How is the Power Expander worth $50?

Chit-Chat / Rumor Mill
#1

Our team recently ordered a power expander from Vex and at $50 l, it seemed sort of overpriced and was a large investment for our team. Today I opened the box, and the bottom plastic plate was warped, and the wires for the plug didn’t even fit in the case properly. At this point I was already disappointed in the quality.

As I unscrewed it to attempt to fix it, I looked at the circuit board, and there are no components that warrant a price of $50. Even a 393 is only $15. For some poorly assembled plastic and cheap circuitry, the power expander is maybe worth $20 at most, assuming it is assembled correctly. Only if were CNC milled out of aluminum with gold plated connectors would it be worth even close to $50. To me it seemed like the $50 cost is for the “privelege” of using 2 batteries, not necessarily for the power expander itself. This makes the ability to run 2 batteries an almost exclusove privelege for teams with extra money to blow.

For all the talk recently about “leveling the playing field” and reducing advantages for teams with more money, this kind of ridiculous overcharging for such low quality control is seems to run quite contrary to the notion of providing an educational robotics system that is accessible to most.

Anyone care to shed a light on how the $50 cost of the power expander can be justified?

#2

Dude that is insane. I would complain to Vex. 1: The non fitting wires and price. 2: The quality is awful. I would seriously chew them for that

#3

It all come to supply and demand. if they can charge more without reducing demand, they will. You probably should get a refund or something. I’m sure that if you brought this to their attention they would be happy to repair or replace it. Vex seems to be good about that.

#4

I was able to fix it on my own, but it for $50, for such a simple component, I should not have to fix it before use.

#5

We have had mixed luck with the power expander. And yes $50 seems a bit much.

The component quality leads to shorting of the battery wire near the base. You must treat these parts with care to use them year over year. We encourage people to put a standoff in the wire end and zip tie the battery wire to it to reduce stress on the wire to base joint.

The Power Expander PTC seems to trip easier than the Cortex PTC. It may just be anecdotal though. We encourage the lightly used motors go through the power expander which then makes you wonder if it is all that worth it if it is barely drawing current compared to the Cortex. So then you have to question do you even need the power expander.

#6

I’ve always found VEX to be a pretty good value. I work for an original equipment manufacturer (OEM). We purchase pneumatic components all the time, I could purchase all the pneumatic components (OEM pricing) to make a pneumatic kit. If I was fortunate, and if I was building about 10 kits, the price would come to the same price as I can buy the kits from VEX… MAYBE I could beat the price by a few dollars, but not easily.

The power expander pricing really comes down to how much VEX purchases the part for. If the company making these for VEX is doing a run of 10,000 parts, VEX (and you) will get a better price than if VEX is only buying a batch of 2,000.

If I took a wild guess, I would say that VEX pays around $30 for each power expander, not counting the cost of their overhead. I would guess that VEX pays around $8 to $10 for each 393 motor they buy from their supplier. Of course VEX probably purchases 50 times more 393 motors than they buy power expanders.

#7

+1 to this. Vex is a great value compared to the other platforms and competitions. This one part just seems out of the normal pricing and is probably due to what you said. Recouping the engineering costs is another factor as well as hyper expansion costs too. I think they may have passed that break even a while ago and are now in the “gravy train” mode. Maybe VRC parts are paying for IQ development costs a bit too. That must have been expensive to develop.

(And if you tout a price for Arduino, please add in all the h-bridge costs and enough ports to be 1-1 in capability including something like VexNet to two joysticks. It adds up.)

#8

We go through 2 power expanders per season.

#9

This is exactly my point. It shouldn’t be $50, but since it is, it shouldn’t be disposable. If I’m paying around 2x what the component is actually worth, I expect a pretty high threshold of quality to justify the price, and I assume many others would as well. To me $50 for a power expander reeks of “museum gift shop pricing”.

#10

Based on the new parts and new lines, I’m going to guess that a good chunk of the gross is going towards new engineering. You have to give VEX credit, there is new stuff coming out, it’s not like they are sitting there just taking the money in.

You should have sent the power expander back. They stand 200% behind their products. You’ve seen tons of posts by VEX support saying “Call me!!” Beside replacing it, they would have seen first hand how it was damaged and be able to make changes to reduce the chance it happens again.

Feel free to check out McMaster prices if you think VEX is really high…

#11

Personally, I have felt the opposite way. We seem to have better luck using the power expander as a high current draw option.

#12

We have been using the same one for 3 years … no issues. I do agree that it is a bit overpriced, but it definitely is not as poor quality as you are making it sound. You may have just gotten a bad one…send it back.

#13

vex is a normal firm. Their goal is also to make profit whil educating kids. lol.

#14

Umm, not that normal. I don’t know if you know the insane hours the management team puts in mentoring robotics teams in both VEX and FRC programs. The number of teams they support is on the par with companies 8-10 times their size.

#15

One thing I’ve had issues with on the PE on the past is the battery plug. Many times I’ve seen it not make proper contact with the plug on the battery. This means that the PE does not work and it’s especially annoying when it loses contact partly through a match from the shaking. We’ve had some luck bending the pins a bit so they fit tighter, but over time they get bad again.

#16

We usually tape the battery, or use a battery extender, which has a tighter fit, and zip tie the batteries. Both ways are inconvenient, but we learned our lesson after our drive train stopped working in a finals match.

#17

You should use the ‘Battery Extension Cable’ with anything that connects to a battery.

That way the cheap extension cable ($4.99) gets beat up. The Microcontroller ($249) or Power Expander ($50) are left untouched each time you switch out a battery. http://www.vexrobotics.com/276-3442.html

#18

+1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1 +1

Why most teams don’t do this is beyond me. I was talking with a coach the other day and he didn’t even know the extension cables existed!

#19

This also makes placement of the Power Expander and Cortex 271828182845904523536x easier. But a hint: don’t hook up multiple extension cables to get to some remote location on your bot. It makes it a ton easier for them to get caught and break. And make sure the plugs are easy to reach. Not fun to stick your hand through a flywheel hole to get to the battery :open_mouth:

#20

IFI sponsors several FRC teams, including 148 “Robowranglers”, 3310 “Black Hawk Robotics”, 1114 “Simbotics”, and 987 “High Rollers”. However, they only “mentor” one team directly, 148 “Robowranglers”. They do not sponsor or mentor any VEX teams.