this chart is what most of us are using for general amperage capacity. Green is continuous red is burst generally with allowances for airflow. All the copper wire on the chart is assumed to be silicone 200°c super fine flexible conductor.
You should be good for 5a safely as long as the cable doesn’t route through anything as a tight bundle and is isolated with fish paper from the cells you could do comfortably.
I like to oversize my charging connections because i also like to charge at high rates. 50.5v x 5a = 252w of charging isn’t nothing but it should be fine. If you’re overly concerned you should open the enclosure and charge then feel around on the cable and your connections for anything that gets hot. That’s what i did the first time i changed at 3000w. Hot isn’t necessarily bad as long as it’s not too hot or in the wrong places.
Also keep in mind the cell’s rated maximum charge rate is not realistic or achievable, specs max charge rate is a single cell in free air with close monitoring of the cell temperature. Ive been able to get to 50% of that reliably in a tight enclosure but have to make allowances for my temperature rise and monitoring closely. (Fyi my bms was the bottleneck not the cells 
)