If your headlights are dim and appear yellow, instead of white, your battery's power may be declining. You might also notice that interior dome lights appear dim, or flicker, and warning lights may display on the dashboard.
Place the positive multimeter lead on the positive battery terminal and the negative lead on the negative terminal. Have a helper turn the ignition on for no longer than 15 seconds and watch the multimeter. If the battery voltage drops below 9.6 volts, this is an indicator of a weak battery.
In general, your car will usually need a new battery after three to four years. Replacing your car battery is another part of routine maintenance. Getting your battery checked and inspected is standard for your service visits after three years, even if you haven't needed it replaced yet.
If your battery is over 4 years old we'd advise replacing it with a new one. You may find you're able to temporarily recharge a battery this old, however it's likely to lose its charge again very soon. Older batteries do deteriorate over time and naturally lose their ability to hold a charge.
Service experts estimate that you should replace your car battery every four to five years.
An effective method to determine whether it's your battery or alternator that's gone bad is to connect jumper cables from a running vehicle's battery to yours. After a few moments, try starting your vehicle. Once it's started, remove the jumper cables — if your engine stalls, your alternator has probably gone bad.
Parasitic Drain - If the electrical devices in your car or the lights on your car are left running even when your ignition is off, they will suck the juice out of your battery slowly but dramatically. This is often eerily described as parasitic drain.
A corroded or defective alternator diode will faultily continue charging the circuit even when the car off. This, in turn, will drain your car battery and cause the car not to start.
Factors that can shorten its life include an extended period of partial or full discharge, vibration from not being properly secured, under- or overcharging, extreme temperatures, water loss, electrolyte contamination and corrosion on terminals.
Depending on power, size, and quality, prices for a replacement car battery range from about $45 to $250. Your local dealership, auto parts store or automotive service center can check your current battery or hook you up with a new car battery.
A battery might need replacement if its volts suggest it's gone bad. As your battery ages, it loses its capacity to hold an electrical charge. An old battery can cause some identifiable issues, especially when you're starting your car.
Batteries gradually deteriorate until they can no longer provide enough power to start an engine. This wear time could take three to five years and a vehicle's usage pattern is one factor contributing to the rate at which a battery will age.
Why won't my car start but I have power? If you attempt to start up your car but the engine won't turn over and the dashboard lights up, then you most likely have an issue with your battery. You could have a damaged or corroded battery terminal, which is stopping the engine from starting up when you fully turn the key.
Signs of a Bad Alternator
Some of the things to look for are no-starting and trouble starting, dimming lights and problems with stereo system output. If your car starts but stalls when you're underway, your battery is probably not being recharged due to a faulty alternator.
The answer is simple - Yes, You can jump-start a car with a bad alternator.
Alternators can average anywhere from $100 to $350, depending on the model. In most cases, costs will average between $350−400 for the alternator replacement if no other parts need to be changed. Add another $20 to $50 to your bill if the serpentine belt has to be replaced as well.