Learn how to choose the battery type you need for your use

We cannot emphasize enough, the solar batteries have become the weakest link in renewable energy systems. They are more and more expensive and are very fragile.

Improper adjustment and they can be quickly under-charged, over-charged, they can become hot, sulfated, owidize, many things can happen to them...

It is often observed that the batteries could last longer if the load was better refulated and if they had been better chosen.

The first step is to choose either open solar batteries or sealed solar batteries.

Exhausted batteries

Sealed solar batteries

There are many reasons that can cause premature battery death

  • Over load
  • Under load
  • Excess heat
  • Non truckload
  • Load too infrequent
  • Adding non distilled water

The main cause of premature death of a battery being forgetting adding demineralized water, we will tend to prefer sealed batteries, called "maintenance-free" or "VRLA" for Valve Regulated Lead Acid.

But the fact that they are maintenance-free requires some special attention. Unlike open-acid batteries

The sealed solar batteries inside

  • First, too much heat because when the water heating too much, it evaporates and is released by the control valves wich act as safety valves.
  • Second, too raise the voltage that produces an excessive gassing with consequent drying of the electrolyte mixture and rapid death.

ADVANTAGES of sealing solar batteries :

  • A self-discharge less important than flooded batteries
  • A zero maintenance
  • They can be installed in places difficult to access because they require no attention
  • They do not require equalization charge
  • A significant number of cycles (depending on the manufacturer)

DISADVANTAGES of sealed solar batteries :

  • They are more expensive, at least 35-50%
  • They are more fragile and less support heavy amperage
  • They cannot withstand excessive heat, optimum temperature load should not exceed 35°C.
  • They are not made to perform very large discharge cycles load but prefer to stay in ranges little remote voltages.

Open solar batteries

Open batteries, they require more maintenance and are more rustic :

Open solar batteries ADVANTAGES

  • They are less fragile than their sisters and better withstand heat so large amperage
  • Can be loaded faster
  • May have a higher voltage
  • Better support deep discharge
  • Are cheaper

Open solar batteries DISADVANTAGES

  • Cannot be used in unventilated areas
  • More significant auto discharge so must be charged regularly
  • Require an equalizing charge and thus a more complex suitable apparatus

Open load solar batteries in 2 volts elements


Sealed batteries are preferred if you do not wish to maintenance or if your site is a very remote and difficult to access place. They also prefer the boats as they do not risk losing their acid.

For applications where the battery voltage undergoes large fluctuations (important cycling), as in a domestic installation, the batteries are charged the day if possible to 100% and discharged significantly night which produces a full cycle.

In this case, open lead batteries or lead-antimony batteries can be chosen in the condition that the maintenance is carried out rigorously

Solarmad batteries shop

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