I never said analog meter is useless! In fact I just replied to suggest the same thing you suggest - recalibrate the scale.
Regarding battery current - DC controllers gurus can answer this better but I believe free-wheeling diode is on the motor side only and this is the one which keeps the current flow (energy stored in motor inductance) at the moments when PWM output is zero. At this moments controller doesn't draw the current from the battery, so it drops to zero, there is no "free-wheeling" on the battery side, and cannot be - there is no inductance there. This is my understanding. Victor Seth Murray wrote: > > Don't say your analog ammeter is unuseful! I think the whole point > behind the analog gauge is to give you a more easily readable > indication of of approximate power usage - when you mash the pedal, it > pins the meter, when you are cruisin' it is much lower. keeping the > meter steady is good, spikes are bad. more accurate readings you'll > want to take off your Emeter. if you want to make your analog gauge > more accurate, I think what it needs is not a compensating circuit but > just a calibrated scale on the face of the meter. I imagine however > that this would be different for every application and therefore not > practical. > > just curious Victor - don't the pulses mostly get filtered out on the > battery side? How does the Emeter stay accurate? > > Seth > > On Wednesday, October 9, 2002, at 08:39 PM, John Lussmyer wrote: > > > At 05:26 PM 10/9/2002 -0700, Victor Tikhonov stated: > >> 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. > > > > Is there any kind of simple circuit I could add to the ammeter to make > > it useful? > > > > -- > > John G. Lussmyer mailto:[EMAIL PROTECTED] > > Dragons soar and Tigers prowl while I dream.... > > http://www.CasaDelGato.Com > > > > > > > > > > -- > QUESTION INTERNAL COMBUSTION > > My electric truck page, with lots of photos and a 25 page conversion > journal. Check it out! > http://users.wpi.edu/~sethm/ (no more popups!) > > My EV Album page > http://www.austinev.org/evalbum/387.html
