Bigger or Second Alternator?

[dwh]

A 100a alternator at 14v would be 1400 watts. 240a at 14v would 3300w. Most alternators derate to 80% when hot so 2800w.

That's what you'd have to work with, provided you have a way to keep the throttle up over 1000 rpm.

Usually cheaper and easier to just run a generator for a/c. And/or a big battery bank and big inverter (and you'd need the inverter anyway). But a/c runs even a big battery bank down pretty fast.

 

[Ducky's Dad]

Seems to me that the simple answer is that for a new truck, order dual alts. If you are dealing with a truck you already have, replace stock alt with the biggest one that makes sense for your use.

When I faced that issue on my 2005 Power Wagon with factory 160 amp alt, I could have retrofitted dual alts but chose to go aftermarket with a 270 that used stock pulleys and belt for ease of maintenance. The 270 gives me plenty of juice and the bench test sheet that came with it showed 285 amp max output. After it was installed in the truck, it tested at a little over 115 amps at normal idle. The newer PW's have a couple of dual alt options and that's what I would order if buying today.

 

[DiploStrat]

Come over here: https://www.expeditionportal.com/forum/forums/power-systems-12v-solar-gen.48/

This stuff gets thrashed all day (and night) long.