Too much light!?

DirtDgr

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Just installed Baja Designs 40” Onyx and 20” Onyx and a couple xlr pros for ambers on the 1/2 1600.

Turned everything on in the car with all the lights on and it killed the battery. Was just idling so I know thats part of it.

How do I go about figuring out what I have to shut off or combo of lights to use so I don't kill it during a race?

Can I just use a volt meter and try different things? As long as the volt meter is over 12 when things are on the alternator is keeping up correct?
 

DirtDgr

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CF7CCFF0-39FA-4738-B9DF-8371D16372EA.jpeg
 

az_amsoil

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The quick and easy is with the vehicle running, measure you voltage at the battery. Your alternator should be providing at least 13.5Vdc at idle...then turn on each light until the voltage drops below 13.5Vdc. At this point you will not be charging the battery with that particular combination of load on the battery.
 

paranoid56

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you might be pulling to many amps for your alt. if your alt is stock then thats like 60-80amp setup.
27amp 40" bar
17amp 20" bar
3amp per xl pro

so your lights are pulling 50amps just in lights. that doesnt leave much for the rest of the car
 

cjohnson

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We went through this issue with our setup. It's painful but we had to finally go through a complete load calculation. We had a couple small fans that took a surprising amount of current.

Also keep in mind alternators, stators, generators, etc are rated at a certain RPM. In our case our load was OK for the rated output but we spent too much time at lower RPM in technical sections at night and slowly drained our battery. For example you might get 80 amps at 4000 RPM but much less at 1500-2000. Depending on how low of RPM your engine idles you may not be getting much current (amps) at all so testing at a higher RPM might be more realistic.

Monitoring the voltage, as mentioned above, is the best method to make sure you're not draining your battery. We now have a voltmeter in our car and start turning off lights at night if we see too much drop in the battery voltage but we haven't had to do that once we listed all the battery loads and reconfigured our setup to match our available stator output.
 

burninfuel

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We ran a 9 car at Fallon, VORRA, back in 2008, first daylight laps were fine and then the lights were turned on.
My Son said it had no power anymore.
Class nine champ runs little or no lights, he said your car was like a spaceship when he passed it .
pulls lots of horsepower to make 40-50 amps.
Forrest Creasy says he gets behind a 10 car, with in feet and stays on their bumper as much as he can.

You need a big altenator
 

cjohnson

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We ran a 9 car at Fallon, VORRA, back in 2008, first daylight laps were fine and then the lights were turned on.
My Son said it had no power anymore.
Class nine champ runs little or no lights, he said your car was like a spaceship when he passed it .
pulls lots of horsepower to make 40-50 amps.
Forrest Creasy says he gets behind a 10 car, with in feet and stays on their bumper as much as he can.

You need a big altenator
1 HP = 745.7 Watts. At 12 V that's 62.14 amps/HP ideal. In the real world alternators are only about 55% efficient so it would take about 2 HP for 60 amps. The big losses are parasitic. Just having the alternator takes some HP.
 

brad inch

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i only ran two lights at a time on my 1600 and found that the radio used alot when talking out of the car.check your radio for incoming and out going amps,get a 75 amp alt for night races only.also take as much weight out of the car to make up for the weight of the lights.i had a 25lb plate under my seat that i would remove for the night races.
 

y2kbaja

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The RPM's brought up a good point in my head. When you come into check points with speed zones and the rpm's are lower you should lower your lights anyway, thus drawing less power. High speed sections with high rpm's you'll want max lighting which the alternator may be able to produce. Lower speed technical sections you can turn the high power driving lights off.
 

Bert is my name

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Why not drive a secondary alternator off the output of the trans. Save some space in the engine bay. Probably easier then reconfiguring the front of the engine.
 

mgobaja

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Why not drive a secondary alternator off the output of the trans. Save some space in the engine bay. Probably easier then reconfiguring the front of the engine.
I'm not sure there is a simple way to do that off of a VW type transaxle.
 

mgobaja

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Haha. You're right. Spaced on the vw part.
but back in the 90's there were a few VW based cars that did run a 2nd alternator for races that had lots of night driving. Mounted it on the rear cage, ran another pulley on the engine, belt in between the two. i want to say they used 95 amp GM alternators.
 

jon coleman

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jeep grand Cherokee alt the hi out put one is pretty good, i stuck the biggest pully i could find on it, never had any issues
 

DirtDgr

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Well I did not seem to have any issues. Never ran all the lights together. 40” upper in the fast stuff which was most of the course. 20” and the small ambers in the slower sections and extreme dust and in the pits. A few spots it was ambers only for short periods at checks too so I dont blind them.

This Onyx 40 Baja Designs is bright! The 20” is too! Worked great and really no need to run all lights at once. So still dont know if it is possible.
 
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