Problems Hi13 doesn't start

Hello, I have a problem with my Hi 13. It doesn’t start.
I wanted install kubuntu in dual boot with this “how to” :
http://chuwi-hi13-install-ubuntu.blogspot.com/2017/04/how-to-install-ubuntu-on-chuwi-hi13.html
There was a problem during installation of kubuntu, the screen was flashing and i could not stop the tablet. So I let the tablet until there was no battery.
Now I can’t charge the battery and the tablet don’t want to start.
I test some combination of touch with the keyboard and start button find on the forum. I open the tablet and unplug the battery. Nothing happened.
When i mesure the tension on the battery. There is 0V…

Probably the system crashed and completely discharged the battery, causing the battery controller to lock up. Try charging the tablet for a few hours. If this does not work and there will still be 0V on the battery, you need to charge it directly. Also check if there are short circuit on battery connection.

Thank you for you help.
I’m going to try.

How can i charge the battery directly. It work if I cut the USB plug of a charger and solder directly the + on one of the two + of the battery (the same with the -) ?
There is 6 cables on the battery plug (2 red at the left, 2 black at the right and 1 white and 1 black in the middle). What are these 2 cables in the middle?

Sorry for my english.

This is probably thermal and bat ID contacts. For direct charge you need to connect power through the 3 consecutive schottky diode to + for drop voltage to ~ 4.2v. Or you can use zener diode with 3.9 \ 4.3 voltage stabilisation.
Keep an eye on the battery temperature, it shouldn’t heat up.

Also i’m not sure about possibility of charge throug battery controller, maybe you will need to disassemble battery controller.

I Tried charging the tablet for 20 hours. It doesn’t work.
I’m going to charge directly the battery.

Hello, can you send me a schéma with the zener ?

подключение диода зенера
Use 1.1-2Ω resistor and 3.9v zener diode.

Hi 13 battery is 8.4V

It has 2 packs of 4.2 battery, if you want to charge it you need to disassembly battery pack. If you want to charge all 2 packs together you need to use 12V power supply, 4Ω resistor, 8v diode.

Mine is a 2 packs of 7.4V !

Wow, these batteries are rarely used in tablets.
So there is no way to charge it with 5V charger directly.