AGM batteries are not even close to conventional lead-acid batteries. Despite the fact that both have identical main components, their structures have a lot of differences. This is their main discrepancy.
Unlike lead-acid batteries, AGM ones have a chemical structure with no electrolyte of a liquid type. The unique AGM batteries composition makes them significantly safer to use than their lead-acid counterparts. As for recharging, they were designed for a slow and low charge. Attempts to do this thing fast will destroy the battery itself. For this reason, standard charge devices cannot be used to charge a glass mat battery.
The vast majority of the devices used for AGM recharge are equipped with special microprocessors that collect information about the power elements. As a result, this processor monitors the state of charge and regulate the voltage and current.
Best AGM battery charger reviews
Has a patented 8-step charging system. It checks the battery status while charging it. Such a system ensures maximum battery life and performance. Pulse charging technology also increases battery life. Charges 12-volt lead-acid batteries (Wet, MF, Gel, AGM and Ca) with four separate modes of operation. Protection against short circuit and reverse polarity is also available, and the patented desulfation function restores slightly sulfated batteries. The charger is safe for children and can be used in any climatic conditions. The design is compact, with special mounting holes. A good choice for any batteries up to 150 Ah. Two interchangeable connecting wires are attached. One with clamps and another with eyelet terminals. CTEK (56-353) MULTI US 7002 can be named as the best AGM battery charger in terms of steps charging number.
- Equipment is protected by the five-year warranty.
- Various modes for charging.
- Absolutely safe and spark-protected.
- Compact size good for easy transportation.
- There is no ability to jump-start batteries, solely charge.
- Deep cycle batteries are not supported.
- Not so durable than larger models.
This device is well-protected from sparks and reserve polarity. A good choice to recharge and maintain the 12-volt lead-acid batteries (Gel Cell and AGM). Four-step charging program is used for this. Armed with 80-hour safety timer. Thanks to it, there will be no overcharge and power of battery stays well-optimized. Can automatically switch to the float mode after complete battery charge. LED indicators are used to monitor the state of charge. If the voltage drops, the work of Battery Tender 021-0123 will not stop. The tool is completely automatic and quite easy in use. Has a low weight and goes together with a 12-feet output cord. The five-year warranty period is on.
- A great feature is that if you touch both connectors, there is no chance of a spark.
- Store and use it in the unheated garage without any problems.
- Does not overcharge the battery as it has overload protection.
- This is not a 100% charger. Used only to maintain slightly discharged batteries.
- Despite the long warranty period it quickly breaks.
- Customer service not very polite.
Here is a 12V AGM IntelliCharger with 15A output. Supplied with six reliable cables with clamps and a built-in fan for cooling. Has three-stage of operation and works with constant current and voltage. Has low weight and compact size. XS Power HF1215 is of high-frequency and maybe the best AGM battery charger that can charge and maintain AGM batteries. The voltage and amperage of the charge are controlled by computer analyzer in order to measure up the best charge rate. The last one can be monitored with the help of special LED indicators.
- The small and compact design.
- Just plug it and turn on. The chipset inside does the rest.
- 3 stages prevent overcharging of AGM batteries.
- Can keep working all night long.
- 6-ft. long cables missing.
- Quite expensive.
- It would be nice to have a meter instead of two small LEDs.
This battery charger for AGM battery has four charging stations independent from each other. Each of them is able to simultaneously charge 12-volt (1.25 amps) battery. Constant current charging goes under the strict control of the microprocessor. The optimal voltage of charge is in accordance with ambient temperature. The safety of the user is guaranteed by spark-proof design together with reverse-polarity and short circuit protection. Addition safeness is achieved by a switch-off 72-hours timer. Brilliant for AGM (absorbed glass mat) batteries. The best AGM battery charger for those who prefer lightweights – only 3 lbs.!
- Excellent fastening system.
- People from Alaska wrote that it works well even there.
- Microprocessor controlled three-stage charging program that works independently for each battery.
- Manufacturers do not replace the battery under warranty and repair it, sometimes up to infinity.
- Cables are too short for a device with 4 banks.
- The product description would be great if there was real info about all types of connectors.
Universal AGM battery maintainer for fast recharge of AGM, Wet and Gel batteries. Can work with both 12-volt and 24-volt types. Do not worry about overcharge as modern technology automatically monitor and maintain this process. There is also Repair Mode for batteries which are left uncharged for a long time. NOCO Genius G7200 can be converted into five-amp constant current and voltage power supply or be used as a DC power source. An optimized charge mode is a guarantee of safe charging and maintenance of batteries. Spark-proof technology and reverse polarity protection are also onboard. In addition, there is a five-year warranty period.
- Suitable for different batteries.
- It is capable of charging a deep cycle AGM battery 2 times faster than a conventional charger.
- Economical, lightweight and compact.
- Will not work on a fully discharged battery.
- 5-years warranty, but warranty repair is possible only for 2.5 years.
- When returning for the repair you need to pay for delivery.
This AGM battery trickle charger can charge those batteries that other ones cannot down to 1.25V. Perfectly charges and maintains 12V AGM and flooded batteries. The easy operation due to quick-set selections accompanied by LCD battery charging gauge. For smartphones, cameras, and tablets Optima Digital 1200 has a USB port. Doing its work really fast. The batteries performance will be maximum without the risk of overcharge.
- Modern digital 6-speed charging.
- Charges a fully depleted battery.
- Recognizes and charges the battery with 1.25 V voltage.
- Not the best service system. All is done slowly, personnel not attentive to the customer.
- Short wires.
- Sometimes becomes very hot.
With this AGM charger will be no fear of battery failure because of sulfation. The automatic full-time desulfator effectively prevents this. The battery life becomes longer up to four times if to compare with unproperly maintained ones. The reverse polarity and short-circuit for safety. Smart temperature sensor adjusts battery voltage during charge. Up to eight batteries at the same time can be connected to BatteryMinder 128CEC1. For use, there is a need for Y-Connectors 210AY which are sold separately. The 90-240V AC 47-63 Hz input allows to use it all over the world. Certified by the California Energy Commission as meeting all efficiency standards and low power consumption.
- The universal device, suitable for different batteries.
- Quite cheap and environmentally friendly.
- Can predict battery failure.
- Rejects weak batteries as defective.
- Poor customer service.
- The charger cannot detect batteries with an average sulphation level.
TPE 12V 5A one of the fastest chargers. Suitable for 12V 5A charging of Lead Pb, SLA, VRLA, GEL and AGM batteries with 15-100Ah capacity. Convenient in use and saves a lot of time. This is provided by 4LEDS for 25% 50% 75% 100% which help to when to unplug the battery and MCU control declines current when a battery is near the complete charge (this saves from overcharging). The device can work outdoors and indoors with the same efficiency due to reliable IP65 waterproof and dustproof technology.
- Working for a long time with no issues.
- Chargers rapidly and shuts off automatically.
- No on/off switch.
- Confusing and unclear compatibility instructions and specifications.
A few words about AGM technology
Absorbent Glass Mat constructed in another way than traditional flooded batteries. The AGM uses a so-called starved electrolyte. Between the plates is placed an ultra-thin fiberglass mat impregnated with battery acid up to 95%. This material is packed between the plates and lightly pressed for greater fixation. Since the plates and mats are packed tightly enough, there is no vibration. Such vibration absence helps to avoid internal battery destruction over time during operation. Thus, AGM is durable and safe. In AGM vs standard battery charging competition, the standard win, as their charge is less complicated. The price for AGM durability and safeness is the need for special charging equipment and increased time of recharge.
How to charge AGM battery?
The right approach to AGM battery charging is an extremely important step in ensuring its long-time service. This type of battery is used in a very wide range and correct charging is a key-note of its work for long years. If the AGM batteries are not properly charged, then they will become obsolete prematurely and begin to discharge much faster than before. Also, improper charging of the AGM battery leads to severe heating of the cells, damage to the battery, or even its destruction within a few hours. Just follow four tips and recommendations for charging AGM batteries and it will serve you for many years:
- Buy a recommended charger.
- Understand how charging affects different types of batteries.
- Charge batteries only at the correct temperature.
- Do not worry if the battery gets warm (but not really hot).
At what voltage you must charge the AGM battery?
The optimal numbers of voltage are from 13.8 to 15 V and with the maximum current. However, the last one depends on the characteristics of the charger. When charging lasts for some time and battery voltage approaches the maximum, the charging current should decrease in proportion to AGM voltage increase.
How to determine the charging time
Everything is simple – the lower the battery charge, the longer it will recharge. The standard charging time of AGM series is between a couple of hours and up to 12 hours or more. Check the temperature of the battery from time to time. If it exceeds 125 degrees Fahrenheit – stop charging it immediately.
Is it possible to charge the AGM battery with standard chargers?
As mentioned above, the AGM battery designed for slow and low charging. Thus, only the use of a charger with microprocessors which adjust the voltage and control the current charge level is allowed. Overcharging can destroy your battery. Thus, standard chargers cannot be used to charge an AGM battery.
How to charge a fully discharged “dead” AGM battery
So, your AGM is “dead”. What to do now? How to “resurrect” it?
- Buy a modern charger with AGM settings.
- Help a charger to find a deeply discharged AGM battery. To do this, put the several batteries, one of which is completely discharged, in one row. Connect this construction to the charger.
- Take AGM battery to a professional who knows this technology. Most experts will provide “check and charge” procedures for free or for a very small fee.
As practice shows, AGM batteries that may look like a dead one are completely OK. They are just deeply discharged.