GEL batteries for solar

Gel Batteries for Solar Guide

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Gel batteries are very useful for small or medium-sized of-grid solar installations.

GEL batteries have the main advantage that they dont need maintenance, in addition to not emitting gases and a great durability. They stand out for their great durability.
As they do not carry liquids inside, they are very suitable for solar installations in places that move frequently such as caravans, motorhomes, boats, etc.

It does not require maintenance and its use is ideal for refrigerator, water pumps, washing machine .. that is to say, apparatuses that have motor, since it supports very well the starting peaks of these apparatuses without this affects its useful life. Being sealed, they are highly recommended for interiors of homes, boats or motor homes, because they do not emit any type of gas.

How Does It Work?

Gel batteries are lead-acid batteries regulated by a valve. When the electrolyte is mixed with sulfuric acid and silica, it becomes a relatively fixed gel substance.

lead acid working
lead acid working

This gel mixture allows the battery to utilize acid and electrolyte in the same way as a traditional lead-acid battery without additional maintenance.

The Pros of Gel batteries 

Maintenance-free: Since the battery is composed of gel instead of liquid, it can keep the battery working normally without maintenance.

No leakage: Even if the wet battery is sealed in a plastic box, there is still a possibility of leakage. Gel batteries are also sealed, but there is a valve to eliminate excess pressure. This means that there is nowhere for the mixture to go between the gel mass and the pressure relief.

Install them anywhere: The advantage of gel batteries is that they can be used almost anywhere, because they will not leak and generally require no maintenance. This greatly increases the number of applications available for gel batteries.

Minimal risk: When the traditional lead-acid battery is damaged, you will face a large-scale dangerous cleanup (not to mention the impact on the battery acid that may be exposed in the process). If the casing is damaged, the gel battery will not leak, thus reducing the risk of injury to the device and eliminating the danger.

Anti-vibration: One of the biggest complaints of wet batteries is that they are very susceptible to extreme vibration and other shocks. Gel batteries absorb shock and vibration, making them excellent batteries for four-wheeled vehicles and other items.

Smokeless: Because these batteries are composed of gel material, they produce very little smoke during use. This means that the need for ventilation is reduced, which increases the potential uses for gel batteries and makes them easier to charge anywhere.

Discharge resistance: When using a wet battery, please do not discharge the battery too much. This is very important. Otherwise, it will never be able to charge. Gel batteries are not like that. They are deep-cycle batteries, which means they can discharge more and still be charged like new batteries.

The Cons of Gel batteries 

Price: Although the benefits of gel batteries are obvious, so are the price tags. Many people want to switch from wet batteries to gel batteries, which is the biggest disadvantage.

The challenge of charging: When charging a gel battery, you need to plan to give it more time. The charging cycle of these batteries is very slow, but you cannot leave it and leave it. Because it is a gel and not a liquid, it needs to be removed from the charger immediately after completion. Leaving it on may cause electrolyte voids, which is irreversible damage.

Thermal control: This is indeed a disadvantage for most batteries, and gel batteries are no exception. Heat is one of the fastest ways to shorten battery life. By controlling the battery’s exposure to heat, you can extend its life and keep the battery running like a new battery.

15 Advantages of Gel Batteries:

  • Full recovery from deep discharge, even when the battery is not recharged immediately.
  • Ideal for repeat cycling daily use.
  • Excellent performance over long discharges
  • Good tolerance to higher temperature applications
  • Improved resistance to freezing
  • Suitable where mains power is unstable
  • Zero stratification due to immobilized electrolyte
  • Reduced self-discharge
  • Limiting design protects the positive plates to greatly improve cycle life Thicker plates for reduced grid corrosion and increased cycle life
  • Improved charge acceptance due to low internal resistance
  • High resistance to water loss with the right charging set up
  • Ultra-stable polymer separator with glass mat for increased performance
  • High resistance to shorting due to superior mechanical strength of the polymer separator
  • Increased tolerance to poor charging parameters
  • Can be discharged even when full recharge has not been achieved, without loss of battery capacity

Why Choose Gel Solar Batteries?

When it comes to solar batteries, many experts will debate the merits of gel batteries and AGM batteries. No two solar installations are identical, and factors such as climate and discharge demands can have a big impact on what type of batteries you need. However, we believe that gel batteries provide a number of benefits to solar users for long term energy storage.

Temperature Considerations

Gel batteries tend to outperform AGM batteries in solar functions where heat is a concern. Gel batteries adapt better to extreme temperatures and are less likely to experience thermal runaway, a condition that occurs when the internal battery temperature rises too quickly and too far.

Life Cycle

Anotherindisputable fact about gel solar batteries is that they can provide nearly twice the lifespan of an AGM battery. In particular, Brava solar batteries are designed for 600-800 complete lifecycles, while an AGM battery is typically in the 400-500 range. AGM batteries are generally less expensive, so paying for frequent replacements can be a deterrent.

Storage Properties

When it comes to long term passive storage of energy when the system is not in use, gel is on par with AGM, and both battery types exceed lead acid with less overall maintenance. With a gel battery you can relax knowing that the power isn’t going to leak away over time.

5 technical features of Gel battery technology :

  • Using gel as electrolyte
  • Plate thickness tolerance is not critical since the high compression of plates group assembly is not necessary
  • More electrolytes for better contact with plates and active materials and container walls, it is good for releasing internal heat and cooling battery temperature.
  • Using the extra microporous separator which can:
    a/ reduce the depolarization of the negative electrode and avoid negative plate sulphation
    b/ without any liquid, significantly decreases thermal runaway
    c/ Help to prevent short circuits by dendrite growth between the positive and negative plates during deep discharge
  • Better vent valve design to lower gas leaking rate to extend battery lifetime.

8 advantages of Gel battery , Compared to flooded battery:

  • Maintenance free, no need to add water
  • Safe operation since no liquid inside
  • Can be installed sideways ( upside-down is not recommended )
  • Long cycle life
  • Low self-discharge makes shelf life longer.
  • Long standby life due to its ability to keep electrolyte inside and steady
  • Performance stays high and stable until the end of life
  • Tolerance to abuse and heat during operation, good for extreme weather


6 advantages of Gel battery in application :

Maintenance free

When battery is charging, hydrogen would be absorbed and reversed to electrolyte by plates. It doesn’t need to refill water and balanced charge, which makes maintenance free.

Flexible installation

AGM separator keep electrolyte absorbed in glass mat and still. Battery can be used or positioned in any orientation.

Longer lifespan in extreme weather

Gel cell electrolyte prevent electrolyte being evaporated in high temperature or being frozen in low temperature, which keep battery in high performance in extreme weather. Extremely safe When excessive gas production by inappropriate charging occurs, safety valves will automatically emit the gas to prevent battery cracked.

Long standby life, Better cycle performance

Anti-corrosion lead-calcium alloy plate provides longer float charging life. AGM separator can trap electrolyte and prevent active materials on positive plate dropping at the same time. Moreover, it gives better deep discharge cycle performance.

Longer shelf life

Special lead-calcium alloy plates make lower self-discharge for longer shelf life.

High rate performance

Low inner resistance allows higher discharging and charging current for better performance in high rate application

Are 12V Gel Batteries Good for Solar energy?

A 12V 100AH gel battery does have possible applications for solar energy. However, not all solar setups will work well with deep-cycle gel batteries. Because of the amount of energy these batteries produce, along with their cost, 12V solar gel batteries work best with off-grid solar energy systems, such as small solar panel kits designed for RVs, boats, tiny homes, vans, and small cabins.

Deciding on Deep-Cycle Gel Batteries

Solar gel batteries can be an excellent option for certain solar energy system setups that don’t require powering an entire residence or building. These batteries operate much like other lead-acid batteries but come with a few extra advantages.

Deep-cycle gel batteries release less hydrogen gas during discharges. Because of their interior gel design, you can store them in various ways without the risk of leaks or malfunctions. They also cope better with being kept in higher temperatures but still have heat limitations.

Choosing Your Solar Batteries

If you have decided to use either an off-grid or grid-tie with battery backup system to power your home, the next step is to choose your solar batteries. While many different kinds of batteries are used in solar electricity storage, lead-acid batteries are most common. Competitors such as nickel-cadmium and nickel-iron can be expensive, inefficient or hard to dispose of. The three main lead-acid batteries are:

  • Flooded (FLA) → unsealed with liquid electrolyte
  • Absorbed Glass Matt (VRLA) → sealed with electrolyte held captive by glass mat
  • Gelled (VRLA) → sealed with gel electrolyte

Below is a table comparing some of the characteristics of the three lead acid batteries. In order to look at battery capacities and other technical data.

Lifespan* Minimal Gassing Spill Proof Rating Flexibility in Mounting Charging Voltage Sensitivity Maintenance Price
Flooded 3 1 1 1 3 1 3
Gelled 2 3 3 2 1 3 2
AGM 2 3 3 2 2 3 1


*if well cared for Rating: 1 – poor 2 – good 3 – excellent

Your choice of battery will dictate your solar experience. For the average homeowner, we do not recommend gel batteries because of their high sensitivity to charging voltage. If you make a mistake, you could quite easily destroy your battery bank. If you don’t mind monitoring and maintaining your system, and want the lowest installation cost possible, you should be looking at flooded batteries. On the other hand, if you would rather pay extra and never have to touch the batteries after installation, AGM is the way to go.

Go to the product: deep cycle batteries

Tag in this article: #Deep-cycle Battery

Tips: more detail information, for deep cycle batteries.

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