Drivetrain stalling with just crossing the 10 point zone

VEX V5 General Discussion Technical Discussion
1

Our drivetrain has a very light chassis weighing under 7.25kg. It is built only using aluminium. It worked fine yesterday, but it started stalling today at practice after crossing the 10 point zone. We noticed that the main battery (a brand new one) was discharging in less than 5 minutes. Has this happened to anyone, can you share with me was resolved it for you?

Motor Distribution:
4 HS Motors

2

Lel that’s your problem. Upgrade to something like a 6 motor turbo or at least a 6 motor hs for a little more power.

3

6 motor turbo is roughly equivalent in torque to 4 motor high speed. The problem is likely friction. Try pulling your drive shafts out of the motors and spinning the wheels to see if they spin freely. If they don’t, check for sources of friction like tight chain and bent axels.

4

It shouldn’t be doing this. If your motors are stalling when not crossing the 10 point zone, probably one or more of these problems are happening:

  • You aren’t accelerating first before going over the bump (1)
  • Your drivetrain has a pretty high amount of friction (2)
  • Your robot is too heavy and you should try to remove some weight (3)
  • You aren’t distributing the drivetrain across two or more PTC’s (4)

(1) If you aren’t accelerating to get over the bump, try doing that instead of trying to slowly get over it.
(2) Try having your axles that are connected to the wheels be directly connected to the motor instead of a chain or gears. Make sure you also do not have any bearing flats on the side of the motors.
(3) If you are using steel, make sure to try to replace as much as possible with aluminum. If you are using a ton of thick nylocks, try either using the less important connections with KEPS or order thinner nylocks at robosource.net(If you are in an area that provides the shipping from robosource). If you have a ton of metal to try to stiffen something up, you can try doing research on how to provide support that allows practically the same amount of structural stability but with less metal ;).
(4) The CORTEX has two PTC’s; PTC 1 is on 1-5, and PTC 2 in 6-10. The expander has a single PTC as well. Since I’d suggest having your drivetrain on your CORTEX and NEVER on an expander, I’d suggest you have your two front motors on PTC 1, and two of your back motors on PTC 2. If you are Y-Cabling, I suggest not Y-Cabling your drive if you are using just 4 motors. (Your drivetrain is the most important thing on your robot. Without a drivetrain, you cannot score what-so-ever. Y-Cables can make your drivetrain less consistent because of more connections as well as I’ve heard there may be some problems when using Y-Cables. So use Y-Cables on an area of less importance).
Hopefully this helps :smiley:

  • [TVA]Connor