General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

6 KC's how big of an alternator?

Old Jul 28, 2009
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6 KC's how big of an alternator?

Me and my mechanic were discussing this a few weeks back, he thinks Ill blow up my 95 am alternator if I turn them all on at once.

Seems logical. But then I remembered, Nothing I have wired in the truck goes thruogh the Alternator. And, from my own tests and what I have read, new cars and trucks today dont run directly off the alternator either. Instead they go thruogh the battery, so all the alt is doing is recharging the battery.

If that is the case, then I could run my KC's all 6 of them at once, but I would have to let the truck run for a bit after I turned them off to recharge the battery.

True or False?

Zach?
 
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Old Jul 28, 2009
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you wont blow the alternator, you will put a strain on the electrical charging system. The alternator will not be able to keep up and your battery will die. This will shorten the life of the alternator but as long as you don't leave them on for long periods of time it will work.

How many watts total will you be pulling? They may not be able to get enough power to them to begin with.

I had 600 watts of lights on my truck and it would kill my battery in a matter of minutes if the truck wasnt running.
 
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Old Jul 28, 2009
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What happens is if you leave the lights on long enough while running, your battery will slowly be drained bc the alternator isn't able to keep up w/the load. Just do what I do, what till you kill it, then upgrade.
 
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Old Jul 28, 2009
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I beleive its just under 1000 watts all together.
 
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Old Jul 28, 2009
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I'm guessing you have the 150 watt Daylighters? I have over 1,100 watts of lights on my truck. My battery just finally keeled over (it was less then a year old). Its getting warrantied, then I'm probably going to be getting a Yellow Top. I don't know how often you plan on using all of them or when you do how long you plan on using them. That all factors in on whether you should upgrade. Like they say, if it ain't broke, while bother fixing it.
 
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Old Jul 28, 2009
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i have 5 kc that are 100 watt and two 55 watt fogs and 2 55 watt back up's and i run them off an explorer 130 amp alt.. but u can see the volt guage go down when i turn on the kc's..also when my stereo hits hard u can see it go down...lol
 
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Old Jul 28, 2009
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Originally Posted by FMD
Me and my mechanic were discussing this a few weeks back, he thinks Ill blow up my 95 am alternator if I turn them all on at once.
This is the same mechanic that thinks you can safely put several thousand pounds in the bed of a your Ranger and be perfectly safe. Apparently your mechanic also knows nothing about alternators as well. You really need to find a new mechanic.

Alternators don't blow up. They will flow as many amps as they can when under load. When the load exceeds that which the alternator can supply, the load will start to draw the difference from the battery. In doing that, obviously the battery won't be charging either, in fact it will be discharging. Once the battery is run down, the ignition system will no longer be able to generate spark and the engine will stall. You'll need a jump start and soon a new battery.

Six 150 watt lights are 75 amps total. Since you haven't told us how many amps your alternator is, I can only assume it is 90. Which leaves only 15 amps to run the rest of the truck, which is not enough. You need a bigger alternator. Not because it will explode like you moronic mechanic says, but because it will simply drain your battery.
 
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Old Jul 28, 2009
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Originally Posted by FireRanger
This is the same mechanic that thinks you can safely put several thousand pounds in the bed of a your Ranger and be perfectly safe. Apparently your mechanic also knows nothing about alternators as well. You really need to find a new mechanic.

Alternators don't blow up. They will flow as many amps as they can when under load. When the load exceeds that which the alternator can supply, the load will start to draw the difference from the battery. In doing that, obviously the battery won't be charging either, in fact it will be discharging. Once the battery is run down, the ignition system will no longer be able to generate spark and the engine will stall. You'll need a jump start and soon a new battery.

Six 150 watt lights are 75 amps total. Since you haven't told us how many amps your alternator is, I can only assume it is 90. Which leaves only 15 amps to run the rest of the truck, which is not enough. You need a bigger alternator. Not because it will explode like you moronic mechanic says, but because it will simply drain your battery.


BUT THIS ALTERNATOR CAN RUN 1.21 JIGGAWATTS! I RIGGED IT UP MYSELF! IT'LL BLOW UP! IVE SEEN IT A MILLION TIMES!!


(has anyone heard of an alternator blowing up?)
 
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Old Jul 28, 2009
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All Lights off:
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All Lights on (4-150W lights, high beams, running lights, reverse lights, dome lights):
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Size:  25.1 KB

The engine is under quite a bit of load with all of that running but that battery was holding 13.7 volts. It held it there for atleast 5 minutes. I then turned the truck off and it was holding 13.7 volts for 6 or 7 minutes before it started to drop.
 
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Old Jul 28, 2009
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Four of them is only 50 amps which still leaves a surplus of 40 amps to run the rest of the truck. That will work fine.
 
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Old Jul 29, 2009
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I have 2 150's on the waag bar. and then 4 130amp KC's both long range and driving lights, on the back bar. I was going to leave the waag bar lights alone, an put the 4 new KC's on their own switch.

Matt, if you start your truck, and then, disconnect the battery, as soon as you turn on your parking lights your truck will stall. I have done this. Unlike older vehicles that only need the battery to actually start the car, new ones now require the battery to be there in order for the car to run. This leaves me to believe that the alternator's sole job is to keep the battery charged. And that the entire electrical system is NOT being charged by the alternator directly, but instead by the battery.

Just an observation though I could be wrong.
 
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Old Jul 29, 2009
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Originally Posted by FMD
Matt, if you start your truck, and then, disconnect the battery, as soon as you turn on your parking lights your truck will stall. I have done this. Unlike older vehicles that only need the battery to actually start the car, new ones now require the battery to be there in order for the car to run. This leaves me to believe that the alternator's sole job is to keep the battery charged. And that the entire electrical system is NOT being charged by the alternator directly, but instead by the battery.

Just an observation though I could be wrong.
Your observation is wrong. That isn't how electricity works. The battery and alternator are in parallel. The alternator supplies power to all vehicle systems and charges the battery. It can't just charge the battery and there is no way to make it charge the battery but not flow power to everything else connected to it. Electricity doesn't do that. If you disconnected your battery with the engine running and the parking lights stalled the truck, you probably have other issues to deal with, the least of which are additional lights.

What I described in my initial reply is accurate. 1000 watts of lights is more than than your stock electrical system can supply and will draw down your battery (and your mechanic sucks). Take it or leave it.
 
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Old Jul 29, 2009
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Just wire all 6 straight to the switch. I promise you wont need a relay. Make sure you put in a 90 amp fuse to make sure you dont pop it. 14 gauge wire will work perfect for this application.

With that set up you will start your truck on fire and we wont have to listen to any more of your stupid ideas. But I supposed we would have to listen to hows its a conspiricy and that the government didnt want you to have that truck

[/douche baggery]
 
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Old Aug 14, 2009
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6 x 150 watts = 900 watts and draws as stated above 75 amps.
This could be the total output of your alternator, now what do you think will happen here...

You need amperage to run the truck, you need amperage to listen to the accessories and maybe the killer amp, if there are any of the above you want to do along with running the kilowatt of lights you will need to replace the alternator at the least.
Add up all of your amperage requirements now and future, add on 10% safety factor, 20 % even better, and install an alternator with that amperage rating.

Don't forget to replace the main power wire going from the alternator to the battery and size all power and ground wires according to the amperage draw attached.

Do I hear dual batteries somewhere in your future ?
 
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