Our immediate answer is NO, ABSOLUTELY NO. But lets have a look at that a bit more…

Technically speaking, yes lithium batteries will output power even without a BMS. However, it is unsafe to do so. The BMS is a protection circuit. It protects the batteries from over-voltage, under-voltage, and sometimes also over-current and over temperature.

Running a lithium battery without a BMS is a safety hazard. Even if the batteries don’t vent or catch fire, the batteries will almost certainly be damaged and swell if discharged too much. Overdischarging or overcharging is a common way that a lithium battery can be damaged when not using a BMS. Running the battery even slightly too flat will severely reduce the capacity of the batteries.

So you may say why can’t I run a battery protect to protect my lithum battery? That is unfortunately not good enough for lithium. Every cell of a lithium battery needs to be monitored and protected. If even one cell goes over-voltage or under-voltage you will permanently damage the battery pack.

Using a lithium battery without a BMS is a bit like having a car without brakes. Sure the car drives just fine without them, however, it is an inevitable safety hazard.

So while yes, technically you can run your lithium battery without a BMS, for the relatively low cost of a BMS is it worth damaging thousands of dollars worth of lithium cells or worse?