Re: regulated power for potentiometer
 

So they're calling a 10K pot an "electrical load"?

It's more like a reference voltage.

Oh, well.

Re: regulated power for potentiometer
 

I don't make the rules. :D

Re: regulated power for potentiometer
 

All brand new batteries. I'm not the programmer, so I'm just told that we are having this issue with the potentiometer.

-Aaron

Re: regulated power for potentiometer
 

Can I see a driver station log where you drop below 6 volts?

Re: regulated power for potentiometer
 

I'll email our programmer and ask him to post it or send it to you. Due to work schedules, it likely won't be available right away. Thanks for following up with this.

Re: regulated power for potentiometer
 

This.

A serious mechanical issue can cause a severe battery drain too.

2474,

Without knowing more about your robot, assembly techniques (how did you crimp your 6awg terminals?), its mechanisms, etc. I fear that you are trying to band-aid the symptom of a much more significant problem.

Re: regulated power for potentiometer
 

I cannot answer your question about the 6awg terminals right now, but as for the Mechanisms:
Drivetrain- 2 CIMs on this Sonic shifter (am-2509_37) for a total of 4 regular CIMS

Collector- 2 banebot RS-550 motors each on P60 PGBs with 5.09 ratio

Pneumatics- We use pneumatics for shifting and lifting our collector up and down. The compressor only runs when motors (other than the drive motors) are not spinning.

Arm/Shooter- 2 am-0912 with that are reduced by 630:1 ratio. The shooter uses 2 more CIMs for spinning up our wheels.

Summary:
- 6 CIMs total
- 2 banebot RS-550
- 2 am-0912
- 1 Compressor

-Aaron

Re: regulated power for potentiometer
 

Assuming an 11 milliohm battery internal resistance and 4 total feet of 6 gauge wire on your electrical system, you only need about 400 amps to lose 5 volts. 4 CIMs alone can use over 400 amps at stall. If you run most of/all your motors at once, you could be looking at significantly more than 5 volts of loss.

Re: regulated power for potentiometer
 

I'm curious about your drivetrain. I wager a guess you're seeing this in high gear when accelerating your cims near stall from a stand still.

The sonic shifters in their default ratio, direct driven to four inch wheels with 4 cims are at the very extreme end of gear ratios - a full battery easily drops to 8 volts under acceleration from a stand still in high gear.

Re: regulated power for potentiometer
 

This can be fixed by having your shifter shift to low gear when the robot's not moving. Shouldn't take more than a few lines of code.

Re: regulated power for potentiometer
 

I forgot to mention that we are using 4" wheels. Voltage is not as much of a problem accelerating as it is turning. We are going to switch our outer wheels on our 6 wheel drive to omni wheels.

Re: regulated power for potentiometer
 

You're using a flat 6wd? (As opposed to a drop-center 6wd.)

Do you know what your drivetrain is geared for?

Re: regulated power for potentiometer
 

Correct. We have a wide base.

The ratio in high gear is 3.7 : 1.

Re: regulated power for potentiometer
 

We never run all of our motors at once. The AM-0912 motors power the arm which has very high torque and holds it's own weight un-powered. The collector wheels spin only when we pick up a ball, so it's not the often. The shooter CIMs spin only when we are shooting a ball. The 4 Drive motors are the ones that spin most often.

Re: regulated power for potentiometer
 

Wow. :eek:

I used the JVN calculator (which I think everyone should have in the Excel 'recent docs') and it seems that in high gear you're set for 20+ft/s. Which is insanely fast. It predicts a maximum drive-train draw of 680A, which will definitely cause the voltage sag issues you've been seeing.

This issue is probably compounded by the fact that you've so deeply discharged most, or all, of your batteries by now and damaged them.

Omni wheels will definitely help turning. I would strongly encourage some sort of software feature that uses low gear as much as possible.