You are in a hurry on the way to work, and you jump into your car and quickly turn the key, but nothing happens.
The car battery is drained. You have a car battery charger in your garage, but how long does it take to charge a car battery?
Charging a car battery is not always as easy as it sounds; there are several tricks out there to save your battery and give it a longer lifetime!
In this article, you will get all the answers you want for this question, and a bit more!
How Long Does It Take to Charge a Dead Car Battery?
Generally, it takes about 2 to 4 hours to fully charge a normal-sized car battery with a 20 Amp battery charger and about 12 to 24 hours with a 4 Amp charger. The charging time heavily depends on the car battery size and the charger’s power output.
The most common rate for car battery chargers is around 4 amps. To fully charge a battery of the size 52 Ah would take about 10 hours from dead to fully loaded, but you could probably start your car within 1 hour.
First, you have to look at your car battery charger to find out how much ampere it’s giving out. High amperes charge your car battery faster. Low ampere is better for maintenance charging of your battery over long periods.
You also have to look at the size of your car battery and the battery type. Usually, a mid-sized car uses a battery of the size 40-80Ah. You also have to take in mind the kind of car battery. An AGM/GEL battery can charge up a bit faster than a regular wet battery.
Charging times with different battery chargers
Different car battery chargers give different amounts of power, so the charging time of a car battery will depend a lot on this. For sure, it takes a different amount of time to charge different types and sizes of batteries also, but there are times for a normal-sized car battery around 62 Ah.
Here is how long it takes to charge a car battery:
- 2 Amp charger: 24 to 48 hours
- 4 Amp charger: 12 to 24 hours
- 10 Amp charger: 3 to 6 hours
- 20 Amp charger: 2 to 4 hours
- 40 Amp charger: 30 minuter to 1 hour
What is the best speed to charge a car battery?
The amount of time it takes to charge your car battery should depend on what you want to acquire. Fast charging can damage your battery and will make its life shorter. Long-time charging with low amps is best for keeping the battery’s lifetime long.
Usually, a standard car battery charger is giving out 4-15 amperes. 2-4 amperes is typical for maintenance charging, and it will take around 24 hours to fully charge a dead battery at this load. Check your car battery charger for any settings for the charging rate and apply the charging rate for your needs.
To charge your car battery quickly without damaging your car battery, I would recommend charging your battery at the rate of 8-15 amperes. Charging your battery over 15 amperes can damage your battery if you are unlucky and make the lifetime shorter.
What causes a battery to go flat?
There could be many reasons why your car battery went flat. The most common reason is that you forgot a light or something similar in the car before leaving it. It can also be a problem with some electrical function that does not want to switch off when you turn off the ignition.
Also, a bad car battery can cause your battery to drain. To learn more about the different causes, you can see our article about the main reasons why your car battery is flat.
How long does a car have to run to charge a dead battery?
If you jump-start, you can also let your car’s alternator charge the car battery for you. How long it will take for your car to charge the battery depends a lot on the car engine and the size of the car battery. Cars have very different effects on the alternators, giving everything from 30 to 150 amperes.
The engine’s RPM also matters when charging a car battery, because the alternator is charging harder when it is spinning faster. If you want to charge your car battery fully with your alternator, you can expect it to take some hours.
It is always recommended to charge your dead car battery with a car battery charger instead of the engine though.
Which car battery charger is best to use?
First, you have to figure out what type of battery charger you need. Maybe you need a fast one or just a maintenance charger?
Modern chargers are easy to connect and have battery charging monitoring, which will regulate the amps themselves, but you should still check to see how many amps it’s charging with before buying one.
Cheaper chargers often promise more amps than they charge with. It’s better to choose a quality charger that gives lower amps instead. It will save your car battery, and it will minimize the risk of damage to your vehicle.
A car battery charger I really can recommend is the CTEK charger. You can find them here on our list of “Best Car Battery Chargers.” They have several sizes of their chargers for your needs, and it’s a well-known brand probably making the best car battery chargers on the market.
29 thoughts on "How Long Does it Take to Charge a Car Battery?"
John Meyers
I haven't AC Delco professional gold battery in my 2003 GMC Sierra that only has 87,000 miles. My question is what is the best ctek battery charger for this battery. I seldom drive the truck, sometimes leave it in the garage for the winter and it still starts after the winter. I recently went out to started after it hasn't been run for about a month and it was dead so rather than use jumper cablesc is there ctek charger you would recommend? I'm looking for the best quality and easiest to operate charger. Thank you
Joey
https://www.amazon.ca/CTEK-40-206-5-0-12-Battery-Charger/dp/B00CD44RQO This will work with your battery, group size 78
Brian Williams
M y 2007 Seat Ibiza has been stood for 3 weeks. It is a sealed battery and the battery indicator is black. Is it dead or can I trickle charge? I have a battery charger with 'start/boost' option but this needs two people according to charger manual. (One to turn key, one to press switch to starter/boost).Thank you in advance
Tony
My battery is my battery is fully charged and it will start the car the same day however when I start my car the next day it will not start what is a problem
Ostyn
It could be that did your cold cranking amps could have run out so you can’t start your car
Vincent
Sorry for random question on fbook. If you are familiar with the batteries can you tell me a battery charger controller which will cut off the charging power source to avoid the battery to be overcharged. They told me that overchaging the battery is not good and I am not going to wait 10-20 hrs for my battery to be full charged. I may even charge it overnight which means I cannot monitor the charging percentage. Thanks
Kate
Do I have to drive my car right after I charged it? Or can I Waite til the next day to drive it?
Shelly
I have an ‘05 Mercury Mariner that was in a recent fender bender. Had a new radiator installed and drove it around town no problems. But then it has sat for a few days. Last 2 days the battery is dead. Could it be from not having driven it much so the charge is gone? I cleaned the terminals and the posts. It’s on a charger now. How long will it take to charge and do you think it could be something else? I also live on the desert and rodents are a pain in the ass. Thanks for your input.
Chantal St Jacques
If I'm charging a battery thats half in the yellow using a 10 w how long would it take to start it?
Joey
With a 40-65ah battery, anywhere from 3-6 hours with a 10 amp charger
Michael J Norris
My explorer battery was dead last week and i took it 2 have it checked and they said it was a bad battery so i got a new one and now i tried 2 start my suv n its a week later and the car only unlocked the doors n nothing else so the battery is dead again. I am charging it and im not sure how long i need 2 charge it 4 and what the problem might be.
Renato
Will I be able to run a 3kw BLDC motor with a battery and recharge the battery with an alternator
Lucia
Hello, is it better to take my car to tire plus to charge my car battery complely?, thank you.
Viktor from Husqvarna
Hi there! Just being a random guy from Sweden, with cold winters and Polar bears on the streets and all that, I would suggest y'all just getting a CTEK MXS 5 charger (yeah, they are a bit expensive but hey, quality has it's price!) and then mount the quick-connect eyelets, included, to your battery. Whenever you're not using your car then just attach the charger and it will charge the battery until full and then automatically switch to maintenance mode. Totally hassle-free and well worth its money, especially on the day you would have been standing there with a flat battery. Sure, if the battery is totally dead it takes its time to charge but using it regularly will save the battery and the charge time will be shorter.
Marua
I will take vacation for three weeks . So nobody will start my car . My question is , is it ok that my car will not start or used for three weeks. What will happen to my car then
Tahir Butt
Unhook battery terminals. Reconnect when u return. It will still. Be able to start car.
Joe
How long a recharged battery lasts? Is it worth charging or just buy a new one? I don't want to got stuck in the middle of nowhere with a dead battrry...thanks.
Tahir Javed
It should last for more than 10days idle. But make sure its fluid is full. In case its dry then no need for fluid. Start the car after 10 days and leave it running for like 10 mins. Stay in peace.
Becky
Hello, my car battery just died for reasons I do not know of and I am currently about to charge it. When it is charged, what are the chances the battery would go dead again? Do I have to drive the car everyday? I am asking because I use my car only twice a week. Also the battery in question was newly bought in March. Thank you
Tahir Butt
Charge it. No need to spend money. Charge it ans drive it atleast 10 miles. And start leave it for 10 mins every 10day.
Ronald mendez
Can i charge another battery using a jumper to my car with engine working connecting to my car batttery
Muppet's Dad
I am charging a larger than normal 2003 Mercedes 100A battery for the second time with a 5A Ring smart charger. The 1st charge was a year ago and it took 4-5 days from dead. Tha car travelled 250 miles in 12 months and is dead again. No surprise. It has been charging for 60 hours and the charger is indicating that the process is over half way. My garage tested the battery 9 months ago and said it is in good condition. My question is: Is this reasonable given that 5A is only a max applied for only part of the process?
Dorothy Leach
I have a 8Amo charger , how long does it take to charge a 12 volt battery
JOHN HADDEN
I want to recharge a varta E11 battery but there is no way to get to the distilled water caps to unplug them. Would it be dangerous to go ahead and charge anyway?
Malanie
Hi there I have a 2009 Fiat Punto 1.9 in a 2 litre. The car has been standing for a very ling time and the battery is totally flat. I have a Battery Carger 4 AMP 12/230 VOLT. Can I use this Charger? I’m scared that the charger is not strong enough and will damage the battery
Magnus Sellén
Hello. It's not a problem to charge it with a charger that is charging it slowly, it's actually better than a fast charger in these situations. However make sure that you are connecting the positive and negative clamp on the right connectors when the battery is flat!
King Mclaurin
I have 2006 Cadillac the battery has been dead for about 6mos or more practically new. Can it be charged up while still in the car?
Israel Bamidele
Hi Magnus, My own question is about the device amidst the exhaust system in the form of honey comb shape, quite real that it lessens the noise of the exhaust system while working, but , does it really reduce the fuel consumption of the car?
Fola
Hello , I drive a Toyota Corola 2002, I haven't driven it for a month and half. When I tried to start the car. It wouldnt start neither was there any sound heard. I called in a mechanic who did a jump start left it to run for only 15mins, and put off the engine. I tried afterwards to start the car but still wouldn't start. I figured out the battery was dead. I called him again ,and he told me it will take 3days for have a fully charged battery. Is this true?