[robocup-small] Zach Noyes: University of Rochester Robotics: Batteries and charger ideas

[Andy Bardagjy]

Zach,

4000mAh is a lot. We can typically run (real world) several hours on a  
2000mAh pack. I know many teams have much less capacity then that  
usually around 1200mAh.

If you actually can drain a 4000mAh pack in a match, uh you must go  
really fast.

We have the typical 30W maxon motors and our kicker pulls around 2-4  
amps (depends on something top secret) continuous when charging (takes  
about 4/10s of a second to charge).

Typically you will play several matches a day (at least 2-3) and  
you'll want some capacity to practice.

As a side note, for the first two years we built our own NiMh packs  
out of whatever Chinese AAs we could find at Frys. We got about  
2000mAh out of AAs labeled 2200mAh and each pack cost about $12 (10  
AAs + connector + wire + heat shrink). We had more then two packs per  
robot.

Now there are also charging specifications for LiPos in terms of the  
percent C you should charge at. You may be damaging your packs by  
charging them so slowly. Battery university is a good resource.

Hope to see you in May!

-Andy

On Feb 23, 2009, at 9:12 AM, Zachary Noyes wrote:

> Hi small league,
>
> I'm Zach from University of Rochester Robotics. For our batteries  
> and charger, we found a set of 5 batteries that each take an hour to  
> charge. The charger only charges one battery at a time, so charging  
> takes a total of five hours. In your experience in actual rounds, do  
> you need a total charging time shorter than 5 hours? How much  
> shorter? We calculated that one battery charge would last the robot  
> 52 minutes, so that is almost 3 rounds. We will be trying to go to  
> the US open this year, so there may not be as many rounds as in the  
> world tournament.
>
> If any one wants ideas for batteries and a charger, here's the  
> batteries we are using:
> http://www.all-battery.com/148volt-4000mah20cli-polylipo4cellsbatterypack.aspx
>
> And here is the charger we are using:
> http://www.all-battery.com/micro-controlledli-poli-ionbalancechargerwlcddisplay.aspx
>
> Thanks.
>
> --Zach
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