Managing Battery Use

dekrwright

I will be using the Scribbler robot in my high school programming class next year and need assistance on how to manage the battery consumption for 30 students.· In working with my Scribbler, the batteries lasted about 2 hours in use time.·Are·rechargable batteries cost effective and do they stand multiple charges sufficient to run the robot.
Thanks for any ideas,
dekrwright

Franklin

Don't know how many batteries the scribbler takes but if like the boebot it has 4 you will need to add a fifth to bring the total voltage to 6v.

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- Stephen

dekrwright

I am using the Scribbler robot.· My concern is the cost of 6 AA batteries in each robot that I have found last about two hours.· With a classroom of 30 students, that's a lot of batteries over an 18 week class.
I was considering rechargeable batteries, but now sure they'll be a cost savings in the long run.· Anyone out there have experience in this?
Thanks again,
dekrwright

erco

Scribbler uses 6 AA cells. It works fine running off 6 NiMH cells, I'm using 2500 mAH cells. The red "low voltage" LED will start blinking long before they get low, it's apparently tuned for alkaline cells. Doesn't cause a problem. The Scribbler draws 20 mAH idling, turned on and running but all LEDs and motors off. I'm sure you could drain the batteries in 2 hours if you had the motors on continuously, but that's not the case in your typical classroom setting. You should be fine.

I wrote an article for Robot magazine on the Scribbler, but it hasn't gotten published yet. You'll like the auto-dock with charger modification I did. Brief post & videos at http://forums.parallax.com/showthread.php?p=716431

BTW, my article got bumped to the next issue of Robot. They just went from 4 to 6 issues a year, so maybe June?

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·"If you build it, they will come."

Mike Green

A number of companies (Energizer, RadioShack) have AA NiMH batteries with capacities in the 2300-2700mAh range which should give you at least 3-4 hours of use per charge with several hundred charges possible. READ THE LABEL! Any number of companies (including Duracell and Energizer) are willing to sell you "heavy duty" rechargables with 1/3 to 1/2 this capacity. RadioShack has 2300mAh cells in packs of 2 for $13. I got Energizer 2500mAh cells from BestBuy. You can get chargers that will recharge these in an hour or two. I suggest you get a set of batteries and a charger and see how long they last. If you only have one class per day and it's only a couple of hours, you may be able to manage with one set of batteries per Scribbler. If not, you'll need two sets, one to use and one to sit in the charger, then swap when the first set runs down.

Whit

I would add to what Mike and erco said, that yes, this would be very cost effective.

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Whit+


"We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

erco

Mike's mention of Energizer and Radio Shack reminded me to mention that you might get batteries and chargers donated for FREE if you identify yourself as an educator to a big corporation like those. I teach a course at a local college in programming Basic Stamps and I was about to buy a large quantity of Stamps 2 years ago. Parallax donated very generously.

It helps that companies·are trying to get RoHS compliant. I bet·someone is fire-saleing·or even giving away nicads. Those have less capacity, but free is free. Try to hold out for NiMH cells, though. Either way is a nice tax writeoff for the donating company.

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·"If you build it, they will come."