Why does my Windows 10 mobile update suck of the battery?

[Windows Central Question]

Windows 10 mobile update Stuck of the battery

Hi.

Started to update my lumia to windows insider 10 mobile.

When started my phone had 70% of battery life (recomended 40%) so I thought i was fine.

After download i was able to push update and it got to about 60% and then the battery was done.

Now I am in state when phone starts update, after ~1 minute screen flashes, phone restarts -> NOKIA logo -> update starts from 0 and this continues over and over again.

soft/hard reset is not doing anything
Windows phone recovery surely does not find my phone.

How I could charge my phone so it would be able to finish update ?
PS. phone is plugged in to the 220.

 

[milkyway]

it happened to me to! and I thought I was the only one. what phone do you have? mine is 1020.
after 2 hours of this loop I used WPRT to roll my phone back to 8.1