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Weird issue with 12V Battery

goodbadboys9

Member
Apr 22, 2018
100
23
NJ
I am having weird issue with my car.I am getting error messages if I dont drive the car for a day or so.

Below are the error messages.
Voltage supplied too low
vehicle might shutdown
schedule service immediately

What I noticed is when I park the car my dc-dc converter isnt charging the 12V battery but it is charging the battery when car is on or If I restart the car by disconnect the battery & fireman loop for couple of hours.

Does any one know if 12V battery send signal if it is running low or is there any fuses I can check to see why dc-dc converter isn't charging the battery when car is off
 

goodbadboys9

Member
Apr 22, 2018
100
23
NJ
Do we know how frequent does 12v gets charged from dc-dc converter?

I read that there is some switch on MCU in service menu to disable 12V support do you think it might be related to that?
 

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kindred7

Member
May 18, 2019
20
7
Canada
When the car is resting, wake the car with the app and run the hvac for about 1hr.

After that go out to the car and change the wheel configuration in the settings and reset the car, this is a deep reset. Remember to change the wheel configuration graphic back if you like.

See if this solves your problems. If not you need to change your 12v.
 
  • Informative
Reactions: FlatSix911

goodbadboys9

Member
Apr 22, 2018
100
23
NJ
Thanks Kindred.Will follow your steps & see how it goes.

I tried to change wheel configuration when I had the errors & errors came right back after reset.

I thought it was 12V battery issue & I put in a new battery to rule it out but I still have the issue
 

VTompson

Member
Oct 31, 2020
6
0
Ukraine
When the car is resting, wake the car with the app and run the hvac for about 1hr.

After that go out to the car and change the wheel configuration in the settings and reset the car, this is a deep reset. Remember to change the wheel configuration graphic back if you like.

See if this solves your problems. If not you need to change your 12v.
hey! what is hvac?
 

goodbadboys9

Member
Apr 22, 2018
100
23
NJ
Tried this procedure, I hear contactors closing & when I try to start the car after reset using wheel configuration update got the errors right back
 

Doanster1

Member
Feb 14, 2018
949
490
Oregon
Could be the battery sensor attached to the 12v. Just had mine replaced a couple weeks ago after getting “Power reduced” msgs every so often without any subsequent ill-effects. SC tested everything else, including health of the 12V battery and deemed it good so the sensor must’ve been flaky and sending false readings every so often which triggered the errors.
 
  • Informative
Reactions: Xenoilphobe

goodbadboys9

Member
Apr 22, 2018
100
23
NJ
There was a thread here a couple years ago that was about replacing blown fuses in the dc-dc converter, have you checked this out?

I dont think it is blown fuse in DC-DC converter here is my logic & I might be wrong too if fuse is blown it shouldn't charge the battery at all but the battery is being charged when I rest the car or when driving or when charging the car(I mean using wall charger or supercharger)12V Battery isnt getting charged only when car is off(I plugged in aftermarket battery monitor in the afternoon & I haven't seen it charging 12V battery since then)
 

Doanster1

Member
Feb 14, 2018
949
490
Oregon
Might be my issue too.Do you know part number for the battery sensor?
SENSOR INTELLIGENT BATTERY(6007953)

Reading through the old text exchange with the SC on this, they orig said the sensor reads out values from the DC/DC converter and was passing wrong values every so often. They called the part (multiple times) the 12V sensor though so now I’m curious as to where it actually is so will look it up on EPC later tonight. It was def a Ranger serviceable part so I’m thinking on/around the 12V battery.
 

Doanster1

Member
Feb 14, 2018
949
490
Oregon
I was right. Sits on the positive terminal of the 12V battery. Number 14...
 

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goodbadboys9

Member
Apr 22, 2018
100
23
NJ
Last night DC-DC converter kicked in & charged the battery but most of the time my battery stays at 12.3-12.7V
I think for Tesla's battery are supposed to be @13.7V right ? or Is it normal for 12V battery to be @12.3V

I attached some of the graphs below & 13.7Voltage until 09:30AM is while charging the car
 
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