Lithium Battery 12V/90Ah - 1.1kWh - BMSIn this article, you are going to learn all about Solar Batteries.

You will understand what the differences are between the types of solar batteries, how they fit into a Solar System, how many you’ll need and more.

Here’s the breakdown:

Let’s get started.

What Are Solar Batteries

The whole idea of a battery is to store energy to use on demand, the concept is exactly the same when dealing with Solar Power but there are some fundamental differences between the typical battery we use every day to a Solar Battery.

For Solar Power we need to:

  • Charge the battery during the day using the sun
  • Use power from the battery during the evening when there is no sun
  • Then recharge again the next day, repeating the process over and over again

What Kind Of Batteries Are Best For Solar Power

In short, there are 2 main types of Solar Batteries, here they are.

Flooded Lead Acid

For solar applications the Lead Acid battery works perfectly, they’ve been used for solar since the very beginning. Recommended for those on a budget these batteries are cheap but require regular maintenance.

How do they work?

Lead Acid Battery

Lead Acid Battery

Typically referred to as flooded or wet cell batteries, they have cells submerged in a sulphuric acid solution.

The maintenance consists of adding distilled water every month, ventilation for the gasses to escape. With FLA model batteries the acid solution reacts with the lead plates, which gives off hydrogen and oxygen.

Pros

  • Cheap, ideal for starting out
  • Lifespan around 5-7 years (depending on brand)

Cons

  • Require regular maintenance
  • Ventilation is required

Sealed Lead Acid

AGM Lead Acid

AGM Lead Acid

An upgrade to the flooded version, Sealed Lead Acid eliminates the maintenance required compared to its counter partner.

It’s not without its drawbacks, however, a shorter lifespan (depending on the brand) and higher price they can make a difference if you require a large amount of storage.

How does it work?

AGM (Absorbent Glass Mat) are capable of handling higher temperatures with a lower self-discharge when they are idle. The cells have a lower resistance compared to conventional cells, they don’t leak and they don’t need to be in an upright position.

Pros

  • Completely sealed so the risk of acid leaks
  • No maintenance is required
  • Don’t have to be mounted upright
  • Charge quicker with a lower voltage

Cons

  • Lifespan from around 3-5 years (depending on brand)
  • More expensive

Lithium-ion

Lithium-ion Battery

Lithium-ion Battery

The most efficient battery on the market Lithium-ion technology is the future of solar storage. They waste significantly less power when charging and discharging. The cycle is deeper using more of their capacity with a long lifespan.

Completely maintenance free they are lighter, smaller and they don’t produce as much heat as other Lead Acid batteries which are perfect for setups that have space restrictions.

Pros

  • Maintenance free
  • Lighter and smaller
  • Don’t have to be mounted upright
  • Produce more cycles (5000 – 7000)
  • Can produce 100% of the stored energy
  • Lifespan from around 10-20 years
  • High charging and discharging efficiency, more than 95%

Cons

  • Highest cost

What Solar Batteries Brands Are Best

As like with the other components the brand of the battery is closely related to the quality of the product, Solar Batteries are no different in this regard.

Here’s a selection of brands which we recommend:

Hoppecke

HOPPECKE has been making batteries since 1927!

The group is the largest producer of batteries in Europe, their headquarters are in Brilon-Hoppecke. They have subsidiaries, offices, partners, distributors, production and assembly facilities worldwide. They have almost 2000 employees with a €400 million turnover.

Top features:

  • High-quality
  • Production lines worldwide
  • Very Established
  • Maximum compatibility
  • Excellent cycle stability
  • Very high expected service life

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LG Chem

LG ChemA huge producer of electronic equipment LG Chem is part of the LG group. Established in 1947 this Korean company leads the way in the chemical industry. With almost 30,000 employees this giant produces batteries for almost every industry.

Their flagship Lithium-ion batteries are high quality perfect for home or business.

Top features:

  • High-quality
  • Very Established
  • State-of-the-art
  • Optimal
  • Long life-span

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Omnipower

A division of Sinetech, OmniTech have been in the PV solar industry since 1995, Sinetech is a South African brand that has gained a solid reputation for Solar Batteries and other Solar Energy products for over 20 years.

Top features:

  • Affordable
  • Good reputation
  • Long life-span
  • Robust for African conditions
  • Good support

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PylonTech

Pylon Technologies, Co. Ltd founded in 2009 is regarded as the pioneer for LFP (lithium iron phosphate) battery deployed in ESS (energy storage system).

Pylontech’s battery products and solutions have been used for high-end vehicles, cloud computing system and telecom power backups, new energy storage systems and electric vehicles.

Top features:

  • Innovative
  • High Quality
  • Specialise in Lithium technology
  • Used by companies such as Apple
  • Award-winning
  • Great value for money

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Tesla

Unless you’ve been living under a rock you would have heard about Tesla, their reputation for innovation has made news headlines.

Founded in 2005 Tesla branched out into Solar Energy in 2016, although a young company it has well design solar products.

Top features:

  • Innovative
  • High Quality
  • Modern

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Victron

Victron has a strong reputation for their technical innovation, build quality and reliability.

Founded in 1975 this Netherlands based company manufactures a wide variety of solar energy products, they distribute internationally and supply a large majority of installers and resellers.

Top features:

  • Internationally recognised
  • High Quality
  • Modern
  • Good support
  • Good reputation
  • The lithium-ion range is good quality at an affordable price

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How Many Batteries Do You Need For A Solar System

Working out how many batteries isn’t as difficult as you might think.

What you need to start with is looking at your electricity bills, get the last 12 months and add the kWh together, and work out a daily average. From that average, figure out what portion of the average you use during day and night. Night time usage is required to be cycled through the use of batteries.

Say it is 5kwh required for night and you wish to use lead acid batteries, using the formula “watts = volts x amps” this is what the equation will look like:

5000 watts = 12 volts / (?) Amps

5000 / 12 = 416.66 Amps

Now because with lead acid you can only use 50% of the battery to not damage it, you would have double the amps to have 5000 watts of available power. Therefore 12v 833.33 Amps gives you 5000w of usable power.

Changing the voltage of the battery bank:

If you were to use a 24 volt battery bank (2 x 12v in series) you would require a 24 volt 416 Amp battery bank, and so on. This is where you choose the required battery for your needs.

You commonly get 100A or 200A batteries, so you would require 4 x 12v 200A batteries to get a 24v 400A battery bank (2 in series and 2 in parallel), if it was a 48v bank, would be 4 in series, so 48v 200A bank. All of these give the same amount of usable power, just configured differently.

Add the result of this into the calculator below to get your battery size in kWh.

The next step is to decide how much backup you need, if you are going Off-Grid you will need to consider how many days you want power for.

To do this you will need to add the result by the number of days you want.

Sizing Your Battery Bank

Depending on which battery type you will be using you will need to do some further math to work out the actual amount, this is because the batteries are not 100% what they output, there are variables which affect the overall result.

Be aware that you need to double up for Lead Acid batteries.

Here is an example of sizing a Lead Acid battery:

  • 10kWh x 2 (for 50% depth of discharge) x 1.2 (inefficiency factor) = 24 kWh

Here is an example of sizing a Lithium battery:

  • 10kWh x 1.2 (for 80% depth of discharge) x 1.05 (inefficiency factor) = 12.6 kWh

How Much Do Solar Batteries Cost

This all depends on the type you choose (Lithium or Lead Acid) and how much storage you need.

  • The cheapest Lead Acid battery starts as little as R1600 and up to R500k plus.
  • For the Lithium-ion batteries, they start from around R20k plus depending on how much you need.

Resources

Here’s a list of external resources that will help you learn more about Solar Batteries:

Overall Review

SolarAdvice Rating
Overall
4
  • Return on Investment
  • Affordability
  • Energy Saving
  • Overall Cost
  • Installation (Speed)
  • Installation (Cost)

Solar Panel Review Summary

Overall Solar Batteries are only important if you need backup storage if are looking for a Hybrid or Grid-Tied system you can rely on the grid to provide electricity when the sun goes down.

If you opt for the low end of the battery range it can be a maintenance nightmare, if you invest Lithium however it will save you a lot hassle with the added benefit of being cleaner and longer lasting.

This doesn’t come without a high cost though, just make sure that you are utilising the backup power on a regular basis to make it worthwhile.

 

Pros

Power backup for the evenings

Can be completely independent (Off-Grid)

Cons

High cost

Potentially high maintenance

Ask A Question About Solar Batteries

If you have a question feel free to add a comment below or contact us directly.