Hi, Demon_llama!
Thanks for reaching out to Microsoft Community and posting your inquiry.
The recommended charger for Surface Pro (5th Gen) should have an output of 15 volts @ 2.58 amps=39 watts, while 15 volts @ 1.6 amps=24 watts for m3.
Furthermore, we don't recommend any modification on Surface devices/accessories as it voids the warranty of the device. Please see https://support.microsoft.com/help/4036296/ for Surface Warranty Information.
If this answers your question, please let our Community know by marking this post as an answer. Otherwise, don't hesitate to respond to this thread if there’s anything else that needs to be addressed.
Kind regards,
Janette_Z