VEX IQ Battery Concern


We haven’t used our VEX IQ kits for almost 2 years. Now we’re trying to test all of the kits as observed some batteries are fully charged but when I installed it into the VEX IQ brain it suddenly went too low and some of the batteries can no longer be recovered. Is there any recommendation you can advise me? Please help me. Thanks

Connect a motor to port one and put a wheel or gear onto the motor axle .
Put your empty battery in and spin the wheel a number of times. The brain screen will flash and your battery will be charged enough for the charger to recognise it and then charge it fully


Just my two cents, This is not an end all solution, it does work sometimes, but I have also destroyed motors using this. It is a risk. Full instructions from the official VEX IQ Knowledge base, click here

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I’ve done this across multiple teams, multiple years, and have never had an issue with the motor. But since you said you had a problem, two questions

  1. Did the Motor then show up as just a bumper switch?
    – I’ve been able to fix that by force reloading the motor firmware.
  2. Were you doing this in port one or a random port on the brain.

While we are here, it’s a good place to remind teams to not store their robots with the battery packs installed. With the end of the season and school for lots of robots, take a second to make sure the battery packs are pulled out.


Seems like you have two problems here.

So they charge until the light turns solid green? And then once you put them on the bot they die quickly? These batteries have probably degraded beyond any usefulness.

These batteries are “blinking-red-dead?” Try the above listed techniques.


Port one, it was at worlds, not that the motor came up as a bumper switch, my bad as I should have explained better, but the square axle port is now a circle, I might be able to find a picture of it on Tue if you want

You are telling me that you rounded the motor axle connection from being square to now being round.

I’m going to guess that’s not from driving the motor with the wheel to make it act like a mini-generator, and using that power to put a small charge on the battery. That small charge is enough to tell the charger there is a battery there.

There is something else going on there.

But the rounding is pretty impressive. I’ve seen the plastic shafts break because of too much torque. I’ve seen twisted metal shafts, but not off the motor, but at the end of a longer gear train (lots of torque via gears).

So, yes, if it’s not too much of a problem if you can post a picture of the rounded motor to shaft connection, I’d love to see it.


Yep, it is so drastic that we can now fit a peg in it, fitting enough it turns a plate. Probably not legal, but cool. I will get a picture to you on Tuesday at the latest.

Yes, that is exactly what the pit admin told us. It needs enough charge to actually charge the battery, which is kinda funny.

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One of my students managed to do this once a while ago, I think I just gave the motor to the kid who found it like that. Whoever managed to pull it off never fessed up to how they did it!

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