Starting Battery

Discussion in 'Mech Tech' started by MorkC68, Feb 5, 2024.

  1. Meltman

    Meltman Sprout Lover

    They definitely made Halfords batteries that's why he visited them, but I don't know if they made all the Halfords batteries, if you get what I mean, but I suspect they did. This was about 2 years ago if I recall so things could have changed of course.
     
  2. Tanya have been spot on, if you want a branded battery. For leisure batteries I have tended to use Alpha.
     
  3. mikedjames

    mikedjames Supporter

    And usually when a battery ends up flat in a bus its all the modern things that drain it down. The original wiring had minute leakage currents.

    Anything connected to the battery since..
    Things that have glowing LEDs or listen on Bluetooth..
    VSRs. Stereos. Battery meters. Fridges. Gas or diesel heaters. USB charger outputs. Trackers.. solar panel controllers in the dark..

    Modern cars - some cant last 2 weeks .. but then nobody can nick them with a keyless entry radio relay attack if the battery is flat.
     
    MorkC68 likes this.
  4. Cranking current is dependant on the compression ratio, not the cubic capacity.
     
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  5. mikedjames

    mikedjames Supporter

    Yes, but given the engines I have seen have been pretty stockish without extremes, the 2L engines were 200A, and the 1600s are 160A.

    And a 2110 I measured was 200, 200, 200, 100.. where the valve seat was rattling around. I was showing off the current measurement using a 2000 Amp clamp probe and a battery powered oscilloscope..and we found the first evidence for zero compression..


    Not the same engine...
    This has low compression on one cylinder, and the next one is higher.
    20220904_151001.jpg
     
    Last edited: Feb 14, 2024
    nicktuft likes this.
  6. Interesting conversation recently when I bought a new starter battery and the numty sales guy asked what size leisure leisure battery I was using ?? Odd question but his reply made sense - just bear with me - in that if you run a larger than specified starter battery and it takes a hammering the split charger takes the alternator charge straight to the van battery and ignores the leisure battery until the van battery is 100% , then it fires its amperes into the leisure . His point being if you run a bigger van battery it takes longer to charge on the alternator before it graces the leisure with an amp or 3 ...
    He seemed pretty clued up and was running his T25 he's had from new . Not your usual Halfrauds nugget and got me thinking ....

    Any thoughts ??


    Sent from my SM-G960F using Tapatalk
     
    Last edited: Feb 14, 2024
    Chrisd likes this.
  7. Chrisd

    Chrisd Supporter

    I guess it depends on how easy your van is to start..my 2l with twin Weber's and no choke is a pain to start on cold damp mornings. So I'd rather have a big starter battery and manage leisure accordingly.
     
  8. The same amount will be drawn regardless of the battery size so the same amount will have to be replaced

    Your more likely to kill a smaller lead acid battery by depletion because a larger battery has more capacity to take from.
     
    Matty74 and Zed like this.
  9. Once the VSR has triggered, both batteries will be connected in parallel, so that's what the alternator will see as a load.
     
    Matty74 and Bigherb like this.
  10. Maybe he was talking about the modern battery to battery chargers
     
  11. MorkC68

    MorkC68 Administrator

    Usually on the button, no twiddling around with pumps on the throttle but the battery on Major is around 15 to 20 years old and has passed its best!
     
    Chrisd likes this.
  12. mikedjames

    mikedjames Supporter

    Neither a VSR nor a B2B will bridge the batteries until the starter battery has charged to a high enough voltage. Then with a VSR it links the batteries, the starter battery will then see a lower voltage and cease charging until the leisure battery voltage rises up to the point its high enough to continue topping off the starter battery again..

    Sort of the same with B2B, once you load up the starter battery and alternator by drawing current into the B2B , the starter battery stops charging.

    The only things a B2B provides is allowing the use of mixed battery technologies each side, and being able to completely charge the leisure battery by controlling its output current and voltage independent of the starter battery voltage.

    TLDR fitting massive batteries only charged by the alternator will result in none (maybe leisure battery with B2B) of them ever getting to 100% charge. If they are lead- acid based then they start dying of sulphation.
     
    redgaz likes this.

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