So I asked my battery
manufacturer and they say:
"Yes, like you said. The lithium battery
bank will output current if the starting battery starts have power
drops. But the starting process will only take few seconds for the starting battery to power
, so as long as the starting battery is fully charged, it should be able to start the engine
just fine. For a 12.8V400Ah battery bank, the maximum continuous output will be 400A max, so maximum power of 5120W. So what is the rated power/current for your windlass? If the amp draw to the battery bank exceeded the maximum current the BMS can handle, the BMS will cut the battery off for protection. Best wishes, Your friend Mike From Power Queen"