[marshall]

Originally Posted by ASD20

I don't think powering your 10W raspberry pi off a separate battery is really going to noticeably reduce the power consumption of your 6-CIM drive robot.

It removes the hassle of a brown out by enabling two different and disconnected power systems so one does not interfere with the other. It's pretty similar to the way some vehicle power systems are designed.

Originally Posted by asid61

Coin cells aren't a concern as much as the others.

They are a problem though because they are currently illegal based on the rules. And why aren't they a concern? I've seen them go boom the same way I've seen LiPos go boom.

Originally Posted by asid61

If we allow even small USB li-ion packs, then what's to stop somebody from manufacturing a 60c lipo pack that can output 10 amps through the USB port?

Nothing other than the USB spec but you can dodge the spec. USB C is rated for 5 amps continuous and I'm not sure about surge but something tells me it could handle it. What's wrong with pulling 10 amps from another power source though? Is there something inherently dangerous about 10 amps? Doesn't the existing battery allow me to pull 10 amps?

Again, the safety concerns come from something going boom or something moving when it shouldn't be. Or maybe you are worried about someone being shocked? Either way, all of these can happen and have happened with the existing battery.

Originally Posted by asid61

And that's not even including the inherent risk of cheapo battery packs that do catch on fir sometimes due to internal shorts. It's a lot safer just to use the existing battery which has proven to be extremely robust and safe IMO than to risk unknown, possibly dangerous components.

There is no inherent risk that is not already present with existing batteries and as I've already pointed out, these cheap battery packs are WAYYY more common than FRC batteries and many people seem to be using them everyday without issue to charge their cell phones.

Originally Posted by asid61

The safest solution to avoiding sensor issues and brownout is just good power management. Unfortunately, that's definitely limiting, but safety is #1.

While safety might be #1, making it easier on teams to do cool stuff should be #2 or maybe #3. Enabling teams to run co-processors without worry of brownouts and similar makes it easier on the teams to do cool stuff.

Originally Posted by asid61

If FIRST partnered with Samsung or another reliable company to supply teams with a FIRST legal battery pack, that would be a good solution to the problem without allowing weird loopholes or dangers.

[sarcasm]Yes, because partnering with another company to deliver parts is just that simple and that has never produced supply problems for FRC teams in the past...[/sarcasm] It also does allow weird loopholes and dangers... the part could become obsolete or it could have a manufacturing defect (*cough* white exploding tanks *cough*). Just because you think a company is reputable doesn't mean they are impervious to turning out a malfunctioning product.

Originally Posted by GeeTwo

More seriously, inspection is already a challenge for many inspectors; there should be a better reason than this to make it more difficult. If FRC can find a standard 5V power source for which they can provide a concise list or (even better) get something donated as part of the KoP, wonderful! Otherwise, this is (IMHO) a pound of solution for an ounce of problem.

Inspection is a challenge and I'm very cognizant of that. So, instead of training the inspectors on a particular part, train them to look at the control system and power pathways for the motors to ensure they are not being interfered with from a USB power source... I'm not saying it will be as simple as asking the team to point out any onboard power sources other than the big robot battery but you could and then verify they aren't plugged into any motors or motor controllers.

You guys need to get real about this though. If you actually want to see this rule changed then suggesting that FIRST partner with another supplier for it and make rules about requiring specific part numbers just makes it more difficult, not easier. It puts the burden on the FRC folks to track down parts, get them donated, include them in the kit, write specific rules about them, etc. That's a lot of work for some already overworked people.

An alternative, as I have suggested, is to change the existing rule to fall in line with the example that is already allowed under the batteries integral to COTS computing devices. No one is checking those specific devices or batteries but they are typically checked to make sure they aren't powering any moving assemblies on the robot.

Also none of you addressed the existing loop holes that I already pointed out including a flashlight that could be considered a COTS computing device and using super capacitors, which I'm more worried about other teams trying to use than I am a cheap LiPo pack (I'm not actually worried, I encourage it, go use them because they are legal under the existing rules!). It is possible to make all of these items secure and safe though.

And with that I'm done with this thread. I could argue with you guys all day about this. I've offered up a solution that makes sense and should make it easy. Stop arguing and actually think about the problem for a while. What I've said isn't crazy talk and is a good way to solve this.