How to charge AGM battery

Charging an AGM battery on a regular basis is very important. It helps to keep the health of the battery. Besides, it prevents the discharge of the battery from time to time. This ultimately enhances the depth of discharge(DoD) for the battery.

How to charge AGM battery

There are some specific procedures to be followed for charging the AGM battery. Not following the proper guideline to charge the AGM batteries may result in the degradation of the battery.

It is because AGM batteries are highly sensitive to overcharging. Long exposure to overcharging reduces battery health dramatically. And this is an irreversible process. That is why you must know the exact process of changing the AGM battery.

How long does it take to charge a 12V AGM battery?

How long does it take to charge a 12V AGM battery

The charging time depends upon the remaining battery charge for a 12V AGM battery. Considering the battery being discharged to 10% to 20%. Then it may take roughly 6-8 hours for the AGM battery to be completely charged. Moreover, the charging time also depends upon the charger you are using and the charging profile. A standard AGM-specific battery charger will take 7-9 hours for completing the charging process of the battery. 

How to charge your AGM battery – fastest ways

How to charge your AGM battery

Out of several ways of charging the AGM batteries, some fastest methods are stated below. An AGM battery charging profile should be well defined. For a 12V AGM battery, the amp should be set within 0 to 10amp. Slower charging is better. If your battery has been completely discharged then you can use 20 amps which is also known as fast charging.

But, a working battery amp setting should not be over 10 amp. Fast charging results in overheating which reduces the battery life permanently. An ideal environment for charging AGM batteries is 32F to 100F. Charging in extremely hot conditions is not recommended. The charging area should be well ventilated. Besides, the charger to be used should be strictly AGM-specific. You cannot use a Li-ion charger to charge the AGM battery.

AGM battery charging voltage chart

Maintaining the voltage chart is mandatory for keeping the battery healthy. The state of charge is the minimum requirement of voltage required to charge the AGM batteries.

State Of Charge(SOC) after restOpen Circuit Voltage
20%11.7-11.9V(No discharge)
0%11.4-11.4V(Dead battery)

Charging from the household socket

Charging from the household socket

For this process, you must get the standard and compatible battery charger for your AGM battery. This works on the principle of regular charging of any electronic appliances.

  • Firstly, Connect the terminals of the chargers to the battery terminals. Make sure the polarity is well defined while making the connection.
  • Secondly, plug the smart battery charger into the wall socket with 120V output.
  • Select the required charging profile for your AGM battery. In general, 10 amps are to be selected.
  • Switch on the charger and text the initial voltage of the battery using a voltmeter.
  • Keep track of the charging process from time to time.
  • The digital smart chargers show the charge percentage of the battery. So make sure that the charging process needs to be terminated before reaching 100%.
  • Use protective gears while making the connections and complete the charging procedure in a well-ventilated area.

Using Generator

How to charge your AGM battery using generator

Electricity generators are the secondary method of charging the AGM batteries effectively. It is a more portable and easier way to charge the AGM batteries. It is better to make sure that the portable generator has a built-in DC charging circuitry within it. If not you must get a device that converts the power to a compatible format.

Using the basic principle of making connections between the generator and the AGM battery, the charging can be done. But, you have to continuously monitor the voltage input and input of the battery using a digital voltmeter. Since there is no way to track the percentage, it is better not to go for prolonged charging.

Solar Panel Charging

How to charge your AGM battery using solar panel

It can be an expensive way to charge the AGM battery. But it is a more environmentally friendly and sustainable way to charge AGM batteries. All you need are the 12V solar panels, regulator device, jumper cables, AC-DC interchanger, etc. Simply set up the devices in a well sunny location. Make connections with the AGM battery and switch on the solar regulator. This will initiate the charging of the AGM Battery.

Can you use a regular battery charger on an AGM battery?

Can you use a regular battery charger on an AGM battery

We cannot use a regular battery charger for AGM battery charging. AGM batteries are very sensitive to overcharging. Besides, a correct charging profile based on the Soc is important for AGM batteries.

AGM selective smart battery chargers are designed for selecting the best suitable mode for charging the AGM battery. Besides, selecting the amp required for the proper profile cannot be provided by normal chargers.

Do AGM batteries need special charging?

Do AGM batteries need special charging

The AGM batteries do require a compatible charging profile for good battery health and extended longevity. These criteria can be fulfilled by a smart automatic charger. These automatically detect the best settings for the AGM battery. Since overcharging can damage the AGM batteries, it is recommended to use AGM-specific chargers for better performance.

Can you charge an AGM battery with a trickle charger?

Can you charge an AGM battery with a trickle charger

You can charge an AGM battery with a trickle charger. The trickle charger uses a low amp for the charging process. And slow charging is always preferable for AGM batteries. Because it doesn’t create any overheating.

Therefore, trickle chargers with the ability to deliver 2-10 amps while charging would be good for an AGM battery.

What amp should I charge my AGM battery?

What amp should I charge my AGM battery

AGM batteries are designed for slow and steady charging using a lower amp. You must set the amp range between 2-10amp. This will steadily recharge the AGM battery without causing any sort of overheating. 

Using over 20 amps is considered to be fast charging. This is used for discharged batteries. Usually, for jump kicking, higher amps are used. For regular charging, you should not exceed 10 amps.

What voltage is a fully charged AGM battery?

What voltage is a fully charged AGM battery

A fully charged AGM battery shows a voltage of around 13-13.5V. It depends on the battery health and duration of the battery usage. A rarely used AGM battery fully charged shows voltage greater than 12.7V. 

Whereas, an old AGM battery after rough usage shows 12-12.5V when fully charged. The discharge takes place due to the degradation of the electrolyte and electrodes.

What happens if you charge an AGM battery with a normal charger?

What happens if you charge an AGM battery with a normal charger

You cannot set the correct charging profile required for an AGM battery using a normal charger. For AGM batteries it is not recommended to exceed 10amps while charging. Besides, you cannot see the soc of the battery. And also, a normal charger fails to let you know the voltage reading to and from the battery. 

As a result, using a normal charger may result in overcharging your AGM battery. Now, overcharging AGM batteries degrade the battery life actively because there are no free electrolytes.

Do you love your batteries? Follow the maintenance tips.

Do you love your batteries Follow the maintenance tips
  • Keep the surface clean and residue-free.
  • Remove the corrosions from the terminals on a regular basis.
  • Do not over feel your lead-acid batteries.
  • Do not overcharge your battery.
  • Maintain polarity connection while charging.
  • Charge the batteries in well-ventilated areas
  • Use smart automatic chargers for charging our AGM battery
  • Do not discharge your battery lower than 20%
  • Don’t 100% charge your battery.


Recharging an AGM battery can be tricky for beginners. Using the faulty procedures and not knowing the limits may cause permanent damage to the Battery. Besides, many people prefer fast charging which decreases the longevity of the battery.

That is why it is good know-how to charge AGM battery and the correct procedures. If you can elongate the lifespan of your existing AGM battery then some buck can be saved. Otherwise, you need to buy new AGM batteries from time to time which can be over budget. With a simple process and instruction following, you can avoid that quite easily.

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