Tag: stop start engines

What is an AGM battery?

AGM car batteries (Absorbent Glass Mat) were developed for use by the military in the 1980’s. Their high performance and enhanced reliability also suit todays modern vehicles that are often heavily equipped with sophisticated electrical systems. The last decade or so has seen an increase in the number of cars using stop/start technology and AGM batteries – but what does this mean? In this short article, we will explain the technology and outline the advantages of AGM batteries.

What is stop/start technology?

The stop/start system was developed to help reduce fuel consumption and CO2 emissions, to create a safer environment. A stop/start system shuts off your vehicle while stationary and can be restarted once the driver puts pressure on the accelerator or clutch. By shutting the engine off after about 1.5 seconds and prolonging this until it is safe to drive off, this technology is designed to reduce fuel consumption and CO2 emissions by 5-10%. However, vehicles with stop/start technology place a greater demand on a vehicle’s battery – and this is where the AGM battery stands head and shoulders above the more conventional acid flooded lead battery.

What are the advantages of an AGM battery?

The AGM battery is cheap to manufacture compared to other strategies used to help reduce carbon emissions, making vehicles more efficient and cleaner. AGM batteries offer a number of advantages over traditional lead batteries, including;

  • Less expensive – they can typically last up to two times longer.
  • More reliable – greater tolerance to hot and cold temperatures.
  • Greater performance – ideally suited for vehicles equipped with lots of electronic devices and accessories.
  • Slower discharge whilst not in use.
  • More durable – greater vibration resistance.
  • Safer – no free-flowing electrolyte, therefore no spill hazard.
  • More powerful – improved performance.
  • AGM technology batteries can typically reduce CO2 emissions by up to 8% more than traditional batteries.

Vehicles fitted with AGM batteries must be re-coded whenever removed or replaced; therefore is is recommended this be done by a professional. Do you need a replacement AGM car battery? Or would you like to know if your vehicle is compatible with AGM battery technology? Simply enter your registration number or make and model. Whichever battery you have, make sure you use the right charger. If you would prefer to speak to one of us, give us a call on 0800 164 9361. We’re happy to help.

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Top 10 Car Battery Facts

A car battery gives the initial boost that cranks and starts the engine of your vehicle. Once the engine is running, the battery could, theoretically be removed and the car would run quite happily. However, we wouldn’t recommend testing this theory as you’d have a problem restarting the engine once the ignition was switched off.

There are many misconceptions and myths surrounding car batteries, so below we have set out ten facts about the battery under your bonnet, facts that may provide you with a better understanding of how it works and how to get the best out of your battery.


Batteries naturally discharge

Vehicles need to be driven regularly and for distances that allow the battery to recharge itself properly or it will discharge its power and run flat. In fact, regular longer runs could double the life of your battery



A weak battery can have a knock-on effect on other parts of the vehicle such as the charging system and starter as they have to draw excessive voltage due to the reduced battery power.


Providing the battery fitted to your vehicle is designed to meet the demands of your particular make and model, is properly maintained, and your vehicle driven for distances that give the battery time to recharge itself, it should last for up to five years.


We strongly recommend that you avoid replacing the battery yourself because if you make a simple mistake it could damage the whole electrical system of the vehicle.


Don’t be fooled, or rush out to buy a new battery if the battery warning lights up on your dashboard; it doesn’t always mean that there is a fault with the battery. It could be a problem with the vehicle’s charging system, or some other electrical fault. But we do recommend that you check with your nearest garage or contact us as soon as possible because to delay could result in serious damage to the electrical system and may indicate an imminent breakdown


If the car battery leads are connected incorrectly it can cause the electrical current to flow in reverse polarity resulting in serious damage to the vehicle’s electronic system. Consequently the fuses could be destroyed and potentially cause the battery to explode.

For this reason many motorists have their batteries fitted by a professional and why we encourage motorists to have their batteries fitted by us.


A faulty or failing battery can affect the fuel economy as the vehicle’s alternator will have to draw more horsepower to charge the battery adequately, meaning the added load puts more pressure onto the battery and uses more fuel.


Extremely cold weather can result in the battery losing power. For this reason, today’s batteries include cold cranking amps (CCA) that give that extra boost to assist starting on cold winter mornings. CCA is the number of amps delivered by the car battery at 0℉ within 30 seconds without dropping below 7.2 volts. The higher the CCA of a particular battery the better will be the performance. But be aware, hot outside temperatures can also deaden your battery – for more on this click here to view our article titled ‘Has my car battery died’.


All dead car batteries should be recycled as they contain lead dioxide and sulphuric acid which can harm the environment, as well as being dangerous to your health.

If you have replaced the battery yourself you should take the old one to your local recycling centre or scrap metal facility, however as part of our fitting service, we can do this for you, completely free!


Car battery size and choosing the correct battery for your make and model of vehicle is important – pick the wrong one, then no matter your cars specification, or how well it is maintained, it simply will not perform as it should or could.


When you need a new car battery, simply visit the RAC Shop and enter either your vehicle registration or the make and model then pick from the selection of batteries chosen for being the correct one for your car. You can then decide whether you want to fit it yourself, or leave the job up to a professional by contacting us here at the RAC Shop.

When you need a new car battery, simply visit the RAC Shop and enter either your vehicle registration or the make and model then pick from the selection of batteries chosen for being the correct one for your car. You can then decide whether you want to fit it yourself, or leave the job up to a professional by contacting us here at the RAC Shop.

Whichever battery you have, make sure you use the right charger. Choose the correct charger for your battery by clicking on the link, or if you would prefer to speak with one of our advisors regarding the appropriate battery or charger for your vehicle, then give us a call on 0800 8620676. We are here to help.

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