Discovery II Talk about the Land Rover Discovery II within.
Sponsored by:
Sponsored by:

Need guidance on battery draw readings please

Thread Tools
 
Search this Thread
 
  #1  
Old 03-27-2019, 11:21 AM
bcurtman's Avatar
Mudding
Thread Starter
Join Date: Jan 2019
Location: Rosebud, Mo
Posts: 161
Received 24 Likes on 20 Posts
Default Need guidance on battery draw readings please

Drove to work after being on charger last night. When I got ready to leave work at 5, it was dead. Jump box got me going. When I got home I checked it out pretty thoroughly as follows.

Charging 14.2

Shut it off, battery holds 12.8 Battery is a known to be good one.

Started the milliamps test with my Fluke set on 30mA scale and connected between unhooked battery ground and battery ground post

About 46.2 mA consistent draw. Barely enough to flicker a 12 volt tester

Pulled every relay and fuse in the engine compartment panel one at a time with no more than 1 or 2 mA total change

Unhooked lead to alternator. No change

Wife got home. Asked her to watch the Fluke while I pulled the fuses on the drivers side interior panel

Opened the door and it went to 400+ mA

Thought I'd hold the door switch while I pulled fuses. Silly me, it doesn't have a typical door switch, and I couldn't find it....

Closed the door. Draw stayed up around 290mA. Cycled the key and closed the door. Dropped back to 46.2mA

Opened the doors and made sure every dome light was in manual off position. Unplugged ultragauge. Cycled the key. Closed doors and it stayed at 290.

On a whim, I hooked battery ground back to battery and pulled it back off and checked draw. 27mA

Opened door and cycled key. Back to 290. Went to feed cows, gone 30 minutes or better. Still 290. Everything was off, key out of ignition, dome lights off, doors slammed. Never got it back to 27, which I suspect is approaching acceptable. I noted that cycling hood switch by hand jumps it up.

Put it on a 2 amp charge and came in for dinner. Gonna get the rave open on my tablet. (electrical section)

I'm thinking at this point its the door switches or security system. Looking for some help / guidance / been there done that, please...
 
  #2  
Old 03-27-2019, 11:35 AM
Ben Matheson's Avatar
Winching
Join Date: Feb 2018
Location: Orlando FL
Posts: 568
Received 43 Likes on 36 Posts
Default

Pretty sure bcu retains power for a couple minutes after door is shut...


Load test the battery...
 
The following users liked this post:
shanechevelle (03-27-2019)
  #3  
Old 03-27-2019, 02:14 PM
bcurtman's Avatar
Mudding
Thread Starter
Join Date: Jan 2019
Location: Rosebud, Mo
Posts: 161
Received 24 Likes on 20 Posts
Default

I just swapped in a 'known to be good" battery last week to eliminate that option. If I unhooked the hot lead to the alternator and there was no amp draw drop, doesnt that kind of eliminate the alternator as well?
 
  #4  
Old 03-28-2019, 07:31 AM
bcurtman's Avatar
Mudding
Thread Starter
Join Date: Jan 2019
Location: Rosebud, Mo
Posts: 161
Received 24 Likes on 20 Posts
Default

Since nobody has come forth, can anyone tell me if pulling fuse 21 in the interior panel to disable the door locks will help eliminate a faulty door switch?
 
  #5  
Old 03-28-2019, 10:36 AM
bcurtman's Avatar
Mudding
Thread Starter
Join Date: Jan 2019
Location: Rosebud, Mo
Posts: 161
Received 24 Likes on 20 Posts
Default

Well, that does'nt work. Pulling fuse 21 does not allow one to shift from Park. Back to the truck and back to the drawing board. Anyone?
 
  #6  
Old 03-28-2019, 11:43 AM
Best4x4's Avatar
Super Moderator
Join Date: Apr 2015
Location: Beaumont, TX
Posts: 7,720
Received 2,237 Likes on 1,660 Posts
Default

Everytime the vehicle is unlocked/opened or a key is cycled the ECU/BCU wakes up. Can’t remember how long it stays active though.
 
  #7  
Old 03-28-2019, 02:34 PM
Motorhead1's Avatar
Recovery Vehicle
Join Date: Oct 2013
Location: Southern OR
Posts: 962
Received 87 Likes on 78 Posts
Default

Only variation on milliamps readings that I find to be different in your original post was: You cycled the key and closed the door and the draw went to 46.2mA. All the other times you were at 290 after cycling the key and closing the door. Maybe try opening and closing each door without key cycling? See if anything reads different? idk. Your definitely on it. Good luck
 
  #8  
Old 03-28-2019, 02:58 PM
Best4x4's Avatar
Super Moderator
Join Date: Apr 2015
Location: Beaumont, TX
Posts: 7,720
Received 2,237 Likes on 1,660 Posts
Default

I’d trick the hood switch lock it up and close it up like normal & check back in a few hours to see if the ECU/BCU went to sleep.
 
  #9  
Old 03-28-2019, 03:13 PM
bcurtman's Avatar
Mudding
Thread Starter
Join Date: Jan 2019
Location: Rosebud, Mo
Posts: 161
Received 24 Likes on 20 Posts
Default

In theory, should I be at 0 mA draw when the ECU /BCU go to sleep; or is something always cooking. I guess clock...anything else?

Does anyone know what "normal" at rest amp draw is? I reckon there are no "normal" rovers then though now are there!
 
  #10  
Old 03-28-2019, 06:52 PM
Motorhead1's Avatar
Recovery Vehicle
Join Date: Oct 2013
Location: Southern OR
Posts: 962
Received 87 Likes on 78 Posts
Default

I hear my ABS pump faintly buzzing a tiny bit, clock and who knows what else is always alive.....
 


Quick Reply: Need guidance on battery draw readings please



All times are GMT -5. The time now is 01:15 PM.