What are High-Rate UPS Batteries?

High-rate batteries are specifically designed for applications where bursts of power are needed for a short time, such as in an uninterruptible power supply (UPS) system during power outages. When the mains power fails, the UPS needs to switch to its batteries instantly to prevent any interruption to the connected load. High-rate batteries can provide this necessary power quickly.

The term “high-rate” refers to the battery’s ability to discharge a significant portion of its stored energy within a short time, typically 15 minutes or less. High-rate batteries are mostly constructed using absorbent glass mat (AGM) technology, which holds the acid within the battery casing in suspension rather than free running like most car batteries have – this is also referred to as starved electrolyte technology. The AGM keeps the acid medium (better known as electrolyte, as it is not pure acid) in direct contact with the battery plates at all times, ready to start a reaction and generate DC power while ensuring the fastest possible electron movement between the battery positive and negative lead plates within the battery. 

High-rate batteries are all about the maximum surface area within a specific size battery box, so lots of very thin plates are used to create a greater surface area to allow for a much higher energy transfer than other makes of lead-acid batteries

Apart from in UPSs, high-rate batteries can also be used in other applications where instant bursts of power are essential, including emergency lighting or certain types of power tools, like cordless drills, grinders, and saws.

Their design and intense discharge cycles mean that high-rate batteries often have a shorter lifespan than other types of batteries that discharge more slowly over longer periods.

High-rate batteries vs deep-cycle batteries

Where high-rate batteries offer higher bursts of power for shorter periods of time, deep-cycle batteries can be discharged over longer periods, to a larger percentage of their capacity – meaning they provide a steady amount of power over an extended time. 

Deep-cycle batteries have thicker lead plates compared to high-rate batteries. This design allows them to withstand deeper discharge cycles without significant degradation. Deep-cycle batteries can withstand more discharge and recharge cycles than high-rate batteries, especially when they are deeply discharged regularly.

The pros and cons of high-rate batteries


Instantaneous power delivery
Because they are designed to provide a burst of power immediately when needed, like when ESKOM’s power fails, they are ideal for UPS systems and other applications where instant backup is crucial.

Compact size
High-rate batteries are often more compact than deep-cycle batteries with equivalent power ratings.

They are suitable for a range of applications, including UPS systems, emergency lighting, and certain power tools. 

High-rate batteries ensure there’s no power supply interruption, safeguarding data and sensitive equipment from potential loss or damage due to unforeseen power losses.

Fast recharge
Most high-rate batteries recharge quite quickly, ensuring they’re ready for the next use or next power interruption.


Shorter lifespan
High-rate batteries might have a shorter overall lifespan compared to deep-cycle batteries due to the intense discharge cycles they undergo.

Limited energy storage
The total energy storage is less than what deep-cycle batteries can offer over extended periods.

Good quality high-rate batteries are often more expensive than other types of batteries with similar ampere hour or AH capacities.

Heat generation
Because the rapid discharge and charge cycles can lead to increased heat generation, additional cooling or ventilation may be needed in some setups.

High-rate batteries that are not based on AGM or gel technologies require more frequent maintenance, regular topping up, and specialized environments to remove the hydrogen generated in the process. 

In Conclusion 

High-rate batteries ensure immediate power backup during power outages. Their design allows for rapid power delivery, making them ideal for uses like UPS systems, emergency lighting, and cordless power tools. They may have a shorter lifespan and cost more than other batteries, but it is within reason, considering that they are ideal for providing quick bursts of energy and are versatile in their applications. 

The choice between high-rate and deep-cycle batteries should be guided by your specific needs, including the balance between immediate power requirements and long-term energy storage. To find out more, read our blog about choosing the right batteries for your UPS system

Standby Systems, with its expertise in the field of UPS systems and UPS batteries, can assist businesses in making informed decisions, ensuring optimal power backup solutions tailored to individual needs. View our batteries here

Visit Standby Systems’ website or contact us at 011 794 2541 or  011 794 3406 or WhatsApp 082 450 2361.  

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