The VEX manual recommends Ni-Cd batteries. Is there any problem with other rechargeable batteries, like Ni-MH?
We suggest that you follow the manufactures recommendations. We have used some Ni-MH batteries and have not seen any problems.
I purchased a Vex Battery Pack from Radio Shack and encountered a problem where the 9 Volt batteries seems to charge OK from either connector but the 7 Volt battery causes the LED to flash and not charge correctly. Is this a defective charger or battery?
Be sure you follow this instruction from the Inventors Guide: Slide the 7.2V Battery Pack so it rests securely in the battery slot and then plug the Pack into the corresponging white port on the front of the Battery Charger. The Battery must be in the Charger Slot to charge correctly and failure to do this can damage the battery.
I carefully seated the 7-Volt battery into either slot and still got the blinking LED problem, whereas the 9-Volt battery works fine and charges correctly. Is this a defective battery or charger?
**Per the Inventors Guide, there is a problem with the battery. If it is under warranty, return it. Also, some batteries have that characteristic yet seem to charge and work fine. **
My battery for the robot itself doesnt work right. i tried running it down then recharging. But sadly the battery still only lasts for 2-5 mins then its it goes weak.
If you have always charged the 7.2V battery seated properly in the charging slot, then you may have a defective battery. If you have charged the battery while not seated properly in the charging slot (just plugging the battery in and laying it beside the charger), then you have overcharged the battery and may have permanently damaged it.
My team is having trouble with the battery charger for the ni-cad 9.6 and 7.2 batteries. Are both the LED lights supposed to turn on when you plug them both in? And What does it mean when the led light is flashing?
Only one of the LEDs will come on at any one time, the one that is currently charging. If you plug 2 batteries in, 1 will begin charging right away as shown by the LED being ON. When the first battery connected is finished charging, the other battery will begin charging and the LEDs will change state indicating the current charging status. When both LEDs are off, both batteries are completely charged and should be disconnected. See above posts for flashing LED.
It is recommended in the manual that NiCd batteries be used instead of Alkaline batteries. I am not sure if alkaline batteries cannot be used at all. I think NiMH batteries have higher energy compared to NiCd. Can they be used instead of NiCd. Because as I understand, NiCd batteries are almost dying technology - no digital cameras company recommends NiCd batteries and almost NiMH batteries are standard.
**Alkaline batteries are not a good choice for driving the robot. Their high internal resistance will cause voltage drop-outs when the VEX motors draw large amounts of current.
NiMH and Ni-Cad batteries have a low internal resistance making them a good choice to power the robot. NiMH does have a higher energy per volume than Ni-Cad and is an excellent choice. Use NiMH chargers only on NiMH batteries and Ni-Cad chargers only on Ni-Cad batteries.**
I took a multimeter to the output of the DC bricks of our 4 charges. two of the bricks output varying voltages below 6volts they are rated acording the label for 12. More alarmingly the other 2 output a steady 24 volts. Should I be worried the power in the shop is clean. Are they just mislableled about there output?
The outputs will not read correctly with no load. You should see the proper voltages when the output is loaded with the correct battery seated properly in the cradle.
I saw you have a Vex Power Pack that has a 7.2 volt NiCd for the robot and a 9.6 volt for the transmitter. Would this work for the starter kit as it takes 6-AA batteries for the motor and 8-AA for the transmitter? (I do see the tray will pop out in the transmitter)
Yes the Vex Power Pack replaces the AA battery holders that come with the Starter Kit for both the Vex Controller and Vex Transmitter.
Is it possible to use any hobby battery pack on a VEX? or does the VEX have some special connector and such…?
**Most Vex products have special connectors and are design to work with only Vex products. Not sure what other battery products are available, so you must compare the connectors to see if they are compatible. We do not carry any connectors that you can use to modify other battery packs.
Radio Shack sells the 23-445 “9.6v Battery Pack and RC Car Connector Repair Kit” and the 23-444 “7.2v Battery Pack and RC Car Connector Repair Kit” that will work for the Vex Controller and Vex Transmitter. Also, Digikey and others sell the Molex 35141-0201 battery side connector and 35727-0201 pin contact along with the mating (VEX microcontroller side) 35143-0201 connector and 35728-0201 socket contact.
**
I read that the robot controller takes a 7.2v NiCd battery pack, and the transmitter take a 9.6v NiCd battery pack. I have two battery packs, but they are both 8.4 volts(1 NiCd, 1 NiMH). I know the 9.6 volt pack is not suggested as a power source for the robot controller, but would my 8.4 volt packs work?
Yes, your 8.4V battery will work but it is not recommend. Operating at higher than recommended voltages may damage/reduce the life of the unit and anything connected to it.