Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!elroy.jpl.nasa.gov!decwrl!netcomsv!netcom.com!nagle
From: nagle@netcom.com (John Nagle)
Subject: Re: Power supply Problems
Message-ID: <nagleCDJ9u8.Fy9@netcom.com>
Keywords: large load battery
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
References: <27bf47$ri4@mtu.edu>
Date: Sat, 18 Sep 1993 04:58:56 GMT
Lines: 39

pwelliso@major.cs.mtu.edu (PETER W. ELLISON) writes:
>This is a request for information on best approaches to solve a power supply
>problem.  Here are the conditions:
        
>1> a 350 tank tread robot (Syndeco Robot X)
      Is "350" the model number or the weight?
>2> there are 12 volt batteries 2 by 6 for a total of 72 amps (3 parallel)
>	by 2 deep.
      It might help if you gave model numbers for the original batteries.
Does "by 2 deep" mean the batteries are 2" x 6" x 2", or the batteries
are stacked in two layers?  Gel cells in the 2" x 6" range are available
from many surplus sources.  And are these lead-acid, NiCd, or what?
>3> they are shot (will not charge, or keep one).
      That's clear.
>4> Initial testing with a 30 amp power supply was not enough to keep the
>	two drive motors going ... Well not exactly they move but slower than
>	with one going and the lights are not running neither is the wireless
>	unit ...
      30A ought to be enough to get things started.  At least the
electronics should come up.  Maybe something else is broken.

>That is the delema ... Here are the suggestions:
>1> Replace the batteries (57 * 7 = 399 + shipping) (too much $$$)
      Again, describe exactly what batteries you have, and maybe somebody
will have a better price.
>2> another 30 amp supply in parallel. (this is a little bit of a problem
>	since we all ready have one ... well I'd like to avoid this)
      Do you know how to parallel DC supplies?
>3> One supply. (big $$$'s)
      Maybe, maybe not.  Try surplus stores.  
>4> build a supply from a transformer and tether it to the robot.
      Tacky.
>5> Deep cycle Marine batteries (this is the most promising)
      No reason to think those will be cheaper than the ones it is designed
to use.  And if the thing is designed for sealed batteries, don't put
non-sealed batteries in it; the inside of your robot will end up looking
like a car battery rack.

					John Nagle
