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Thread: Aux battery running down too quickly

  1. #1
    Join Date
    Nov 2017
    Location
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    Aux battery running down too quickly

    I have a Traxide D4-5U (in my 2011 D4), hooked up to an Optima D34. It's been in there since about April 2018.

    From that I have connected (via a distribution panel and fuses):
    - UHF radio (GME XRS330C)
    - BlackVue 900 2CH Dashcam
    - a couple of wired in micro-USB and USB-C type charges for my 8" tablet and phone, respectively.

    The radio is only on when in use.
    The dashcam is permanently powered.
    Tablet and phone are usually only connected when driving.

    The rear socket, also on permanent power via the distribution box, runs a 40L Engel (also about 3 years old).

    Despite my best effort of trickle charging over two weeks before my last trip, the Engel runs the D34 flat by about 8am.
    The second day, despite being on solar charge (around 3.5/4A all day), the D34 dropped out at 2am.
    When I say runs flat or dropped out, I mean the Traxide ABS-25 hits its bottom limit of 11.8V, and cuts all this out.

    Graphs - green line is the D34:
    Friday - on charge until 5am. Drive to work, home, then about an hour to camp.
    Traxide 210312.jpg
    Saturday - battery has cut out around 8am, turning off fridge, etc.
    8.30am - start the car for 5 minutes to give it a kick
    10-ish, sun is strong enough to kick in the solar panels
    Sits in sun all day
    Traxide 210313.jpg
    Overnight Saturday, 2am Sunday, it's hit the 11.8V cut-out again.
    A little bit of sun from 7am, but doesn't really start charging until 10-ish again when the sun clears the shade.
    Traxide 210314.jpg

    The fridge was only ever on 3 degrees, not freezer setting.
    So, is my Optima on the way out, or is the dashcam sucking too much juice?

    Do I need to put the Power Magic between the dashcam and the D34?

    Appreciate any advice!
    If at first you don't succeed, that's one data point. - xkcd
    ----------------------------------------------------------------------
    2011 Discovery 4 SDV6 HSE

  2. #2
    Join Date
    Mar 2016
    Location
    Adelaide
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    Your dash cam does actually use a fair bit of power. When u had my BlackVue permanently wired in to the aux battery of the D2 that I sold, I had to wire in a permanently mount a solar panel to the roof rack. I was never able to keep my aux battery charged. I donít know how much the BlackVue used, but from what youíve mentioned it seems about right
    "Land Rover - making mechanics out of everyday motorists for nearly 70 years"

  3. #3
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    Hi Redtail, going on the first graph, it looks like you have the USI-160 In-Cab module set to STORAGE mode ( toggle switch set towards the LED ) and this will dramatically reduce your runtime before ABG-25 shuts down.

    Try running the USI-160 in SHEARED mode ( toggle switch set AWAY from the LED ).

    This should near double your runtime.

  4. #4
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    Quote Originally Posted by drivesafe View Post
    Hi Redtail, going on the first graph, it looks like you have the USI-160 In-Cab module set to STORAGE mode ( toggle switch set towards the LED ) and this will dramatically reduce your runtime before ABG-25 shuts down.

    Try running the USI-160 in SHEARED mode ( toggle switch set AWAY from the LED ).

    This should near double your runtime.
    Wonít that flatten his starting battery?
    "Land Rover - making mechanics out of everyday motorists for nearly 70 years"

  5. #5
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    Quote Originally Posted by John_D4 View Post
    Wonít that flatten his starting battery?
    Hi John and NO.

    My SC80, DT90 and USI.160 isolators, when operated in SHARED Mode, separate and isolate the CRANKING battery when the voltage at all the batteries is at 12.0v.

    At 12.0v, your cranking battery still has 50% of its capacity available to start your motor.

    Your CCA rating is based on a battery at 40% of its capacity, a 0 degrees, and you can start most modern vehicle motors with a cranking battery as low as 20%, thats 11.6v.

    So at 12.0v or 50% SoC, there is still plenty in reserve, to be able to start your motor.

    But there is more to it than just starting your motor.

    While my isolators have been operating in this manor for over 30 years, since the introduction of SMART alternators in 2004 ( the D3 was one of the first vehicles to have a SMART alternator function ), my isolators have proven to be far better suited to these new SMART alternator operations, than any other form of auxiliary charging.

    When the cranking battery is NOT used, with any system, not just one of mine, once the vehicleís BMS decides the cranking battery is fully charged, the alternatorís operating voltage is lowered.
    In this situation, because the BMS does not monitor the auxiliary battery ( or house batteries if they are connected to the system ), if the cranking battery is in a high state of charge, the alternator voltage drops shortly after the motor is started.

    This means if the auxiliary battery ( or house battery ) is low, you will need to do some very long driving times to get the auxiliary battery back anywhere near to a fully charged state.
    This is a common result when using one of my isolators when set to STORAGE Mode and the same result when using a standard VSR type isolators.

    When you go camping and have my isolators set to SHEAED Mode, you not have more additional battery capacity available to run your accessories, allowing up to twice the operating time that any other system can provide.

    But you are also setting up the cranking battery so that when you start your motor, the BMS will see the cranking battery is in need of a charge, and as such, the BMS will now run the alternator at a higher voltage for a longer time, to try to fully recharge the cranking battery as quickly as possible.

    This higher operating voltage is also applied to the auxiliary battery and because these vehicles have such large alternators, not only is the cranking battery charged at a very fast rate, but so is the auxiliary battery.

    So I hope this helps to explain why my isolators should be set to SHARED Mode, especially when on a trip.

    There is heaps more info relating to this operation and its benefits and I can cover more if required.

  6. #6
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    Quote Originally Posted by John_D4 View Post
    Your dash cam does actually use a fair bit of power. When u had my BlackVue permanently wired in to the aux battery of the D2 that I sold, I had to wire in a permanently mount a solar panel to the roof rack. I was never able to keep my aux battery charged. I donít know how much the BlackVue used, but from what youíve mentioned it seems about right
    They are thirsty.

    I have one on my primary battery, and a LVC on it. It runs about 2 days before cutting out dragging a fully charged battery down to 12.2v in that time.

    Currently it sits on the charger awaiting reassembly next week
    Cheers
    Tombie

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  7. #7
    Join Date
    Nov 2017
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    Okay, more data and observations.


    In-cab module is definitely in SHARED mode. Confirmed by switch position and LED fading in and out as described.


    Fridge removed, dashcam seems fine.
    The fridge is a 40L Engel Combo, working as a fridge only, no freezer and the divider removed, set to 3 degrees.
    Fridge seems to be the cuplrit!


    Here's the next few days graphs from the battery monitoring app:
    The rest of Sunday.
    Drive about an hour home, back on charge overnight.
    Fridge removed. Dashcam on.
    Graph 210314.png
    Monday
    On charge overnight
    Parked all day at home
    Graph 210315.png
    Tuesday 16/3
    On charge overnight
    Up early, pool, home, work (parked all day) home
    Graph 210316.png
    Wednesday 17/3
    Parked all day at home
    Drop at around 5pm when I open the door to check batteries.
    No charge overnight
    Graph 210317.png
    Thursday 18/3
    Same routine as Tuesday
    Pool, home, work, home
    No charge overnight
    Graph 210318.png
    Friday 19/3
    Home all day
    Dropped a Projecta 12V/5W solar panel on the dashboard around 7.15am to see what it would do.
    Looks like the panel had a very minor lift in the Crank battery.
    Graph 210319.png

    Anyway, it looks like the fridge is the issue, unless the D34 battery is on its way out?
    If at first you don't succeed, that's one data point. - xkcd
    ----------------------------------------------------------------------
    2011 Discovery 4 SDV6 HSE

  8. #8
    Join Date
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    Hi RedTail, and there is something not right about your operation.

    The batteries are being separated at about 12.6v.

    In SHARED Mode, the batteries should not separate ( the USI-160 should not turn off ) till the batteries are at 12.0v.

    Can you tell me where the thin GREY earth wire is connected to?

  9. #9
    Join Date
    Nov 2017
    Location
    West of Perth
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    168
    Sorted!


    A quick call to Tim on Saturday morning confirmed that it was the GREEN earth wire I was after, my USI-160 being an older model.
    I extended it and bolted it to the earth plate near the battery.

    Threw the fridge in the back with a couple of bottles of vino just to give it something to cool, starting from an ambient temp of about 27 degrees, setting it to 3 degrees. (I like my whites chilled!)
    Left it in the car all weekend in pretty much full sun. Temps in Perth were in the high 30's.

    The graph tells the story Ö
    Sunday:
    Graph 20210321.png
    Both CRANK and AUX running down nice and slow.
    Power meter showed the fridge drawing a solid 2.8A most of the day, dropping to 0.15A when the sun went down.

    Finally, about 1.30 this morning, it all shut off as it should.
    Graph 20210322.png

    So, instead of getting maybe a day out of it, that was more like 3 days with very little driving on Sat morning and the one short trip on Sunday.

    Thanks, Tim, for your excellent and patient advice!
    If at first you don't succeed, that's one data point. - xkcd
    ----------------------------------------------------------------------
    2011 Discovery 4 SDV6 HSE

  10. #10
    Join Date
    Nov 2017
    Location
    West of Perth
    Posts
    168

    Something of an epilogue

    Leading up to a 6-day trip we just did, I "reconditioned" the Optima D34 and Bosch battery boxes by putting them each on a smart charge cycle for a week.
    This was to negate sulfation (and storage of the latter) so they'd be at optimum performance.

    Having discovered that my dashcam (BlackVue 9002CH) draws 0.45A, while the fridge only draws about 0.15A, I installed a 2-posn switch to isolate the dashcam.
    The switch provides power to the dashcam either directly via the aux battery or via accessories when the ignition is on.
    Posn 1 is "sentry" mode - dashcam is permanently on, driving (car on) or parked (car off), as long as aux battery supplies power. Handy for security when parked in the city, etc.
    Posn 2 is "driving" mode - the dashcam only powers up while the car is running. Essentially I don't have to remember to turn it on.

    So, when camped up and using the fridge, dashcam isn't on (Posn 2) and behold, the fridge lasts about 3 days, the Traxide does its job, and it's all sweet.
    Most importantly, the beer stays cold!

    Sorted.
    If at first you don't succeed, that's one data point. - xkcd
    ----------------------------------------------------------------------
    2011 Discovery 4 SDV6 HSE

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