The product name is a deception: "F16S48V100A BT". Only after the BMS is delivered the device has printing that says it is rated for 50A charging. Somewhere buried about page 20-30 of the Web page is a picture in very small print, low contrast, unreadable from a phone in a column labeled "Charge" is a number "50". In the column above it says "Discharge" "300+-50". So what does the "100A" mean in the specification? In my opinion, this is NOT a "clear" communication of a max charge current of 50A. The sellers only excuse for not accepting a return is that is a "clear" massage. Another part of the deception is when you find the table (only a computer) that contains the specifications, never is the term 100A mentioned for charge or discharge current. That is left to your imagination or possibly the product name. I find it very hard to trust anything written about this product. I hope AliExpress buyer protection will produce a satisfatory result.
thanks to the seller for answering my questions and recommending.