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AGM DEEP CYCLE BATTERY GUIDE

Table of Contents

Sealed AGM Deep Cycle Lead Acid Battery, is use in solar panel power application for storage and backup. Has a longer life cycle comapred to flooded battery. Designed with a 30% discharge and has a cycle life of 2 to 3 years.

The lead acid battery is the oldest type of rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, its ability to supply high surge currents means that the cells have a relatively large power-to-weight ratio. These features, along with their low cost, makes it attractive to continue to dominate the solar market.

As they are inexpensive compared to newer technologies, lead acid batteries are widely used even when surge current is not important and other designs could provide higher energy densities. Large-format lead acid designs are widely used for storage in backup power supplies in cell phone towers, high-availability settings like hospitals, and stand-alone power systems. For these roles, modified versions of the standard cell may be used to improve storage times and reduce maintenance requirements. AGM absorbed glass-mat batteries are common in these roles, collectively known as VRLA (valve-regulated lead-acid) batteries.

12v200ah deep cycle agm batteries
12v200ah deep cycle agm batteries

WHAT IS AN AGM BATTERY?

An AGM battery is one that uses an Absorbent Glass Mat (AGM) inside the battery. This is a special type of glass material that acts as a sponge, soaking up any extra water in the battery. You can tell if your product has an AGM by looking for “AGM” on the label, or by using the model number to look it up on the manufacturer’s website. If you’re not sure where to look, ask us! If you have a Brava battery or are interested in one, the specifications for our batteries are available online to review.

AGM batteries are ideal for use in situations where you don’t want your battery to be damaged by water or humidity. They’re also great for marine applications because they can withstand the salinity of seawater.

AGM batteries are filled with electrolyte and sealed, which means they don’t need to be topped off or refilled like a flooded battery would. This makes them ideal for use in applications where there is little chance of access to water, such as a marine environment or off-grid power supply.

HOW ARE AGM BATTERIES DIFFERENT THAN DEEP CYCLE BATTERIES?

AGM batteries are more expensive than traditional deep cycle batteries, but they are also more durable. They can be mounted in any position and can take a lot of abuse. AGM batteries are also more resistant to shock and vibration than regular batteries, which makes them ideal for use on motorcycles or in other applications where there is a lot of movement. AGM batteries are less susceptible to heat than traditional deep cycle batteries, so you will experience less power loss during long-term storage or high-heat days.

BENEFITS OF AGM BATTERIES

AGM batteries have a number of benefits over regular lead-acid batteries:

  • More efficient and last longer than regular batteries
  • Environmentally friendly
  • Less toxic than traditional gel or flooded cell batteries
  • Durable
  • Increased safety because they do not allow hydrogen gas to escape during charging or discharging cycles

The main benefit of AGM batteries is their energy density. This means that they can store more energy per unit weight than other types of lead-acid batteries. This makes them ideal for applications where weight is a major factor, such as in marine or RV applications where space and weight can be limited.

Another benefit of AGM batteries is that they can be recharged more often than other types of lead-acid batteries without causing damage to the battery. This makes them ideal for applications where frequent charging is required, such as in emergency lighting systems or backup power supplies.

AGM batteries also have a longer lifespan than traditional lead-acid batteries. This is because they can withstand more charge cycles before losing their ability to store energy. In addition, AGM batteries are also more durable because they do not contain any liquid chemicals which could leak out of the battery if it is damaged during use or transport.

What Are The Types of Deep Cycle Batteries?

The deep cycle function is applied to both lithium and lead acid battery technologies.

The lead acid battery can be divided into the flooded cell and the sealed lead acid battery. And the sealed lead acid category can be further split into AGM and gel cell batteries.

Each deep cycle battery type has its advantages and disadvantages, and you’ll have to decide what works best for you.

Let’s now look at these battery types separately:

1. Flooded Lead Acid

2. Absorbent Glass Mat (AGM)

3. Gel Cell

The gel cell battery is another one of the VRLA batteries (like the AGM battery).

4. Lithium Ion

The lithium battery is a relative newcomer compared to lead acid battery varieties.

HOW TO CHOOSE AN AGM DEEP CYCLE BATTERY

1. CONSIDER RESERVE CAPACITY

Look for a battery with a high reserve capacity. This means that the battery can deliver more amperes (current) for longer periods of time, and has a low internal resistance, which means that it is not prone to overheating or overcharging.

2. CHECK THE LIFE SPAN

Select a battery with a long life span. Check how many years you want the battery to last — this will depend on how often you use it and how much power it provides.

3. CHECK FOR RELIABILITY, SAFETY, AND MAINTENANCE NEEDS

Choose one that is reliable, safe, maintenance free and environmentally friendly. If possible, try comparing standby performance rather than just starting performance because this gives a better indication of what happens when the engine is off but still running other equipment like lights.

If you are buying a battery for an emergency power supply, look for one that has been tested at least once per year and labeled as “spill proof”. This will make it easier to transport and store.

If you need a battery for your car, look for one that has the correct voltage and amperage capacity. This will ensure that it fits your vehicle and can handle the electrical requirements of all its components. If you are planning to get a deep cycle battery, ask how many cycles it can provide before needing replacement — this will depend on how often it is used and how much power it provides.

If you are planning to get a deep cycle battery, ask how many cycles it can provide before needing replacement — this will depend on how often it is used and how much power it provides. If you are buying a battery for an emergency power supply, look for one that has been tested at least once per year and labeled as “spill proof”. This will make it easier to transport and store.

AGM DEEP CYCLE Battery Discharging Characteristics

The rated capacity of BRAVA AGM and Gel Deep Cycle batteries refers to 20 hour discharge, in other words: a discharge current of 0,05 C.
The rated capacity of BRAVA Tubular Plate Long Life batteries refers to 10 hours discharge. The effective capacity decreases with increasing discharge current (see table 1). Please note that the capacity reduction will be even faster in case of a constant power load, such as an inverter.

Discharg time (constant current) End Voltage V AGM ‘Deep Cycle’ % Gel ‘Deep Cycle’ % Gel ‘Deep Cycle’ %
20hours 10.8 100 100 112
10hours 10.8 92 87 100
5hours 10.8 85 80 94
3hours 10.8 78 73 79
1hour 9.6 65 61 63
30min. 9.6 55 51 45
15min. 9.6 42 38 29
10min. 9.6 38 34 21
5min. 9.6 27 24
5seconds 8C 7C

Our AGM deep cycle batteries have excellent high current performance and are therefore recommended for high current applications such as engine starting. Due to their construction, Gel batteries have a lower effective capacity at high discharge currents. On the other hand, Gel batteries have a longer service life, both under float and cycling conditions.

Effect of temperature on service life

High temperature has a very negative effect on service life. The service life of Victron batteries as a function of temperature is

 

Average Temperature AGM ‘Deep Cycle’ years Gel ‘Deep Cycle’ years Gel ‘Deep Cycle’ years
20°C / 68°F 7-10 12 20
30°C / 86°F 4 6 10
40°C / 104°F 2 3 5

Effect of temperature on capacity

As is shown by the graph below, capacity reduces sharply at low temperatures.

Effect of temperature on capacity

Effect of temperature on capacity

Cycle life of Brava AGMDEEP CYCLE batteries

Batteries age due to discharging and recharging. The number of cycles depends on the depth of discharge

Cycle life of Brava AGM DEEP CYCLE batteries
Cycle life of Brava AGM DEEP CYCLE batteries

Battery charging in case of cycle use: the 3-step charge curve

The most common charge curve used to charge VRLA batteries in case of cyclic use is the 3-step charge curve, whereby a
constant current phase (the bulk phase) is followed by two constant voltage phases (absorption and float)

3-step charge curve
3-step charge curve

 

4 Tips For Maintaining The Deep Cycle Battery

Here are a couple of pointers to keep your deep cycle battery in optimal condition:

  • Monitor charge levels: Start charging at 50% and don’t let the charge drop under 20%.
  • Charge even when not in use: This will help to prevent sulfation and maintain battery life. Trickle charge your flooded, gel, and AGM batteries if you’re not using them for a long time (lithium batteries don’t require this).
  • Rest the battery: Let the battery cool down after continuous use to avoid grid corrosion.
  • Clean battery extremities: Keep the battery terminal and covers free of dust and corrosion.
Maintaining The Deep Cycle Battery
Maintaining The Deep Cycle Battery

Now that we’ve covered deep cycle battery basics, let’s run through some FAQs.

Deep Cycle Battery FAQs

Here are some answers to common deep cycle battery questions.

1. Can A Battery Be Both A Deep Cycle And A Starter?

Yes, these are called “dual purpose” batteries.

They deliver the powerful amps for cranking that a starting battery in addition to a low amp draw for steady deep cycle support.

2. What Do Deep Cycle Battery Specifications Mean?

Say you’ve got a deep cycle battery and its specifications list that it produces:

100Ah at 20 hours, rated 1000 full cycles at 80% DoD 

What does this mean?

A. Battery Capacity

The Amp Hour (Ah) denotes battery capacity and shows how much current can be delivered for a specific time.

A 100Ah battery at 20 hours means it can produce 5 Amps for 20 hours (100/20 = 5). Deep cycle batteries are typically rated for a 20-hour discharge.

The main thing to understand is that if you’re going to load more appliances, you’ll need a higher battery capacity.

B. Discharge Cycle

The discharge cycle defines how many times a battery can be discharged and charged without reducing performance or capacity.

1000 full cycles simply mean it can be charged and discharged 1000 times. The more full cycles there are, the longer the battery life.

C. Depth Of Discharge

Depth of discharge determines how much of the battery can be discharged safely compared to its original capacity, before it must be recharged.

Deep cycle batteries are meant to discharge more of their energy. An 80% DoD means the battery can discharge down to 20% of its capacity.

3. What Are Some Deep Cycle Battery Features To Consider?

Apart from Amp Hour, discharge cycle life, and depth of discharge, here are some other features you may want to consider in a deep cycle battery.

  • Size and weight: Smaller batteries are easier to carry and reduce overall vehicle weight.
  • Voltage rating: Higher voltage batteries should be used for larger loads.
  • Charging time: The smaller the number, the faster the battery charges.
  • Durability: Batteries can be susceptible to extreme temperatures, vibrations, shocks. Pick one suited to your usage.
  • Shelf life: The ideal shelf life for a deep cycle battery is 10 years before it loses maximum capacity.
  • Charging method: Note how the battery is charged. You can often use a smart charger to help adjust voltage and current.
  • Temperature tolerance: Check its ability to deliver power at different temperatures, especially if you live in very hot or extremely cold climates.

4. How Long Do Deep Cycle Batteries Last?

For the most part, deep cycle batteries will last up to six years with proper care and maintenance.

In general, their lifespans are:

  • Lithium batteries: 3-10 years
  • Lead acid and AGM batteries: 6 years
  • Gel batteries: 10 years

5. What’s The Charging Time For Deep Cycle Batteries?

The actual timing depends on several factors, including the battery capacity, age, battery charger, etc.

But on average, here’s how long they’d take to charge:

  • Flooded lead acid battery: 8-16 hours
  • AGM battery: 5 hours
  • Gel battery: 5-10 hours
  • Lithium battery: 2-3 hours

6. Where Are Deep Cycle Batteries Used?

Deep cycle batteries are used for anything that requires continuous power for an extended period.

These include:

  • RVs, golf carts, wheelchairs, scooters
  • Marine trolling motor, navigational devices
  • UPS backup technology, emergency lighting
  • Solar battery for off-grid energy storage systems

7. Can I Connect Different Deep Cycle Batteries?

No.

Only connect batteries of the same type, model, capacity, and age.

For example, if you want to connect your deep cycle RV battery with another one to increase output, make sure the second battery meets the mentioned criteria.

8. Can I Start My Car With A Deep Cycle Battery?

No.

Deep cycle batteries aren’t designed to deliver high currents to start a car. Using one could damage the battery or the car. Stick to a starting battery for this.

9. Can I Solar-Charge My Deep Cycle Battery?

Yes.

Any deep cycle battery can be charged with solar panels. Make sure to use a solar charge controller for deep cycle solar batteries to regulate the charge.

 

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