Lithium Ion Battery vs Lead Acid Battery

Is a lithium ion battery better than a lead acid battery?

When reviewing the energy supply options available to power your LED signage, a question many site managers face is what is the best battery to choose. The most common options are lithium ion batteries or lead acid batteries, both of which have their pros and cons.

To help you decide, we have answered some popular questions often asked when considering a lithium ion or lead acid battery.

Do lithium ion batteries last longer than lead acid?

Although all batteries lose efficiency over time, lithium ion (Li-ion) batteries typically last several times longer than lead acid batteries due to higher life cycle numbers meaning the frequency that they need to be replaced will be reduced. This saves money on disposal costs of the batteries as they need to be disposed of in accordance with recycling policies. Lithium ion batteries are also more robust and so will perform better in challenging environments. Are lithium ion batteries more efficient than lead acid batteries?

Efficiency is a crucial point of comparison when considering lithium ion vs lead acid batteries as this relates to the percent of energy stored in the battery that can actually be used. Typically for lithium ion batteries they are at least 95% efficient, whereas lead acid batteries offer efficiencies around 80-85%. This is important as it allows the battery to charge faster and have a more effective battery capacity, which relates to how much energy can be stored by the battery. Effective battery capacity means that more energy can be stored in a li-ion battery to that of a lead acid equivalent using the same physical space and so can power signage for longer periods of time.

Li-ion batteries also have a far superior discharge curve such that the battery voltage falls very little until almost fully discharged, whereas for lead acid batteries , their voltage drops significantly throughout the discharge rate.

Are lithium ion batteries more expensive than lead acid?

Lead acid batteries typically have lower purchase price as well as lower installation costs in comparison to lithium ion options. However, as we have previously mentioned, li-ion batteries last several times longer and so over the lifetime of the two, a lithium-ion battery is more cost-effective.

Can I replace a lead acid battery with a lithium ion battery?

With the range of benefits that lithium ion batteries offer, many lead acid batteries are being replaced with their lithium ion counterparts. It is certainly possible to do so, however, it is important to take advice from a professional in order to ensure safe and optimum performance if this is something you decide.

There are several factors that can lengthen the lifetime of a lithium ion battery, such as using partial-discharge cycles, around 20% – 30% of battery capacity before recharging. Keeping the battery in a fully charged state shortens battery life, equally full discharge cycles are to be avoided if possible. The depth of discharge is critical with lead acid batteries, they should not be discharged past 50 percent, as doing so has a significant negative impact on the lifetime of the battery. Limiting extreme temperatures whilst the battery is charging extends battery life, especially prohibiting charging below 0°C. High currents can place excessive stress on a battery, it is important to avoid high charge and discharge currents. Click here to read in more detail.

The way in which we charge li-ion batteries also impacts battery life and it is therefore important to use the correct charger type for the battery technology. Li-ion batteries have a much more demanding charge regime than lead acid and so it is important that a compatible charger is used. Lithium ion batteries deliver a range of benefits over their lead acid counterparts and can ultimately be more cost effective over their lifetime. There are a range of power options available to power signage, to discuss the options for powering your traffic control systems, contact the TWM team.

TWM forms part of The Pilot Group, click here for more information.