Are Lithium Batteries Better Than Lead-Acid?

Lead acid or lithium batteries last longer with inverters?

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As a general rule lithium batteries are better than lead-acid batteries in several ways:

  • They have a higher energy density
  • They are lighter
  • Much longer life (several thousand discharge cycles possible)
  • More stable voltage over discharge period
  • Low self-discharge rate
  • Deep cycling is standard
  • Very low maintenance
  • Faster charging rate

How Many Different Types of Lithium Batteries Are There?

For practical purposes, there are 6 main types of lithium batteries in common usage:

  • Lithium Cobalt Oxide(LiCoO2)
  • Lithium Manganese Oxide (LiMn2O4)
  • Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)
  • Lithium Iron Phosphate(LiFePO4
  • Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2)
  • Lithium Titanate (Li2TiO3)

Lithium Cobalt Oxide (LiCoO2)

This is perhaps the most common lithium battery and is widely used in many portable appliances such as laptops and power drills. The heart of most store-bought lithium battery packs are built with various combinations of 18650 cells, which are very often lithium cobalt technology.

The basic cell has a nominal voltage of 3.6. volts and current capacity ranging from 2 to 10 amperes, depending on the manufacturer. A number of cells are connected in series to achieve the require voltage and multiple cells connected in parallel to get the desired amp-hour rating.

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For example, to build a li-ion battery pack to replace a traditional 12 volt lead-acid battery, 4 x 18650 cells could be connected in series. Multiply 3.6 volts per cell by 4 and you have 14.4 volts. It seems too high to replace a lead-acid battery with open circuit terminal volts of 12.72V fully charged, but the voltage falls under load and is not an issue.

A common Ah rating for 18650 lithium cobalt cells is 2200mAh. If you wanted a capacity of 12000mAh, simple divide it by the cell rating and you get a little over 5. Choosing 6 will make sure you have 12000mAh. The complete pack would have 4 cells connected in series and 6 more rows of 4 connected in parallel.

Greta for portable applications but not too hot for replacing the lead acid batteries used for marine or auto applications, which generally need to supply heavy motor starting loads periodically. There are significant advantages however – they can be charge and discharged up to a thousand times, for example.

On the downside, the cheaper ones have been known to catch fire and are susceptible to thermal runaway if not treated properly.

Lithium Manganese Oxide (LiMn2O4)

You probably know this type of battery as the coin-type used in cameras and remote controls, but they are also used in much bigger applications, such as the Nissan Leaf hybrid electric car.

Lithium manganese batteries used in electric vehicles
The Nissan Leaf Uses Lithium Manganese Oxide Battery Technology

Discharge rates can be up to 10 times higher than 18650 cells and so very useful for fast acceleration of electric vehicles. Unfortunately the charge/discharge cycle time is lower 600 to 700 cycles in optimum conditions.

They have a much higher thermal runaway temperature than cobalt oxide.

Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)

Lithium Nickel Manganese Cobalt Oxide are generally higher power and capacity and are quickly gaining ground in many applications where weight, power and capacity are at a premium, such as electric vehicles, e-bikes and power equipment. A major benefit is the cycle time, which is up to 2000 charge/discharges.

Lithium Iron Phosphate (LiFePO4)

These are the ones that can replace lead-acid batteries in most applications, particularly auto. They can deliver high currents for starting a car and also sustained current without damage.

Lithium phosphate batteries vs lead-acid
Lithium phosphate batteries – perfect replacement for lead-acid

Not suitable for portable applications, they are ideal for stationary and semi-stationary applications such as auto, marine and solar storage. These are the batteries I use for my motorized solar kayak projects. They are particularly interesting in marine applications.

I have a 90Ah deep-cycle lead-acid battery which was intended to power a trolling motor on an inflatable boat. It wasn’t used for very long because it was very heavy at 30kg! Deep cycle batteries are used because they can be depleted up to 80% of their capacity without damage – a normal auto lead acid battery suffers badly if discharged more than 15 to 20%.

In practice, it isn’t recommended to discharge a lead-acid deep cycle battery more than 50%, because it significantly reduces the number of charge/discharge cycles and therefore the battery life. This means you can only use 45Ah of a 90Ah battery in perfect conditions, which means ideal temperature and moderate discharge rates.

Lithium phosphate battery used to power and inflatable solar kayak
Trolling Motor On Inflatable Kayak Powered by A Lithium Phosphate Battery

If the battery is cold, or heavily discharged, then then the available amp-hours goes down. Let’s say we can confidently use 35Ah of a deep-cycle lead acid marine battery.

Lithium phosphate batteries can be discharged 100% which means you could replace that 30kg, 90Ah lead-acid battery with a 35Ah, 4kg lithium. This is crucial in projects like boating where weight is at a premium.

Other additional benefits (they just keep coming) are the high charge/discharge cycles (500 for lead acid vs 2500 for LiFeP04) and the high thermal runaway temperature – they are very safe.

 

Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2)

These are the batteries used by Tesla. They have a high capacity but reduced cycles of around 500, depending on usage. Multiple combinations of the 18650 form can produce a variety of voltages for different e-vehicle types. The lower thermal runaway temperature causes concern and some Tesla cars have indeed caught fire while driving and charging.

Lithium Titanate (Li2TiO3)

These are fast to charge, have high capacity and are considered the safest type of lithium battery to use. With optimum charging conditions up to 7000 charge/discharge cycles van be achieved, so this battery is bought for life – very cost-effective!

Lithium titanate is eco-friendly, very stable and can be fast-charged at up to 10 times their rated current.

Related Questions

Are lithium batteries bad for the environment?

All batteries represent a risk to environmental cleanliness. Lithium is also a planetary resource that we are rapidly using up. Research is being carried out to re-cycle lithium batteries almost 100% so there’s hope for the future. It’s also a fact that they last much longer than their lead-acid counterparts.

Do lithium batteries catch fire?

Certain types have been known to catch fire, particularly those used in electric vehicles and also if aggressively charged. More and more, it’s becoming common to use types that are much safer. Care should be taken to buy the best quality possible.

Do lithium batteries have memory?

Battery memory affects the speed and capacity at which it charges. Lithium batteries don’t have this characteristic.

 


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