BuTure jump starter test, car battery disconnected 

I tested the Buture BR800 jump starter on a Honda from 1997, gasoline, with 1.5 liter engine.
I disconnecting the car's battery and made the jump starter start the car by itself. I had it charged one or two days previously, the weather was hot, and I tried to start the car two times. The car started at once, both times, very quickly, probably because the voltage was so high, around 16 volts.
I was surprised at how high the voltage was, I know the car goes up to 14.5 volts in normal operation, when it's up, running and charging the battery. But I wonder whether having 16 volts on the system may damage newer cars. I have no idea, I'm not a mechanic.
I'm also not sure how this jump starter would behave with a car that was slower to start. Mine just took off in about a second or less.
I bought the jumper starter from here
www.amazon.es/gp/product/B08T...

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