. But in the 2017 J.D. Power Vehicle Dependability Study battery replacement wound up in the top 10 list.  In fact, 44% more owners report a battery failure in 2017 than in the previous year.

In 3-year old vehicle, the car battery has become one of the most frequently replaced components that’s not related to normal wear and tear—6.1% in 2017 opposed to 1.3% in 2016. According to Jason Searl of Johnson Controls International PLC. battery performance is a leading source of consumer dissatisfaction with vehicles, and it has been increasing each year as vehicles become more complex.

Car battery ratings now emphasize reserve capacity in addition to cold cranking amp

John Munsell is the product manager for General Motor Corp.’s ACDelco battery brand. He states that AC Delco is educating dealers, shops and parts store clerks on the importance of emphasizing reserve capacity as well as cold cranking amps. According to Munsell, “Reserve capacity is important today, and it’s going to be critical in the future. That’s because automakers are making it easy for consumers to plug more and more mobile devices into their cars, trucks and crossovers and use them even when the vehicle is off.”

Designing a car battery with higher reserve capacity while maintaining enough cold cranking amps is a challenge. To achieve higher reserve capacity, you have to use a different plate design, more like a marine battery than a starting battery. Yet the battery still has to output the CCAs on a cold day.

However, many late model engines don’t need the extremely high CCAs required by older engine designs. That’s because new engines use low viscosity oils and gear reduction starters, so the engine can get up to starting speed with fewer CCAs.

Battery testing is becoming more important

Testing battery voltage at rest is no longer a reliable measure of thecondition of the battery. Batteries must be tested using a resistance, conductance and simulated load test to determine its condition.

Replacing a car battery in a late model car takes longer

You could replace an underhood car battery in an older car in about 15-minutes. Try that on a late model car where the battery is stored under the rear seat. If you’re not doing your own work, car battery replacement has changed from a 15-min job into a 1- hour task. So it pays to buy the best battery to cut down on labor costs down the road.

Buy the same battery

If your car or truck has start/stop technology, don’t think you can skimp on a battery replacement. Replacing an AGM start/stop battery with an SLA battery can result in failure in less than 6 months. That’s because the charging systems in start/stop vehicles is programmed to charge an AGM battery, and that protocol will destroy an SLA battery, and vice versa. Never replace an SLA battery on a late model car or truck with an AGM battery.

What else is changing in car battery replacement?

Backup power. If you’re a DIYer and planning on replacing the battery in your late model vehicle and you don’t have a jumper pack and backup power cable, you’re begging for trouble. When you disconnect the old battery, you can lose important “home” positions. Some times you can perform a throttle body relearn without a scan tool, but other cars require a scan tool to perform a relearn. You’ll not only lose the throttle body home position, but radio, memory seat, anti-pinch window, adaptive memory and possibly even steering wheel zero calibration.

The last thing you want after changing your battery is to have to call a tow truck to get your car into a shop for multiple relearn procedures.

©, 2018 Rick Muscoplat

Posted on by Rick Muscoplat


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