How many AMPs does my alternator have to put out?

**HiJackZX1** · 10-26-2009, 03:14 PM

As you guys know, I have bought a 220 AMP alternator to replace my 136 stock amp. Problem is I cant seem to get the thing installed, and the creator of the d@mn thing knows nothing about it. After loosing my hair over getting the thing put in, I simply decided to return the thing, and get me a Duralast alternator, which replaces my stock unit exactly and provides 160 AMPS. Do you think 160 AMPS is enough? I estimate that my install will draw a total of about 2,300 watts on max load.

**malcom2073** · 10-26-2009, 04:35 PM

If your system is actually drawing 2,300 watts, that's 190amps, so no 160 amps will not be enough.

That being said, I don't truly believe your system will draw a steady 2,300 watts, but if you believe it will then that alternator is not enough.

**soundman98** · 10-26-2009, 04:36 PM

realistically, how often are you going to be using all of your system at max wattage? also, how many batteries were you planning on using?

i don't remember you talking of adding any, but you should at least have one other battery in your install to help with the high current draw.

**HiJackZX1** · 10-26-2009, 05:10 PM

Originally Posted by malcom2073

If your system is actually drawing 2,300 watts, that's 190amps, so no 160 amps will not be enough.

That being said, I don't truly believe your system will draw a steady 2,300 watts, but if you believe it will then that alternator is not enough.

I agree, I don't think it will. I do know the AMPS will most likely run at full power, and 2 of the PSUs will run at almost full power, but nothing else. I think thewizard runs the a setup similar in power usage and he manages to get by on the stock 136 amp alternator.

Originally Posted by soundman98

realistically, how often are you going to be using all of your system at max wattage? also, how many batteries were you planning on using?

i don't remember you talking of adding any, but you should at least have one other battery in your install to help with the high current draw.

Really didn't want to add a second battery due to space. Do you really think its needed? What do you think is the type of setup I should do to power everything? I heard battery capacitors are bad. I was thinking of looking into a dual alternator setup, but it requires me to delete my A/C compressor and in FL that isn't an option. Wonder if I can mount the 220 alternator some place else in the engine and have 2 of them. That way, one alternator can power the PC setup and the other, normal car operation.

**soundman98** · 10-26-2009, 05:22 PM

IMO, for all the accesories that you'll be running, it would be in your best interest to add at least one more battery.

**bratnetwork** · 10-26-2009, 05:24 PM

On some of our big trucks where i work we mounted a second alternator on the frame of the truck and then made a double pulley on the crank shaft and ran a belt from the crank to the alternator with am auto tensioner. This was done to power a 2000watt inverter in the back of the truck.

the only issue with mounting off the engine is that in a vehicle like yours the engine moves more on the mounts than in a big diesel truck so you'd have to watch for that.

**HiJackZX1** · 10-26-2009, 07:14 PM

Originally Posted by soundman98

IMO, for all the accesories that you'll be running, it would be in your best interest to add at least one more battery.

I could always add another battery, like a smaller one, dont need a big one do I?

Originally Posted by bratnetwork

On some of our big trucks where i work we mounted a second alternator on the frame of the truck and then made a double pulley on the crank shaft and ran a belt from the crank to the alternator with am auto tensioner. This was done to power a 2000watt inverter in the back of the truck.

the only issue with mounting off the engine is that in a vehicle like yours the engine moves more on the mounts than in a big diesel truck so you'd have to watch for that.

I didnt think of that..... I do have room on the engine......... The issue is that I have no one that can design a bracket. I know that there is a system that allows me to mount a super charger on the setup, if I can find a fabricator, I can maybe add the 220 amp alternator to that area, and run the 220 amp for the PC setup and upgrade the stock alternator to 160 amps, only because I plan to add HID and other stuff, that isnt PC related. If I can add the second alternator, then I can add the second battery.

**justchat_1** · 10-27-2009, 01:59 PM

Originally Posted by HiJackZX1

I could always add another battery, like a smaller one, dont need a big one do I?

Is your current battery an automotive battery or a deep cycle? Is it the one that came with the vehicle or an after market one? if so-which one?

Also, where are you getting your current draw numbers from?? If you can give a breakdown we may be able to figure out a better average load value.

Originally Posted by HiJackZX1

I didnt think of that..... I do have room on the engine......... The issue is that I have no one that can design a bracket. I know that there is a system that allows me to mount a super charger on the setup, if I can find a fabricator, I can maybe add the 220 amp alternator to that area, and run the 220 amp for the PC setup and upgrade the stock alternator to 160 amps, only because I plan to add HID and other stuff, that isnt PC related. If I can add the second alternator, then I can add the second battery.

Your issue isn't going to be a mounting bracket thats the easy part. The problem is trying to route a belt to it and still maintain proper tension in the rest of the system. Also, HID's will decrease power requirements not increase.

this is an '03 durango right?

EDIT:
Also, the above calculation is off -> 2300watts is ~167Amps draw.

**tripzero** · 10-27-2009, 03:03 PM

watts = Amps x Volts

Amps = Watts / Volts

191.666 = 2300 / 12

**HiJackZX1** · 10-27-2009, 03:11 PM

Originally Posted by justchat_1

Is your current battery an automotive battery or a deep cycle? Is it the one that came with the vehicle or an after market one? if so-which one?

Also, where are you getting your current draw numbers from?? If you can give a breakdown we may be able to figure out a better average load value.
Your issue isn't going to be a mounting bracket thats the easy part. The problem is trying to route a belt to it and still maintain proper tension in the rest of the system. Also, HID's will decrease power requirements not increase.

this is an '03 durango right?

EDIT:
Also, the above calculation is off -> 2300watts is ~167Amps draw.

Its a Duralast battery..... Its about a year old, after my install killed the original.

I basically just added all the watts that the manufateurs of the items have listed. I assume its the max it will need.

With me its the other way around, the belt is the easy thing. It has an auto tensioning pulley that keeps the belt tight. The people in the Dakota-Durango forum said it will not be an issue. Its basically the brackets that will be the issue, because the engine is awkward.

Thanx for correcting me, so that means the 220 amp alternator can provide plenty of power, with alot to spare.

I always thought HIDs use more power?