[singhrac]

As someone who knows very little about power systems - is this true? Watts are a unit of instantaneous energy delivery, so if the whole system browns out then doesn’t the battery need to handle 100% of the load? I guess I would expect the entire system not to drop at the same time but worth asking if someone knew this.

[whoisburbansky]

I'm assuming a brownout is usually a drop in voltage (a reduction in output power), so a backup battery wouldn't need to handle 100% of the load, just some fraction, for a short period of time.