Results 1 to 15 of 15

Thread: How many amps??

  1. #1
    RC poster
    Join Date
    Nov 2009
    Posts
    13

    How many amps??

    How many amps does the 775 on the Summit draw?

  2. #2
    RC Qualifier
    Join Date
    Mar 2009
    Posts
    984
    It really depends on how you are driving it, and what gearing you're using.
    I would guess around 10-15A average, with bursts around 40-50 maybe (the ESC itself is rated 30A continuous duty).

  3. #3
    RC Qualifier
    Join Date
    Mar 2001
    Location
    St. Louis, Mo.
    Posts
    327
    I would think it's more than that. 10-15 is awful low. I would have guessed around 40. I haven't put a watt meter on this yet, but I have been wondering this myself. It does seem to be a bit hungry on amps.

  4. #4
    RC Qualifier
    Join Date
    Mar 2009
    Posts
    984
    40 is in excess of what the ESC is rated for.

    I figured the average runtime is 20-30 minutes on a 5000mAh battery, which averages out to 10-15A (actually 10-16.6666666666666666666~ amps).

    If your runtimes are longer, then it's even less current drawn.

  5. #5
    RC Competitor
    Join Date
    Aug 2009
    Location
    Surrey, England
    Posts
    65
    Quote Originally Posted by sfr4x4
    40 is in excess of what the ESC is rated for.

    I figured the average runtime is 20-30 minutes on a 5000mAh battery, which averages out to 10-15A (actually 10-16.6666666666666666666~ amps).

    If your runtimes are longer, then it's even less current drawn.
    I like this analysis, its good science =)

  6. #6
    RC Qualifier
    Join Date
    Mar 2001
    Location
    St. Louis, Mo.
    Posts
    327
    I understand that, but I don't get near those runtimes when I'm at the track. 4800 gives me about 10 minutes.

  7. #7
    RC Enthusiast
    Join Date
    Nov 2009
    Posts
    41
    the calculations give AVERAGE amp draw only. you need a data logger to get peak amp draw.

  8. #8
    RC Qualifier
    Join Date
    Mar 2009
    Posts
    984
    Quote Originally Posted by FastStang
    I understand that, but I don't get near those runtimes when I'm at the track. 4800 gives me about 10 minutes.
    Well... I DID say in my first post here:

    Quote Originally Posted by sfr4x4
    It really depends on how you are driving it, and what gearing you're using.
    10 minutes out of a 4800 battery means an average of 28.8 amps (which tells me you like to run it pretty hard).

  9. #9
    RC Champion
    Join Date
    Sep 2008
    Location
    Edmonton, Alberta, Canada
    Posts
    1,548
    Quote Originally Posted by sfr4x4
    40 is in excess of what the ESC is rated for.

    I figured the average runtime is 20-30 minutes on a 5000mAh battery, which averages out to 10-15A (actually 10-16.6666666666666666666~ amps).

    If your runtimes are longer, then it's even less current drawn.
    The problem with this is its average. Chances are, as soon as you're in an open area, you're gonna floor it. A floored Titan will pull more than 16A. And when you're off the throttle in a turn or something, it will draw next to nothing for amperage.

  10. #10
    RC Competitor
    Join Date
    Aug 2009
    Location
    Surrey, England
    Posts
    65
    Dont forget that Nimh cells rarely deliver the stated capacity. Under load you'll be lucky to get 70% of the stated maximum charge out of it.

    Does your charger tell you how many mah it has delivered?

    Subtracting for heat losses on charge and under load and your down a fair chunk.

  11. #11
    RC Qualifier
    Join Date
    Mar 2009
    Posts
    984
    Quote Originally Posted by Super Dude
    The problem with this is its average. Chances are, as soon as you're in an open area, you're gonna floor it. A floored Titan will pull more than 16A. And when you're off the throttle in a turn or something, it will draw next to nothing for amperage.
    This is very true, but like Jesse J mentioned, a data logger (such as an Eagle Tree system) is needed to measure peak draw accurately. I still feel 50A is a good guesstimate on a stock system running on NiMH however.

  12. #12
    RC Enthusiast
    Join Date
    Nov 2009
    Posts
    41
    If I can get mine working again I will check, but with the stock ESC and two leads..... I don't know if it will record the total draw. Anybody know how to trick it?

  13. #13
    RC Turnbuckle Jr.
    Join Date
    Dec 2004
    Posts
    3,741
    Quote Originally Posted by icucmerc
    How many amps does the 775 on the Summit draw?
    I looked up the data from a speed run performed on a stock Summit last summer. The truck was powered by two, 9000mAh/28C LiPo's. Max load recorded on the BEC side was 45.62-Amps.

  14. #14
    RC Enthusiast
    Join Date
    Nov 2009
    Posts
    41
    Do you think that since batteries are in series the draw should be (pretty much) the same and therefore a good measure of your max load on either side? Hadn't thought about it, but seems to make sense.

  15. #15
    RC Turnbuckle Jr.
    Join Date
    Dec 2004
    Posts
    3,741
    Quote Originally Posted by Jesse J
    Do you think that since batteries are in series the draw should be (pretty much) the same and therefore a good measure of your max load on either side? Hadn't thought about it, but seems to make sense.
    Yes, by definition of a series circuit.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •