BHPian Jeroen recently shared some thoughts on battery testing in general. This thread is about the standard 12V battery for cars. There are many different types of batteries on the market, not referring to capacity here, but rather the battery construction and the underlying chemical principle it is based on. Most car batteries in India are sealed lead-acid batteries. In more luxury cars, you can find AGM batteries (absorbed glass mat). Your car may have a regular lead-acid battery if you need to regularly check its condition and top it up with distilled water.
The most obvious way to check the battery condition is by using a simple voltmeter. Make sure the ignition is off and secure everything that may draw power from the battery. After turning off the engine, wait 10-15 minutes before conducting the test. If you have just started the car and turned it off again, it’s better to wait a little longer.
For modern cars, it may be difficult to measure the battery voltage. Modern cars shut down various systems for the first 30-60 minutes. Especially within the first 10-15 minutes, there may be significant battery drain. (For more information, see my thread on parasitic drain.)
Regardless of the exact battery type, the fundamental principle is that a fully charged battery should show around 12.6 volts. A value below 12.0 volts may indicate battery degeneration.
It is also important to keep the battery terminals clean when connecting the meter. It is good practice to apply a bit of white petroleum jelly to the battery terminals and connectors. This prevents corrosion and damage, but also affects measurement accuracy.
Other methods include testing SOC (state of charge) and SOH (state of health) of the battery. SOC represents the difference between a fully charged battery and the one in use, under a known quantity of charge supplied. It is expressed as a percentage of the available charge in the battery compared to the maximum charge it can deliver. SOH describes the difference between the tested battery and a new battery, taking into account the cell aging process. It is expressed as a percentage of the battery’s capacity compared to the nominal value.
In summary, SOC provides information about the battery’s charge status compared to a new battery, and SOH informs about the rate of battery discharge. The lower the SOH, the faster the battery capacity becomes depleted.
If you are interested, check out this article that explains the above concepts in more detail.
If you follow my thread on car DIY, you may recall that over the past year, I have had several battery-related issues. Sometimes, the blame lay with the battery itself, other times I had to replace the alternator, and currently, my Jaguar has a slight parasitic drain. I always had to rely on the help of others to check the status of my batteries, apart from obvious voltmeter measurements. This led me to come across different battery testers. It turned out to be difficult to find detailed information about what makes a good battery tester. I will come back to this later.
Since I often buy things from Chinese websites like AliExpress and Temu, I frequently see ads related to “tools” in my Facebook and other platform newsfeeds. I noticed a small battery tester on the Temu website. With a discounted price from 150 euros to 25 euros. I simply could not resist such an opportunity, so I immediately used my credit card!
The delivered package arrived within 10 days.
As you can see, it is a very simple box. The manual seems more elaborate than it actually is because it contains text in 35 different languages. So, don’t expect too many details.
In theory, using it is very simple. Just like with a meter, make sure you connect it to clean metal parts of the battery and that the battery is not powered by any devices. If the battery is in charging mode, disconnect it.
You need to check some information about your battery, such as the type and CCA (Cold Case Crank). CCA measures the battery’s ability to start the engine in cold conditions. It indicates how many amps a 12-volt battery can deliver for 30 seconds at -17.8 degrees Celsius before the voltage drops to at least 7.2 volts per cell.
As the atmospheric temperature drops, the battery provides less and less cranking power. However, as the atmospheric temperature drops, the engine will require more and more energy to start!
Finding information about your battery type can be a challenge. None of the six batteries in our car fleet had the mentioned battery type. I had to search for information about each battery online.
FAQ section based on the main topics and information presented in the article:
1. How to check the condition of a car battery?
The most obvious way to check the battery condition is by using a simple voltmeter. Make sure the ignition is off and secure everything that may draw power from the battery. After turning off the engine, wait 10-15 minutes before conducting the test.
2. How to measure the battery voltage in modern cars?
For modern cars, it may be difficult to measure the battery voltage because various systems are shut down for the first 30-60 minutes. It is recommended to wait longer before conducting the test.
3. What voltage values indicate a fully charged battery?
The exact battery type may vary, but the fundamental principle is that a fully charged battery should show around 12.6 volts. A value below 12.0 volts may indicate battery degeneration.
4. What are SOC and SOH of a battery?
SOC (state of charge) is the difference between a fully charged battery and the one in use, expressed as a percentage of the available charge compared to the maximum charge. SOH (state of health) describes the difference between the tested battery and a new battery, taking into account the aging process, expressed as a percentage of the battery’s capacity compared to the nominal value.
5. What are the methods for testing SOC and SOH of a battery?
SOC can be measured by comparing the battery’s charge to a new battery. SOH can be evaluated by analyzing the rate of battery discharge. The lower the SOH, the faster the battery’s capacity is depleted.
6. How to use a battery tester?
Connect the tester to clean metal parts of the battery and make sure the battery is not powered by any devices. Disconnect the battery if it is in charging mode. Check the information about your battery, such as the type and CCA (Cold Case Crank).
7. Where to find information about the battery type?
Information about the battery type can be found online, as it is often not available on the car battery itself.
Useful links:
– Occupational Health and Safety
– AGM Batteries – Guide
– Dead Battery Syndrome – How Car Batteries Work
The source of the article is from the blog agogs.sk