How many amps is your alternator rated for?

[Ferzerp]

This is a totally pointless question, but I'm trying to figure out why I have a 220 Amp alternator. What size do you guys have? (And does anyone have any clue why on earth one would put a 220 Amp alternator in a car?)

 

[DominionSeraph]

125A.

You have 220A as stock in a car?

 

[Howard]

220A at 14.4VDC is only 3kW, or just over 4HP. Not exactly huge, but maybe you have extra loads...?

 

[Ferzerp]

125A. You have 220A as stock in a car?

Yes. I don't get it.

220A at 14.4VDC is only 3kW, or just over 4HP. Not exactly huge, but maybe you have extra loads...?

3kW seems completely overkill to me is the point! Speaker system is only rated at 522W and is the largest stock option.

 

[DominionSeraph]

220A at 14.4VDC is only 3kW, or just over 4HP. Not exactly huge

125A is 1800W, and it runs my stock Monsoon with 1100W of Fosgate pushing three 12W6's without dimming my headlights even on high. (and my low beams stay on with the high beams, so it isn't just switching out 50W for 60W.)
He can go 1368W above that.

 

[NutBucket]

Except there's no way you're drawing that much power for your stereo....ever. 1100w for that monsoon is more like max output at 1khz....for 10 seconds before it overheats and melts

 

[DominionSeraph]

Except there's no way you're drawing that much power for your stereo....ever. 1100w for that monsoon is more like max output at 1khz....for 10 seconds before it overheats and melts

1100W is for my Fosgate amp, and it can and does melt 80A fuses.

 

[LTC8K6]

Grand Cherokee has a 160, 180, or 220 amp alternator.

160 on the base Laredo
180 on the rest
220 with the 5.7L Hemi

 

[Ronstang]

220 amps? That is the size in my 2009 F150. New vehicles need a lot more good quality electricity to make sure all the computers in them function correctly. Trucks usually have the biggest alternators since they are tow vehicles and have to power certain functions on the trailer.

 

[Howard]

125A is 1800W, and it runs my stock Monsoon with 1100W of Fosgate pushing three 12W6's without dimming my headlights even on high. (and my low beams stay on with the high beams, so it isn't just switching out 50W for 60W.)
He can go 1368W above that.

I dunno, maybe his AC compressor runs off a motor?

http://www.globaldensoproducts.com/hvc/electric_compressor.html

Then again, a hybrid wouldn't have a 220A alternator.

 

[LTC8K6]

https://www.fleet.ford.com/truckbbas/topics/2012/12_Electrical_eSB.pdf

Lots of info on the electrical specs of 2012 Ford trucks.

 

[exdeath]

Electric power steering, etc?

 

[Zenmervolt]

'82 CB450SC: 5 amp @ 5,000 RPM (On checking other documentation, it's apparently 170 watts at 5,000 RPM, which should be just over 14 amps; apparently 5 amps is the minimum current in the battery charging circuit)
'07 XL1200R: 32 amp (RPM unspecified)
'86 951: 115 amp (RPM unspecified)
'98 S70 T5: 100 amp (RPM unspecified)

ZV

 

[hdfxst]

160 on the wifes journey and 50 on my harley

 

[herm0016]

160 in my 1/2 ton gmc.

wonder why ford needs 220. strange.

 

[LTC8K6]

Your alternator is capable of far less that it's rated output at idle speed. Keep that in mind. Probably should use half the rating.

 

[Yuriman]

70 amps, 1994 Honda Del Sol

95 amps, 1995 F150

85 amps, 2000 Saturn SL2

 

[HarryLui]

120 amp in the GLH
100 amp in the 855.

 

[thescreensavers]

110 Amp on the G

 

[leper84]

Fuel injection systems take lots of power, and need reliable power. So there is going to be an over-buffer for alternators.

Also...
You have an entire truck's worth of fuel injection/ computer/ diagnostics systems.
Radio going full blast.
Headlights w/ high beams on.
Electronic trailer lights & brakes running
Every single power outlet in the truck with something plugged in charging a smartphone/tablet/laptop
And to top it off, you might even have someone running a power inverter at the same time.

Sounds pretty overkill but people do it all the time; the first time a truck dies on the road because it didn't have enough juice for the fuel pump or injectors its going to be pr suicide for whoever made that truck.

edit: OP said car, then this-

Electric power steering, etc?

 

[Raizinman]

My Chrysler has a 160 Amp alternator. Using Ohms law, 160 amps x 12 volts = approximately 1920 watts. This has to supply:

Headlights 55 watts (Low beams)
Headlights 60 watts (High beams)
Front side marker lights 5 watts
Front fog lights 55 watts
Back up lights 21 watts
Stop lights 21 watts
License Plate lights 5 watts
Interior ceiling lights 8 watts
Glove box 4 watts
Seat heater 150 watts
Side mirrors 60 watts
Electric Seats 150 watts (each)
Each electric window 110 watts
Accessory power socket – up to 150 watts
Premium Stereo with amp 175 watts
Wipers 175 watts
Washers 50 watts
Automatic Braking Systems ABS 80 watts
Fuel Pump 150 watts
SRS (Air Bags) 50 watts
Daytime running lights 40 watts
Moonroof 150 watts
TPMS Tire monitoring system 50 watts
Radiator Fan 150 watts
Rear Defroster 300 watts
Hazard Lights 75 watts
Horn 45 watts
Trailer lights 75 watts
Ignition Coils 75 watts
Fuel Injection 75 watts
HVAC 175 watts
There is much more besides this that take watts.

Adding up much of the above will easily put you past the maximum of my alternator. Obviously many of the items on this list are momentary items, so if it surpasses the maximum of the alternator and starts draining the battery, it will only be for a few seconds and won't really cause any harm.

If an alternator is too small for the load, should this happens the electricity must then come from the battery. If you drain the battery too much, obviously it won’t start when needed. The manufacturer calculates the amount of watts needed to run your car and then builds in some safety. On a cold wet winter night, with the HVAC going, rear defroster going, heated seats, all lights on including fog lights, wipers, and more, you could easily max or surpass your alternator rated load for a period of time.

With modern cars having more and more electrical loads, electric water pumps, electric power steering, and more, the manufacturer is fitting cars with bigger and bigger alternators.

 

[Rifter]

Right now 115, soon to be 300.

 

[LTC8K6]

Police versions of cars usually have a bigger alternator installed because of the extra and sustained electrical loads of police duty.

 

[LTC8K6]

It wouldn't surprise me to learn that modern cars can do load shedding if they need to.

Power could be cut to unnecessary devices in stages perhaps, if the load was too high.

I know that alternators can be "turned off" at times in modern cars for efficiency.

 

[Ferzerp]

Grand Cherokee has a 160, 180, or 220 amp alternator.

160 on the base Laredo
180 on the rest
220 with the 5.7L Hemi

I wonder if it's just that Chrysler mates a 220 A alternator with all their V8s then, just to keep volume up and have fewer parts. If they're using it on the 5.7L in jeeps/pickups, they may as well use it on the 6.4L even though no truck has it. (Though one model grand cherokee does)