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Last Updated: October 2021
In our article about car batteries and how to maintain them, the number one tip is to charge them regularly. Charging and maintaining your car battery can lengthen its life, adding at least 3 years to its life, and often upwards of 5.
Because we’re all about high-quality products and how to make things last, we set out to find the best AGM battery chargers and maintainers.
AGM batteries have become much more common in the last few years due to the many benefits that they bring. They are suitable for start/stop equipped cars, they provide larger power reserves, can be mounted in any position, are maintenance-free, and much, much more.
However, AGM batteries have one major disadvantage and that’s their sensitivity to overcharging.
Traditional battery chargers are not suitable for AGM batteries because they will overcharge them (they can’t detect when the battery is fully charged). To keep your AGM battery in top condition for multiple years, you need a smart charger, which is compatible with AGM batteries.
Here are, according to our research, the best, safest, and most durable car battery chargers available.
Our Top Picks
1. CTEK MXS 5.0 Charger and Maintainer
The CTEK MXS 5.0 smart charger comes with many advanced features, almost too many to list here. First of all, you can charge all your vehicles with this one charger (cars, motorcycles, boats, RV’s, etc.), no matter the battery type (Gel, EFB, lead-acid, and more). It can even revive and refresh old batteries with its “recond” function.
The automatic temperature compensation lets you use this charger even in the most extreme conditions. Not only that, the advanced microprocessor, which is the heart of this unit, can diagnose your battery if it can receive and retain a charge. Before each charging, it will also run a short desulphation program that removes sulphates from the lead plates of the battery.
This product is spark-proof, reverse-polarity protected, and splash & dustproof (IP65). It can charge batteries from 1.2 to 110 Ah (if you have a larger battery, you can opt for the MXS 7.0 or 10.0 model).
And if you need or want to store your vehicle long term, you can do that, too, because this charger comes with one of the most advanced trickle charging capabilities on the market.
Read our hands-on review: CTEK MXS 5.0 – An Advanced Battery Charger & Maintainer
2. Optima Digital 1200 Performance Charger and Maintainer
Not only can Optima Digital 1200 charge almost any battery, but it can help to recover deeply discharged batteries, and will extend the battery life of almost any unit that it comes across.
When it comes to using the charger, you will love the backlit LED screen. The screen is perfect for low-light conditions and gives accurate and clear data. You will have access to battery charging, fill rate, mode settings, fault messages, and more. There is also an LED light to illuminate your charging area, great if you are in your garage, and need more light for access to your vehicle battery.
This charger/maintainer will charge batteries as low as 1.25V and can deal with all 12V batteries. There is also a USB charging port, allowing you to also charge smartphones, cameras, and other smart devices. And, not only that, but you get quick charging too, cutting down on your wait time.
The device is also easy to use, and intuitive enough that it can almost be used without checking the instructions, though we always recommend reading the manual before using any device. That ease of use is also partly down to the integrated charging clamp LED and nonslip grips.
3. Schumacher SC1308 Battery Charger and Engine Starter
The 100A engine start capability makes this a powerhouse charger that can deal with SUVs, large trucks, and RVs.
The automatic volt detection will check for 6V and 12V batteries and charge them accordingly without you having to make any changes.
There is also an inbuilt battery and alternator tester, automatically providing charge levels, diagnosing electrical problems, and displaying the relevant information on the digital display so that you can easily see what is going on with your battery, though, with so many automatic features, you can leave most of the charging up to this device, and relax while optimum charging takes place.
The reverse hook-up protection protects the battery and the charging unit from any damage, and there is a microprocessor controller with float mode monitoring, helping to charge and maintain your battery.
The multi-state charging adds precision to your battery charging, ensuring the safety and integrity of the battery, and the unit meets the highest industry standards for energy efficiency.
4. NOCO GENIUS10
An upgrade to the previous model (G7200), this advanced battery charger comes with a host of great features that make it the perfect charger for all your battery needs.
Taking the best aspects of the previous model, this battery is 17% smaller but delivers 115% more power. It can charge batteries, maintain them, trickle charge, is a battery desulfator, and so much more.
The unit is designed to handle 6V and 12V batteries and it can handle everything within that: automotive and marine, deep-cycle batteries, flooded, gel, AGM, and lithium-ion batteries.
When it comes to charging, the integrated thermal sensor can detect the ambient temperature and alters the charge rate to eliminate over-charging in hot climates and under-charging in cooler climates.
You can charge batteries as low as 1V, and, if there is anything that the automatic charging capabilities cannot handle, or if you want to take more control, you can manually charge batteries, including those that are sitting at 0V.
If you have a battery that you thought was ready to be tossed, try this charger/maintainer first. It can detect battery sulfation, acid stratification, trickle charge, restore lost performance, extend battery life, and give your stronger engine starts.
If you have car battery that is dead, a lawnmower that will not start, or an underperforming RV battery, then give this charger a go.
5. Battery Tender Battery Charger and Maintainer
This 4 amp battery charger may look small, but it is powerful, making it the perfect compact charger to take with you.
The charger will fully charge your battery before switching to float mode to protect the unit, which will maintain proper voltage levels without overcharging or overheating. The controls are also simple and compact, and you can switch easily from AGM to flooded to lithium-ion at the touch of a button, providing optimum charging levels for all 6V and 12 V batteries.
The power that comes from this small unit is a lot more than expected, and it is a great charger when you need to charge on the go. Keep it in your RV, and you can deliver a quick and powerful charge when you are stuck in the great outdoors, providing reliable engine starts and extended battery life.
This charger also brings you safety. Not only will it not overcharge or overheat, but the charger and maintainer is spark-proof too when connected, and automatically detects reverse polarity. These safety measures ensure that you are locked into your connection the right way before powering the battery.
With a 5-year warranty, this solid and dependable charger is compact enough to be stored in any vehicle and taken everywhere with you.
6. Schumacher SC1281 Automatic Battery Charger
This is a battery charger, starter, and maintainer. The Schumacher SC1281 is a powerful tool that can do just about anything related to your vehicle battery, including maintaining it when charged. Now, it doesn’t matter if your vehicle is a motorbike, a speedboat, a tractor, or a truck, this charger will test, charge and maintain its battery. You can also test your alternator, and even jump-start your vehicle.
The unit comes with a digital display, LED indicator lights, auto voltage detection for 6 and 12-volt batteries, and a start/stop button for immediate charging. Unlike many cheaper battery chargers, this unit cannot overcharge your battery. It detects when the battery has reached its full charge and maintains it at that optimum point until it is stopped. It has reverse hook-up protection, which prevents the unit from working, with an LED indicator to tell you if you have connected your cables incorrectly.
The strong starting power of this charger is provided by a 100 Amp jump-start ability, and it has a 30 Amp boost mode. It is controlled by a microprocessor and has multi-stage charging for absolute precision. The unit is compatible with standard, AMG, gel, and deep-cycle batteries, and is DOE compliant.
What To Know Before Buying an AGM Battery Charger and Maintainer
Total Charge Time
The total charge time for your battery will depend on the size of the battery and the rating of the charger.
To get a rough estimate for a full charge, take the amp hours of the battery, divide that by the amp rating of the charger, add 10%, and round up.
For example, let’s look at a 100 amp hour battery and a 10 amp charger. We divide the amp hours by the amp rating (100/10) to get 10, add 10% (10*1.1) to get 10.1, and round up to end up at 11. This means that it will take 11 hours for a 10 amp charger to charge a 100 amp hour battery.
Smart Battery Chargers
Smart chargers take the pain out of charging a battery by constantly monitoring the battery state at all stages of the charge. They add a charge to the battery, but at the optimum level for the condition of the battery, adapting to charge the battery at the most efficient speed.
They will repair batteries too. As batteries age, sulphate builds up on the battery plates and can affect the power output of the battery. Smart batteries use repair functions to remove the build-up of sulphate and have your battery running at optimum power.
Smart chargers actively repair and charge batteries to extend battery life and increase power. If you have an old battery, one that has been dead for a while, one that does not have a lot of power, or any other battery, for that matter, a smart charger can handle it all.
How to Use a Car Battery Charger
Watch this video to learn all about charging your vehicle’s battery.
IMPORTANT: Many newer vehicles are equipped with an Intelligent Battery Sensor (IBS) which can measure the charge and discharge voltage and calculate the charge level and the general condition of the battery. If your vehicle has an IBS sensor (the sensor is usually placed next to the negative terminal (-) of the battery) then make sure that the charge voltage goes through the IBS sensor. Failing to charge the battery through the IBS sensor may result in a dead battery due to incorrect measurements by IBS.
Do AGM batteries require special chargers?
Yes, they do.
AGM batteries require a slow and low charge, and that takes specific charging parameters. AGM chargers come with microprocessors that check the state of the battery and constantly adapt the charge depending on the battery state. A regular charger could easily overcharge and kill an AGM battery.
Can a dead AGM battery be charged?
Yes, it can.
Dead batteries require different processes to charge, depending on the type of battery and how long it has been dead. AGM specific chargers come with the latest charging technology, and that means that they can adapt and charge almost any dead battery. Once charged, these AGM chargers will help to maintain the battery so that you get the most out of it.
Can you jump start an AGM battery?
Yes, but the Ah battery rating of the battery you are jumping from should be comparable to yours.
How many volts is a fully charged AGM battery?
Fully charged AGM batteries hold 12.6V-12.8V. Any battery that falls below 12.4V can start to suffer from sulphation, and that limits the power output. Over time, this will only get worse.
Regular battery use, charging, and a high-quality battery maintainer will stop this from happening.