That was the thread I answered, if the battery light is on then this is not your problem. In any case revving to around 4K will start the charge process as well.

Check the engine earth strap is ok as I assume you mean engine rebuild? Does the battery light go out with engine running, if so this shows it to be charging and so there must be a break between the heavy gauge wire from the B terminal which to battery.

What power are you getting at the battery?

Martin