pic: Battery connector.....

[EricH]

Originally Posted by MrBasse

Last year we ran our robot for hours and never melted a connector, the year before the same, the year before the same. Thousands of other teams have done the same (though maybe they are all being oddly quiet about this). It's not an attack at you, just a sign that something you are doing isn't quite jiving with the required components. The downside is that this problem creates a very unsafe condition.

If I may ask: How many motors are you guys running at a time? 4 CIMs? 6? A couple of window motors? A compressor? And how long at a time? 2.5 minutes? An hour? 6 hours?

See, here's the thing. Sure, hundreds of teams may have run their robot for hours over the season last year. But there are teams who will literally stop driving around only to change or charge the battery in any given multi-hour session. These teams may have 6 CIMS, a pair of MiniCIMs and a pack of other motors of the 550 and 775 varieties, plus the compressor, active at the same time, for much if not all of that time. That's one large amount of current potentially being pulled. Now, I haven't heard of any failures locally, but that doesn't mean that it's not happening--or not at the edge of happening. (The other possible explanation is that the connectors are wearing out due to fatigue/heating of the area around them, then not seating properly and adding a spark to the mix--then they melt, then they burn.)

And I'm pretty sure the Bees tend to run on the high end of both total run time, and time in a session, as well as lots of motors, and they tend to run enclosed bots, which will get some heat build up inside. If you're running on the low end of all of those with an open bot, you probably won't see anything similar.

[sanddrag]

I'm curious about the condition of the contact itself, prior to melting. Was it significantly worn or scratched from touching wires directly to it to test motors, or clipping alligator clips to it?

[MrBasse]

Originally Posted by EricH

If I may ask: How many motors are you guys running at a time? 4 CIMs? 6? A couple of window motors? A compressor? And how long at a time? 2.5 minutes? An hour? 6 hours?

See, here's the thing. Sure, hundreds of teams may have run their robot for hours over the season last year. But there are teams who will literally stop driving around only to change or charge the battery in any given multi-hour session. These teams may have 6 CIMS, a pair of MiniCIMs and a pack of other motors of the 550 and 775 varieties, plus the compressor, active at the same time, for much if not all of that time. That's one large amount of current potentially being pulled. Now, I haven't heard of any failures locally, but that doesn't mean that it's not happening--or not at the edge of happening. (The other possible explanation is that the connectors are wearing out due to fatigue/heating of the area around them, then not seating properly and adding a spark to the mix--then they melt, then they burn.)

And I'm pretty sure the Bees tend to run on the high end of both total run time, and time in a session, as well as lots of motors, and they tend to run enclosed bots, which will get some heat build up inside. If you're running on the low end of all of those with an open bot, you probably won't see anything similar.

With a four CIM drive and a compressor and a 775 powered shooter we would run for two to three hours of practice regularly. Just as a fun question... Would you run your KOP compressor for an hour straight and expect it to maintain peak function?

[EricH]

Originally Posted by MrBasse

Would you run your KOP compressor for an hour straight and expect it to maintain peak function?

Not necessarily--it'd probably do a couple of thermal shutdowns, for one thing; for another, it isn't rated for that. If my robot were going through air that fast, though, I'd have it shut down for an hour so I could hunt down the leak in the system.

That said, if I were using a lot of air, I'd reasonably expect a pretty good amount of runtime on the compressor in that hour.

[Nirvash]

Originally Posted by MrBasse

Would you run your KOP compressor for an hour straight and expect it to maintain peak function?

If by KOP you mean the VIAir, with proper cooling? Maybe. The older Thomas? With cooling, yes.