I don't really understand alternators:
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
What's surprising is that the 12 volt system is still around, it's not 1953 anymore and power demands have increased dramatically. But basically, the same battery is still in use today. There was some talk a few years ago of a new 48 volt system but kind of dropped off the radar.
Super Moderator
Joined: Aug 2003
Posts: 25,479
Likes: 742
From: Isanti, MN
It's kind of an interesting discussion here. I tend to think the parasitic losses of a dual alternator setup may be minimal, but even a fraction of a percentage adds up over time. Think about it, 150,000 miles of fuel at $4/gal is over $35,000.
If a second alternator reduced efficiency by 0.5% it would cost $175 in fuel over that 150,000 miles. Of course it's nowhere near as simple as that in a real world situation, but small losses can add up to big bucks over time.
If a second alternator reduced efficiency by 0.5% it would cost $175 in fuel over that 150,000 miles. Of course it's nowhere near as simple as that in a real world situation, but small losses can add up to big bucks over time.
New User
Joined: Mar 2014
Posts: 1
Likes: 0
My opinion: There is a benefit, whether it's prudent to make a change is another thing. BTW The load on the engine is insignificant (in regards to single or dual).
Advantages:
More available current (if you need it)
Redundant system if one fails (it'll get you home)
Less wear due to working less. The alternator can be viewed the same as your engine; if it has an easy life it has less wear, if it is operating at the top of it's range it has more wear (higher temps, brush/slip ring and bearing wear).
Disadvantages:
An extra part to fail. Even though combined they are working less than a single unit and theoretically can last longer because of this, they are still spinning and wearing in regards to brushes, slip rings and bearings. Not to mention unexpected or premature failure of electronics (regulator and rectifier diodes).
https://www.fleet.ford.com/truckbbas...ml/Q-160R1.pdf
It is offered and is not a difficult modification.
You keep the original 200amp alternator and add a 157 amp alternator. Bolt on the below parts and have Ford program the PCM
Single alternator to dual alternators:
Alternator Assembly:
Primary: 200 amp BC3T-10300-BA
Secondary: 157 amp BC3T-10300-EC
Alternator Belt for dual alternators:
BC3Q-8620-GA
Alternator Fasteners:
W715092-S437: M10 x 92 mm (lower alt bolt) Qty 2
W715094-S437: M10 x 40 mm (upper alt bolt) Qty 2
Secondary Water Pump*:
BC3Q-8501-BB
Wiring Harness:
BC3Z-14305-F
Advantages:
More available current (if you need it)
Redundant system if one fails (it'll get you home)
Less wear due to working less. The alternator can be viewed the same as your engine; if it has an easy life it has less wear, if it is operating at the top of it's range it has more wear (higher temps, brush/slip ring and bearing wear).
Disadvantages:
An extra part to fail. Even though combined they are working less than a single unit and theoretically can last longer because of this, they are still spinning and wearing in regards to brushes, slip rings and bearings. Not to mention unexpected or premature failure of electronics (regulator and rectifier diodes).
https://www.fleet.ford.com/truckbbas...ml/Q-160R1.pdf
It is offered and is not a difficult modification.
You keep the original 200amp alternator and add a 157 amp alternator. Bolt on the below parts and have Ford program the PCM
Single alternator to dual alternators:
Alternator Assembly:
Primary: 200 amp BC3T-10300-BA
Secondary: 157 amp BC3T-10300-EC
Alternator Belt for dual alternators:
BC3Q-8620-GA
Alternator Fasteners:
W715092-S437: M10 x 92 mm (lower alt bolt) Qty 2
W715094-S437: M10 x 40 mm (upper alt bolt) Qty 2
Secondary Water Pump*:
BC3Q-8501-BB
Wiring Harness:
BC3Z-14305-F
Fleet Mechanic
Joined: Oct 2006
Posts: 1,351
Likes: 242
From: North Florida
My truck came with dual alternators and I'm not sure why. I bought it new off of the lot and it doesn't have any special options that I would think requires a second alternator. I don't have the supplemental heat option. I have speculated that someone ordered it then backed out. Any idea what options warrant the additional one?
Postmaster
Joined: Sep 2006
Posts: 2,598
Likes: 5
From: Maryland
For some reason, some dealers order them that way. My brother bought his 2011 off the lot with dual alternators and it was only there a few days before he bought it. I don't think it was a rejected order. The supplemental heat requires either the HD or dual alternator option, but his truck doesn't have the heater either. The only odd option that he has is the plow package.
Lead Driver
Joined: Dec 2013
Posts: 9,762
Likes: 115
Doesn't the cold affect how things charge and draw power as well? In colder areas it might make sense to always get them. I find that good dealers know what sells and what people are looking for and try to order their stock that way.
There is no option that is needed to order duals. at least on the order sheets I see. Seems like if you sell a lot of trucks to upfitters that the dual alternator setup couldn't hurt. I have the Heavy Duty Alternator in mine. Duals are $380 on a 2014.
What is with having to add a secondary water pump for dual alts? That is a new one for me.
There is no option that is needed to order duals. at least on the order sheets I see. Seems like if you sell a lot of trucks to upfitters that the dual alternator setup couldn't hurt. I have the Heavy Duty Alternator in mine. Duals are $380 on a 2014.
What is with having to add a secondary water pump for dual alts? That is a new one for me.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
FTE Leadership Emeritus
Joined: May 2004
Posts: 18,787
Likes: 30
From: Melbourne, Aus
Its just replacing the water pump housing. Part of the housing makes up the mounting bracket for the 2nd alternator. They obviously figured it was cheaper to have 2 pump housings than pay the 10c extra for the additional material for the mounting points to be fitted to every truck.
FTE Leadership Emeritus
Joined: May 2004
Posts: 18,787
Likes: 30
From: Melbourne, Aus
I suppose in theory, yes. Both the 200 and the 157amp alternator use the same mounting points. I am not sure if there are any clearance issues (i.e. is the 200amp physically larger). I know it used to be.
Lead Driver
Joined: Dec 2013
Posts: 9,762
Likes: 115
My theory on two 200 amp alternators is this. In order to run 2 alternators you have to get the ECM reprogrammed. Why would Ford make a 357 Dual Alt. Kit and not a 400 amp?
My fear is that the ECM wouldn't like seeing 2 - 200 Amp alternators. In the old days it really didn't matter, but today, the darn computer knows everything.
My fear is that the ECM wouldn't like seeing 2 - 200 Amp alternators. In the old days it really didn't matter, but today, the darn computer knows everything.
Senior User
Joined: Oct 2008
Posts: 437
Likes: 1
From: Bucyrus, KS
Does anyone know if it is possible to swap the 157 amp for the 200amp? I have a buddy who is shopping for a new Ford and wants a XLT with the center console and the HD alternator. He's having trouble finding a truck with both. I would think it would swap out but I'm not sure.
Thread
Thread Starter
Forum
Replies
Last Post
danorules
2004 - 2008 F150
2
Sep 14, 2012 01:11 PM
Saleenguy
1999 - 2016 Super Duty
7
Feb 14, 2009 12:17 AM