Can multiple batteries be connected safely with one BMS?

Choosing the Right BMS for Multiple Batteries

When connecting multiple batteries to a single BMS, it’s essential to select a BMS that can handle the total capacity and voltage of the connected batteries. A good rule of thumb is to choose a BMS with a capacity rating that is at least 1.5 to 2 times the total capacity of the batteries. For example, if you’re connecting four 12V 200Ah batteries, you would need a BMS with a capacity rating of at least 1200Ah (4 x 200Ah x 1.5).

Preventing Thermal Runaway

One of the biggest risks when connecting multiple batteries is thermal runaway. This occurs when a battery cell overheats, causing a chain reaction that can lead to a fire or explosion. To prevent thermal runaway, the BMS should be able to detect any temperature issues and disconnect the batteries if necessary. Look for a BMS with built-in thermal protection and a high degree of accuracy in temperature monitoring. Some BMS systems also have features such as over-temperature alarms and automatic shutdown, which can help prevent thermal runaway.

Connecting Multiple Batteries in Series and Parallel

When connecting multiple batteries to a single BMS, you can either connect them in series or in parallel. Connecting batteries in series increases the total voltage, while connecting them in parallel increases the total capacity. A common configuration is to connect batteries in series to achieve the desired voltage, and then connect the series strings in parallel to achieve the desired capacity. For example, four 12V batteries connected in series would produce 48V, and then two of these series strings connected in parallel would produce 48V x 2 = 96V with a total capacity of 800Ah.