Frequently Asked Questions

An Absorbed Glass Mat (AGM) battery is a high-performance, sealed lead-acid battery perfect for demanding applications. Unlike traditional batteries that require regular watering, our AGM batteries use a special fiberglass mat to absorb the electrolyte. This creates a spill-proof, leak-proof, and maintenance-free design that you can mount in virtually any position.

VMAX AGM batteries are a class above the rest. We build them with military-grade alloys and plates for extreme durability and a longer lifespan. They are engineered for deep-cycle excellence, meaning they can be drained and recharged repeatedly without losing power. If you need a battery that’s built tough for the harshest conditions, VMAX is the clear choice.

Shipping is FREE to any home or business within the 48 contiguous United States. We ship orders fast—most orders placed before 2 PM EST ship the same day. 98% of our customers receive their batteries within 2-5 business days. Heavy orders that ship via LTL Freight will ship the next business day. We use top-tier carriers for LTL shipments to ensure a safe and quick delivery.

Click here for our to view our shipping policy

We aim for a simple, hassle-free process.

If we made a mistake (damaged in transit, wrong item), we will exchange it immediately at no cost to you.

If you changed your mind or ordered the wrong item, you can return it within 30 days. We offer a discounted return shipping program to make it as easy and affordable as possible. Just email us with your order number to get started.

We stand behind our products with a clear, straightforward warranty.

AGM Batteries & Chargers: 1-Year Full Replacement Warranty.

LiFePO4 Lithium Batteries: 7-Year Pro-Rated Warranty.

You can view the full warranty details on our Warranty page.

Our goal is to be fair and efficient. If you believe your battery is defective within the warranty guidelines, our Michigan-based support staff will first help you troubleshoot the issue. Often, the problem can be resolved with a simple adjustment. If a warranty exchange is needed, we will guide you through every step and offer discounted return shipping options to make it easy. Simply email us at [email protected] for help with a claim.

That depends on your priorities. Both are a significant upgrade over standard lead-acid batteries. Here’s a simple guide:

Choose VMAX AGM if:

You need maximum toughness: AGM is the most rugged battery technology available, offering unmatched resistance to shock and vibration.

You operate in extreme temperatures: AGMs can handle a wider temperature range compared to many Lithium batteries.

You want proven, military-grade reliability: Our AGM batteries are built like a tank and are considered one of the safest battery technologies available.

Choose VMAX Lithium (LiFePO4) if:

You need the lightest weight possible: Lithium batteries offer incredible power at a fraction of the weight of AGM batteries.

You want the longest possible lifespan: Our Lithium batteries provide up to 4,000 life cycles, offering exceptional long-term value.

You demand the best internal components: VMAX Lithium batteries use only top-tier, brand-new cells (never refurbished), a rugged Battery Management System (BMS), and built-in safety features like temperature cutoffs and cell balancing.

That weight is a sign of quality. VMAX AGM batteries are heavy because we pack them with thick, military-grade plates made from 100% virgin lead. More lead means more power, a longer life, and the rugged durability to withstand intense vibration and shock. While our Lithium line offers a fantastic lightweight solution, when it comes to AGM technology, heavy is good. It’s proof that you’re getting the toughest battery for your tough application.

VMAX is a proud American company with a team of battery experts based in Michigan, USA. We operate facilities in the US, Vietnam, China, Taiwan, and Germany to ensure the highest quality standards, with the majority of our products manufactured in our main US and Vietnam facilities.

The right battery depends on your space, desired run time, and charging system. We make it easy to find your perfect fit:

Match the Group Number: If you're replacing existing batteries, simply match their Group Number (e.g., Group 31) to the corresponding VMAX battery on our website.

Let Us Help: If you're unsure, our Michigan-based battery experts are here to help. Contact us via email or phone, and we'll guide you to the perfect battery for your needs. We offer lifetime technical support for all our products.

The best marine battery for a trolling motor depends on your setup and priorities. For many boaters, a deep cycle battery is the right choice because trolling motors require repeated discharge and recharge cycles. VMAX offers both AGM deep cycle marine batteries and lithium deep cycle marine batteries for trolling motor applications, including 12V, 24V, and 36V options.

VMAX batteries are maintenance-free in the sense that you never have to add water or worry about acid spills like with old wet cell batteries. However, like any premium equipment, basic care ensures the best performance and longest life. We recommend periodically checking that all terminal connections are clean and tight.

Using the right charger is one of the most important factors for maximizing battery life.

For AGM 12V Batteries: You need a multi-stage smart charger that has a specific AGM setting. A compatible charger will have a bulk/absorb charging voltage between 14.4V-14.9V and a float voltage between 13.2V-13.8V.

For Lithium Batteries: You need a charger specifically designed for LiFePO4 batteries, with a charging output of 14.4V for 12V LiFePO4 batteries.

Each battery’s product page lists a recommended charging amperage. If your current charger or converter meets these specifications, you can use it.

The lifespan of a battery is measured in cycles. With proper care and charging, VMAX batteries provide exceptional longevity.

VMAX AGM: Designed for an 8-10 year lifespan in float service (like a backup system). In active use, an AGM battery discharged to 50% every other day can last 5-6 years. Daily deep discharges of 90-100% will significantly shorten the life to around 1 year.

VMAX Lithium: Our LiFePO4 batteries are rated for an incredible 4,000 life cycles, offering one of the longest service lives on the market.

While other AGM batteries may look similar on the outside, the real difference is inside. VMAX AGM batteries are overbuilt from the ground up to deliver superior performance, a longer lifespan, and unmatched reliability in the most demanding conditions.

Here’s what sets a VMAX AGM battery apart:

Extreme Durability and Toughness: The heart of every VMAX battery is the unique physical and chemical structure of its heavy-duty, plates. A special manufacturing process gives them strength and performance that far exceeds competitors. We pack these plates tightly with a specially designed Absorbed Glass Matt (AGM) that maximizes the battery's resistance to shock and vibration. The entire package is protected by an extra-strong ABS container that reduces bulging and warping, ensuring high performance for years to come.

Reliability When It Matters Most: VMAX batteries are known for their ability to recover after repeated deep discharges. Our heavy-duty grids provide an extra margin of performance even after being over-discharged. This means you get one of the highest numbers of discharge/recharge cycles in the industry, making VMAX the favorite choice for any application where failure is not an option.

Truly Maintenance-Free & Safe: Our sealed, leak-proof construction guarantees operation in any position. Because the electrolyte is fully absorbed, there is no need to ever add water or check specific gravity. The design controls and recombines over 99% of gases, and a built-in safety valve prevents any excessive pressure, making it incredibly safe. VMAX batteries are classified as non-spillable and non-hazardous, meaning they are not restricted for air, sea, or surface transport.

Longer Life & Better Value: VMAX AGM batteries have an expected float service life of 8 to 10 years. They also hold their charge much longer when not in use, with a self-discharge rate of just 1-2% per month compared to 15-20% for many standard lead-acid batteries. This means your battery is ready to go when you are, even after sitting in storage.

Anyone is welcome to order. If you are a dealer or distributor, please click here to apply for a dealer account.

The lifespan of a battery is measured in cycles. With proper care and charging, VMAX batteries provide exceptional longevity.

VMAX AGM: Designed for an 8-12 year lifespan in float service (like a backup system). In active use, an AGM battery discharged to 50% every other day can last 5-6 years. Daily deep discharges of 90-100% will shorten the life to around 300 cycles.

VMAX Lithium: Our LiFePO4 batteries are rated for an incredible 4,000 life cycles and have a 10-year design life.

The heart of the VMAX is the unique physical and chemical structure of its plates. The special treatment and manufacturing process they undergo gains them unique reliability, strength and high performance far exceeding those of other Pb-Ca plates used in similar looking products. Using our specially designed Absorbed Glass Matt (AGM) between the VMAX plates, adds to it many physical and electrical advantages that make it superior to the Wet Lead Acid Batteries. This also maximizes the VMAX resistance to shocks and vibrations. Since the electrolyte is totally absorbed by the AGM, the VMAX is classified as “non-spillable and non-hazardous”.

A tough Tank seals and protects the tightly packed plates delivering the VMAX in a 100% maintenance-free package.

Though VMAXTANKS™ are best known for their long life span, their capability to recover after repeated deep discharges is what makes them the favorite choice for any application.

To sum it up, VMAXTANKS™ utilize:

Sealed Construction
The unique construction and sealing techniques of VMAX tanks guarantee leak proof operation in any position with no adverse effect to capacity or service life. VMAX tanks are classified as non-spill able, non-hazardous, dry batteries making them NOT restricted for Surface, Maritime and Air Transport.
Electrolyte Suspension System
VMAX tanks utilize an electrolyte suspension system consisting AGM (Absorbed Glass Matt) of a high porosity that totally absorb and contain the electrolyte. No silica gels or any other contaminants are used.
Gas Generation
VMAX tanks incorporate a built-in design that controls gas generation and induces recombination of more than 99% of gases generated during float usage.
Maintenance Free Operation
There is no need to check specific gravity of the electrolyte or add water to VMAXTANKS™ during float service life. In fact, there is no provision for this type of maintenance.
Low Pressure Valve Regulated System
All VMAXTANKS™ AGM batteries are equipped with safety release valves, designed to operate between 0.98-196.1kpa and automatically reseal. Hence, there is never an excessive accumulation of gas within the battery.
Heavy Duty Grids
Heavy duty lead tin alloy grids manufactured with virgin lead provide an extra margin of performance and service life in either float or cyclic applications, even after repeated over discharges.
Cyclic Service Life
VMAX is known to deliver one of the highest numbers of discharge / recharge cycles. (900-1000 Cycles at 50% Depth of Discharge, 3,500+ at 10% Depth of Discharge).

Float Service Life
VMAXTANKS™ have an expected life span of 8 to 10 years in float service applications.
Low Self Discharge
The self discharge rate of the new VMAX tanks at room temperature is approximately 1-2% of rated capacity per month (compared to 2-3% for most other AGM batteries and 15-20% for Lead Acid batteries).
Operating Temperature
VMAXTANKS™ may be operated over a broad range of ambient temperatures.
Ultra Low Resistance
VMAXTANKS™ Ultra Low Resistance make it up to 99% efficient (compared to 85-95% as in Lead Acid Batteries and 97% in most other GEL and AGM batteries).
Higher Power Density
A special assembly technology is used to enhance power density to a considerable level.
Reliable Construction
The extra strong construction ABS container reduces case bulging and plate warping, ensuring long life and high performance.

Storage:

1- Batteries must be stored clean and away from any moisture.
2- Storage room must be dry, ventilated and kept at a temperature range of 10°F (-12°C) – 104°F (40°C) degrees. Storage at room temperature is MOST recommended.
3- Fully recharge your batteries before storage.
4- Though VMAX batteries can be stored for 6-9 months without a recharge, it is highly recommended to recharge your stored batteries at least once every 3 months, or once every 2 months if stored at over 85°F (30°C).
5- If batteries are not accessible, or if they cannot be periodically charged while in storage, then leave your three stage charger connected to them until they are ready to be reused again.

Commissioning:
1- Ensure that batteries are clean. Use a damp cloth to clean battery surface. Dry surface after cleaning. The use of cleaning agents, solvents, petroleum or any other products of the sort is not recommended and may cause damage to battery surface.
2- Fully recharge your batteries. A float charge of 48-96 hours at room temperature is highly recommended (13.5-13.7V for 12V or 6.69-6.81V for 6V batteries). Or you can fast charge your batteries (14.5-14.9V for 12V or 6.9-7.05V for 6V batteries) for 12-24 hours.
3- Check battery voltage with no load. It should be above 12.9V for 12V or 6.45V for 6V batteries.
4- Connect batteries to load.
5- Check the tightening of connections.

Most of the time, this problem happens to sealed lead-acid batteries of either AGM (Absorbed Glass Mat) or GEL (gelled electrolyte) construction. These batteries are known as "recombinant", referring to the absorption of gasses generated by the chemical process of the battery. In order to absorb these gasses, the positive and negative plates must be as close together as possible and are usually held apart by the thickness of the separator. A consequence of the necessity of gas absorption, the pack of plates is inserted very tightly into the cell cavity, resulting in a lack of space for any other components. In the situation of a swollen battery, the cell plate components expanded, and the force exerted on the case will cause it to swell and in some cases split.

The expansion of the plates is a result of internal heat caused by either overcharging the battery or from a drastic shorting of its terminals. Either one of these situations will generate internal heat in the battery. And since lead has a high expansion rate when exposed to heat, the expansion pressure will cause the case to swell and cause battery damage.

Overcharging of the battery can be the result of using a charger that is delivering the wrong Voltage or Current to the battery. Regardless of the cause, the result is almost always the same; swelling and the destruction of the battery.

For your safety and to avoid this problem, it is very important to ask the following questions:

1.  Is the charger designed to be used with my battery (AGM, WET, GEL, LITH…)?
   

2.  Does the charging voltage fall within the range specified for my battery?
   

3.  Does the maximum current of the charger fall within the charging range of my battery?
   

4.  Do I have the right polarity connection between battery and charger?
   

5.  Are the battery terminals prevented from possible shorting at all times?
   

Two popular premium Group 31 AGM marine battery options from VMAX are:

XTR31-135 (AGM Dual Purpose Group 31)

MR137-120 (AGM Deep Cycle Group 31)

The XTR31-135 is ideal for boaters needing dual-purpose performance, while the MR137-120 is a strong choice for deep cycle marine applications.

Yes. VMAX offers AGM deep cycle marine batteries in multiple group sizes, including Group 24, Group 27, and Group 31.

For dual purpose marine applications, VMAX’s premium AGM options include:

XTR31-135 (Group 31 AGM Dual Purpose)

XTR27-110 (Group 27 AGM Dual Purpose)

These are designed for boaters who need a battery that can support both engine starting and exceptional deep cycle performance.

Yes. VMAX is a Michigan-based battery manufacturer, established in 1991.

12V AGM Performance Charts
12V GEL Performance Charts
6V AGM Performance Charts
LIFEPO4 Performance Charts
Number Of Cycles vs Depth Of Discharge Graph
State of Charge Chart
Float Charge Voltage vs Temperature

DC Winches Application Guide
Estimated Wire Sizing Chart
Trolling Motors Breakers and Cables Chart

AC and DC Loads
DC Motors (HP)
Sump Pumps
Trolling Motors
Water Pumps