Hi i think i know where i have gone wrong!
I just found this info on trailtech.net.
I put all my earts to the frame :baseball_bat:
http://www.trailtech.net/ac-dc%20key%20concepts.pdf
STEP 4: FLOAT THE GROUND
Many AC systems have one lead going from the stator to the lights, and another going from the lights to frame ground. For a DC system,
the ground must be floated. DC systems require a continuous circuit and must not be frame grounded. The stator must be rewired to float
the ground. You can get a qualified technician to perform the task. It involves unsoldering several leads, possibly winding extra coils (for
extra wattage) and soldering it back together.
STEP 7: GROUNDING
DC systems require a continuous circuit and must not be frame grounded. Proper grounding requires the ground wires connected to the
negative terminal on the battery. If the battery is frame grounded it will cause extra voltage fluctuation, prevent the battery from charging,
and a larger load will be put on the regulator making it considerably hotter. Light bulbs may flicker or act erratically and most black boxes
will simply fail to function at all.