It appears to be filled with 6 AA rechargeable batteries. Is there any recommended way to recycle them? I have about 20 at this point that are shot.
Totally shot or just discharged past the point of being able to charge them on the VEX IQ charger? I’ve recovered loads by giving them a little boost with a bench PSU before charging.
The batteries charge on the charger but even at fully charged they do not have enough power. A lot of these are more than 3 years old and have been in constant rotation. After a charge, taken off the charger and the robot doesn’t have the power to hang. If I put on a new battery it hangs just fine.
Ahh, totally shot.
Yes… The hangs are straining the batteries in a way that the old games didn’t, so I think that’s why I’m having more of a problem this year. What would normally be a small difference just won’t pick up the robot at all anymore.
@calvc01 If you don’t mind me asking, how did you setup the PSU/battery to boost it. I’ve got a dead battery I would love to try this with.
One way to boost a battery that is too dead to charge on the VEX charger is to plug a motor into a brain with the dead battery and give the motor a lot of spins; you will notice the brain lighting up even though battery is dead. The motor is acting as a DC generator.
Try using some form of VEX gears to speed up the motor, or even drive the motor with another motor hooked to another brain and good battery. After a few minutes the VEX charger might be able to take over.
Yeah, the motor thing can work.
I set a bench power supply to about 8.4V and current limiting set to 1A. Then I just touch the leads to the positive and negative terminals of the battery for 3 to 5 seconds and repeat this a few times until the battery voltage is 6v or higher, then pop it back on the charger.
The batteries can get drained lower than the point where the smart charger can detect them, so this is a fix for that issue. For batteries with a dead cell, there is nothing you can do.
Please don’t. That will keep both the brain CPU as well as the motor MCU under repeated abnormal power supply conditions and it is the fastest way to corrupt the motor firmware. Or course the motor firmware should sustain enough abuse. Of course the HW should keep the MCU in reset the whole time the supply is out of specified range. But that’s not the case and I have seen plenty of “update needed” induced this way by kids playing with the unpowered robot in a match queue. And I have also seen a fair share of motors that gave up completely.
For the bench power boost - limit the voltage, limit the current: Set your supply to the nominal voltage (7.2V) or slightly over (8.4V), place a power resistor (1-3ohm) in series to limit the current. That way, you can leave the battery connected safely even for a little longer (minutes). If you don’t have a real lab power supply, a 9V wall wart would do with a bigger serial resistance and more careful timing.
One reason I didn’t suggest hooking up an external PS is that often a classroom will not have one and if it did I think there is more risk using it than cranking the motor. The methods others have suggested should also work (for the cases where the battery just needs a little boost), but it requires more expertise than might be available in a middle school classroom
Incidentally I got the spinning motor method from a VEX technician on a visit to the Greenville location.
So we went through the same issue with hangs today and old batteries. Problem is vex robotics is out of batteries. I found some at RobotShop and ordered, I assume they are going to fulfill the order Monday, but never know given the regional sales limitations they now have. Tried HEC, but she was out too.
Well… For VRC, I built a battery checker (https://vexforum.com/t/cortex-battery-checker/47764/1) and it would work pretty much the same for IQ batteries. It measures internal resistance as a sign of the battery quality and prime factor of how would the battery behave under heavy load. Time to adapt the terminals for IQ
@nenik Did you ever adapt this project to IQ batteries? We are having battery issues and I feel like I need to do some testing. Would like to find an inexpensive way to measure internal resistance.
I have Battery Beaks that I used for FRC and now use for VRC. https://www.ctr-electronics.com/battery-beak.html I wrote to them in the spring about getting a VIQ version and they passed. Maybe if more people write they will change their minds.
I have an earlier version of this device https://powerwerx.com/cba-iv-4-computerized-battery-analyzer that I’ve run VRC battery packs to find ones with dead cells. It may be helpful to see which ones are tired, vs dead cells.