Can Use Lead-acid Battery Charger To Charge Lithium battery?

- May 23, 2020-

Due to the rapid development of lithium battery technology, the penetration rate is getting higher and higher. Some people think that they are too heavy after buying lead-acid batteries, and they have bought a special 12v lithium battery that is lightweight and easy to carry, but at the same time can not help but question: Can the charger use 12v lithium battery to charge? 

The answer is no. This is because the lead-acid battery charger is generally set to a two-stage or three-stage charging mode, and the voltage levels of the 12v lithium battery and the lead-acid battery do not match. There are many types of lithium batteries, and battery performance and battery protection board parameters may be different. Therefore, lithium batteries do not have universal battery chargers like lead-acid batteries. 

A 12v lithium LiFePO4 battery fully charged to 100% will hold voltage around 13.3-13.4v. Its lead acid cousin will be approx 12.6-12.7v. A lithium battery at 20% capacity will hold voltage around 13V, its lead acid cousin will be approx 11.8v at the same capacity. A Lithium LiFePO4 charger is a voltage-limiting device that has similarities to the lead acid system. The differences with Li-ion lie in a higher voltage per cell, tighter voltage tolerances and the absence of trickle or float charge at full charge. While lead acid offers some flexibility in terms of voltage cut off, manufacturers of LiFePO4 cells are very strict on the correct setting because Li-ion cannot accept overcharge. The so-called miracle charger that promises to prolong battery life and gain extra capacity with pulses and other gimmicks does not exist. LiFePO4 is a “clean” system and only takes what it can absorb. 

Lithium chargers are based on a CV/CC (constant voltage/constant current) charge algorithm. The charger limits the amount of current to a pre-set level until the battery reaches a pre-set voltage level.  The current then reduces as the battery becomes fully charged.  This system allows fast charging without the risk of over-charging and is suitable for Li-ion and other battery types.

If you want to use a lead acid charger on a lithium battery you can, HOWEVER, you must NOT use a lead-acid charger if it has an automatic “equalisation mode”, which cannot be permanently turned off.  A lead-acid charger that can be set to charge no higher than 14.6v can be used for regular charging and then MUST be disconnected after the battery is fully charged.  DO NOT leave the lead-acid charger connected to maintain or store the battery, because most will NOT maintain the proper voltage charge algorithm for lithium batteries and damage will occur to the battery and this is not covered under battery warranty.

Generally speaking, the 12v lithium battery is equipped with a special charger at the factory. In order to protect the lithium battery, it is best to use the corresponding lithium battery special charger.