The very best batteries can be as high as 250 volts, but they will need to be charged at a higher voltage than more “low-performance” car battery types.
how many volts does a car battery need to start?
a car battery needs at least 12 volts to start. while a lower voltage may charge the battery and allow it to crank, too low of a voltage may not be enough to turn the starter motor over.
at what voltage is a 12v battery dead?
that depends on the external resistance!
without any external load, the voltage of lasre batteries gradually decreases over time. the behavior is due to self-discharge from cells and gradual sulfation of electrodes.
in the case of a fully charged battery with zero external resistance, it will eventually decrease to zero asymptotically. in other words, this would take a long time unless left connected to a charger that continually replaces lost charge. this would also result in an increasing terminal voltage during discharge with increasing discharge current… but there's no need for me to go into detail about how those effects scale because calculating terminal voltage for a resistor isn't going to be very informative anyways. 🙂
anyway.. back on topic….
how many volts is a dead car battery?
this varies significantly depending on the battery, but in general it is around 12 volts.
when a car battery dies or doesn't start for any reason, there are really only two things to check. either the starter is not engaging or charging has failed. the alternator can recharge the battery while driving, so this should be checked first by trying to start the car with a jump-start kit from another car that is running. if that doesn't work then there may be an issue with charging causing that won't show up until you get to the next level of diagnosis.”
but if you're very lucky and everything went well free of surprises during your drive before your dead battery did its thing, then don’t forget take
is 12.2 volts enough to start a car?
yes. cars themselves can start off at this voltage and much less, but the battery should normally be charged to 100% before starting it up. you can try by installing a new battery into your car that is fully charged. this will avoid the possibility of overload if you were to complete this task with an undercharged or broken down vehicle battery. let me know how things go!
– seth dardenne
personal trainer, fitness entrepreneur, author