ok to crank the engine with battery charging? | FerrariChat

ok to crank the engine with battery charging?

Discussion in 'Technical Q&A' started by 24000rpm, Jan 18, 2021.

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  1. 24000rpm

    24000rpm F1 Rookie

    I am going to do a compression test so I have to maintain consistent battery power.
    I wonder if it is ok to use a regular battery charger(not a trickle charger). Would that damage any electronics?
     
  2. moysiuan

    moysiuan F1 Rookie
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    Nov 1, 2005
    3,628
    Canada
    I would not be aware of why it would do any harm to the car electronics, but it could damage the charger to have a huge current draw, most have an overload protection to prevent that. I would charge the battery full, remove the charger and you should have enough juice to do the comp test, it only requires about 4 cranks per cylinder. Then recharge the battery when done.
     
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  3. EastMemphis

    EastMemphis Formula 3
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    May 25, 2019
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    John
    Considering the amp draw and the potential for voltage fluctuations, I would opt for a second battery connected in parallel if you think your internal battery isn't up to the task.

    If you had a specific starting charger (GPU or Ground Power Unit) like they make for airplanes, then it would be fine.
     
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  4. 24000rpm

    24000rpm F1 Rookie

    isn't connecting a second battery in parallel the same as jumping start the car, which is presumably bad?

     
  5. EastMemphis

    EastMemphis Formula 3
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    Connecting a battery (donor car engine off, key out) in parallel is electrically the same as having a much larger battery. Zero risk there. If you use a donor battery still in a car, it would be best to disconnect the negative terminal on the donor car but probably overkill. Just be sure the donor car is not running. Use a heavy gauge jumping cable to connect them for the best results.
     
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  6. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,114
    Georgia
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    Wade Williams
    I have performed compression test with a charger on the battery many times. However, I activate the starter straight on the starter and have the key off.
     
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  7. moysiuan

    moysiuan F1 Rookie
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    Very few battery chargers will charge quick enough to make any difference regarding a compression test.
     
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  8. 24000rpm

    24000rpm F1 Rookie

    so the next question:
    on 360, when 1st cylinder is at TDC, which other cyl is at TDC,
    im doing leak down test, see if I can save some energy finding tdc.
     
  9. eric355

    eric355 Formula 3
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    Nov 30, 2005
    1,158
    Toulouse (France)
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    Eric DECOUX
    None !! Number #4 is physically at TDC but not ready for leak down as valves are opened.
    You will have to rotate the crank by 90° each time to go to the next cylinder in firing order.
     
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