I put a rollbar and lights on my truck a few months ago, and posted this thread asking about this. there is some good info in there that helped me out, with the power draw, recommended wire sizes, etc. Although I did go with relays in the end....


https://dodgeforum.com/forum/1642891-post9.html

edit: can't post a link to the thread, but here's a single post with the electrical math required...

 

I want a rollbar sooo bad ...bought one but it didnt fit right.... as far as the alternator I thought the rams had high output alternators in them already??...... I agree on using one if not equipt.... my stereo sytem alone puts my guage down to like 11 volts and the lights dim bad while idling (on bass note).... however when you have a couple grand on the rpm guage the alternator puts out way more amperage than idle...
the disadvantage is poorer fuel economy with the larger draw on alternator....also agree on steel wool for cleaning chrome but gently as you can scratch chrome with even it if you rub hardand long enough....I used it to remove all the blueing off a russian m91 I redid reciently....they make a synthetic type that looks like heavy steel choirboy but is some type of fiber...its used by shooters to keep their bores clean in rifles and such...I cant remember the name to save my life though...its very course yet doesnt scratch at all....

 

when i worked at autozone i got me a duralast gold but i got the one with 1000 cold crankin amps and 800 crankin amps and i run a kenwood head unit with a 700 watt amp and 2 10inch kicker subs and the 2 100 watt driving lights on my pushbumper and when im driving my amp meter never goes below 14 at idle or driving with the system up and the lights on when im wheeling

 

yeah well Im pushing 400 watts rms 800 max to my single sub alone.....amp required to seperate positive and negitive inputs...when I had it in my jeep it was wired for 800 watts rms in 1 ohm load bridged.cap and all wired up...my engine would stall when idling on a long bass note .(it drew 155 amps)...and I popped a window out of my hardtop.....your eyes would vibrate so much it was hard to see a stop light clearly....ahhh my dumb youthful days... I cant stand hearing those systems go by now...

back on topic...(sorry) one thing that would make a big difference is also whether you have 55w or 100 watts offroad lights.... and you could always convert them to HID's which are three times brighter and use like half the power....(I would wire them up first and see how the alt guage reads when in use at normal usage speeds)...use nice thick wire...unless your going to use these often (they may be for looks like many use them for ) or only get used once ina blue moon (or no moon )
in either case I think the lights would only draw from battery at idle.there is also a formula you can use to find your ampherage draw....add up all the wattage of the lights and divide them by something....forgot...sorry google it or maybe someone else here can chime in.

 

I'm going to install a chrome "Triple/Double Roll Bar" with the 5-light system.