Saturday, May 25, 2013

How To Extend Your Car Battery Life

Tweet

Battery Life in cycles as impacted by Depth of Discharge

This Graph by Power-Sonic illustrates the relationship between depth of discharge and number of cycles as well as increases of capacity during the early cycles.

This article contains information you need to know about flooded lead-acid and sealed lead-acid car batteries and will give you insight on how to extend your car battery life.

If you find yourself replacing your car battery every 1-2 years, you need to read our complete “Use it or Lose it Guide to Car batteries”.

Car batteries have a calendar life meaning at one point whether you use them or not, you will need to replace them. This article provides you with valuable knowledge about car batteries along with some quick tips and more extensive guides to extend your car battery life.

Quick 5 Step guide to getting the most out of car batteries

Keep the battery terminals clean and inspect regularly (i.e. monthly) for corrosion.
Start the car before operating car accessories and operate (drive) the car to allow the battery to get topped off by the car alternator which produces electricity and as a by-product charges the car battery after voltage drops in the battery.
Keep the battery secure and free from vibration. Batteries that shake can become damaged and short circuited or worse cause damage to your car.
Insulate the battery from extreme temperature changes with a car battery insulation kit. These usually come with new cars already, however you can find replacements specifically made to fit your car’s battery compartment. The sleeves are usually plastic or an acid resistant/thermal resistant material that insulates your battery but still allows it to vent.
Invest in a car battery charger that will maintain an optimum charge level when your car is not in use or when you go on vacation.

One last recommendation:

Check the car battery water level indicator on a regular basis! Most car batteries will indicate if it needs more water. It may never require water, but if so only use distilled water.

Use it or Lose it Guide to Car Batteries
There is some truth to the adage “use it or lose it” when applied to batteries. When a car battery is not being used, it still loses energy or capacity even without external drain. We call this self discharge. The self discharge rate varies based on chemistry and ambient temperatures. At room temperature 20 degrees Celsius (68 degrees Fahrenheit) a lead-acid battery typically self discharges at a rate of 3% per month. This rate drops for colder temperatures but increases with warmer temperatures. If a lead-acid battery is stored for months on hand it will eventually lose capacity which is a result from sulfation.

Car batteries are kind of like the human body which functions best with regular exercise, food and water. If you think about a car battery in this way, you can say a car battery is exercised when it is starting a car and being fed when it is recharged by the alternator or car battery charger. Water maintenance is an important part of conventional flooded (wet) car batteries that require water maintenance. Some car batteries are maintenance free and don’t require you to add water. In most cases except in “deep cycle” situations you may never need to add water throughout the car battery life cycle. Inspect your car battery for a water level indicator. It usually displays a light green color if water is level is good and a dark color if it needs water.

Maintaining a balance to the battery’s charge/discharge state is critical to the longevity of your car battery. If your battery requires “watering” then you will need to check water levels regularly such as every month or more depending on the ambient temperature or if your battery is getting overcharged. If you are not diligent at vehicle maintenance be sure you buy a sealed lead acid car battery that is maintenance free so it won’t ever require adding water to it. The

A car battery is exercised or “discharged” when it starts your car, however a car battery has secondary functions such as maintaining power for onboard car computers and powering everything from the ignition, lighting, electrical accessories such as air conditioning, power windows, power seats, electric rear defogger, driving lights, and more when the car is not running. Car batteries are often denoted as SLI batteries (starting, lighting, ignition). Once the car is started, the alternator generates a continuos circuit of electricity needed to operate the car and electrical accessories.

The car alternator does not store energy but the car battery does store energy which creates a harmonious relationship between the battery and alternator. When the alternator is running after the car is started, the battery is still part of the alternator charging circuit and it will become recharged/receive voltage from the alternator when the difference in the circuit is higher in the alternator.

The car battery is not designed to provide continuous high levels of energy. It’s main purpose is to provide a high level of energy for a short period of time to start the car. The amount of energy a battery can produce for this purpose is referred to as CCA or it’s cold cranking amps. Each car will have unique requirements for the neccessary CCA required for starting.

Energy is drained or discharged from the battery when it starts the car as well as from the accessories it needs to power. Restarting a car before the energy lost is restored will cause the battery to have a greater DOD (depth of discharge) meaning it requires more and more energy to be restored to it’s fully charged state. This is why it’s not healthy for the battery when you have to frequently start and stop the car. When you stop the car, the alternator is no longer capable of charging the battery so if the battery did not get fully recharged, it will have to start the car next time from a weakened energy state (from a greater depth of discharge).

It’s like going to the gym then going to sleep and then going back to the gym without eating in between. Pretty soon it will become more and more difficult to lift those weights.

Most batteries will have a “cycle life”. Cycle life is usually referring to how many full cycles a battery can withstand before it is no longer useful. One full cycle usually refers to taking a baterry from 100% charged state to a 20% charged state. This can also be stated as an 80% depth of discharge for one cycle. You can find out the cycle rating from the battery manufacturer. The rule of thumb is you do not want to discharge your car battery more than 50%. The longest car battey life is usually achieved when your depth of discharge is between 5 to 10%. If you find yourself replacing your car battery too often, be sure to check the car manufacturers CCA rating and buy a battery that is either equal to or greater than the CCA rating of your car.

So how do I apply Atbatt’s “Use it or Lose it” car battery philosophy?

Avoid frequent short trips in your car
If you don’t drive very often, invest in a good car charger like the Noco Genius 26000 which has multiple capabilities such as float charging, pulse mode to remove sulfation, charging flexibility to support various battery types, fail safe modes, and temperature sensor for monitoring the ambient temperature to automatically adjust the charge profile as conditions change.
If you go on vacation invest in a car charger to maintain your car battery. This also prevents your battery from going dead (flat) which can cause onboard car computers to fail.
Avoid operating car accessories if the car is not running
A healthy battery gets discharged 10-20% and then recharged to full capacity. Performance data indicate batteries that get discharged only 5-10% tend to last the longest.
Make sure the CCA rating of your battery is equal to or greater than the CCA rating of your vehicle

Why is my car battery getting drained (becoming flat) when the car is off and it’s not powering anything?
The battery loses capacity from self discharging. If it is connected to your car, it could also have a small load from accessories or car computers that will draw current from the battery which will also aids in the battery losing capacity if it is not being recharged. Bad cables causing short circuits and bad alternators which don’t effectively recharge the battery are sometimes the culprit as well. If you suspect a bad alternator you should take your car to a car battery specialist or a mechanic that can test the battery and check for parasitic drain.

Car Battery Tip #1
If you plan to disconnect your car battery from your car, be sure you read your car owner’s manual! In most cases (unless otherwise stated in your manual) you will need to disconnect the negative cable first and then the positive cable. When you reconnect the battery you use the reverse order by connecting the positive cable first and then the negative cable. Doing this simple step incorrectly can have adverse affects on fuses and other electronics especially in Mercedes Benz and BMW type vehicles resulting in $$$ hundreds of dollars in repair. Even keeping the keys in the ignition when connecting or disconnecting may have negative effects so always read the manual.

You can also invest in a specialized 12v battery or specialty device that will maintain power to the electronics in your car so onboard computers, lighting, fuses and car radios do not get affected. Many things you wouldn’t think about are actually controlled by computers in cars. So read the Car Manual before attempting removal of your car battery.

Car computers control things like your car idle settings and when reset may force you to make a visit to your mechanic. Also some car stereos may require a special code provided by the manufacturer to be entered if power is disconnected.

Car Battery Tip #2
Never overcharge your car battery! When lead-acid batteries are overcharged, they could release oxygen and hydrogen gases which could be explosive. Also this causes decomposition of the water in the battery leading to premature aging of the battery. Hit

SAFETY CAUTIONS
Never try to open a sealed lead acid battery to attempt something crazy like cleaning the lead plates. That’s just way too dangerous and not worth the health risk. It will also damage your battery and likely cause bodily injury. Batteries contain dangerous chemicals and heavy metals and create explosive gases when charging so never tamper with them and always charge in a well ventilated area. Before handling a car battery that is installed in your car, open the hood and allow time for natural ventilation to take place.