Scooterotica

I converted my gp to a full 12v dc set up last year but recently the battery ran down and I realised that without the battery connected that the lights were very dim, any idea what might be wrong with the wiring set up or the conversion to cause this?

It sounds like you aren't generating enough power. With everything in place you should get a minimum of 13V across the battery. Any less than that and it won't charge properly.

Charge the battery and refit it. There probably nothing wrong with the system, the reg/rec isn't designed to operate without a battery in circuit.

Check any in line fuse on the battery.