Adding light - alternator/battery question

raceinfan · **Posted:** Mon Oct 08, 2007 9:09 am

HI guy's I'm in the process of adding 6 hella 55watt lights, now should I also chng. the alternator to the Renegade alt. ( 160 amp) I currently have the 130amp alt. or just chng. the battery to an Optima red top ?

they WON'T be run with the KJ off at all this is a just incase I end up running in the woods when it's dark on a trail ride, as it is now with just the headlights on & I put the brakes on or hit the window swithes I notice the lights dim for just a split second because of extra load I guess

any help would be appreciated

JHCRASH · **Posted:** Mon Oct 08, 2007 9:39 am

I would do both wont hurt. Deffinately the red top best batterys in the world.Just myo2

WoodysKJ · **Posted:** Mon Oct 08, 2007 10:41 am

I was just about to ask the same question, almost.

I too have the 130 amper and will be upgrading to the 160 or higher (if available) for additional lighting.

Question: Switching to a higher amp alt., will i need to do anything to the PCM or any other computer in the KJ to make allowances for the additional output?

tjkj2002 · **Posted:** Mon Oct 08, 2007 11:15 am

raceinfan wrote:

HI guy's I'm in the process of adding 6 hella 55watt lights, now should I also chng. the alternator to the Renegade alt. ( 160 amp) I currently have the 130amp alt. or just chng. the battery to an Optima red top ?

they WON'T be run with the KJ off at all this is a just incase I end up running in the woods when it's dark on a trail ride, as it is now with just the headlights on & I put the brakes on or hit the window swithes I notice the lights dim for just a split second because of extra load I guess

any help would be appreciated

You'll be fine,adding a Optima battery will help greatly.The alternator will be fine,just don't run everything at the same time with the lights and you'll be fine.When I'm offroad evrything is off anyway(radio and such).

Quote:

WoodysKJ

I was just about to ask the same question, almost.

I too have the 130 amper and will be upgrading to the 160 or higher (if available) for additional lighting.

Question: Switching to a higher amp alt., will i need to do anything to the PCM or any other computer in the KJ to make allowances for the additional output?

Don't need to change a thing,the PCM has the voltage regulator in it,READ-voltage regulator not amp regulator so you'll be just fine.You'll just not be tapping into the battery power as much and when you do the battery will charge faster.

JL Rockies · **Posted:** Mon Oct 08, 2007 11:54 am

If the charging system cannot handle the load, switching the battery will not change that. Batteries do not generate any energy and are there primarily to start the vehicle. Once they do, they become an additional load on the alternator (as it charges). If the battery you have now is worn out, changing it will help reduce it's load on the alternator.

Ohm's Law is always on-hand to save the day:

Current = Power / Voltage

55 Watts / 12.5 Volts = 4.4 Amps for 1 light * 6 lights = 26.4 amps

The vehicle will need 60 - 80 amps to operate add to it the 26.4 amps and you get 86 - 106 amp requirement when the lights are on. Due to the fact that you will most-likely have the stock headlights on as well, you'll be in the upper range. If your alternator is 130 amps now and your battery is in good shape, you should not have to do anything.

This Topic is probably in the wrong section.

WoodysKJ · **Posted:** Mon Oct 08, 2007 11:55 am

tjkj,

i was hoping you would reply.

thanks that is what i figured. my XJ didn't have all the computer crap they have now.

Hey check the email i just sent to marty about satelite antena clearance on your Gecko rack and the rear cross bar.

Thanks.

jason thompson · **Posted:** Mon Oct 08, 2007 6:38 pm

OK in my past "old heep days" I learned more then I care about electrical systems in cars
what I know
it takes about 25 amps to run you head ,break and fog lights
abot 5-10 for your wipers
and 10 for you heat/ac/defrost (not the rear)
so at best you are pulling 50-60 amps when running on a HOT rainy night

your batt. handles the short high load of turning on a motor like the power windows ect.
it also handles the draw of a winch ,a 800 amp batt can run a 8K winch at full load for around 50' (about that)
with no help ,engine off
if you add to your system you need to add up what you are going to draw + 10 amps for charging
under normal conditions ,winching is not normal ,running 6 100W KC's is not normal
wich by the way I like to use the 6 100W example cause it is 50 amps

so in theory you could be comfortable running on that HOT rainy night with a 130 amp alt. and a GOOD batt.
with the 6 100W KC's
now if you have a big boomin system with say a 600W power amp guess what?
some thing will go bad but guys dont think twice about putting the boomin system in ,but want to up grade the electrical system over a couple of lights that may run for an hour max

Just think about it?

JL Rockies · **Posted:** Mon Oct 08, 2007 7:03 pm

Due to the dynamic nature of music, a 600 Watt system does not pull current like a headlight does, unless you're listening to sine waves clipped by 3dB (A sinewave has a Crest Factor of 3dB). The average person will use 20% of their amplifier power average over time (when listening to music). This means the typical person with a 600 Watt system would use 120 Watts average over time. When you factor in efficiency of 50% (typical of A/B designs) and you go back to Ohm's Law:

240 / 12.5 = 19.2 Amps

So the typical 600 Watt system would draw less current than the lights we are planning to add.

With today's fuel injected computerized vehicles, there is a lot more drawing from the charging system than you're considering.

I still feel this is in the wrong section.

raceinfan · **Posted:** Mon Oct 08, 2007 7:43 pm

I put it here for more exposer :wink:

thanks for the answers so far..although I'm lost on the scientific portion but it's all good

just mainly looking for yes or no answers & NOT anything about audio stuff ( not my thing)

RQuarte · **Posted:** Mon Oct 08, 2007 8:06 pm

I currently run 6 hella 55w driving lights on my stock alternator and a regular battery, no problems as of yet.

BeepBeepJeepJeep · **Posted:** Mon Oct 08, 2007 8:15 pm

Sometimes I feel as if the 160a alternator in my renny isn't enough... if you can upgrade, do it!

Jeepjeepster · **Posted:** Mon Oct 08, 2007 8:39 pm

(hellas)55watt*6/13.5=24.4 amp

(headlights dim)55*2=110/13.5=8.1

(Fog lights) 55*2/13.5=8.1

Like tjkj said, you should be ok if you dont run everything at once.

IE, defroster(rear window and side mirrors), heated seats(if you have them), radio, headlights, fog lights, 6 hellas, A/C(defroster for windshield). You get the idea.

raceinfan · **Posted:** Mon Oct 08, 2007 9:03 pm

would just be headlights & cb if anything running at the same time, this is just a precautionary measure, I DON'T wheel at night, but with a bunch of jeeps you never know

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

Here ya go. 160 amp alternator for $140 plus shipping.

http://cgi.ebay.com/ebaymotors/DODGE-DURANGO-RAM-PU-JEEP-LIBERTY-ALTERNATOR-01-04-160A_W0QQitemZ8074231206QQihZ019QQcategoryZ33573QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

WoodysKJ · **Posted:** Tue Oct 09, 2007 8:27 am

OK, SO if I buy one of theose really cool Gecko roof racks Rock Lizzard is making (Which I am, I can't wait) and put 4 lights up top, (I am thinking 2-100 watt driving lights on the outside and 2 130/150 watt long range lights on the inside) and have a ARB with at least 2 more 55 watt fogs on it besides the factory relocated 55 wat fogs, What should I do?

2x100=200/12.5=16 amps
2x150=300/12.5=24 amps
4x55=220/12.5=18 amps
2x65=130/12.5=10 amps (factory headlights on highbeam)
car needs 60-80 amps to survive

80+16+24+18=10=148 amps

Say I need to get a 160. I am sure all lights wont be running at the same time, why run fogs and driving and long range lights?

Say I run the top lights and headlights highbeams together.

16+24+10+80=130 amps

Looks like I will be getting a 160 just as a CYA.

Is my math correct?

Another question, is there a higher amp alt for the KJ, Like one used for police cars or what not? Just curious.

Thanks guys.

tjtk, start welding that gecko dude! (actually its a bolt together)

tjkj2002 · **Posted:** Tue Oct 09, 2007 10:30 am

Might want to check out Mean Greanalternators,I think they have a high output alt. for the KJ,200 amps I believe.

Fulltimer · **Posted:** Tue Oct 09, 2007 11:59 am

You can also run 2 alternators and 2 batteries :shock:

Terry

raceinfan · **Posted:** Tue Oct 09, 2007 5:58 pm

tjkj2002 wrote:

Might want to check out Mean Greanalternators,I think they have a high output alt. for the KJ,200 amps I believe.

I had thought of that but might be overkill

I don't plan on using them often, just a precautionary measure incase there needed

raceinfan · **Posted:** Tue Oct 09, 2007 5:59 pm

tjkj2002 wrote:

Might want to check out Mean Greanalternators,I think they have a high output alt. for the KJ,200 amps I believe.

I had thought of that but wouldn't it be overkill ? these aren't going to be used often at all, just a precautionary measure

WoodysKJ · **Posted:** Wed Oct 10, 2007 2:01 pm

Update on this,

Mean Green makes a 202 amp alternator for the KJ, Part Number MG1387, listing at 369.00 right now.

Thanks tjkj.

Adding light - alternator/battery question

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