My battery is showing 11.5 which I believe means its discharged. I'm not sure how to recharge it.

Will simply using jump leads from another car and running the second car for n minutes cause the battery to recharge? how long should I leave the second car running for?

Will a car booster work? As far as I'm aware this doesn't recharge the battery like a car battery charger does so won't work?

Can I disconnect my battery and take it to the shop, is there anything they can do to recharge it?

Basically these seem the simplest options to avoid buying a new battery but I just want to know if they may work?

3 Answers 3


The best way is to connect it to a BATTERY CHARGER for an amount of time that depends on the output capability of the charger and the capacity of the battery. For example if the battery has a capacity of 250 AH (AH = Amp Hours) and your battery charger supplies 10A, it will take 250/10 = 25 Hours to fully charge.

Connecting to another battery via jumper cables can be done but it's harder on the battery being charged due to the very high charging current supplied.

Not all batteries can be successfully charged, however. Batteries used in cars (i.e. LEAD-ACID technology) have a limited lifetime and often fail quickly if discharged too deeply or cycled between charged and discharged multiple times. These batteries can also develop dead cells, internal open-circuits, and other problems that end their useful lives.

Most auto shops can load test a battery for you and determine if it can be charged and used or if it needs to be replaced.


If your battery is at 11.5V, a jump-start will be successful. Follow the instructions on the leads. Once you get the car running, put your meter across the battery terminals. If it still reads 11.5V, your alternator is done. If the battery reads about 13-13.5V, your alternator is good. Drive the car to a spares store for a full diagnostic once you get it running - you need to know why it's at 11.5V.


The boost starter (jump pack) just provides a extra boost for your car to help it start. They do not provide charging the same as a battery charger or maintainer.

How old is your car battery? As I know, they work well for the first 1-3 years depending on type. Check if it needs to replace or not, if yes, just replace it.

There is absolutely no need to take it to the shop (yet). Its easy to take the first steps of checking the battery and charging system at home.

  • 1
    My car is 16 years old - should I have replaced it 12 years ago?
    – Solar Mike
    Feb 12, 2020 at 9:08
  • you might want to take a look at other brands of cars,i am guessing here but i think most of the users on our site have cars that are more than 3 years old.(i was thinking of making an apple joke now but forget it they have their own problems) Feb 12, 2020 at 10:05
  • Thanks for all your advice. It's my mistake. Now I have more knowledge of car batteries's longevity. Thanks again
    – Jolie
    Feb 12, 2020 at 10:12
  • @Solar Mike If not maintained properly like many batteries, then yes. Probably so.
    – narkeleptk
    Feb 12, 2020 at 20:41
  • I like this answer, not sure why the -2 down votes. Battery's these days do tend to fail after a few years when not tended to properly. Maybe the users just had trouble understanding what you meant. I hope my edit helps a little in that case.
    – narkeleptk
    Feb 12, 2020 at 20:45

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