Chosen Solution
I have never come across a iPhone where the draining is caused by the wifi, I would not charge over night and would be around %70 full and would be dead the next morning…. when put on airplane mode It would not drain overnight… does the motherboard need repairing or wifi?
Unless you determined for sure it’s the Wifi that causes the drain, you may want to do some additional testing, as airplane mode shuts down all and everything, including cellular part which is another very likely candidate. You can turn off wifi from settings and check if the battery drain persists. You may also try removing your sim card overnight to see if the cellular part is involved. If that’s the case, first thing to try would be, after backing up your data, a DFU restore, sometimes that fixes radio issues. Keep us posted with the outcome.
You might need a new Wi-Fi diversity antenna or a new battery. First I would go to settings on your iPhone, scroll down until you see battery. Click on battery health and if the maximum capacity is 89% or below, its time for a new phone battery. If the battery is all good, its most likely the Wi-Fi diversity antenna that is at the bottom of the phone with the loudspeaker or its the Regular Wifi Antenna in the top left corner of the phone. Heres where to get them. Bottom right next to speaker: iPhone 7 Wi-Fi Diversity Antenna Top left of the phone: https://www.amazon.com/COHK-Antenna-Sign…
