haha nah no amps in the ute just a head unit and 2 speakers

You can figure it out by summing up the power of all electrical items that are on at once, keep in mind that if this is only ever for a minute the battery can cover that.

Power = voltage x amps

I wouldn't worry about it unless you find the battery slowly goes flat at night while you're driving.

no, not necessary. but high-power amps would make it necessary.

yeah had a good read up will have to investigate if i have one with an internal voltage regulator, if so i will have a dig at polishing up my old gal otherwise i will look into some kind of upgrade later.

would it be neccissary to upgrade alternator if im putting halogen lamps in and a CD player?

The stock Datsun alternators are aluminum, so polish yours and make it shine!

Yes, you can fit other Alternator Upgrades

You just need make sure that if you have an external voltage regulator the new alternator suits or you mod the wiring so it works with the internal regulator. Check out alternators in the tech section, explains swaps and how to mod to internal reg. The polished ones I've seen have been single wire, i.e. internal reg.

You could just polish the one you have.

The other thing is to make sure the pulley's the right size and that it lines up with the other pullies. Generally they run at 2x engine speed.

forgive my ignorance here i know nothing of alternators, i believe they keep your battery charged but i was wondering what the difference was between alternators as ive seen some very nice polished ones for hot rods etc that look identical to my A series alternator, is there anything stopping me from being able to use these nicer looking alternators?