Another Alternator Question

[Copasetic]

I'm soon to be upgrading to a 200 amp alternator for all of my aftermarket crap I've put on my truck. Here's my question. With the stock sized pulley the 200 amp alt says it puts out 90-100 amps. Say if I had 12 of the 14 lights on at night, both electric fans were running, the a/c on, and I was idling on a trail, waiting for whatever reason (the lil lady peeing, looking at scenery, etc.) would 90-100 amps be sufficient at idle? I could get them to put a smaller pulley on there to put out more amps at idle. Oh yeah, I do have a dual bettery setup and all of my accessories are ran off of the aux battery. Just the factory stuff is running off the main starting battery. Thoughts? Thanks!

 

[BILTIT]

I'm soon to be upgrading to a 200 amp alternator for all of my aftermarket crap I've put on my truck. Here's my question. With the stock sized pulley the 200 amp alt says it puts out 90-100 amps. Say if I had 12 of the 14 lights on at night, both electric fans were running, the a/c on, and I was idling on a trail, waiting for whatever reason (the lil lady peeing, looking at scenery, etc.) would 90-100 amps be sufficient at idle? I could get them to put a smaller pulley on there to put out more amps at idle. Oh yeah, I do have a dual bettery setup and all of my accessories are ran off of the aux battery. Just the factory stuff is running off the main starting battery. Thoughts? Thanks!

You need to break it down and figure out what each light, fan, etc. will draw for amperage when on full load. Once you know the maximum current needed you can decide on the alt.

wattage=current X voltage OR current=wattage/voltage

remember you want 12 volts minimum at all times, 13-14 is better.

Here is a good formula page:
http://www.sengpielaudio.com/calculator-ohm.htm

 

[JPMSK5]

200amps, you better have a 1/0 cable coming off that alternator,
Seriously dont use the factor wiring, the worst thing you can do is starve the component for amps. KC lights are 7amps, 2 of them is 14amps, continuous duty, NOT momentary like a starter soleniod, needs to be used for 4 or more KC lights with one switch. I have a ton of stuff on my K5 and I run a 140amp alternator with a battery isolator and a dioded switch into the idle up soleniod for the A?C on the carb. If I am winching or have all the lights on, I can flip that switch and raise the idle to 1500rpms and it works really good. The truck is on one battery and all the accessories are ran off the 2nd battery. Watch your wire size you are feeding your stuff with, my Fire dept. red necked the lights on a truck and while they were putting out a fire, they had a fire in the roof of their truck from too small of wire for the amp draw. Email me if you need any wiring help.

 

[Copasetic]

200amps, you better have a 1/0 cable coming off that alternator,
Seriously dont use the factor wiring, the worst thing you can do is starve the component for amps. KC lights are 7amps, 2 of them is 14amps, continuous duty, NOT momentary like a starter soleniod, needs to be used for 4 or more KC lights with one switch. I have a ton of stuff on my K5 and I run a 140amp alternator with a battery isolator and a dioded switch into the idle up soleniod for the A?C on the carb. If I am winching or have all the lights on, I can flip that switch and raise the idle to 1500rpms and it works really good. The truck is on one battery and all the accessories are ran off the 2nd battery. Watch your wire size you are feeding your stuff with, my Fire dept. red necked the lights on a truck and while they were putting out a fire, they had a fire in the roof of their truck from too small of wire for the amp draw. Email me if you need any wiring help.

Wow. I bet that was tough to explain to the Chief. I was told by the alt company that I'm getting mine from that I will have to upgrade the alt wire to the battery, or isolator in my case, so I'm good there. When I wired up my lights and other accessories I used a larger gauge to connect everything up than the lights and whatnot already had hooked to them so I believe I'm good there also.

My high wattage lights (the 4-100 watt square ones) have relays on them but all of my other lights are 55 watts each so I just have them running on 20 amp rocker switches. I still try to feel on the wires coming from the switches while anything has been running a while and so far everything is staying cool. The only heat I have inside my switch plate comes from my 2 gauges when I have the headlights turned on and they are lit up. Thanks for the info!

 

[badmix]

Ive got a mean green 200amp alt. Ive ran a seperate cable going straight to the battery from the alt. I think I need to add a thicker one though. Im running 2 8" KCs and 2 5" 55watt grill lights. If I run all these together at the same time , it pulls my volt meter down in the 13s (normally it should be above 14v while running). So if your going to run 12 off road lights, that alt. may not be enuff. I would also considering running dual batts.

 

[muddybuddy]

where did you get the 200amp alternator? u say it only put out 90-100amps with stock pulley...then why upgrade? why not get the right pulley? im still using my 100amp one like a sucker, but always like more power...who doesnt?

 

[87 Blue Beast]

^^x2, where are you getting it from and whats it running you? im lookin for one also for all my junk. 2000w amp, air compressor (for air horn), lights, it all really draws the stock charging system

 

[ryoken]

where did you get the 200amp alternator? u say it only put out 90-100amps with stock pulley...then why upgrade? why not get the right pulley? im still using my 100amp one like a sucker, but always like more power...who doesnt?

thats at idle...