Could you guys possibly consider changing battery connectors?
The old “Molex” style clip on connectors are outdated, have a lot of resistance, wear fairly quickly and are difficult to get apart with sweaty hands. Dean’s are a proven design, and they would be more up to the task should you guys ever decide to adopt Li-Pos.
I would advocate for XT60’s, seeing as they seem to be more robust :P. In all fairness however, Tamiya connectors do fine for what they’re meant to (low-ish amperage, easy to connect/disconnect, cheap), and both Deans and XT60 (from personal experience, at least) are much harder to pull apart than Tamiya are with sweaty hands.
I whole heartedly agree with using XT60’s. the only other place that I know of that Tamiyas are commonly used is in airsoft guns and most serious players hate them and switch them out for deans connectors. the problem cost. Tamiyas are just dirt cheap. it would probably raise the cost of batteries about $1 each…
Well I am sure IFI/Vex has the margin on batteries to support a $1 difference. I can find 7.2V 3000mAh NiMH batteries for less than half the price. Not sure how they compare technically but the specs say they are equal at 3000mAh 7.2V.
We’ve seen wear on the Cortex connection with the female end of the connection causing power disruptions. Does the XT60 hold a connection better? Do the seemingly larger terminals stay put? What advantages are there of the XT60 versus a T connector configuration?
Note: I am all for a level playing field in the game so I support the use of only Vex batteries - it is just a bit economically limiting part at $29.99 a piece.
Li-Po Batteries are generally far too dangerous for VEX. Charging them incorrectly can cause very serious fires. :eek:
From personal experience, they make VEX run like a beast, upping the motor speed, torque and stall time quite a bit, but the cons of dangerous explosions outweigh any benefit. 
Maybe in VEXU someday 
Truth be told, I’d want the old style Traxxas Connectors, for those of you familiar with RC. They are easy to solder, require no heat shrink, and are ribbed so they are easy to pull apart. I use them on all my RC cars.
It’s just that I doubt VEX would be willing to go out of their way to license a proprietary design, etc. I suggested Dean’s because they are a close second, not proprietary and they come on a lot of higher end batter packs.
I would love for VEX to switch to deans connectors or even make a tamiya to deans adapter. In our club, we have many cortexes that have seen years of service and much wear. As a result, the contacts inside the tamiya connectors wear out and cause momentary dropouts. Also I strongly disagree with using XT60 connectors as they aren’t common connectors (unless you order electronics from hobby king) and the amount of force required to disconnect them is absurd.
Detail detail details the benefits are much better then the danger its not as bad as battle of the bots were they set bots on fire on purpose.
I honestly think it’s quite entertaining seeing the widespread phobia of Lipos. I use Lipos all the time in RC and you probably use them too, they or some other Lithium battery derivitave make up nearly all portableelextronic batteries these days. With a basic $30 peak sensing lipo trickle charger, it is nearly inpossible to do any harm. The things that cause dangerous situations with Lipos are overcharging, which nearly all modern chargers prevent, overdischarging, which can be dealt with using low voltage alarms when a Lipo hits 3.3 volts per cell, and puncturing. Puncturing used to be an issue with soft case Lipos, but now most are hard case plastic lipos.
I think a common misconception is that Lipos, can just catch flame out of the blue. They will not catch fire unless you are doing something stupid and it really just boils down to common sense and good judgement around them. If you fear the Lipos, chances are you won’t take stupid risks with them. Lipos also don’t really explode per se, rather when they fail they catch fire and burn really hot, but they don’t explode. On the other hand Ni-Cds do explode, and those are like frag grenades :rolleyes:.
I’ve used lipos for about 2 years, and never had one puff, catch fire or explode.
Having said all that, the main benefit lipos is the high discharge rate they maintain through the charge. Where as, NiCd and NiMh batteries slowly drop off, Lipos provide steady performance, you just can’t completly discharge them like NiCds and NiMhs. One last benefit is their ability to hold a charge for long periods of time unlike NiCds and Nimhs which discharge themselves over time rather quickly.
Anyways, regarding connectors, I think XT60’s are too uncommon like Marty said. It would be nice if VEX supplied Tamkya to Dean’s connectors, but they wouldn’t be worth the price, and they would defeat the purpose of reducing resistance. However, they would be useful for practicing with your own batteries, and I think you’d be best off soldering up your own adapter.
I also strongly agree with Team80_Giraffes, I think it is important to level the playing field, and keep design as the factor that makes people win, not money to spend on expensive batteries.
Well we had a smoldering toolbox the other week from two nine volt batteries touching terminals the wrong way. Now I know why the battery pack had plastic caps on all the 9 volt batteries.
I know it’s apples and oranges to LiPo but these batteries carry some punch and could do some damage. Minimizing the risk seems prudent.
This is not Vex’s fault though. I strongly disagree with the mentality of… “some team might do something stupid with LiPo’s, so we better not allow anyone to have it”
I have been using LiPo’s for a long time…hundreds of charge cycles in my quadcopters. Not one of them has ever given me an issue. I use a $20 smart charger. Our fear of LiPo’s is irrational. (you all have one in your pocket right now most likely)
The current used plugs look like large type Tamiya, not that great of a connection. I use deans and small type tamiya for airsoft, and the deans work better. In a Vex application, somehow using deans (or the larger RC version) could mean less shorting out issues, longer battery life, and better battery efficiency. That being said, I’m not sure if it would be legal for a competition, but certainly worth looking into if you are encountering issues. As for lipos, it seems like a horrible idea to me. If the cortex was somehow adapted to work with lipos, any impact to the battery could easily start a fire. In airsoft, I have seen lipos get shot and catch fire or blow smoke out and get extremely hot, or even the same happening from guys falling on one they had on their gear. Sorry for wordiness 
I agree with you, but they need to be used responsibly and for the right purposes, like RC and airsoft. They need to be covered for impact protection, be charged at the proper levels and not be discharged completely, and maybe be required to be charged in lipo bags at comp. I think phones usually use lithium ion.
Every connector has a design specification and VEX somewhere along the line decided the number of mating cycles an AMP Mate-N-Lock connector clone can withstand was appropriate for their products. Ultimately these are really a connector for wiring harnesses and not regular mating cycles but everything’s a compromise I guess.
In FTC teams are permitted to cut them off and replace with Anderson Power Pole connectors which although overrated for the application are just awesome. This connector type is also extensively used by FRC teams. I would take these hands down over any of the suggested alternatives.
I’m not sure why Robotics couldn’t be considered the “right purpose”. High amperage discharge rate, stable voltage while battery is draining…seems perfect for robotics to me.
While this is of course advisable, I have crashed my quadcopters dozens of times (free fall from 200 feet up) with the battery simply strapped to the bottom of the quad. They have taken MASSIVE impacts, and NEVER had a problem. Could they potentially start on fire? Of course…so can my cell phone. My point is that we are being irrational and blowing the safety concerns WAY out of proportion. Driving cars is a very dangerous thing to do also, but I assume most of you ride in motor vehicles?
That’s probably correct.
Simple…modern electronic speed controllers are capable of shutting themselves off when the voltage gets too low. Every RC flight craft does this already.
I will gladly use a bag to charge my batteries if I can use LiPO.
The only good reason to not use lithium based batteries is this:
The TSA does not like them. It would make flight to the World Championship bothersome. Not impossible, but bothersome.
Ya, that came out wrong. If the Cortexes were adapted for lipo, it would be a good upgrade. It’ll probably end up being a lot more than the current NiMH batteries, but depending on voltage there should be performance upgrades and much higher capacity for the size.
As for the crashes, that’s pretty impressive. I’ll have to pm you about multirotors
Feel free!
I’m no multirotor expert, but enjoy playing around with them. I built myself a relatively large quadcopter, which has crashed many times. I’m not the best pilot yet. I just got done 3D printing myself a frame for a new quad that I designed on Sketchup…lots of fun!