14.4 volts is the gassing threshold. The battery above will slightly gas, but not enough to be harmful, and the battery will get a quick full charge recovery after starting. 14.8 would start to be a worry (there might be liquid or corrosion on the battery) and 15 volts would be a real concern, but 14.6 is fine.
If the voltmeter reads between 14-15 volts then the battery is normal. But if the battery reads over 15 volts or less than 13 volts, then there might be a problem with the alternator. The alternator is over charging the battery or not giving enough charge to the battery.
If your battery has a charge between 12.4V and 12.7V, your battery is fully charged and ready to run. If your voltage is below 12.2V, it needs to be recharged. Take a 30-minute drive on the highway or pick up a charger to bring the voltage back up. If your voltage is higher than 12.9V, the battery is overcharged.
A good alternator should produce about 13.5 to 14.5 volts with the engine idling. If the voltage reading is low (12.5 volts or less), it indicates a charging problem but does not tell you what's causing it.
A good alternator should maintain battery voltage between 13.9 and 14.8 volts (14.2 is optimum). Even worst-case, with all accessories turned on, there should be at least 13 volts at the battery.
14.4 volts is the gassing threshold. The battery above will slightly gas, but not enough to be harmful, and the battery will get a quick full charge recovery after starting. 14.8 would start to be a worry (there might be liquid or corrosion on the battery) and 15 volts would be a real concern, but 14.6 is fine.
The ideal car battery voltage with the engine running is between 13.7 and 14.7V. With the engine off, you should get a reading of 12.6 volts. If the battery isn't fully charged, it will diminish to 12.4V at 75%, 12V when it's only operating at 25%, and down to 11.9V when it's completely discharged.
With the motor running, the multimeter rating should stay in the 14 to 14.5 volt range. Dropping below 14 means either the battery is weak and unreliable for sustained vehicle operation or the alternator is failing.
Measuring your car battery's voltage can help you determine how charged your battery is. A perfect voltage with the engine running is between 13.7 and 14.7V. With the engine off, it should be 12.6 volts.
The actual voltage regulator set-point is typically between 14.1 and 14.8 volts and that is why an alternator may be referred to as a 14 volt alternator instead of a 12 volt alternator. The battery needs to receive 14+ volts in order to maintain its charge. The same rules apply for a 24 volt system.
14.5-14.6 is normal voltage while the alternator is running.
12-volt batteries supply useful energy only through a limited range — from over 14 volts (when fully charged and unrested) down to 10.5 volts in use/under load (when lights dim, pumps groan and TV pictures get small). No 12-volt battery will remain at over 14 volts for more than seconds unless it's being charged.
When a car battery is fully charged, the voltage values should measure at 11.9 volts or above. When the car engine is running, this measurement should be 13.4 to 14.8 volts. but the low voltage doesn't necessarily equal a bad battery.
The target voltage for a 12 volt charger for AGM or some flooded batteries is 2.4 to 2.45 volts per cell, which is 14.4 to 14.7 volts. Some flooded cells will tolerate over 15 volts.
It'll be fine. 14.6, 14.4, 14.8... All of these are well within the variations expected for the "nominal" voltage for Lithium-ion batteries. These are clearly four-cell batteries (nominal 3.6 V/cell, 3.7 for some slight variations in chemistry), but when freshly charged they'll be at more like 4.2 or 4.3 V/cell.
Fully charged batteries should produce between 13.7 and 14.7 volts while you're driving.
A good car battery should read 12.4-12.9 volts when the car is off. Anything lower doesn't necessarily mean the battery is bad. Your car's electrical system may have drained it, or there may be an issue with your alternator. Recharge the battery and test it again later to see if it's holding a charge.
12.6V volts or above - Your battery is healthy and fully charged. No further action is required. 12.5 volts - Your battery is at a healthy state of charge, but we'd recommend re-checking it within a few days to ensure the voltage hasn't dropped any further.
When we take a closer look, we see car battery voltage can range anywhere from 12.6 to 14.4. With the engine off, the fully charged car battery voltage will measure 12.6 volts. This is known as “resting voltage.” When the engine is running, battery voltage will typically rise to 13.5 to 14.5 volts.
So, to answer your question, Yes, 15 volts is too high. Most car alternators, that normally recharge your battery after every start, and provide power while the engine is running, are normally voltage regulated to about 13.8 to 14.0 volts.
A fully charged car battery should be between 13.7 and 14.7 volts while you're driving. One way to test your battery's power is by starting the engine and turning the headlights on. If the headlights are dimmer than usual, this could be a sign of a poorly charged battery.
14V is fine - most cars charge their batteries at around 14.4V.
When fully charged, how many volts should a car battery have? charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts.
Fully-charged, most car batteries will measure at least 12.6 volts (~13.0-13.2V for OPTIMA YELLOWTOPs), but low voltage doesn't necessarily equal a bad battery. Modern cars are very demanding from an electrical perspective, even when they're not being used.