Page 3 of 3 FirstFirst 123
Results 21 to 27 of 27

Thread: Electrical mods

  1. #21
    Join Date
    Jun 2016
    Location
    Perth
    Posts
    148
    Total Downloaded
    0
    Quote Originally Posted by drivesafe View Post
    OK folks, I think there needs to be some research done on just what sort of alternator charging goes on in the DS.

    I have not had the time to even look at a DS, let alone test their voltage operation, and it sounds like they may not have a “smart” alternator operation, because there does not seem to be any monitoring of the cranking battery.

    So if someone has the means, can you monitor the voltage of your DS while it is in use.
    Oh there's definitely battery monitoring going on, and from the excerpt from the DS service manual below, I'd say it's a "smart" alternator with variable voltage charging and regenerative braking.

    BATTERY MONITORING SYSTEM (BMS)
    The BMS (Battery Monitoring System) control module is located on the battery negative terminal, and connected to the
    BCM/GWM assembly via a LIN bus connection. The BMS module contains software maps that provide a mathematical model of
    battery conditions, and constantly receives information from the BCM/GWM assembly regarding the vehicle state and electrical
    loading.
    The BMS control module monitors various battery parameters, which are directly measured and predictive values:
    Battery current and voltage are the result of direct measurement;
    while State of Charge (SoC), State of Function (SoF) and electrolyte temperature are predicted values.
    These signals are used by both the charging system and the stop/start system to ensure the vehicle functions are optimized.
    The measurement is autonomous and happens in all states to enable an accurate condition of the battery to be assessed at all
    times. Software based values are calculated and used as a backup in the event of a system fault condition.
    The BMS control module also has a hardwired connection to the battery positive terminal. This connection is used to avoid any
    potential voltage drop in the circuit which results incorrect information received by the BMS control module. If this connection
    becomes open, the BCM/GWM assembly detects a communication loss with the BMS control module. Then the BCM/GWM
    assembly default to a fail-safe fixed charging voltage of 14 Volts, stores a related DTC, and sends a message to the
    Instrument Cluster (IC) via the MS Medium Speed (MS) Controller Area Network (CAN) comfort systems bus to illuminate the
    charge warning indicator.

    OPERATION
    The charging system consists of a generator and regulator assembly and the BCM/GWM assembly. The generator and
    regulator assembly generates electrical power for the vehicle electrical system and maintains the battery in a charged state.
    The rate of charge for the battery is controlled by the BCM/GWM assembly.
    The charging voltage range is 12.3V to 14.8V (at the battery).
    A smart regenerative charging system increases the alternator output when the vehicle brakes or decelerates. This converts
    the kinetic energy of the vehicle into electric energy without having to use additional fuel.
    The smart regenerative feature is allowed to operate within certain environmental constraints to ensure the feature delivers
    the greatest benefit possible whilst maintaining system integrity.
    The ‘free’ electric energy is captured by charging the battery above the target level. This energy can be used by the electrical
    systems at a later stage. This could be when the engine is switched off during a stop-phase, but can also be when the
    generator is operating in a less efficient mode.
    In fact the Service manual also contains the following warning:-

    BMS.jpg

    Is this the reason you suggest not connecting auxiliary power take-off directly to the negative terminal of the battery, because it could damage the sensitive BMS unit? Though I would have thought there would be a difference between a "slave" power supply which is putting electrical power into the battery, and an auxiliary take-off which is taking it out, but happy to be corrected by those with more experience than me...

  2. #22
    Join Date
    Oct 2017
    Location
    Brisbane
    Posts
    1
    Total Downloaded
    0
    Quote Originally Posted by drivesafe View Post
    OK folks, I think there needs to be some research done on just what sort of alternator charging goes on in the DS.

    I have not had the time to even look at a DS, let alone test their voltage operation, and it sounds like they may not have a “smart” alternator operation, because there does not seem to be any monitoring of the cranking battery.

    So if someone has the means, can you monitor the voltage of your DS while it is in use.
    Hi all, I'm new around here, although been driving a disco sport for almost 2yrs. I'm looking at doing some electrical mods in the near future so this thread grabbed my attention.

    While doing some short drives around town today I managed to track the battery voltage a bit:


    • 12.7V battery only
    • Dropped to low 11's during cranking
    • The alternator seemed to initially put through 14.5V, dropping to 14.1V over about a minute
    • After a few minutes, it was fairly stable at 13.8V with the A/C on and 14.0V with A/C off.


    I'm fairly new to vehicle electrics, but that looks like the behaviour of a smart charger to me. Hope that's the sort of info that's useful, drive safe.

    MY16 2.2L diesel btw.

  3. #23
    Join Date
    Jan 1970
    Location
    Queensland
    Posts
    7,768
    Total Downloaded
    0
    Hi Malim, and where on earth did you get that from.

    Calling the alternator a generator sounds like the backward mouthings of Land Rover.

    Next, the use of the expression Regenerative Braking is a misnomer, because there is no such thing as Regenerative Braking in a conventional vehicle.

    Regenerative Braking is only found in electric hybrids or all electric vehicles, where they have electric motors directly driving the wheels.

    The only part of that “info” they got right was that it is the vehicle’s kinetic energy that is used to power the alternator.

    And note, the alternator voltage level has absolutely nothing to do with the use of the Brake Peddle.

    The alternator’s Voltage raises every time you lift your foot of the ACCELERATOR Peddle.

    Any one can test for this by driving their vehicle up a hill and the coast down the other side.

    While going up the hill ( provided the cranking battery is near fully charge ) the voltage will be low, and then when you lift your foot off the accelerator peddle, the voltage rises, and it remains high while you coast down the other side of the hill.

  4. #24
    Join Date
    Jan 1970
    Location
    Queensland
    Posts
    7,768
    Total Downloaded
    0
    Quote Originally Posted by Burndtjamb View Post
    Hi all, I'm new around here, although been driving a disco sport for almost 2yrs. I'm looking at doing some electrical mods in the near future so this thread grabbed my attention.

    While doing some short drives around town today I managed to track the battery voltage a bit:


    • 12.7V battery only
    • Dropped to low 11's during cranking
    • The alternator seemed to initially put through 14.5V, dropping to 14.1V over about a minute
    • After a few minutes, it was fairly stable at 13.8V with the A/C on and 14.0V with A/C off.


    I'm fairly new to vehicle electrics, but that looks like the behaviour of a smart charger to me. Hope that's the sort of info that's useful, drive safe.

    MY16 2.2L diesel btw.
    Hi and thanks Burndtjamp, that is exactly what is needed.

    The info Malim posted about not touching the negative terminal is correct and commonplace on most new vehicles, not just Land Rovers.

    The voltage levels are determined by the SoC of the cranking battery.

    Lower the voltage of the cranking battery, which is exactly how my isolators work, when using the auxiliary battery while the motor is off, and once the motor is running again, because the SoC of the cranking battery has been lowered, the alternator voltage will run higher for longer, to recharge the cranking battery in the shortest drive time.

    This also means the auxiliary battery is teated to a high charge cycle as well.

    There is more to is but thats the basics.

  5. #25
    Join Date
    Jun 2016
    Location
    Perth
    Posts
    148
    Total Downloaded
    0
    Quote Originally Posted by drivesafe View Post
    Hi Malim, and where on earth did you get that from.
    As I said in the original post, it's straight from the Discovery Sport workshop manual, I'm just relaying what LandRover say about their system.
    However, you still haven't answered my question, ie: why do you say not to attach the negative of an auxiliary feed to the battery negative post, and attach it to the chassis earth connection instead? Thanks.

  6. #26
    Join Date
    Jan 1970
    Location
    Queensland
    Posts
    7,768
    Total Downloaded
    0
    Quote Originally Posted by Mamil View Post
    As I said in the original post, it's straight from the Discovery Sport workshop manual...
    Thanks Mamil
    For the life of me, I have no idea who they get to write these documents.

    Using the brake, and decelerating, has nothing to do with the voltage levels.

    As I posted, and anyone from Land Rover should be aware that the voltage is controlled by the accelerator peddle.

    Simple measure the battery voltage as you roll down a hill, which by the way, is where you will get the longest charge periods.

    While coasting down a hill, just touch the accelerator peddle and the voltage drops.

    The only time using the accelerator peddle does not effect the voltage is when the cranking battery is low and the BMS overrides the info from the accelerator peddle position.

  7. #27
    Join Date
    Aug 2014
    Location
    Melbourne
    Posts
    3
    Total Downloaded
    0
    sorry off topic: I can't create a post for some reason.

    how do I get this electrical diagrams and part numbers? I tried register in TopiX but can't get these diagram unless you paid subscription.

    Thinking to do retrofit memory seat for my Discovery Sport, anybody have a clue how to do this?

    TIA

Page 3 of 3 FirstFirst 123

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Search AULRO.com ONLY!
Search All the Web!