John Lussmyer wrote: > > At 01:11 PM 10/9/2002 -0700, Victor Tikhonov stated: > >How does your analog meter averages battery amps? It is not a DC, > >it's PWM'ed DC so the error for odd wave form may be as much as 50%. > > The little analog amp meter in my Sparrow is small, and does seem to read > 30-40% low most of the time. I have no idea what kind it is, or anything > else about it. I do believe it measures battery amps, and not motor amps.
Yes, its battery amps, but the number is not real. If you draw PWM 200A pulses 50% duty cycle (like 200A-0A-200A-0A every 100us or so), the average current is 200*0.5=100A but your analog movement meter may show 60...70A. A good way to check is to connect a scope to the shunt and get the average voltage reading ar some load. Divide it by shunt resistance and you'll get the current your analog meter should show. Victor
