I doubt that 29V is a problem.
We have AGM batteries and the absorption voltage is specified to be 29.2, which is what is set on both chargers and the alternator regulator.
We don't blow lamps.
think about it...if 29V was a problem you'd be blowing other lamps as well
its your anchor light that is the problem.
Elyse SM437....Presqu'ile de Uitoe...blowing 30+ knots at anchor...