Fully charged car batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts.
- Slow engine crank:
When you attempt to start the vehicle, the cranking of the engine is sluggish and takes longer than normal to start. You’d best describe it as the “rur rur rur” starting noise sound & engine will take time to start after doing more cranks.
- Check engine light:
The check engine light sometimes appears when your battery power is weak.
- Low battery fluid level:
Car batteries typically have a part of the casing that’s translucent so you can always keep an eye on your battery’s fluid level. If the fluid level is below the lead plates: (energy conductor) inside, it’s time to have the battery and charging system tested.
- Swelling, bloating battery case:
If your battery casing looks like this you can blame excessive heat for causing your battery case to swell, decreasing your battery life.
- Battery leak & there’s a stinky, rotten egg smell:
You may notice a pungent, rotten egg smell (sulfur odor:) around the battery. The cause of Battery leaks. Leaking also causes the corrosion around the posts (where the (+) and (–) cable connections are located.) The gunk may need to be removed; otherwise, your car may not start. How to remove by hot water
- Battery age:
Three years + battery age is considered an old timer: Your battery can last well beyond three years but, at the very least, have its current condition inspected on a yearly basis when it reaches the three year mark. Battery life cycles range from three-to-five years depending on the battery. However, driving habits, weather and frequent short trips (under 20 minutes) can drastically shorten the actual life of your car battery. (As per the Vehicles)