Watched several videos and gave it a try, after a bit of carefully messing around I got it working. I can now parallel charge my batteries.
First had to discharge 2 batteries to equal the others. When I finally started charging I found it went very slow, so I slowly raised the amps step by step, while checking the batteries for heat. All remained cold so I assumed it was good, and waited till they finished charging. Once done I checked and saw they where all charged exactly the same voltage.
Very happy with this. Not only it saves time and trouble, it's also nice I don't have this 'fire alarm' going off in my house 5 times a day.
The batterycharger has a rather loud 'finished charging' alarm sound that sounds exactly like a fire alarm.