sorry Roman, wasn't trying to teach you to suck eggs, I know your extensive background from your other posts but not everyone reading is in the same position.

if you have a voltage dropper close to where your 12v demand starts then you will minimise the effects of voltage drop. I believe they are quite expensive but you could probably get one from a landcruiser. my H60 has one for the towing electrics which is behind the panels in the side of the boot space, I think on the right hand side, but don't quote me on that, or maybe it's the left. I believe there is a second one for the radio.

otherwise I would imagine truck parts shops do them so truckers can fit standard stereos. I would imagine truck accessories in 24v would be more durable than their 12v equivalents simply because they are built for a commercial environment. this may not apply to marine quality 12v stuff such as lights etc.

Even in the 3rd world the lorries will be 24v so availability of basic parts (bulbs etc) shouldn't be a problem.

I am sure many of the big commercial motor homes and boats are 24v with 12v accessories and I would guess there's a good reason. It may be nothing more than a wider choice of accessories.

reading that back you may think I am undecided which is best. thats because I am! it's a good point for discussion as it's far from black and white

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1990 Landcruiser H60. Full rebuild completed 2014