How to Balance Aolithium 51.2V 100Ah Server Rack Batteries?

When you purchase Aolithium Server Rack Batteries and you notice a breakdown in battery performance, it could be due to battery imbalance. Battery imbalance is a common problem.

First, because federal DOT shipping regulations require that all lithium or LiFePO4 batteries must be shipped in a low state of charge (<20%). This means that each cell arrives nearly depleted and at a slightly different charge and voltage.

Secondly, the internal resistance and capacity of the cells will vary, within standard limits, without affecting the capacity and life of the system. Each cell is completely discharged from the factory and then recharged to the same capacity. The pressure difference is because there is a capacity difference, usually the cell manufacturers factory control the difference of 2-3%, while Aolithium requires the cell to pick 1-2% tolerance.

It is also possible that the batteries have been stored for too long (more than three months), and all of these can cause server rack batteries to be unbalanced.

How To Balance Aolithium Server Rack Batteries?

Aolithium Server Rack Batteries can connect up to 16 units in parallel. Many customers are discussing how to balance them. The following are suggestions from Aolithium engineers:
1.Aolithium Server Rack Batteries built-in BMS has a balancing function, but the equalization current is small and the balancing time will be longer. If you don't care to spend a few days to make the batteries self-balancing, you can do so.

2. If you want to achieve perfect balancing quickly, you can charge each Server Rack Battery and rely on the control of the cells for balancing. We recommend that you use a 60V/5A adjustable power supply. First you need to bring the batteries up to maximum voltage.
Differential voltages are controlled at <350mv (0.5Cx current) at the end of charging and <400mv (0.5Cx current) at the end of discharging; this meets the cycling performance requirements in the product manual. In order to further enhance the usable power of the product, we recommend you to do the equalization adjustment after the power of the product has decayed to 80%, which is helpful for prolonging the life of the battery.

3. We also recommend that you balance the battery once a year to extend the battery life.

More to Know

Charging each 51.2V 100Ah server rack battery individually ensures that each battery is full and of the same voltage before it is connected in parallel. This is called “matching voltage/voltage matching” or “balancing the batteries” and increases total runtime and lifetime.

If batteries are connected in parallel near depletion and then charged with a higher voltage charger, the battery charger will read the system as “full” as soon as one of the batteries in the set is fully charged, even if one or both of the other batteries in the set are also fully charged. The set is only 75% full.

If one battery in the system is at 75% capacity, the system will only operate at 75% capacity even if the other batteries are at 100% capacity.

If one battery in the system is at 75% capacity and the other batteries are at 100% capacity, each time the system is depleted, the individual batteries are discharged to zero and subjected to higher stresses, resulting in shorter life.

By charging each battery individually before connecting in parallel to create a higher voltage system, you can ensure that all batteries are 100% full and your system is at peak performance.