The Most Efficient Batteries for Best Solar Panels Power

There are some ways to sort out battery type, in this article I will sort out two main types of batteries that are popular. These are classified by the structure and applications, with their own advantages and disadvantages.

The Most Efficient Batteries for Best Solar Panels Power

*** The Li-Polyme and Li-Ion Batteries are using in solar power too. However, their price are high so they are not popular.

Batteries are classified by the structure, we have two main types of batteries are:

  • Flooded Lead Acid batteries (FLA) and
  • Sealed Valve-Regulated Lead-Acid batteries (VRLA).

Flooded Lead Acid batteries (FLA):

FLA batteries are the most commonly used batteries. FLA batteries require periodic topping up with electrolyte so that we call it is “Wet” or “Flooded”. This is the traditional technology that having been used for decades.

The word “flooded” is used because these types of batteries contain an excess of electrolyte fluid so that the plates are completely flooded. The level of electrolyte should be above the tops of plates which serve as a reservoir to make sure that water loss during charging does not lower the level below the plate tops and cause damage.

They usually have the long life and the lowest cost per amp-hour of any another choice. The cons are that they do require regular maintenance as add watering, equalizing charges and keeping the terminals clean. They produce more combustible gases when charging too so we need put them in airy place.

Sealed Valve-Regulated Lead-Acid batteries (VRLA):

VRLA batteries are more commonly known as “sealed batteries”. In fact, they are called valve-regulated is more suitable than “sealed” because VRLA batteries are fitted with a pressure vent that allows surplus gas to be vented when the internal gas pressure builds up.

VRLA batteries were designed to eliminate the need for water addition and to provide batteries that could be used in any position.

The cost of VRLA batteries is higher than FLA batteries and because of their “sealed” construction, VRLA batteries are considered “maintenance free” and require no addition of electrolyte or water to the cells.

VRLA batteries types are commonly classified as:

  • Absorbed glass mat (AGM) batteries – has the electrolyte absorbed in a fiber-glass mat separator.
  • Gel batteries – “gel cell” – has the electrolyte mixed with silica dust to form an immobilized gel.

Batteries are classified by the applications, we have two main types:

  • Starting (Shallow-Cycle) Batteries and
  • Deep-Cycle Batteries.

With all of FLA and VRLA batteries types which was classified above, they also has classified as deep cycle and shallow cycle batteries.

Starting (Shallow-Cycle) Batteries:

Starting (Shallow-Cycle) Batteries

  • Sometimes called SLI (Starting Lighting and Ignition) battery for starting, lighting, ignition batteries that having short or “shallow” depth of discharge.
  • Because the battery plates designed for have a large surface area (the thin sponge-like plates lead structure) for instant chemical reactions. It’s mean that they are designed to produce a very high starting current in a very short time.
  • These batteries are not recommended for use in solar power system because they would quickly be ruined by the deep cycles required for extended use.
  • These batteries type will generally fail after 30-150 deep cycles while they may last for thousands of cycles in normal starting use (2-5% discharge).
  • The starting battery is designed to start the vehicle engine.

Deep-Cycle Batteries:

Deep-Cycle Batteries

  • The main difference between the best deep cycle batteries and starting batteries are the battery plates are SOLID thick lead plates – not sponge-like lead as of starting batteries. This gives less surface area, thus less “instant” power like starting batteries.
  • Deep-cycle batteries are designed to be large discharged down to 80% capacity of battery but the best long life-span is to keep the average cycle at about 50% discharge.
  • The deep-cycle batteries are made to provide stable continuous power.

Which battery type is best and most efficient battery for solar panels power?

As above mention, starting (shallow-cycle) batteries types are designed to deliver short and high-current for only starting the engine. They are designed to discharge only a very small (2% – 5%) part of their capacity too.

Read more:

So the best and most efficient battery for solar panels power is deep-cycle battery types. Deep cycle batteries are designed with larger plates and different chemistry to avoid the corrosive effect of frequently using the full capacity. They are designed to discharge deeply (up to 80%), using most of its capacity.

Below is a comparison table that will let you know about the best as well as affordable batteries which is Most Efficient Batteries for Best Solar Panels Power for many years.

How to choose the best battery for your solar power system?

Now, you known that the best batteries for your solar panels power are deep-cycle batteries types. Below I’ll write details for it.

What is a Best Deep Cycle Battery?

Best deep-cycle batteries types are designed for regularly depth of discharge that using most of its capacity.

What is depth of discharge (DoD)?

DoD is a measure of battery capacity which is used to describe how deeply the battery is discharged.

For instance:

  • If a battery is 100% fully charged, it means this battery has 0% DoD.
  • If a battery has delivered 30% of its capacity, here are 70% energy reserved, it means the DOD of this battery is 30%
  • If a battery is 100% empty, the DOD of this battery is 100%

DoD always can be known as how much energy that the battery delivered. For deep-cycle batteries types, do not fully discharge them to 100% DOD, it would shorten the cycle life of batteries. Highly recommend for discharge is 50% DoD.

The Differences between Deep-cycle Flooded (FLA) and Deep-cycle Valve-Regulated Lead-acid (VRLA) Batteries for best solar panels power:

Choosing the best batteries types for your solar panels power system is important. That why understand the main differences between deep-cycle flooded (FLA), and Deep-cycle Valve-Regulated Lead-Acid (VRLA) Batteries is essential. With the VRLA type will be subdivided into two types, Absorbed Glass Mat (AGM) and Gel Batteries.

Deep-Cycle Flooded Lead-Acid Batteries (FLA):

Deep-cycle flooded lead-acid batteries are very versatile and should be the first choice for renewable energy systems where maintenance can be carried out and ventilation is available.

The pros of using deep-cycle flooded batteries:

  • Lower cost than deep-cycle VRLA batteries.
  • Longer deep-cycle lifespan than deep-cycle VRLA batteries.
  • Simple maintenance by addition of distilled water.
  • High discharge rate capability.
  • Good Performance in hot climates. (>90 oF)
  • More available worldwide.
  • Operation better then deep-cycle VRLA batteries when regularly in a partial state of charge.
  • Long, proven history of use.

The cons of using deep-cycle flooded batteries are:

  • Period of adding distilled water is must have.
  • Can only be used in an up-right position.
  • Produce gas (oxygen and hydrogen) when charged.
  • May emit acid spray if overcharging.
  • Require ventilation.
  • Higher self-discharging rate than deep-cycle VRLA batteries.
  • Cannot be used in the near areas of electrical equipment or anything highly flammable.

Absorbed Glass Mat (AGM) Batteries:

AGM (Absorbed Glass Mat) is the safest and best option. They require very little or no maintenance. There is no need for ventilation and they will not spill.

The pros of using deep-cycle AGM batteries:

  • Cheaper than deep-cycle Gel batteries.
  • Temperature range for operating is wider than deep-cycle Gel or FLA batteries.
  • Slowest self-discharge rate than FLA, AGM and Gel batteries.
  • Best shock/vibration resistance than FLA, AGM and Gel batteries.
  • Best for high power applications than FLA, AGM and Gel batteries.

The cons of using deep-cycle AGM batteries:

  • Don’t perform as well as deep-cycle FLA or Gel batteries for systems that require regular deep discharge. (i.e. 80% DoD)
  • Do not operate as well as deep-cycle Gel batteries in low power applications.

Gel Batteries

Gel batteries are generally superior to AGM in recovery from deep discharge because they contain more electrolytes and are less susceptible to stratification than either flooded or AGM batteries. The gel electrolyte has a higher resistivity than fluid electrolyte therefore Gel batteries have lower high rate charge and discharge capability than AGM and flooded types.

The pros of using deep-cycle Gel batteries:

  • Operation better than deep-cycle AGM batteries for systems that require regular deep discharge. (i.e. 80% DoD)
  • Perform better than deep-cycle AGM batteries for low power applications.

The cons of using deep-cycle Gel batteries:

  • More expensive than deep-cycle FLA and AGM batteries types.
  • Do not perform as well as deep-cycle FLA or AGM batteries in cold temperatures. (< 40 oF)
  • Do not perform as well as deep-cycle FLA or AGM batteries when they regularly reach a shallow depth of discharge. (i.e. 20% DoD)
  • Higher self-discharge rate than deep-cycle AGM batteries.

In Summary

The Best and Most Efficient Batteries for Best Solar Panels Power are deep cycle batteries types that are designed with larger plates and different chemistry to avoid the corrosive-effect of frequently using the full its capacity. They are designed to be regularly deeply discharged using most of its capacity.