A flat battery is a sure-fire way to ruin your day. You’ll have to wait around for a roadside assistance service to show up (forking out for a hefty fee if you’re not a member) or try and find someone to kick start your battery with jumper cables.
Neither option is ideal. But there’s one way to revive a flat battery yourself without having to rely on outside help: an AGM battery charger.
These handy high-tech devices are capable of consistently and safely recharging any AGM battery, perfect for when you’re running low on juice, or you’ve accidentally let your battery run completely flat. And they’re not just for automobiles, either, as they can charge the leisure battery on your boat or RV as well as the starter battery for motorbikes, jet skis, ATVs, and a whole host of other mechanical toys.
To help you find the best AGM battery charger for you, we’ve put together an insightful buyer’s guide and compiled a list of the top 10 AGM battery chargers on the market in 2024.
- Features to Consider
- Top 10 Best AGM Battery Chargers 2024
- 1. Best AGM Battery Charger Overall: NOCO GENIUS5
- 2. Best PowerSports AGM Battery: Battery Tender Plus Charger and Maintainer
- 3. Best Budget AGM Battery Charger: AmazonBasics Battery Charger 12 Volt 2A
- 4. Best Premium AGM Battery Charger: CTEK MULTI US 7002
- 5. NOCO Genius G750
- 6. Best AGM Battery Maintainer: Schumacher SC1299 Automatic Battery Maintainer
- 7. Schumacher SC1281 Fully Automatic Battery Charger
- 8. Best AGM Battery Charger for Boating: Promariner 43021 Battery Charger
- 9. Optima Digital 400 12V Performance Maintainer and Battery Charger
- 10. NOCO GENIUS2
- AGM Battery Charger Buyer’s Guide
- The Best AGM Battery Chargers
Features to Consider
Before you start sifting through our top recommendations, it’s essential to get a little background info on what to look out for. Take the following points into consideration when shopping for an AGM battery charger.
Price
There’s no point forking out $100 when a $50 charger will do everything you need, so look for a charger that covers your core requirements and nothing more. If you plan on using your AGM battery charger frequently, such as to charge the house battery in a boat or RV, then investing in a more expensive model would be worth it in the long run. Conversely, you plan on using your AGM charger on the rare occasion, a budget option such as the AmazonBasics Battery Charger would suffice.
Type
AGM battery chargers come as chargers, maintainers, and re-conditioners, or a combination of the three. Make sure the model you go with covers what you need. See our section on for more info.
Furthermore, some AGM chargers are explicitly built for PowerSports batteries, a special kind of battery commonly found in jet skis, snowmobiles, ATVs, and other small vehicles. PowerSports chargers won’t work on the starter batteries of bigger vehicles like cars and vans.
Discharge Rating
You need to make sure the discharge rating, which is classified in a unit called amps (A), is suitable for your needs. If you’re not sure what you should get, consult the owner’s manual of your automobile or the sticker attached to your battery for more information. It’s crucial to get a charger with a suitable discharge rate; otherwise, the device mightn’t work at all.
Voltage
Another critical consideration is voltage, which refers to the pressure of the power source on an electric circuit. Look at the voltage of your battery—usually either 6/12V, although it may be higher for large batteries such as those used on boats—to ensure you’re buying the correct product. Take the time to investigate your requirements carefully because if you mess up the voltage, the charger won’t work at all.
Safety
Safety is an important consideration, both for you and your battery. A poorly designed, off-brand charger could cause a potentially lethal electrical shock, while a model without an automatic shut-off could overcharge and damage your battery. We only recommend quality products from trusted manufacturers, so your safety is assured if you shop from our list.
| Product | Type | Volts | Amps | Size | Weight | Rating |
|---|---|---|---|---|---|---|
| NOCO GENIUS5 | Charger / Maintainer / Re-conditioner | 6 / 12V | 5A | 4.61 x 3.43 x 7.95 inches | 5 | |
| Battery Tender Plus Charger and Maintainer | PowerSports Charger / Maintainer | 12V | 0.75 / 1.25A | 11 x 4 x 11 inches | 5 | |
| AmazonBasics Battery Charger 12 Volt 2A | Charger / Maintainer | 12V | 2A | 2.88 x 3.13 x 8.63 inches | 5 | |
| CTEK MULTI US 7002 | Charger / maintainer / re-conditioner | 12V | 7A | 7.52 x 3.5 x 1.89 inches | 4.5 | |
| NOCO Genius G750 | Charger / maintainer | 6 / 12V | 0.75A | 4.5 x 2.7 x 1.3 Inches | 4.5 | |
| Schumacher SC1299 Automatic Battery Maintainer | Maintainer | 12V | 0.08A | 3.00 x 4.00 x 9.00 inches | 4.5 | |
| Schumacher SC1281 Fully Automatic Battery Charger | Charger / jump starter | 6 / 12V | 30A (charger) / 100A (jump starter) | 11 x 10 x 8 inches | 12.65 pounds | 4 |
| Promariner 43021 Battery Charger | Charger / Maintainer | 12 / 24 / 36V | 20A | 14.5 x 6 x 8.5 inches | 4 | |
| Optima Digital 400 12V Performance Maintainer and Battery Charger | Charger / maintainer | 16V | 4A | 8.2 x 3.7 x 7.4 inches | 4 | |
| NOCO GENIUS2 | Charger / maintainer / re-conditioner | 6 / 12V | 2A | 3.43 x 4.25 x 6.97 inches | 3.5 |
Top 10 Best AGM Battery Chargers 2024
1. Best AGM Battery Charger Overall: NOCO GENIUS5
Editor’s Rating:
Quick Facts:
- Type: Charger / Maintainer / Re-conditioner
- Volts: 6 / 12V
- Amps: 5A
- Size: 4.61 x 3.43 x 7.95 inches
If you’re after a single, high-quality product that does everything you could ever want and more, then you can’t go past the NOCO GENIUS5. As the latest in the company’s highly sought after GENIUS range, this unit is smaller and more powerful than ever before.
The reason the GENIUS product range has achieved such widespread popularity is because these devices offer more versatility than their competitors. The unit will quickly and safely charge just about any AGM battery on the market—think automotive, marine, RV leisure batteries, and more. It even works on lithium batteries as well, which would save buying a new one if you decide to upgrade further down the track.
Another massive plus is the automatic temperature control, which monitors the outside temperature and adjusts the charging rate accordingly. Should you live in an extremely hot or cold climate, the tech will significantly enhance the shelf life of your AGM battery.
For car owners who forget to switch the headlights off, rest assured the GENIUS5 will get her ticking over again. The device charges batteries as low as 1V, so it’s a brilliant ‘get-out-of-jail-free’ card when you’ve let your battery run fully flat, and charging cables come included as part of the deal.
It’s not the cheapest option on our list, but well worth the expense for those with demanding needs.
Note that the device is rated for batteries up to 120 AH. If you’ve got something bigger than that, consider upgrading to the NOCO GENIUS10.
Pros
- Charger, maintainer, and re-conditioner in one
- Temperature monitoring and compensation
- Works on small and large vehicles alike
- Good for lithium as well as AGM
- Compact design and lightweight
Cons
- More expensive than other chargers
2. Best PowerSports AGM Battery: Battery Tender Plus Charger and Maintainer
Editor’s Rating:
Quick Facts:
- Type: PowerSports Charger / Maintainer
- Volts: 12V
- Amps: 0.75 / 1.25A
- Size: 11 x 4 x 11 inches
Deltran is one of the biggest names in the AGM charging world, and this model—their flagship product—is a runaway success. The widely popular 0.75 / 1.25A charger works wonders on smaller vehicles like motorbikes and UTVs, and it’s so simple to use even a complete novice could work it out in minutes.
A super basic two-color monitoring light lets you instantly know the state of charge. If the battery level should drop too low, an ISM adaptive charging function will automatically kick start the power again. Then, once the power level maxes out, it’ll switch back to float mode to avoid overcharging and damaging your expensive AGM battery.
The other big reason we rate this unit so highly is its versatility as the Battery Tender Junior works on a wide array of setups—choose from either 6V or 12V and 0.75A or 1.25A and you’re ready to start recharging your rig. Whether you’ve got a flat battery on your jet ski or ATV, or you just need to restore the leisure batteries of your boat or RV, this nifty little unit will get the job done.
Oh, and the fact it’s small, lightweight, and very reasonably priced also adds to the appeal.
Now, note that this model is a PowerSports battery, so it’s not going to work on cars or larger vehicles.
Pros
- Available in multiple volts/amps
- Automatic charging capability
- Easy to use
- Reasonably priced
Cons
- Only suitable for PowerSports batteries
3. Best Budget AGM Battery Charger: AmazonBasics Battery Charger 12 Volt 2A
Editor’s Rating:
Quick Facts:
- Type: Charger / Maintainer
- Volts: 12V
- Amps: 2A
- Size: 2.88 x 3.13 x 8.63 inches
If you just want a straightforward AGM charging solution that actually works, you might want to take a closer look at this cost-effective unit from AmazonBasics. Forget about maintaining, conditioning, or any other fancy bells and whistles, because this model does one thing only: charging AGM batteries.
With either 6V or 12V options, it’s compatible with cars, boats, motorbikes, and most other small vehicles, so there’s a good chance it’ll work for you. Of course, you’ll need to check whether 2 amps are enough for your battery as that isn’t quite enough juice for the bigger power banks found on SUVs and RVs. On the flip side, however, if 2 A are too much, you can easily downgrade to save even more (The 0.08A model comes in at under $20).
Worried it might be a little too cheap? Amazon backs the product with a one-year warranty, so you know it’s not going to break straight away.
On the downside, it’s more of a trickle charger than a jump starter, so don’t expect the unit to work on a heavily drained battery. Buy this to keep your batteries well charged rather than to bring them back from the dead.
Pros
- Super cheap
- Easy to use
- Works on a wide range of vehicles
- Small and lightweight
- One-year warranty
Cons
- Won’t charge a heavily drained battery
- Not powerful enough for bigger batteries
Editor’s Rating:
Quick Facts:
- Type: Charger / maintainer / re-conditioner
- Volts: 12V
- Amps: 7A
- Size: 7.52 x 3.5 x 1.89 inches
If you’re happy to invest a bit more cash in a powerful AGM battery charging solution that’ll last you for years to come, then the MULTI US 7002 from CTEK is about the best money can buy.
The high-tech charger, maintainer, and re-conditioner combo pumps out a whopping maximum level of 7A, which means it’s suitable for starter batteries of bigger vehicles like trucks and oversized RVs. Specifically, the system will recharge any AGM battery under 150AH, even if it’s been left to run down almost entirely flat.
CTEK incorporates an innovative 8-step automatic switch charging system into the design, allowing it to slip between different modes seamlessly for an all-round smoother charge. And that has two distinct benefits for the user: you can set it and forget it plus it’ll extend battery longevity (up to three times the battery life compared to a cheaper charger). Another plus for folks living in harsh climates is the system adapts to all weather conditions, making it capable of charging efficiently between –4°F and +122°F.
Despite its state-of-the-art functionality, the MULTI US 7002 is remarkably easy to use—the simple interface with big buttons and LED display lights is intuitive for novice and experienced users alike.
The desulphation process used in the re-conditioning mode also works better than most, allowing you to extend the shelf life of your AGM battery longer than ever before. And that reason alone is largely why this state-of-the-art charger can command such a high premium.
Pros
- Extends battery life
- Doesn’t require any monitoring
- Works on big batteries up to 150 AH
- Great for harsh climates
- Easy to use for novices and pros
Cons
- Expensive compared to other chargers
5. NOCO Genius G750
Editor’s Rating:
Quick Facts:
- Type: Charger / maintainer
- Volts: 6 / 12V
- Amps: 0.75A
- Size: 4.5 x 2.7 x 1.3 Inches
If you liked the look of our top pick, the NOCO GENIUS5, but have less demanding charging needs, then the G750 of the GENIUS range is well worth a look. Expect to find many of the same high-tech features and quality craftsmanship as the GENIUS5, but with a lower amperage rating, which equates to a much lower price.
But the lower discharge rate doesn’t mean the G750 won’t be any good for your vehicle as its 0.075 A is ample for charging and maintaining most AGMs, including bigger automobile batteries for cars and trucks. The big difference here is that it won’t charge big batteries that have run completely flat, although you can still use it to revive smaller vehicles such as motorbikes and jet skis (anything up to 30AH can be brought back from the dead).
The system works on a variety of other lead-acid type batteries and has both 6 and 12V settings for optimal versatility. And like other NOCO products, all you need to do is plug it in and let the automated system work its magic.
The G750 comes with a generous 5-year warranty, which is far longer than most options on our list.
Pros
- Compact and affordable
- Highly regarded brand
- Can maintain and charge large batteries
- Can charge small batteries from a low voltage
- User-friendly automated charging
Cons
- Won’t charge big batteries from a low voltage
6. Best AGM Battery Maintainer: Schumacher SC1299 Automatic Battery Maintainer
Editor’s Rating:
Quick Facts:
- Type: Maintainer
- Volts: 12V
- Amps: 0.08A
- Size: 3.00 x 4.00 x 9.00 inches
Should you already have an AGM battery charger, and you’re looking to add a maintainer to your tech collection, then the Schumacher SC1299 is an excellent choice. Because the product serves solely as a maintainer, it works exceptionally well and comes in at a very reasonable price.
Although the unit runs on a modest 0.08A, that’s more than enough given the task at hand. While chargers require higher amperage to get batteries back up and running again, maintainers only need a small amount to keep them level. The bottom line? 0.08A is pretty decent in this context.
A handy multi-stage charging mechanism allows for optimal precision, which helps enhance the longevity of your precious AGM battery. It’s easy to use, too, with charge status LEDs and a simple interface. And just in case you do mess up and hook the clamps in reverse, a built-in protection device will automatically switch it off to stop you overcharging the battery.
While it does a brilliant job on most vehicles, don’t expect the product to maintain big batteries for trucks, tractors, RVs, and the like. You’ll have to look elsewhere for that, specifically, something like the CTEK MULTI US 7002.
Pros
- Purpose-built maintainer
- Affordable maintaining solution
- Easy to use even for novices
- Reverse clamp protection
Cons
- Doesn’t charge batteries
- Not suitable for large vehicles
7. Schumacher SC1281 Fully Automatic Battery Charger
Editor’s Rating:
Quick Facts:
- Type: Charger / jump starter
- Volts: 6 / 12V
- Amps: 30A (charger) / 100A (jump starter)
- Size: 11 x 10 x 8 inches
- Weight: 12.65 pounds
Sometimes you don’t have the time or patience to wait around for hours to trickle charge your AGM battery. There will be times when you need to juice up your car battery straight away so you can take it for a spin. And at those times, you need the Schumacher SC1281, a fully automated AGM battery charger that doubles as a jump starter.
A powerful 100A in jump starter mode gives you the energy you need to get the engine ticking over straight away, affording you the freedom to hop in the driver’s seat and get on the road. It’s not just for small cars either, as the SC1281 has enough power to jump-start SUVs and pick-up trucks.
Another great unique feature about this product is its alternator-run diagnostic function, which allows you to pinpoint electrical issues with your battery. The feature is probably best left to the techie types, but it’s nice to have nonetheless.
Of course, the Schumacher SC1281 works wonderfully as an everyday battery charger; its beefy 30 A of power and microprocessor-controlled automated float mode allows you to recharge rapidly and safely. What’s more, the included LED lights, and a simple push start/stop button improve usability.
The only drawback? It might be a little too powerful. You’ll need to carefully check whether the system is appropriate for your battery to avoid frying it through overcharging.
Pros
- Able to jump-start cars big and small
- Whopping 30A of power
- Electrical diagnostic function
- Fast and precise charging
- Easy to use (aside from diagnostics)
Cons
- May overcharge your battery
- No maintainer or re-conditioner function
- The diagnostic process is complex
8. Best AGM Battery Charger for Boating: Promariner 43021 Battery Charger
Editor’s Rating:
Quick Facts:
- Type: Charger / Maintainer
- Volts: 12 / 24 / 36V
- Amps: 20A
- Size: 14.5 x 6 x 8.5 inches
Sailors in search of a turbo-powered battery charger and maintainer for their beloved seafaring vessel have long been turning to Professional Mariner. The industry-leading maritime battery specialist has been producing high-quality products for over 35 years and the Promariner 43021 lives up to their high standards.
This powerful maritime charger is designed to be installed onboard, which negates the need to carry around various portable chargers to kick start your ship. And its impressive in-built energy-saving mode and fast-charging capability allow you to bring your battery back up to full in as little as 8-10 hours—an easy overnight charge.
The fact the company has included an automated multi-stage digital charging function ensures your marine AGM will last longer than ever before, and that’s a definite plus as batteries of this size don’t come cheap. Another cool feature is its ‘distribution-on-demand’ technology, which automatically allocates amperage from your engine starter battery to your house or trolling motor battery as required—a truly high-tech innovation that optimizes efficiency.
The battery charger has been known to overheat, although it does come with a respectable two-year warranty so you can expect to get a good amount of use out of it.
Pros
- Powerful 20A for big marine batteries
- Multi-stage charging improves battery life
- Distribution on demand enhances efficiency
- Installed onboard, so no portable battery required
- Charges fast from 8 to 10 hours
Cons
- Rather expensive
- Sometimes overheats
9. Optima Digital 400 12V Performance Maintainer and Battery Charger
Editor’s Rating:
Quick Facts:
- Type: Charger / maintainer
- Volts: 16V
- Amps: 4A
- Size: 8.2 x 3.7 x 7.4 inches
Who said good things had to come in big packages? The Optima 400 is one of the smallest chargers on our list yet pumps out a whopping 4A, enough to bring back most AGM batteries from the dead. The potent little unit has enough juice to restore flat batteries as heavily discharged as 1.25V, far lower than most other chargers on the market.
Aside from being small and lightweight, we also love how the Optima 400 can be set upright on an included stand or hung from above—perfect for home or professional garages with a scarcity of space.
A hybrid LED charging gauge and LCD display lets you monitor the state of charge at any time, making this swanky device more user friendly than most. Furthermore, a built-in battery health and performance monitor enhances the battery maintainer function, allowing you to extend the overall longevity of your AGM.
The unit costs quite a bit more than a basic AGM charger, but it’s worth it for frequent users. Although it comes with a generous three-year warranty, you’ll need to be careful to keep your original receipts.
Pros
- Small yet powerful 4A device
- Revives car batteries as low as 1.25V
- Comes with stand and hook for hanging
- LED gauge / LCD display for usability
- Works well as a maintainer
Cons
- Costs more than other chargers/maintainers
- Impossible to claim on the warranty without original receipt
10. NOCO GENIUS2
Editor’s Rating:
Quick Facts:
- Type: Charger / maintainer / re-conditioner
- Volts: 6 / 12V
- Amps: 2A
- Size: 3.43 x 4.25 x 6.97 inches
While the NOCO GENIUS5, is our favorite battery charger overall, the lower amperage version of the NOCO GENIUS2 is an outstanding alternative for users who don’t need stacks of power. This compact model is significantly cheaper, smaller, and lighter, all valid reasons to purchase it if 2A is sufficient for your needs.
Other than the amperage rating, there isn’t a whole lot of difference between the two models. Both have precision charging with an integrated thermal sensor to power you up in any climate, as well as an anti-sulfate re-conditioning function to get your time-worn AGM back into good health. And despite coming in at a notably lower price point, the GENIOUS2 can still revive 40 AH batteries from as low as 1 V. You can even use it on lithium batteries should you decide to make the switch at a later date.
Before you get too excited, remember that 40 AH is well below the average car battery size of 50-100 AH. In short, it’ll work brilliantly on your motorbike or dune buggy but not the family car.
Pros
- Small and affordable
- Charges, maintains, and re-conditions
- Precision charging and temperature control
- Revives batteries as low as 1V
Cons
- Modest 2 A discharging rate
- Doesn’t work on batteries over 40 AH
AGM Battery Charger Buyer’s Guide
It’s always wise to do a little background research into a product before pulling the trigger and making a purchase. We’ve done the legwork for you by compiling this in-depth guide on everything you need to know about AGM battery chargers. Read on to become an expert on AGM batteries and how those techy types manage to keep them adequately charged.
What Is An AGM Battery?
AGM, which stands for absorbent matt glass, is a type of lead-acid battery that’s especially common in automobiles, from motorbikes to cars and oversized trucks. The key to the AGM’s success is its absorbency—it’s capable of soaking up the sulfuric acid inside through superfine fiberglass mats, which prevents the corrosive acid from spilling or leaking.
As a result, AGM batteries can withstand an enormous amount of bumps and vibrations, far more than most other battery types on the market. And for that reason, coupled with a relatively cheap manufacturing process, they’re the electric battery of choice for just about anything that moves.
Amps and Voltage
We pay close attention to amps and voltage in all our reviews, as these are two critical factors that determine whether a product will be right for you.
Voltage (V)is the pressure an electrical current is under when it passes through a circuit board. In simpler terms, you can think of voltage as kind of like a system. American homes run on a 120V system, which powers all the appliances you use in your day-to-day life. Generally speaking, however, in the automotive space—think RVs, cars, boats, etc.—we tend to use 12V, although lower (6V) or higher (24V / 36V) isn’t unheard of either.
Amps (A) basically refer to the electrical flow or power of the charger, and the higher the amperage, the more powerful it will be. Small AGM batteries like those found in motorbikes are fine to be charged on something as little as 0.75-1.25A, while bigger batteries might need 3A or more. If you have to charge an extensive battery system on a heavy vehicle like a yacht, then you might need as much as 20A (like the Promariner 43021 Battery Charger, for example).
Understanding Amp Hours
Whether it’s AGM, another lead-acid type, or even lithium, we use the term Amp Hours (AH) to refer to how much power you can draw from a battery before it runs flat.
To give you a rough idea, a small motor found on something like a dirt bike or jet ski will have a starter battery of approximately 30 AH. Bigger vehicles require more amp hours in the starter battery to get the engine running, with most cars sitting somewhere between 50 and 100 AH. The leisure batteries of boats, RVs, and off-grid homes will be bigger still, sometimes up to 200 AH and with multiple cells connected to the same system.
Note that some AGM battery chargers are rated for use up to a maximum number of AH. If you’ve got a bigger battery than that, you’ll need to find a more powerful charger.
AGM Battery Charger Types
There are three different types of AGM battery chargers, each of which performs distinct functions. It’s quite common for a unit to do the job of more than one type; for example, charger/maintainers are particularly prevalent.
Chargers
These are by far the most common variety, and they do precisely what the name implies: recharge an AGM battery to top it up or bring it back into a working state.
AGM chargers are specially designed to run on the correct level of voltage and amperage to safely and efficiently restore power to an AGM battery. Using any other kind of charger could damage or destroy your AGM, so never try to mix and match.
Maintainers
Battery maintainers, as the name suggests, maintain the current level of the charge in the battery—it won’t go up nor down.
But why would one want to maintain the same battery level, you may ask? Well, when AGM batteries are kept in storage for a lengthy period, the battery will slowly discharge and eventually run flat. Over discharging an AGM battery will damage the system and significantly reduce its lifespan, and an AGM battery maintainer will prevent this from happening.
Re-conditioners
Again, re-conditioners do exactly what they claim: re-condition a badly worn and poorly performing battery back into a more effective state. Over time, contaminants will build up inside a battery cell and prevent the unit from producing the optimal amount of power—and eventually, it could even stop working entirely. The re-conditioner uses a high-tech system to clean out the blockages and improve the overall performance of the affected battery.
These dedicated devices are commonly found in auto-repair shops. The fact they’re rather expensive and not entirely necessary for day-to-day use means they’re not widely purchased for domestic purposes, although you will find a few combo options on our list.
PowerSports Batteries
PowerSports batteries are specifically designed for small, outdoor leisure machines like ATVs, ski mobiles, jet skis, and low-horse-power motorbikes. Some battery chargers, such as the Battery Tender Plus Charger and Maintainer only work with PowerSports batteries. Therefore, if you buy one to use on your car battery, you’ll only be wasting your money as it won’t work at all.
Battery Jump Starters versus Battery Chargers
Generally speaking, battery jump starters are a different product altogether, one that’s designed to immediately pump enough power into your AGM battery for you to start using the vehicle straight away. Battery chargers, on the other hand, will slowly recharge a low (or perhaps even fully flat) battery over time, anywhere between two and twelve hours.
However, some manufacturers combine both functionalities into the same product. See our review on the Schumacher SC1281 if that sounds like something you need.
The Benefits of Owning an AGM Battery Charger
The primary purpose of owning an AGM charger is the ability to recharge your vehicle battery once it runs flat or dangerously low. AGM batteries need to be charged slowly with the correct amperage and voltage; otherwise, you could end up damaging or ruining it. Attempting to charge an AGM battery with any other kind of charger that isn’t specifically built for the purpose is asking for trouble.
Having an AGM charger at home is convenient, as it allows you to recharge your battery without removing it from the engine bay or getting the car towed to an auto repair shop.
Aside from recharging your battery, AGM chargers have another useful purpose: monitoring. Many varieties come with an electronic display that tells you the current level of charge and can give you an indication of how badly worn out your battery is. That way, it won’t come as a surprise when it comes time to buy a new one, and you can budget your expenditure accordingly.
Using an AGM Battery Charger
Non-mechanically minded folks don’t need to worry about wracking their brains to comprehend an overly complex system because AGM battery chargers are remarkably easy to use. Although the exact process varies between models, the general procedure is to connect the cables to your battery, plug the charger into the power grid, and switch the unit on.
High-quality AGM battery chargers will automatically shut off at the appropriate time to avoid overcharging the battery. Furthermore, the better models have in-built microprocessors that gather information about the relevant elements within the battery and regulate the correct voltage and current. In this situation, it’s just a matter of ‘set it and forget it.’
There are a few simple things to remember, however:
- Clean the cable connectors before using them because dirt and dust can accumulate and significantly reduce the efficiency of the charger.
- Always connect the cables to the car battery before plugging it in and turning it on. You don’t want to be handling a live current under any circumstances.
- It’s best to wear a thick pair of gloves while connecting the cables. A thin layer of dried sulfuric acid, which looks like a chalky white powder, may accumulate on the battery, and it’s best not to let this come into contact with your skin. Alternatively, you can carefully wipe it clean with a rag.
- Remember to connect the positive and negative cables into the right port—there will be a marking engraved into the battery. No matter what battery you buy, the red cable will be positive, while the black cable will be negative.
When to Charge Your AGM Battery
Most AGM batteries reside within the engine bay of an automobile, and these generally don’t need to be charged up at all (at least not manually, anyway). A car’s alternator draws electricity from the pumping pistons inside the engine to recharge the battery as you drive, which means you don’t have to worry about it. However, if you run the A/C too long or forget to turn the headlights off, then you’re battery will run low, and you’ll need to recharge.
Leisure batteries, AKA house batteries, which are used in boats and RVs, will also usually (but not always) draw power from their gasoline-operated engines. However, as the engine isn’t running all the time, it’s often necessary to charge them from an external source, the most efficient of which is the AGM battery charger (solar panels can only provide so much juice).
AGM batteries shouldn’t be discharged more than 50% to avoid permanent damage over time. The avid sailor and RVer has a voltage meter installed in their rig and knows to stop drawing power and start recharging once it hits 12.05V in order to preserve the longevity of their battery.
The Charging Time
The amount of time it takes to charge an AGM battery depends on several factors—the battery capacity, condition, and the charge rate—so it’s impossible to provide an exact figure. Expect to wait anywhere between two and twelve hours for a full charge up. A high-end AGM battery charger will automatically shut off when it reaches the optimal level, which makes life easier.
Of course, you don’t need to recharge a battery fully to start your car. Many cars can start with a battery voltage as low as 11.9V.
The Best AGM Battery Chargers
If you’ve made it this far through our guide, you’re now something of an expert on AGM batteries and the best ways to charge them. Whether you just want to maintain or re-condition your AGM to extend its shelf life or you need to charge it regularly from the mains, there’s an AGM battery charger out there to suit your needs.
Take the time to mull over our meticulously researched top 10 list of AGM battery chargers to find the device that best works for you.
Does repair mode (12v) work for AGM batteries?
Yes, it does