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Subject: 
Re: RCX Virus? - battery output and RCX performance
Newsgroups: 
lugnet.robotics
Date: 
Fri, 19 May 2006 17:44:04 GMT
Original-From: 
Bruce Boyes <bboyes@systronix.STOPSPAMcom>
Viewed: 
2326 times
  
At 09:08 AM 5/19/2006, Jonathan Spitz wrote:
plugged in but not connected to any mechanism. However, when I try to run the
program with all 3 motors connected and in place, the RCX goes off and the
motors keep going.
I tried "stopping" one or even 2 of the motors connected to the RCX but
disconnected from the mechanism and it worked. I'm still really confused. What
kind of load can the mechanism excert so that the RCX goes off that I can't?

The Lego geared motors can pull about 250 mA when stalled, and close
to that when heavily loaded. So for three motors, that may be more
current than your batteries can deliver. Rechargeable batteries, esp
NiMH, don't deliver the same peak current that Akaline disposables,
or NiCd can. I'm told this is why NiCd are still used in power tools,
in spite of their other disadvantages. Lithium batteries have high
peak current output but are more temperature-sensitive than alkaline
or NiMH, so everything is a tradeoff.

So try again with some fresh, good alkalines. There's quite a
variation in alkaline outputs across brands and versions too.

Best regards

Bruce


If the human brain were so simple that we could understand it, we
would be so simple that we couldn't.  - Emerson Pugh, 1977



Message has 1 Reply:
  Re: RCX Virus? - battery output and RCX performance
 
(...) I think that NiMH should be up to the task at that power level (difference between NiMH and NiCd occur at much higher discharge rate). But maybe there is one or more dead cell that cant't hold its charge? Since NiMH provide 7.2V instead of 9V, (...) (18 years ago, 19-May-06, to lugnet.robotics)

Message is in Reply To:
  Re: RCX Virus?
 
ok, I finally got to trying some of the stuff you recommended. I recharged the batteries and tried downloading the firmware. It can run the whole program without the motors being plugged in. It can even run the program with all motors plugged in but (...) (18 years ago, 19-May-06, to lugnet.robotics)

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