Battery packs with different capacities

Is it safe to use batteries with different capacities?

No, no, not safe. Overcharged battery may explode because of overheating. why would you want to use batteries with different capacities? If your BMS is completely trustworthy, it will cut off charging when the smaller cell is full and discharging when it is empty, restricting the larger cell to the smaller capacity.

Can you mix different capacity lithium batteries?

Yes, you can mix different capacity lithium batteries, whether a normal 12V 100Ah battery or a Lithium server rack battery. You can combine different capacity batteries in parallel. You cannot combine different capacity batteries in series. There are a few points you need to consider when wiring in parallel. Let’s explore these three points.

Are cell capacity and pack size linked?

Obviously Cell Capacity and Pack Size are linked. The total energy content in a battery pack in it’s simplest terms is: Energy (Wh) = S x P x Ah x Vnom Hence the simple diagram showing cells connected together in series and parallel. What about flexibility in pack size?

What voltage should a battery bank be?

The total battery bank must be at the same voltage. You must create a separate system for different voltages if you have different voltage batteries. Your total battery bank, which can have multiple different capacities (Ah), all need to be the same voltage, whether 12V, 24V, or 48V. You need to choose one of these three voltages.