Re: [mowbot] Basic platform

Terry (cefpearson nospam at
Fri, 15 May 1998 22:57:46 -0500

At 12:14 PM 5/15/98 +1000, you wrote:
>At 10:23 AM 14-05-98 -0500, you wrote:
>>The 20 amp
>>hour batery last about 15 miutes between charges before the voltage effect
>>the timer chip's duty cycle to the point that it just turns in erratic
>>circles. The high power requirment is a must to climb the hills I have here
>>and to cut grass at the same time. I tried smaller drive motors and found
>>them to be too small to get the job done.
>You might get longer running times by running the electronics at 5v via a
>That way the timing will be consistent.
>What is the battery voltage when it starts behaving erratically?

10.5 volts is where things tend to crap out. But the timer chip voltage
is only a part of the problem. The relays also drop out because they are
really 24V AC relays that only just work at 12V DC. Not really a concern
though as the mower will have about the same run/charge ratio rather it
runs 15 minutes or 1 hour. The electronics of my mower is not well
designed, but the chassi, drive motor, wheels and cutting motor have lasted
and worked well at a cheap cost. I have run the arrangment for about a
total of 20 hours.

I hope to get a picture scanned and into the robot mower gallery as soon as
I can (I lost my camera and the sofware quit working on my scanner), but
that might be a few weeks.
Cef Pearson (Terry)
cefpearson nospam at
Clinton County, Indiana