Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

650 AMPS!

Discussion in '1982-Present GM Diesel' started by calcide, Mar 19, 2002.

  1. calcide

    calcide 1/2 ton status

    Joined:
    Dec 21, 2001
    Posts:
    283
    Likes Received:
    0
    Parf and I did some checking (he bought a fancy fluke clamp-on ammeter) to see how much current the starter draws in our 6.2s. Both of our trucks took 650 amps to crank over, and both were warm from being driven recently. My starter is newish, only 4 months old. Glow plugs took 153 amps, but the current dropped as they heated up (we both have a set of 60Gs).

    As a side note, the ford powerstroke that hangs around the house took 710 amps to start and 160 amps for the glow plugs. The 600 watt amp in my Bug took 70 amps peak, about 45 amps average.

    Maybe we will be able to see how much current it takes to crank over a 6.2 on a cold morning before winter is over. I'm guessing it will be around 900 amps.
     
  2. René

    René 1/2 ton status

    Joined:
    Mar 14, 2002
    Posts:
    208
    Likes Received:
    0
    Location:
    Michelbach, Germany
    I understand your calculation not completely.
    Each glow plug has a performance of 85W. That results in 57A. If your starter takes 650A, it would have a performance of 7800W. That cannot be...
     
  3. calcide

    calcide 1/2 ton status

    Joined:
    Dec 21, 2001
    Posts:
    283
    Likes Received:
    0
    These readings are not derived from a calculation, they are direct readings from an accurate instrument. The fluke 36 we used has a DC current accuracy of plus or minus 3%+4 counts.

    That said, power equals voltage times current. 153 amps for the glow plug system works out to about 19 amps for each plug. Assuming the system was at 12V, that would be 228 watts per glow plug. 7800 watts for the starter is accurate, at 12V and 650 amps. 7800 watts is 10.45 horsepower.

    I did not measure the battery voltage, so these power figures are estimates. Also, this measurement includes power lost due to bad connections, wire restances, etc.

    It would be cool to see how much voltage that #4 battery cable drops at 650 amps. I can't believe GM put in a cable that small.

    Measurement is my life. I gotta get out more.
     
  4. NewK5Guy

    NewK5Guy 1/2 ton status

    Joined:
    Mar 2, 2001
    Posts:
    556
    Likes Received:
    0
    Location:
    Alexandria, VA
    Stupid question. You said "assuming system at 12 volts" or something to that effect. I thought the glow system on the 6.2 was 24 volt. Would that not change anything? I still am interested in those readings you took.
     
  5. Tybee

    Tybee 1/2 ton status

    Joined:
    Mar 25, 2001
    Posts:
    1,565
    Likes Received:
    0
    Location:
    Centennial, CO
    Miltary vehicles operate on a 24 volt system.
     
  6. René

    René 1/2 ton status

    Joined:
    Mar 14, 2002
    Posts:
    208
    Likes Received:
    0
    Location:
    Michelbach, Germany
    Only the military versions have 24V. However their glow plugs (13G) need only 8V for the remainder are responsible the resistor behind the air cleaner.
     
  7. René

    René 1/2 ton status

    Joined:
    Mar 14, 2002
    Posts:
    208
    Likes Received:
    0
    Location:
    Michelbach, Germany
    In the Diesel Engine Repair Manual of Haynes, chapter 2, side 73, the test of the glow-plug system is described…
    G-Van 50A min.
    C, K, P 55A min.
    CUCV 35A min.

    About the starter I did not find anything, but it must have for instance 1500W. That makes then 125A.
     
  8. Parf

    Parf Registered Member

    Joined:
    Nov 16, 2001
    Posts:
    81
    Likes Received:
    0
    Location:
    Golden, Colorado
    Thats great.

    My truck's glow plug system drew 153 amps.
    While cranking the starter over, it took 650 amps.
    <a target="_blank" href=http://www.tequipment.net/FlukeClampMeter36FE.html> This </a> is the meter we used.
     
  9. René

    René 1/2 ton status

    Joined:
    Mar 14, 2002
    Posts:
    208
    Likes Received:
    0
    Location:
    Michelbach, Germany
    I believe it to you!
    But I can't understand it...
     
  10. OFFRDK5

    OFFRDK5 1/2 ton status Premium Member

    Joined:
    Oct 2, 2000
    Posts:
    1,881
    Likes Received:
    2
    Location:
    Central IL
    After I melted my starter cable twice I went to a 0 cable...aut cable.....no problems with starting after that!!!
    Talk about BIG!!!
     
  11. calcide

    calcide 1/2 ton status

    Joined:
    Dec 21, 2001
    Posts:
    283
    Likes Received:
    0
    Perhaps those values given were for stock plugs, the measurements I gave are for 60g plugs.

    Starters draw a lot of power period. A powerful starter for a gas engine produces 1700 watts, but you have to keep in mind that nothing is 100% efficient. I do not know what the efficiency rating is of the average starter, but I DO know that drawing 200 amps for a starter is not uncommon. I measured a chevy 350 gas motor as drawing 250 amps for the starter. There is a reason the diesels have dual batteries, and it's not so your lights will work longer with the engine turned off.

    If you want me to explain why your book is wrong, maybe you should contact the publisher instead. I didn't write it.
     
  12. SlickCUCVRi ck

    SlickCUCVRi ck Registered Member

    Joined:
    Mar 30, 2002
    Posts:
    33
    Likes Received:
    0
    Location:
    Wylie, TEXAS
    Helllppp I am installing a duel alt 24 volt system out of a military AMB and will install in CUCV blazer with standard stuff.. where can I go to research this topic
     
  13. rugger03

    rugger03 1/2 ton status

    Joined:
    May 14, 2000
    Posts:
    829
    Likes Received:
    0
    Location:
    around
    Your M1009 should already have dual Altenators and a 24v sarting system the same as the ambulance.
     

Share This Page