Ok done it. Wire'd in the rectifier and made up a jury rig harness to the battery for now. Run the engine in a tank and took my life in my hands and started it up. At tickover to about quater throttle it registers 11.7V. From quater to half it gives just 0over 12V. From half to full throttle it rises from just over 12V to max of 15V.
I think that with those results I'll not bother with a regulator.
If I use a big enough batt it should take a few volts over without doing any damage. There'll be something running off of it to take care of those extra volts anyway. Had to stop messing with it as one of the neighbours complained, which seems pretty academic seeing as its like world war 3 out there with all the fireworks. Now all I've got to do is sort a suitable plug and socket for the engine and make up a proper harness for the battery cables. Dou you think I should put a fuse in line. It seems prudent to do so.
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