what sort of supply would i need for a 400w amp do i need it to be fed from the battery or could i use the power from the cig lighter plug since its fused either 15 or 20amp?

400w / 13V

= 30A

fed from battery for sure

most wiring for ciggerette and accesories is only capable of handling 15A without getting to hot

so you think fuse would blow
?

only running 2 12'' 400w subs cheepys

i thought since a cig lighter is a direct earth 15 amp would be plenty for a small amp

Definetly run a new wire... Fused at the battery...

what size are those gold fuses that every one seems to buy they look overkill?

ANL fuses. Just a bigger fuse to allow more surface area and hence better power flow.

You would be able to get away with a cheaper fuse though as ANL fuses and fuseholders are pretty exxy.

how many amps are they good for?

80 to 500+

Depends what size fuse you get.

http://www.clarion.com.au/2005%20Catalogue/Summer%20Edition%20Nov%202005.pdf

first one top left

this is the amp what size fuse do u guys recomend?

As Tim eluded to above, I too would recommend you run a new 8AWG cable from the battery to the amp. Make sure you also run a new 8AWG negative from the battery to the body too (remember electricity travels in a circuit). The fuse holder I would recommend for your application would be a MAXI fuse holder with 30 amp MAXI fuse. We use MAXI's because tube fuses tend to come apart at the ends so we rely on solid state fuses. The ANL fuse is nice but is somewhat of an overkill for your power requirements. Something like this:

http://www.stingerelectronics.com/web/prods/prod_images/sfb1max.jpg

Most stores including us sell them for just over $30. :)

run the standard fuse from a wiring kit. the $70-90 that you pay for the kit will save you a lot of trouble