Using Lithium Batteries in Power Backup Applications

This blog post discusses the differences between Lithium Ion (Li-Ion) or Lithium Iron Phosphate (LiFePO4) batteries and selecting a suitable battery charger.

When people talk about Lithium batteries, they usually mean Lithium Ion (Li-Ion) or Lithium Iron Phosphate (LiFePO4) batteries. 

Li-ion is commonly used in power tool battery packs and electric vehicles. This type of battery requires a special charger to accurately balance the charge of each individual cell in the battery.  

LiFePO4 is growing in popularity as a replacement for lead acid batteries. All the ones we have seen so far have an internal battery management system BMS, which prevents overcharging, overload, and over discharge. 

Care must be taken when discussing Lithium Ion and Lithium Iron batteries as phonetically they sound the same. 

When people ask about charging Lithium batteries, they are most likely talking about Lithium Iron (LifeP04) batteries. These batteries are increasingly being used to replace Lead Acid, AGM, and Gel type deep cycle batteries in many applications, including in caravans and Power Backup (UPS) systems. 

Useful Tips on Selecting a Battery Charger for Lithium Batteries  

First check the battery manufacturer’s data sheet for the recommended charge voltage. 

The data sheet may also stipulate the recommended charging regime. For example, it may state that the battery should be at least half charged for maximum life. 

For 12v batteries, In the absence of any information on the charging voltage, leave the charger set to its standard 13.8V output (27.2V for 24V batteries). Lithium batteries emulate 12V lead acid batteries so this should be fine.  

Do not increase the charge voltage to 14.6V (28.8V for 24V batteries), even if the data sheet says this is OK. It is not good to charge Lithium batteries at full voltage 100% of the time. It could shorten the lifespan of the battery. 

When using a programmable charger, set the boost voltage to 13.8V and the float voltage to 13.8V (27.7V for 24V batteries) and use 2-stage charging. 

Please do not hesitate to contact ADM if you would like assistance in selecting a suitable battery charger for your Lithium batteries. Our friendly team will gladly answer any questions that you may have.