Learn about charging batteries in series and parallel
In this article, we'll dive deep into the mechanics of series and parallel battery connections, providing you with the knowledge you need to make informed decisions for your specific needs.
How to charge lithium iron phosphate batteries in parallel?
While LiFePO4 batteries offer advantages such as high discharge rates and long life, parallel charging requires specific precautions to ensure safety and optimal performance. Here's a breakdown of the key points:
- Precharge: Charge each LiFePO4 battery individually before use. Connect them in parallel. This ensures that all cells are at similar voltage levels, minimizing the risk of current surges and cell imbalance.
- Voltage balance: Check the voltage of each battery with a voltmeter after a few hours of charging. The goal is for the voltage difference between any two cells to be less than 50mV (0.05V). Significant voltage differences indicate an imbalance in the battery, which can reduce battery performance and lifespan. In this case, consult the battery manufacturer for recommendations on resolving the imbalance before connecting batteries in parallel.
- Keeping the Balance: Monitor battery pack capacity over time. Decreased capacity may indicate cellular imbalance. If this happens, break the parallel connection and charge each battery individually to rebalance them.
How to charge series connected lithium iron phosphate batteries?
Like parallel connection, each battery should be charged separately and check the voltage of each battery with a voltmeter to make sure it is within 0.05V or 50mV. Afterwards, the cells can be connected in series.
Remember not to mix batteries of different voltages. Using batteries with different voltages can result in uneven charge and discharge rates, causing stress and imbalance between cells. If the batteries become unbalanced, disconnect them, charge them individually, and then reconnect them.
It is highly recommended to use multiple chargers to charge series connected lithium batteries. This means that each battery is charged simultaneously but independently during the charging process.