Official manual tells you how to care your microsoft surface pro 4 power cord

Power cords, like any other metal wire or cable, can be weakened or damaged if repeatedly twisted or bent in the same spot. Here are some things you can do to keep your power cord from being damaged:

Avoid twisting or pinching your power cord.
Don't wrap your power cord too tightly, especially around the power brick. Wrap it using loose coils rather than tight angles.
Inspect your power cord regularly, especially where it joins the power brick.

Avoid pulling on the power cord when unplugging your Surface. Gently removing the connector from the charging connector can help prevent damage to your power cord.

Source from https://www.manualslib.com/manual/1210140/Microsoft-Surface-Pro-4.html?page=32#manual

microsoft surface pro 4 battery

Also if you are looking for a brand new microsoft surface pro 4 battery, we got this in stock, the price is 101.56 NZD free shipping this week. You can also use coupon code NZ47 to have 5% off. 

Voltage: 7.5V

Capacity: 5087mAh (38.2Wh)

Battery cells: 2-cell

Chemical: Li-Polymer

Battery Color: white

Condition: new original battery

Warranty: 9 months