Lithium battery or lead acid battery, which one is better for your solar power system?

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G7solar
Ngày pubslished
30/12/2020
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If you are looking to buy solar batteries, or want to add extra storage batteries to your home system or remove them, the following article will provide you with all the information you need. that you will need to take.

Through the article, you will know the strengths and weaknesses, the different uses for the system of lead acid batteries and lithium-ion batteries.

• Lithium batteries have a relatively high initial investment cost, because they possess more advanced battery technology, provide greater efficiency and a longer lifespan than the acid battery series.

• Lead-acid batteries have low-cost technology that requires regular maintenance and a shorter lifespan than lithium batteries.


Features of lithium battery and lead acid battery

The battery series currently has 3 main options that you can use for your solar PV system: submerged lead acid batteries (FLA), closed type lead acid batteries (SLA) and lithium batteries.

Lithium batteries


Using high technology, the best chemicals used in the lithium batteries of solar power systems are Lithium Iron Phosphate (LiFePO4 or LFP). Compared to lead acid batteries, this new technology has a longer lifespan and also does not require frequent maintenance or ventilation.

Lithium batteries are more efficient, possessing outstanding advantages, so they cost more than two acid batteries.

Floded Lead-Acid batteries


FLA batteries use acid solution H2SO4 as electrolyte. Therefore, after a certain period of use will evaporate, to ensure the good and stable operation of the battery, we need to be checked regularly and "refill" more solution every 1-3 months. .

Failure to do regular checks and maintenance can shorten the life of the battery and, in the worse case, lose functionality, fail to repair. In addition, FLA batteries also need to be installed in a ventilation box to allow battery gas to escape.

Sealed Lead-Acid Batteries


SLA batteries are classified into two types: AGM (Absorb Glass Mat) and Gel, they have similar properties and do not require frequent or maintenance-free.

The main difference between the AGM and the Gel is that the Gel has a lower charging speed and power output. Since Gel batteries can generally handle multiple charging currents, they take longer to recharge as well as provide less power output.

What is the difference between a lead acid battery and a lithium battery


Life expectancy

- One charge cycle is each time you discharge the battery (use the battery to power your electrical equipment) and then recharge the battery using your solar panels. Battery life is measured by calculating how many charge cycles they can go through until they are no longer used. Home-installed lead acid batteries can typically go through 100 cycles in 4 years.

Efficiency

A used lithium battery is more efficient because you can store and use more solar energy.

The efficiency of lead acid batteries is only 80-85%. That means if the solar panels absorb 1000 Watt, then when entering the storage battery and using only 800 - 850W. And the efficiency of lithium batteries is up to 95%, the same amount of absorbed electricity for lithium batteries will store up to 950W.

Depth of discharge

Depth depth is related to the overall capacity used before recharging a battery.

For example: The Depth Depth will be 25% if you use a quarter of the battery capacity for your electrical appliances.

When using you should not completely discharge the capacity. Depending on the battery type, they have a different appropriate depth of discharge: Lead acid batteries should only be operated at 50% deep discharge. Exceeding this level, there is a risk of a negative effect on their lifespan. For lithium batteries can handle a discharge depth of more than 80%.

Charging capacity

With higher efficiency, lithium batteries also possess faster charging speeds. They can handle a higher amperage from a charger, which means they can be recharged much faster than lead acid.

Lead-acid batteries are limited in the amount of charge they can handle, mainly because they overheat if you charge it too quickly. In addition, the charging speed will be significantly slower when you use up the capacity.

Power density

A lithium battery weighs about 87 kg, for a lead acid battery has a mass of about 57 kg. Therefore, due to the heavier weight, lithium batteries will be harder to install. Although more difficult to install, lithium batteries have a much higher energy density than lead acid, which means that in terms of efficiency, lithium stores more electrical capacity in less space.

For example: With a 5.13 kW system you only need two lithium batteries to power the system, while for lead acid batteries you need 8 batteries to power the same system. In general you may find that using a lithium battery is many times more efficient than lead acid batteries.

The choice of battery type depends on the space where you want to install the solar system is wide or narrow, please install yourself a battery that is most suitable.

Choosing between lead acid and lithium batteries?

Lead-acid batteries and lithium-based batteries cost as much as how they last owned them. The lithium battery is a much bigger investment up front, which will be more suitable for you when you use your solar power system every day. Below are the types of batteries we recommend for a wide variety of applications:

Residential houses - independent system


You should opt for a flooded lead acid (FLA) or lithium battery

If you live in a house with an independent solar system that uses full-time off-grid full time, choose FLA (if you don't mind regular maintenance) or you can choose to use a high-end Lithium battery than.

Use for remote industrial zones


You should opt for sealed lead acid batteries (SLA) or lithium.

If you want to power a variety of electrical equipment in your plant area, then using a lithium battery makes sense. If your purpose is only to supply camera equipment, then choosing a sealed lead-acid battery will save you a lot of money.

Vacation home - independent system (less electricity)


You should choose sealed lead acid batteries (SLA)

If you own a vacation home, villa ... and you'll only be there a few times a month or year. This means that you will not be able to regularly maintain the battery system.

Therefore, the choice of the SLA system is perfectly reasonable, both saving you money and does not require regular maintenance.

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