DonFang DF150ST battery dying question

Hi everyone,

First post here, hopefully someone can point me in the right direction.

I just bought a brand new DongFang DF150ST scooter. The battery died a few days after I bought it so I put a new battery in it and it also died after a few days. I remove my key every time I park it so I know I'm not leaving the headlights on. I don't know what else could be draining it.

When I check voltage from the battery cables while running and battery disconnected, it shows about 6 volts. Is this normal? Is that enough to keep the battery charged?

Please help!

Maybe the problem is not in the draining, but in charging, in his absence, to be more exact.