Cimple Boxes

[gpetilli]

Originally Posted by DavidGitz

I highly doubt this would ever fix a problem, since I'm sure most teams (if not every single one) uses smart chargers that after reaching the battery's full charge state will drop the current output to a very small value for "trickle charging". What you are referring to is a concept called "surface charge", which Al talks about here:

http://www.chiefdelphi.com/forums/sh...47&postcount=8

Madison is most assuredly correct. Even if you find that one battery is indeed bad you should use the fantastic spreadsheet that JesseK made to help on this:
http://www.chiefdelphi.com/media/papers/2469

Since you are running 6WD, in the spreadsheet linked above consider it as a 4WD with a shortened wheel base. Make sure to find the appropriate coefficients of friction for your wheels. You did not indicate the type of wheels, just the diameter. Assuming you are using all KOP wheels the friction coefficient is about 1.

When I put in this data in this spreadsheet it shows that you are geared way too high (15 fps, wow...). It is important to go through a good design process when you are involved in this kind of competition. After putting in for the Toughbox that brings you down to 7.2 feet/second, much more tolerable and even able to rotate, how about that.

Keep in mind that if all wheels are identical, you theoretically can not turn if the width of the wheel base is less than the length of the wheel base. The six wheel design intends to essentially half the length by turning on the center wheels. This only works if there is more weight on the center wheels - which is why the drop in the center. To make this technique most effective, it is best to make sure the COG is over the center wheels as well. If you have too much weight on front or back it will cause more scrubbing, increase friction, increase current and make it hard to steer. The other way to reduce scrubbing is to replace front and/or back wheels with Omniwheels - replace the ones on the side with more weight.