Run without a battery?

Discussion in 'Mechanic and Repair' started by dahammer, Jan 17, 2014.

  1. unkownfl

    unkownfl LawnSite Gold Member
    Posts: 3,838

    Check your charging fuse should be on the left hand side by the throttle there should be two plugs with fuses in them once you unplug it from the box. Or disconnect the battery and go from the positive lead to the center position on your voltage regulator and ohm.
     
  2. dahammer

    dahammer LawnSite Member
    Posts: 227

    Both fuses are good and I have continuity between the center terminal on the regulator and the positive battery cable.

    It needs a battery regardless, so I'll put one on it. I just wanted to confirm there isn't anything wrong with the charging system before I put a new battery on it. I'm guessing there is a switch inside the interlock module that kills the engine if the battery voltage drops below a certain threshold, irregardless of the charging system.
     
  3. unkownfl

    unkownfl LawnSite Gold Member
    Posts: 3,838

    If your charging system was up to par how would it know if your battery is in place or not? Electricity isn't discriminant.
     
  4. unkownfl

    unkownfl LawnSite Gold Member
    Posts: 3,838

    doesn't discriminate

    You did have the engine at WOT when you disconnected the cables?
     
    Last edited: Jan 17, 2014
  5. dahammer

    dahammer LawnSite Member
    Posts: 227

    That's what I'm wandering! That's why I came here and asked the question because it seems to me like in a simple system such as the one on this machine, the charging system should be able to support the engine electrical demands perfectly fine without a battery. And I wouldn't think it would be complicated by something in the circuitry that monitors battery voltage, but I'm not certain of that. I didn't want to put a new battery on it only for it to be discharged by a problem in the charging system. I'm sure it work great with a new battery but the question is for how long.

    No I didn't. Interesting observation though. Perhaps the charging system can not support it on it's own at idle but could at WOT. I'll check that. Thanks,
     
  6. dahammer

    dahammer LawnSite Member
    Posts: 227

    After doing a little digging, it seems my engine has a DSAI ignition and it DOES require 12v battery voltage. It also seems Kohler has decided that simple is better and has discontinued the DSAI coils and gone back to the old style. So that answers my question. It's a wander I didn't fry the DSAI coils playing with it, as I probably disconnected the jumper cables, while it was running, a dozen times. When they do go, I'll convert it back to the old style that has become the new standard.
     
  7. unkownfl

    unkownfl LawnSite Gold Member
    Posts: 3,838

    No offense, but I think you're wrong. How would it know it doesn't have a battery, if it's already running, and the regulator is supplying 13+ volts back to the battery already. The only way it would know is if the voltage drops. Therefore, the engine would be consuming more power than the charging system is producing. The battery is just being used as a big capacitor once the engine is running. The reason some very smart vehicles quit is because the ECM regulates the alternator. Smaller engines in jet skis, motorcycles, etc quit because they don't produce very much voltage if any below a certain RPM thus inhibits the flow of current through the diode. I think your machine is seeing this drop thus shutting off ignition wise. If it was cutting fuel it would sputter out and die over a longer period of time than an ignition cut out.
     
    Last edited: Jan 18, 2014
  8. whiffyspark

    whiffyspark LawnSite Fanatic
    Posts: 6,093

    ^ the voltage drop is exactly the problem. Any engine is going to shut off on a large voltage drop
    Posted via Mobile Device
     
  9. dahammer

    dahammer LawnSite Member
    Posts: 227

    Well I don't know but I have another piece of equipment with a CH730 on it, I checked it today and it does the exact same thing. It has a hot Optima battery on it and as soon as I pull one of the battery cables off of it, it dies immediately. Perhaps the charging systems on these engines simply aren't designed to support engine's electrical demands on there own.

    I also tried it with machines at WOT throttle and they die immediately when the battery is disconnected.
     
  10. ericg

    ericg LawnSite Silver Member
    Posts: 2,547

    On a charging system, you need battery voltage on the B+ terminal on the regulator to produce charging voltage. Without battery voltage applied, the regulator will not produce dc voltage. You will produce ac voltage from the stator but it will not be rectified without 12v at the B+ terminal. The fuel solenoid would drop out and the engine would stall.
     

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