Re: New main battery connectors allowed
 

I'm reassured to know that we're not the only ones that have had this problem. We've found that the pink connectors are fine when mated with a red connector, but can get very stuck when connected to another pink connector.

We've put all of our pink connectors on batteries and are using only red connectors on the robot to avoid the pink-to-pink issue.

What really baffles me is the our lack of success at determining the specific "mechanism of getting stuck" when two joined pink connectors become nearly impossible to remove from each other. We haven't been able to figure out what it is about the connectors that sometimes has them get stuck to one another. The problem doesn't happen all the time, but when it does happen, they're really stuck!

Re: New main battery connectors allowed
 

Yep... we'd had them together and apart several times before. It always took more effort to separate the two pink ones than it did two red ones, but it usually just fit the "stiff" category, not the "OMG" category. We all humbled ourselves grunting in futility, pulling with vise grips and prying with screwdrivers. It was suggested that separating the battery connectors was a "sword in the stone" test, and whoever managed to do it would drive the robot to victory!

Putting an old red one (recycled from an old team 1346 robot, in fact!) on the robot not only solved the problem but contributed to the recycle rush theme!

Jason

Re: New main battery connectors allowed
 

On the first couple of uses some of the members of the all gire rookie team I've been helping out did have trouble disconnecting them. Now that they have been connected and disconnected a number of times I've not had one of the students ask me or someone else to disconnect the battery for them. So I think that one of the reasons that people are experiencing easier disconnection of a red/pink combination is that the red has worn in already and any pink/pink connection is of two new connectors.

Re: New main battery connectors allowed
 

I found that pulling at an angle was easier than trying to pull straight. That way one side breaks free before the other. Think of trying to "break" the connector in half in the long dimension.

Re: New main battery connectors allowed
 

It does not have anything actually to do with the Red or Pink Plastic SB Series Housings or even the housing keyings at all. It is however the "high detent" style cable ends that are being supplied w/ them (Pink SB50's), that the (opposing 4 retaining/mating springs forces the 4 cable ends together properly), spring clips lock into...With continued use, those contacts will ramp a slight amount from wear and allow less force to be required to detach them w/ each couple/decouple.

Below is the link to the Tech Data Sheet Drawing. (Notice it says "High Detent" in the Drawing Key).

http://www.powerwerx.com/techdata/5915.pdf
______________________
Now look at the SB50 Data sheet (Pay attention to the top center & lower right hand corner of that data sheet....See the drawings of the SB50 Contact choices between the high detent & low detent contacts? The High detent have a higher ramping on the contact faces that contact each other, If 2 high detent contacts are used together...Then they will require more force applied to uncouple (or pull apart). Their ramping is simply higher on the contact faces that lock together to allow the current to flow.

http://www.powerwerx.com/techdata/SB50.pdf

I Reprinted the SB50 INDIV. AVAIL. Contacts listing below from the data sheet.

50 amp Contacts*
Part Wire
Number Description AWG sq. mm
903G1 Contact set (2) 5900 #6 13.3
904G1 Contact set (2) 5915 #10/12 5.3/3.3
5900 Individual - HD #6 13.3
1307 Individual - LD #6 13.3
5952 Individual - HD #8 8.4
5953 Individual - LD #10/12 5.3/3.3
5914 Individual - HD #10 5.26
5915 Individual - HD #10/12 5.3/3.3

*Notice the HD & LD in the list?
Denotes High Detent/Low Detent contacts

Now look at the drawings lower RH corner. See the Indiv. High & Low Detent Drawings.....See the ramping differences on the contact faces that lock together? A simple design difference between the 2 on both faces-the Spring side/and the Current Flow faces.

_____________________________
NOTE: While some may think that bending the internal contacts retaining/pressure springs to possibly alleviate or lessen the pressure and make unmating them a bit easier...I personally WOULD NOT DO SO, as the mfg. spring pressure makes sure your electrical connection remains when mated, sound & consistant and less internal arcing occurs and retains the cable ends properly in the housing. Any arcing between any of the 4 contacts while the juice (current), is flowing, surely degrades the connection and causes current flow problems/arcing issues you will not see. But, you will encounter.

You would be better off just replacing the cable ends on the cables w/ low detent or just use Pink on battery ends/Red on Robots or switch the ends (contacts), to low detent on both.

Bottom line is the new PINK SB50's received (internal cable ends), seem to have the High Detent Contacts installed on them.
______________

Note: If anyone starts seeing any intermittent powering down of the robots this year whatsoever, personally then, I would switch the contact ends to high detent on all ends used in the SB50's period. The Cheap fix,....Then add a handle or 2 to make the decoupling action a bit easier.

http://www.powerwerx.com/powerpole-a...andle-kit.html

Re: New main battery connectors allowed
 

This is guaranteed to cause excessive heating of the connector. I have seen at least one connector every year that has failed after the team tried to modify the springs. The connector ratings (and the UL approval) is based on proper spring tension.

Re: New main battery connectors allowed
 

Yep... that worked for me a few times. But this weekend, those two connectors were STUCK. We pried, we wiggled, we twisted and we torqued... we wrapped the housings in high grip material... there was no way that they were coming apart.

I'm not 100% sure that we had used these two particular connectors together before... it may have been the first time that particular battery was connected to the robot. I don't really expect anyone to believe just how firmly they were stuck together because, honestly... I find it kind of hard to believe myself!

Maybe they were "ultra high detent". Or maybe we're all just wimps. :)
Jason

Re: New main battery connectors allowed
 

Ah...Normally I would go with the 'wimp' definition but you beat us last night (Canucks vs. Blackhawks) so I can't say that for at least a couple of days. It might be temperature related and humidity might even factor in for new connectors.

Re: New main battery connectors allowed
 

We made some makeshift handles by threading zip ties through the bolt holes on both of the connectors and pulling on them (with gloves on). And then promptly changed from pink connector to red on the robot.

Re: New main battery connectors allowed
 

They make real handles apparently for this reason.

http://www.powerwerx.com/powerpole-a...andle-kit.html