Drive motors drawing too much power

[kitare102]

The drop center appears to be behaving as expected.

I don't know about current on each motor w/o load, as two of the motors currently connected we didn't test last time. I'll see if I'll be able to take apart the boxes again tonight.

4amps higher is consistent both on the ground and on blocks.

Hadn't thought of checking for balanced drivers, thank you.

Thanks for pointing the battery safety issue out, I'll see what we can afford to put on weight-wise.

Gearboxes are toughbox minis geared to 8.45:1 with 6" wheels.

[jeremylee]

Originally Posted by kitare102

The drop center appears to be behaving as expected.

In the one pic, it looked like all wheels where in contact with the ground. Do you notice some rock back and forth on concrete?

10.71 or 12.75 (which is what we are using with 6 in wheels) would help, but shouldn't be nessesary with drop...

Omnis on ends would help if it is a scrub issue, but shouldn't be nessesary with drop...

Do you notice the battery voltage drop much when turning?

[Jeffrafa]

Unrelated, but something else to note is R67B & R76 - I don't see a pressure relief valve connected to the compressor.

For testing drivetrain, I would recommend similar to one of Dale's suggestions - electrically disconnect the motors and test one at a time, making note that speed/direction is consistent, and listening for any unusual noises.

For PWM I also suggest to CAL the controllers together, but I don't think this is a problem over CAN. I would check that the 2 talon's status lights have the same color/blink rate throughout the output range, as a sanity check that they are being commanded with the same output.

Most mechanical issues can be heard, or felt by turning the wheels manually. With the motors electrically disconnected, the two sides should be relatively easy to back-drive on blocks, and should feel/sound consistent, no periodic difficult spots.

[Nathan Streeter]

Originally Posted by kitare102

Gearboxes are toughbox minis geared to 8.45:1 with 6" wheels.

While probably not the leading cause of high motor temps, this way too fast for this year's game (imho). Seems like teams will usually be driving a few feet, almost never going farther than 15ft without stopping and starting. While 8.45:1 with 6" wheels (adjusted top speed of 13.3fps on JVN's spreadsheet) was very good last year, you'd probably be better off having an adjusted speed closer to 7fps.

Perhaps you have a dead motor or one that's fighting the others?

Cantilevering your axles the extra bit to put the chains on the outside probably doesn't help your efficiency, but it hardly seems like that should contribute that dramatically by itself.