Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 10-06-2022, 10:15 AM   #1
Member
 
Join Date: Jun 2022
Posts: 43
Alternator Output at Idle

I have a 1997 Monaco Executive with the Cummins M-11. What should my alternator output be at idle?
dblong is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 10-06-2022, 10:25 AM   #2
Senior Member


 
Join Date: Aug 2011
Posts: 5,365
What measurements are you taking? Amps or volts? Both are affected by the load.

Assuming your batteries are already charged, no other heavy draws on the system, it should produce 13.8v

You would need to know the specific alternator installed on your engine to know theoretically it’s max amp output, previous owners could have changed the unit from what was originally installed.

Also what is your idle speed? 600? 800? 1000?
pasdad1 is online now   Reply With Quote
Old 10-06-2022, 11:45 AM   #3
Member
 
Join Date: Jun 2022
Posts: 43
800
dblong is offline   Reply With Quote
Old 10-06-2022, 12:38 PM   #4
Senior Member
 
Ray,IN's Avatar
 
Join Date: Aug 2001
Location: North America somewhere
Posts: 27,312
After an hour of searching, the only M11 alternator output I found said 130A maximum at max. RPM of 2100.. Some alternators are designed for high output at idle speed, which is 700 for Cummins engines.
Interestingly, I stumbled across this information about the M11 engine, which is unrelated to your question..https://www.cummins.com/engines/m11
__________________
2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy
Ray,IN is offline   Reply With Quote
Old 10-06-2022, 01:03 PM   #5
Senior Member
 
Jon_C's Avatar
 
Join Date: Jul 2018
Location: Southeast Texas
Posts: 876
I have a 340 amp alternator and at idle around 700ish rpm I get 14v with normal loads.

I can get around 150 amps at idle at 13.8v but I don’t do that for long.

It also has to do with the size pulley on the alternator, smaller = more at idle.
__________________
1998 HR Endeavor Cummins ISB 275 / Banks Allison 3060
20014Jeep Wrangler JKUR with M&G air brake with breakaway
Jon_C is online now   Reply With Quote
Old 10-06-2022, 01:14 PM   #6
Senior Member
 
Join Date: Oct 2014
Posts: 6,158
Quote:
Originally Posted by dblong View Post
I have a 1997 Monaco Executive with the Cummins M-11. What should my alternator output be at idle?

While I am sure there will be answers posted, even for your specific coach there is no single answer.


First, alternators put out less amps at engine idle speed than at higher RPM.


If the battery banks are discharged, that alternator output may be only enough to bring battery voltage up a little over what it was before starting.


Later/when the battery banks are charged, so not many amps are required (similar to float voltage for a smart charger) it should read around 14 VDC.


Basically, your battery bank demand will have a lot to do with your voltage reading, particularly at idle speed.
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
wolfe10 is offline   Reply With Quote
Reply

Tags
alternator



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Turning Turn Signal output to Steady Output Waggy MH-General Discussions & Problems 10 10-30-2020 12:01 PM
To idle or not to idle jmoffat Caterpillar Engine Forum 36 05-11-2014 11:54 PM
Checking frequency output and voltage output of Onan 5000 Genset Generator. MajesticRV MH-General Discussions & Problems 4 11-07-2012 11:16 AM
Alternator Output Voltage SafeDave Winnebago Industries Owner's Forum 6 07-14-2006 03:51 AM
8.1 Vortec Alternator Output Bob (WA0MQE) Workhorse and Chevrolet Chassis Motorhome Forum 20 05-08-2006 03:39 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 05:02 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.