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

Quote: 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.

Quote: 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

Quote: 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?

Quote: 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

Quote: 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.

Quote: 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.

kev000 · 10-27-2009, 03:03 PM

watts = Amps x Volts

Amps = Watts / Volts

191.666 = 2300 / 12

HiJackZX1 · 10-27-2009, 03:11 PM

Quote: 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?

HiJackZX1 · 10-27-2009, 03:12 PM

Quote: Originally Posted by kev000

watts = Amps x Volts

Amps = Watts / Volts

191.666 = 2300 / 12

AHHHHH, so I was close.

soundman98 · 10-27-2009, 05:13 PM

Quote: Originally Posted by kev000

watts = Amps x Volts

Amps = Watts / Volts

191.666 = 2300 / 12

...or 164.286 if measuring voltage off the alternator (usually at or around 14v)

justchat_1 · 10-27-2009, 06:57 PM

Quote:

watts = Amps x Volts
Amps = Watts / Volts
191.666 = 2300 / 12

Yea 12v is the "commonly known value" but vehicle voltage is regulated to 13.8V when the vehicle is running. Actual alternator voltage ranges from 13.6-14.4V depending on RPM and age.
On battery power amp current doesn't really come into play -> but 160Amps will kill a battery in minutes so thats a non-issue.

Quote: Originally Posted by HiJackZX1

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.

Thats probably the safest method although realistically max current draw would be a lot lower. Theres lots of variables that come into play, like initial draw verse continuous draw but i'll spare the technical stuff. Only thing to make sure is that your looking at current used not current produced which can be different based on voltage, efficiency, etc.

Quote: Originally Posted by HiJackZX1

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?

Well yes with a stock configuration (straight alternator replacement or a/c compressor replacement). For dual alternators with a custom bracket, belt routing can be a little tricky. If I remember correctly durangos use a serpentine belt setup with a spring tensioner. In custom setups you need to swap in a larger belt with possibly different sized idler pulleys and depending on placement the tensioner can actually become a disadvantage. The tensioner applies a varied force depending on position (which is really cool because you can use it to guage belt wear), but if the belt routing changes significantly it can provide the wrong amount of tension causing problems. Just a heads up if you go with completely custom dual alternators (which I don't think you need).

Yup should be more then enough power. Can't comment on the battery without seeing specs but I would recommend not running the system on battery unless its a deep cycle->you'll do permanent damage pretty quick.

Your average cars headlights are 40-50watts with 50-60watt high beams. Most HID kits are 35watts total continuous draw. If you know where to look you can find a 50watt kit but i've never seen more then that. While its true the ignition voltage for the headlights is in the 1000's of volts, this only lasts about a mili-second.

HiJackZX1 · 10-27-2009, 08:34 PM

Quote: Originally Posted by justchat_1

Yea 12v is the "commonly known value" but vehicle voltage is regulated to 13.8V when the vehicle is running. Actual alternator voltage ranges from 13.6-14.4V depending on RPM and age.
On battery power amp current doesn't really come into play -> but 160Amps will kill a battery in minutes so thats a non-issue.

I have no idea what the new alternator runs at, infact, I have no idea what the factory one puts out either, lol.

Quote:

Thats probably the safest method although realistically max current draw would be a lot lower. Theres lots of variables that come into play, like initial draw verse continuous draw but i'll spare the technical stuff. Only thing to make sure is that your looking at current used not current produced which can be different based on voltage, efficiency, etc.

I agree with you.

Quote:

Well yes with a stock configuration (straight alternator replacement or a/c compressor replacement). For dual alternators with a custom bracket, belt routing can be a little tricky. If I remember correctly durangos use a serpentine belt setup with a spring tensioner. In custom setups you need to swap in a larger belt with possibly different sized idler pulleys and depending on placement the tensioner can actually become a disadvantage. The tensioner applies a varied force depending on position (which is really cool because you can use it to guage belt wear), but if the belt routing changes significantly it can provide the wrong amount of tension causing problems. Just a heads up if you go with completely custom dual alternators (which I don't think you need).

Here is the setup I came up with.

I tried to keep it very similar to what I have now. Obviously I will need a longer belt, but not much longer. What do you guys think?

Quote:

Your average cars headlights are 40-50watts with 50-60watt high beams. Most HID kits are 35watts total continuous draw. If you know where to look you can find a 50watt kit but i've never seen more then that. While its true the ignition voltage for the headlights is in the 1000's of volts, this only lasts about a mili-second.

So why do I always read, that when installing HID lights, you have to upgrade all the electrical wires, because HIDs will fry the stock wires.

justchat_1 · 10-28-2009, 12:43 AM

I assume the belt tensioner is on the far left? In that case the above setup should work fine. Just make sure the new belt is the same type as the old belt.

Regarding the HID:
For the most part thats not even remotely true->the wires the get replaced go from the ballest controller to the actual lights but for safety reasons on the higher-end units that wire cannot be disconnected. All of the stock wiring can be used right up to the ballest controllers (and most people leave the ballest controllers right behind the headlights-even though I think it looks tacky). HID's draw a lot of current for such a short period of time that it really doesn't cause any problems.

User Name		Remember Me?
Password