Upgrading Alternator will Save Money? Now With Curve Charts!

Mister Luck

cassis tvtissima virtus
Joined
Aug 25, 2020
Posts
800
Reaction score
264
Location
WEST COAST
Ram Year
2016/2017
Engine
5.7 V8
2016, 1500 , 5.7 V8
160 alt - to 220 alt

The settings in the (BCM) body control module for the (IBS) intelligent battery sensor are the same for the
(5.7 V8 2016, 2500) , as my 1500.

Do I need to upgrade anything else or is it a straight swap ?

Parts Supplier mentions upgraded Alts actually give you better gas mileage?

Rock Auto:
Tip: Alternators work best when operating between 30%-50% capacity. Upgrading to an alternator with higher Amp output than required may improve fuel economy and extend the life of your battery and replacement alternator. “
 
Last edited:

Lyle Longboat

2011 Ram 1500 5.7 Sport CC
Joined
Jul 30, 2019
Posts
1,639
Reaction score
1,601
Location
Moosonee, ON, CANADA
Ram Year
2011
Engine
Hemi 5.7
Something I’d like to know and do as well. I have a alternator sitting on the shelf in my garage, may take back and opt for something with higher output.
 

kurek

Senior Member
Joined
Aug 7, 2019
Posts
2,431
Reaction score
3,293
Location
Northwest
Ram Year
2015
Engine
Hemi 5.7
Oh man I remember going through the effort of calculating out fuel consumption for headlights years ago on ecomodder.com because somebody was going to disconnect a headlight to save fuel..

It was something like one gallon of gas saved per 40,000 miles of after-dark driving (because it only matters while the headlight would be on anyway).

Remember that your alternator is sized to deliver enough power for everything to work at the same time. Ignition firing at high rpm (16 plugs, that's 1.5-2A per 1000 rpm..) and fuel pump delivering ~395hp worth of fuel and headlights on and air conditioner clutch engaged and heated seats on and HVAC fan going full and stereo cranked to 11 and the ABS pump running traction control and a 5th wheel connected with incandescent running lights all along it and your electric power steering working and your inverter charging a laptop and your 12v port charging a phone and your 2nd 12v port charging a tablet...

If you're anywhere over ~50% of your alternator's full capacity during everyday driving I think it's pretty likely you're doing something pretty far out of the ordinary to begin with and rectifying that behavior might be more cost effective than trying to swap in a larger alternator that might take years or decades or centuries of hypothetical driving to realize a return on investment in fuel savings.
 

Jeepwalker

Senior Member
Joined
Sep 8, 2017
Posts
1,138
Reaction score
733
Location
WI
Ram Year
2012 Reg Cab, 4x4
Engine
5.7 Hemi
Interesting idea. "May" is the operative term. Mfgrs would probably size accordingly if they could add to fuel economy. Pickup owners would save a lot on fuel if they didn't speed away from stop signs, and drove 5mph slower ...didn't use larger tires, and other fuel-wasting things people do (like me).

:cool:
 
Last edited:

bm02tj

Senior Member
Joined
Aug 7, 2019
Posts
790
Reaction score
2,189
Location
B C Canada
Ram Year
2018
Engine
5.7
I would say BS on better mileage as it take the same energy per watt produced
 

crash68

ACME product engineer
Staff member
Super Moderator
Joined
Mar 20, 2016
Posts
7,828
Reaction score
10,863
Ram Year
2015
Engine
3.0 EcoDiesel
Interesting idea. "May" is the operative term. Mfgrs would probably size accordingly if they could add to fuel economy.
for fuel economy purposes auto manufacturers can actually control the capacity of the alternator by varying the field voltage. The IBS feeds information to the ECM that controls the alternator.
 

Hemi395

Senior Member
Joined
Mar 18, 2013
Posts
8,323
Reaction score
13,618
Location
Cape Cod MA
Ram Year
2013
Engine
5.7 Hemi
Went thru this a couple years ago. I was going to upgrade my 180 amp alternator to the 220 amp one thats on the HD 5.7 trucks. Got the 220 amp one home and realized the positive post and electrical connector on the 220 amp alt are facing up whereas the original 180 amp has them facing out the back of the alternator. The harness will reach, but not without unhooking and stretching the whole harness way more than I liked. Ended up returning the 220 amp alt.

You could always go with a custom alternator. PM me if you go this route, I can tell you what company NOT go with. Needless to say I'm back to the original 180 amp alt.

One thing to note, the fuse on the positive battery post is rated at 180 amp so if for whatever reason a higher amperage alternator puts out more than 180 amps its going to blow that fuse.

Honestly the cheapest and most beneficial thing you can do for your vehicles electrical system is to do the Big 3 upgrade.
 

GTyankee

Senior Member
Supporting Member
Military
Joined
Nov 2, 2020
Posts
5,083
Reaction score
5,835
Location
El Cajon Calif. 92021
Ram Year
2016
Engine
3.0 ecodiesel
Chrysler products Alternators have a built in Voltage Regulator
The ECM controls the output
The ECM cuts off the Alternator about the time that the Battery reaches 85 to 90 something %

Many owners will run a Battery Tender to get a higher percentage of charge to the battery

Other owners don't care for the built in voltage regulator, They purchase a good quality Voltage Regulator & other components, then they mount it on the firewall, just like it was done in days gone by.
This comes in handy when you have a TT
 
OP
OP
Mister Luck

Mister Luck

cassis tvtissima virtus
Joined
Aug 25, 2020
Posts
800
Reaction score
264
Location
WEST COAST
Ram Year
2016/2017
Engine
5.7 V8
for fuel economy purposes auto manufacturers can actually control the capacity of the alternator by varying the field voltage. The IBS feeds information to the ECM that controls the alternator.
the 160amp alternator would still need to work harder than a 220 at lower RPM’s to keep up
 
OP
OP
Mister Luck

Mister Luck

cassis tvtissima virtus
Joined
Aug 25, 2020
Posts
800
Reaction score
264
Location
WEST COAST
Ram Year
2016/2017
Engine
5.7 V8
Went thru this a couple years ago. I was going to upgrade my 180 amp alternator to the 220 amp one thats on the HD 5.7 trucks. Got the 220 amp one home and realized the positive post and electrical connector on the 220 amp alt are facing up whereas the original 180 amp has them facing out the back of the alternator. The harness will reach, but not without unhooking and stretching the whole harness way more than I liked. Ended up returning the 220 amp alt.

You could always go with a custom alternator. PM me if you go this route, I can tell you what company NOT go with. Needless to say I'm back to the original 180 amp alt.

One thing to note, the fuse on the positive battery post is rated at 180 amp so if for whatever reason a higher amperage alternator puts out more than 180 amps its going to blow that fuse.

Honestly the cheapest and most beneficial thing you can do for your vehicles electrical system is to do the Big 3 upgrade.
Thanks I checked that
my 160 does have the rear post and the harness can be adjusted by replacing two zip tie straps on the left side front at the cylinder head and the block.
 
Top