Vex iq brain whining and saying low battery

I recently got a vex iq construction kit, and once I built an Ike robot I started the driver control program. I noticed that about a minute into the program, the brain said that the battery was low, despite putting in brand new batteries very recently. I shut the brain down and turned it back on, and when I started the driver control again the same thing happened. Does anybody know how to fix this, or if it is simply the brain eating batteries faster than expected?

Also, I’m not sure if it is the brain or a motor, but at the same time, the robot is emitting a high-pitched whine. I’m not sure what it means, and would like an answer. Does anyone know what is causing either of the problems, or how to fix them?

Are you using the “AA” Battery adapter? Primary or rechargeable AAs? What brand?
Get a “real” battery:

Pretty complex and heavy robots can ofter run for more than an hour on a single charge…
High-pitched whine might be a motor being pushed against a hard stop - you can try to locate it by disconnecting the motors one by one or running the brain alone.

yes, I am using the AA battery adapter because that is what came with the construction kit, with energizer brand non-rechargable batteries. Thanks for the solution to the whine! As for the battery issue, I have noticed that it continues to tell me low battery past the point where a normal battery would run out of charge, which I use in school.

What kind of batteries are you using? Lithium, Alkaline? I only ask because there are different discharge curves for different battery types and maybe the IQ software is pretty picky about the voltage it sees. Maybe, just a guess, the battery chemistry for the VEX brand rechargeable has a more sustained high voltage then drops off and maybe your batteries drop off more quickly initially then trail down. This would point to Lithium for the VEX battery and Alkaline for the ones you are using.

I’ll pile on to the suggestion of getting the IQ power brick and the charger for it. It’s expensive at $40, but the long term hassles make it worth it. (You mentioned that you have the IQ power bricks at school, so maybe just buy the brick for home and charge it at school?) Like others I can get 90+ mins drive time on a clawbot/Stretch and over an hour on a 4 motor drive base.

Your Energizer alkaline battery isn’t going to manage the high current load for long.

Please report back what you found with the whine noise and what you did about battery set ups!!

NiMH rechargeable AAs could work to some extent, certainly better than alkalines. 228-2604 is pretty much 6 little bigger NiMH cells welded together and NiMH have really good power density (don’t confuse with energy density). But even with good NiMHs (where you’d at least save some money by recharging), you’ll suffer from all the spring contact resistances, not present in the welded design.

OK, just go with 228-2604 :wink:

I did back-to-back testing on a Bankshot robot a few seasons ago using the standard IQ NiMH rechargeable battery vs. both alkaline AA and lithium-iron disulfide AA cells using the AA battery holder. The difference was night and day, the alkaline and lithium iron-disulphide batteries couldn’t even run the robot for a single match.
I didn’t ever try putting rechargeable NiMH cells in the AA holder but as Nenik says, just get the proper rechargeable battery.

For the reference, I just did an experiment using the VEX EDR AA battery holder (6 AA batteries, so should be similar to the IQ holder). I measured the internal resistance of the pack at the output connector using 1A load.
Fresh new alkalines “Energizer eco advanced” in the holder had 1.1 ohm internal resistance
Little used Energizer 2300mAh rechargeable AAs (without charging them first) have measured 0.625 ohm
Then I have measured two normal 2000mAh NiMH Vex IQ rechargeable bricks. The worst one, 3 years old that we have marked and no longer compete with had measured 0.74R, while another, randomly picked one had 0.44R (both of these measurements might be a little off since I had to use extra wire to connect them to my meter, which has a fixed VRC connector)

So unless the IQ AA battery case has significantly worse spring contacts than the VRC case, I’d say good NiMH AAs could be almost comparable to an average IQ battery pack.

For the reference, offical VRC 3000mAh NiMH battery pack (using the same connector) has only about 0.11 ohm, while cheaper 3rd party 3000mAh NiMH one (that we use for practice) measures 0.125 ohm