perez1989
NAXJA Forum User
- Location
- Pharr, Texas
I have a stock 100amp alternator. Will be hooking up 4-130w off road lights to my setup burn out my alternator or electrical wires? Gonna get a 124amp alternator but later on.
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Can a stock Alternator burn out because of High Amp demands
- Thread starter perez1989
- Start date
collkid
NAXJA Forum User
- Location
- Highlands Ranch, Colorado
I did kind of the same thing for a while, make sure first that you have large enough wires to the lights. I noticed for me that the lights took a full 3 seconds to come on and I think it was because You really have to push the alt to get that much power out.
MoparManiac
NAXJA Forum User
- Location
- Amherst, NH
Some years have a fusible link coming out of the alternator, so if you start exceeding that demand (like a higher amp alternator with lots of add-ons) you'll run the risk of popping it.
Other years have 2 60A MAXI fuses in parallel (for a total of 120A) to handle the alt loads. I believe there might even be another setup, but not sure.
Check with 5-90 on here about what you have, and he is also a source for upgraded stock wiring to handle the kind of outputs a winch, lights, etc require.
Other years have 2 60A MAXI fuses in parallel (for a total of 120A) to handle the alt loads. I believe there might even be another setup, but not sure.
Check with 5-90 on here about what you have, and he is also a source for upgraded stock wiring to handle the kind of outputs a winch, lights, etc require.
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Yep, agree, especially with contacting 5-90. You need to calculate your needs to meet the load you will be running--Google for a conversion application to see how many amps those lights will draw.
5-90
NAXJA Forum User
- Location
- Hammerspace
It's possible - but it's more likely you'll cook the battery first (since the battery makes up the shortfall when the capacity of the alternator is exceeded.)
Since lighting is rated in Watts, and nearly everything else electrical in Amperes, you need to convert. Fortunately, the conversion is simple:
Use a nominal 12VDC (instead of the actual system voltage, with is 10-15% higher,) and you'll have a safety margin inbuilt without thinking about it.
Ex: You have two 55W fog lamps. 2x55W = 110W. 110W/12V = 9-1/6A.
Effectively, design and build it as a 10A circuit, and fuse with a 10A fuse. You can use the calculated figure when calculating current draw, but round up to the next rating if you're in between fuse ratings to protect the circuit. Select feed wire gage accordingly after that.
Ex: You have 2x100W off-road lamps. 2x100W = 200W. 200W/12VDC = 16-2/3A. Fuse and wire for a 20A supply, but recall that you're only drawing 16-2/3A at "nominal" system voltage (this will also help to prevent your hitting your head on the alternator max output - since the actual draw in a circuit, all else being equal, equates to a lower current for a higher supply voltage.
But, that's probably wandering a bit far into theory for you, so we'll leave it be for the moment.
Total draw for those two pair if lamps would be 9-1/6A + 16-2/3A = 9-1/6A + 16-4/6A = 25-5/6A.
Bear in mind a couple of things:
1) Fuel injection systems require anywhere between 20A and 40A - right off the top. If that current doesn't go out, your engine don't run.
2) Alternator output can vary by as much (typically) as -5%/+10%. I've seen it swing a little wider (usually in favour of the vehicle,) but it's been rare. You want to know what you're really getting out of your alternator? Take it to a shop and have it spun to check. If they can load it so that it will hole min. 13.2VDC and give max current output, you've found out what you needed to go.
Since lighting is rated in Watts, and nearly everything else electrical in Amperes, you need to convert. Fortunately, the conversion is simple:
Amperes = Watts/Volts
Use a nominal 12VDC (instead of the actual system voltage, with is 10-15% higher,) and you'll have a safety margin inbuilt without thinking about it.
Ex: You have two 55W fog lamps. 2x55W = 110W. 110W/12V = 9-1/6A.
Effectively, design and build it as a 10A circuit, and fuse with a 10A fuse. You can use the calculated figure when calculating current draw, but round up to the next rating if you're in between fuse ratings to protect the circuit. Select feed wire gage accordingly after that.
Ex: You have 2x100W off-road lamps. 2x100W = 200W. 200W/12VDC = 16-2/3A. Fuse and wire for a 20A supply, but recall that you're only drawing 16-2/3A at "nominal" system voltage (this will also help to prevent your hitting your head on the alternator max output - since the actual draw in a circuit, all else being equal, equates to a lower current for a higher supply voltage.
But, that's probably wandering a bit far into theory for you, so we'll leave it be for the moment.
Total draw for those two pair if lamps would be 9-1/6A + 16-2/3A = 9-1/6A + 16-4/6A = 25-5/6A.
Bear in mind a couple of things:
1) Fuel injection systems require anywhere between 20A and 40A - right off the top. If that current doesn't go out, your engine don't run.
2) Alternator output can vary by as much (typically) as -5%/+10%. I've seen it swing a little wider (usually in favour of the vehicle,) but it's been rare. You want to know what you're really getting out of your alternator? Take it to a shop and have it spun to check. If they can load it so that it will hole min. 13.2VDC and give max current output, you've found out what you needed to go.