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Topics about Stop-Start Batteries

Modern Car with Stop Start systems can detect when the car is not moving and subsequently shut down the engine in order to reduce greenhouse gas emissions and fuel consumption. These features of Stop Start technology are particularly beneficial for those instances where the Car is stopped traffic lights, as it eliminated the unnecessary idling of the engine while waiting for a green light. In the same scenario, the engine in vehicles without Stop Start technology would continue to idle, wasting fuel and emitting pollution.

What is start/stop technology?

As the name suggests, Stop /Start (or Start/ Stop batteries, take your pick) is a system in newer car models that automatically starts and stops the car’s engine when the vehicle is stationary, then restarts it when the brake is disengaged (in cars with automatic transmission) or the clutch is actuated (in cars with manual transmission).

Stop-start batteries are designed to reduce the fuel usage and emissions whilst also saving on running costs. In a, standard car, the engine continues to run while the car is stopped (say at the traffic lights) and fuel is being used which increases running costs and Emission levels. In Stop /Start cars, the engine is stopped completely when not required, so no fuel is burned. Thanks to the cycling ability of Stop /Start batteries power is still available to run the car’s accessories, so you don’t have to stop listening to the radio or enjoying the AC.

In general, Stop /Start systems are estimated to produce 3-8% lower emissions and provide the same in greater fuel

start-stop batteries topic
start-stop batteries topic

Why do I need a special battery for start/stop cars?

In a standard vehicle, starting the car is typically a one-off event in your journey. You’ll start the car at the beginning and keep it running until you arrive. Standard starting batteries are designed for this purpose. They discharge a large, short burst of power, then recharge using the car’s alternator over the course of your journey.

In a start/stop vehicle, the car will restart frequently. With a standard battery, this frequent restarting will require numerous large bursts of energy that would rapidly discharge the battery before the alternator can fully recharge it.

A start/stop battery has to endure a double load, meaning that it remains in use after the initial starting of your car. It will continue to power your ancillary systems like the radio, lights and air conditioning even when while the engine is stopped. Furthermore, it uses regenerative braking, which converts some of the car’s kinetic energy into electricity when you brake, helping to restore charge to the battery for the following restart. Due to some of the unique features of stop / start batteries they are able to recharge much faster than a conventional battery and also discharge to a much deeper state. These special features enable the battery to recover charge faster and utilize some of newer vehicle systems like regenerative braking and battery management Systems, all aimed at reducing vehicle emissions and increasing fuel efficiency.

The different types of stop-start car batteries

There are two main types of batteries you’ll find when looking for start/stop car batteries: absorbent glass mat (AMG) and enhanced flooded battery (EFB).

What is an AGM start/stop battery?

AGM batteries are considered the most powerful start/stop batteries. They’re best suited for heavier or more demanding vehicles, rather than your everyday passenger car.

This technology was originally developed for military usage years ago, but has since found popularity in the passenger car battery market. AGM batteries are often required to keep up with the demands of hungry vehicle systems, gear shift indicators and advanced in-car technology. They are able to provide a deeper discharge without compromising the battery. AGM Start/Stop batteries combine cranking power with deep cycle ability to deliver the best hybrid battery solution for modern vehicles.

The benefits of AGM batteries

  • 3-4 times more cycling life than standard batteries.
  • Up to 8% lower emissions and greater fuel efficiency.
  • Greater vibration resistance
  • Lower internal resistance allowing faster recharging.
  • High charge capacity, which is crucial for regenerative braking and energy management systems.
  • Reliable, strong starting power even at low charge.
  • Completely maintenance-free.
  • 100% leak-proof and sealed, with no loose acid.

What is an enhanced flooded battery (EFB)?

The other kind of start/stop battery you might find is called an enhanced flooded battery (EFB). These batteries are essentially more modern, advanced versions of your standard car battery that are specifically designed to be suitable for start/stop vehicles. EFB batteries are wet-filled with electrolyte and similar to standard flooded batteries, however, there are technical differences that give these batteries enhanced cycling ability and improved charge acceptance.

EFB batteries are more affordable, less powerful start/stop batteries that are best suited for your everyday private passenger vehicle without any significant power demands.

If your car is already equipped with an EFB, it can be upgraded to an AGM, but should not be replaced with a standard flooded battery. Likewise, a car that was designed with an AGM battery should not be used with an EFB or standard flooded battery.

The benefits of enhanced flooded batteries

  • 2x cyclic durability of a standard flooded battery.
  • Up to 6% reduced emissions and greater fuel efficiency.
  • Designed to meet most OEM vehicle demands.
  • Suited for entry-level start/stop cars.
  • Fully sealed and maintenance-free.

Why are start/stop batteries becoming increasingly common?

In general, start/stop technology is becoming more popular as governments throughout the world create greater restrictions on CO2 equivalent emissions. Start/stop technology allows manufacturers to reduce the emissions of their vehicles, meet targets and work together towards a more stable, healthy global environment.

Which manufacturers use start/stop technology?

Today, most car manufacturers throughout the world at looking at start/stop technology and incorporating fuel economy systems in their latest models. In particular, Audi, BMW, Fiat and Volkswagen are known to promote the use of start/stop systems across Europe. More recently, American Ford vehicles have been equipped with automatic start/stop systems.

Which Stop Start battery is right for my vehicle?

It is important to note that although both EFB and AGM batteries are suitable for Stop Start systems, they are not necessarily interchangeable. EFB batteries can be replaced by AGM batteries in some applications however vehicles designed to use an AGM should only use AGM batteries. As mentioned earlier, conventional calcium batteries are not suitable for Stop Start vehicles.

How long does a Stop Start battery last?

Conventional lead acid batteries can last for up to 4-5 years if maintained properly. Stop Start batteries are put under constant pressure in a Stop Start vehicle and may not always last as long as a battery in a conventional vehicle. If you are seeking a long lasting Stop Start battery for your vehicle, consider investing in reputable brands of batteries such as Delkor or ACDelco.

Brava AGM and EFB automotive batteries are powered. More durable and with superior electrical flow, this award-winning range is designed specifically for vehicles with Stop Start technology.

Do you need a battery charger for Stop Start battery?

Stop Start batteries may require a different battery charger compared to conventional batteries. A smart battery charger with selectable battery types will allow you to charge EFB and AGM batteries safely and efficiently. Visit your local R&J Batteries branch to get a smart battery charger for your Stop Start battery.

Can I put a Stop Start battery in a conventional vehicle?

Stop Start batteries are not limited to vehicles with Stop Start systems. AGM batteries are widely used in conventional vehicles due to their array of benefits.

Why do I need a special battery for the automatic start-stop system?

Every start-up process is related to the large amount of energy of the car battery. The battery must be in a very good condition to reliably provide high starting current. Especially for modern vehicles equipped with automatic start stop system, the engine will shut down many times during driving. During these phases, the battery continues to power all consumers. Traditional starter batteries are not designed for this charging output.

Only the battery with start stop technology can meet these requirements and withstand pressure.


How to Solve the “Stop Start Not Ready Battery Protection Mode” Warning?

There are ways you could try to resolve the “stop/start not ready battery protection mode” warning:

  1. Getting a charger should be your first step. Plan to charge for an entire day if your charger is small. It would be ideal if you could drive to a nearby auto parts shop that provides free battery tests. If you have another vehicle and can drive, you can remove the battery from the Jeep and test it (if you feel comfortable doing so). The battery is the one that can be tested the quickest. Check it out first, then the battery sensor and the alternator.
  2. Set it up for overnight trickle charging. Give the trickle charger 12 to 16 hours to run continuously. If no battery tender is available, simply go for a long drive with stop start turned off, preferably at highway speeds. That’ll charge both batteries via the PCM and BCM.
  3. To restart the Jeep after the proper voltage has been restored, turn it off, let it sit briefly, or open a door. Until the voltage drops again, it will reset the system.
  4. If your Jeep was sitting in the dealership for a while, charge it sufficiently while driving it home, and you won’t have the issue again.
  5. Sometimes you can resolve the issue by charging the Aux battery properly. But if the AUX is dying or there is a bad relay, what I have encouraged you to do will not be a remedy.
  6. Only drive for a short time with the AUX battery connected if it appears that your main battery is running low; doing so will also drain it. Unplug the AUX negative terminal until you get a new battery.
  7. After replacing the batteries, did you perform a battery reset? Detach the negative cable(s), press the brake pedal for 30 seconds, reconnect, and start the engine. If that does not make a difference, check the charging system if you haven’t yet.
  8. If your battery is currently in its fourth year and dying, replace the battery, or it will deplete your other battery. On both batteries, unplug the negative cable after waiting around five minutes. Reconnect the device and take a 30-minute drive on the highway to recharge the battery. “stop start not ready battery protection mode” message will not return.
  9. Your battery might have been accidentally heavily discharged; all it needs now is a good/full charge. Additionally, make sure the battery connectors are tightly fastened.
  10. Remove the cap from the fuse box (power distribution hub) next to the main battery. Now, apply pressure firmly to each fuse and relay inside. There, you’ll discover improperly seated fuses and relays.
  11. Have your mechanic perform a re-learn procedure on the Jeep if the “stop start not ready battery protection mode” message appears after you’ve changed your batteries. Everything will work out fine.
  12. A 100% fully charged battery is required for stop-start systems. Check your battery. It may work fine for everything else but may be less than 100%. The stop start system will resume regular operation once the battery is replaced. Factory batteries are typically poor quality and only last 3–4 years, whereas a high-quality aftermarket battery may last up to twice as long.


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