I would like to put an air compressor, off road lights and maybe a winch on my truck in the near future. Would I need a bigger alternator for this? I don't know the specs on these alternators, maybe the stock one will do just fine? Does anyone know where I might be able to get an upgraded replacement alternator?

 

I would comfortably assume your OEM could handle it. Unless it's already weak you shouldn't have any problems. Just remember to use relays for power...not OEM wires.

A.D.D. thought...
With all of that add-on stuff, perhaps a second battery would be a better option. Just run a heavy gauge wire from your current battery to your new one (wherever you put it) and they will both be charged by the alternator. Run your extras off of the second one so you don't put too much pull on the one battery. Just a thought...

Ground the second battery to the frame, not the other battery... Use a second ground (its better that way).

 

+1 on the extra battery

 

Well think about it...
Winch pulls a lot of amperage - electric over hydraulic, just like a plow.
Air compressors use a lot of juice too
Aftermarket lights dont use much

But adding all of that pull to your existing system your REALLY drag it down. Probably to the point where it drains the battery faster than it can charge...

 

I know that in the rare occasion that I would be using all three at the same time I would need some robust electrical. But I'm going to say that won't ever happen. I've thought about the second battery and I think maybe I'll try that. I know you used to be able to buy a Super Duty with a larger alternator. That's why I asked the question. Thanks for the replies.

 

NP man, glad to help! And all in all, the second battery may be a little more work with the new wires and finding the right location for it and all... but I think the alternator would have higher cost (potential problems) in the long run. Also, if your battery has..say 1000CCA (typical yellow top) then I would say you don't need a second battery. So I suppose that's yet another option for you, and you don't have to add wiring... Just buy a yellow top Ultima.

 

I would go with a second battery.

 

adding a second battery will only be good when the motor is off... and with it on will put more load on a already over taxed alt.... when the motor is running your probably 95% getting juice from alt.. and if it cant produce the amps.... its gonna drain your battery....a battery is just to start the car or run **** with the motor off..... I am a car audio nut and I see this all the time... guys put like 2- 3 bats... and stock alt... with no big three... and wonder why there lights dim and battery is always dead....cause the alt cant charge fast enough...... do it right, your spending $$$$ to get all those accessories, and you skimp a extra 200$ for a nice 250amp alt? come on!....

 

I'm pretty sure that whatever electronic youre pulling it from the battery. The alternator is just feeding into it as fast or faster than you're draining it. Thats why diesel engines have two batteries. It's not a matter of the alternator keeping up, its a matter of having the juice to use it if you needed it (not continuously). So... You don't need a BIG alternator, you need a continuous source for a short time. The bigger alternator would work if you were continuously using a lot of juice, but he isn't. This isn't car audio, this is electric over hydraulic - very amp hungry short term draw.

NVM... No, a bigger alternator is not the solution. You will only be recharging the battery faster. If you're draining it faster than it can charge it, then you have a very serious electric issue.
When you use the extras (NOT VERY OFTEN) only one of the listed add-ons would have a substantial amount of pull anyway. When you are bumping subs and thousands of watts of power, then yes you have to have a bigger alternator to replace the juice you are using FASTER. You do not pull the charge directly from the alternator, your electric system is not connected to your alternator.

Say you use one of the power hungry add-ons... You will likely use up a fair amount of the juice stored in one of the batteries, but since you are not putting a constant demand on the line the alternator output will not affect it in any way. If you are using the juice in two batteries faster than the OEM alternator can replace it you wired something wrong.

 

I believe the factory alternator is rated at 110 amps. Someone please correct me if I'm wrong.