Lawrence Rhodes via EV wrote:
I had a Jet Courier truck using the same controller. It was reliable. However a simple Curtis/Chopper controller is much easier to set up and I bet someone would donate one to Gramps if asked. They are also more efficient.
The EV-1 is pretty efficient; notice that it has no fans or heatsinks. There is also a "bypass" mode where it closes a contactor so it's simply straight through to the battery (100% efficient).
The hangup is that the EV-1 has no input filter capacitors; so nothing prevents the battery from seeing its pulsing on/off current. This didn't matter with huge industrial batteries. But it's hard on small batteries, whose Peukert exponent means that their amphour capacity is less when drawing (say) a 0a - 200a pulsating current instead of 100a continuous current.
Modern controllers use a big bank of electrolytic filter capacitors on their input. They also run at 15 KHz or more, which reduces the size of the capacitors needed. The EV-1 runs at more like 1.5 KHz, so it would need 10 times more capacitance to accomplish this filtering.
-- In computing, the mean time to failure keeps getting shorter. (Alan Perlis) -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
