View Single Post
Old 08-29-2018, 12:57 PM   #1 (permalink)
Daox
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,203

CM400E - '81 Honda CM400E
90 day: 51.49 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)

Daox's Volt - '13 Chevrolet Volt
Thanks: 2,501
Thanked 2,585 Times in 1,553 Posts
Help me kill my alternator - it is stubborn and won't die

For the past few days I have been attempting to do an alternator disable on my 2014 Mitsubishi Mirage. I'm going to do it electrically, not unbelting, or removing the alternator. I've done this on several vehicles, but this one is proving to be a bit of a challenge!

Here is the system description of how it works, and diagrams to go along with it for reference.







My first thought was to cut and put a switch on the FR (field regulator) wire. I did this and it did stop it from charging... kinda. As soon as the engine revved up too high, it would start charging (self exciting I am guessing).

So, version two. I figured that killing the S (sense) wire would do it. However, I couldn't be more wrong. Instead of defaulting to not charging at all, the alternator blasts on at 15V.

I am thinking that my next step will be to install a dc-dc converter that takes 12V and converts it to 15V. I will send this 15V signal to the sense wire when I want the alternator to turn off, and let it see normal battery voltage when I want it turned on. The service manual specifically says (see above):

Quote:
When the battery voltage (generator "S" terminal voltage) reaches a regulated voltage of approximately 14.4V, the field current is cut off.
So, I am hoping that 15V will do it. I have already ordered a tiny $3 dc-dc converter to do this job.

However, if you see a simpler way to do this, I am all ears!

Attached Thumbnails
Click image for larger version

Name:	charging system.jpg
Views:	1193
Size:	162.0 KB
ID:	24744   Click image for larger version

Name:	system diagram.jpg
Views:	1109
Size:	43.0 KB
ID:	24745  
__________________
Current project: A better alternator delete
  Reply With Quote