Performance and Parameters

Time Posted on September 09, 2010 User ChargeCar Team

Recently, the Civic was modified by setting up the tachometer (motor rpm) and placing a force-sensing resistor on the brake pedal.  We have mapped the regenerative braking to this sensor and taken it for drives.  The result is a very sensitive first regime of braking (regenerative) that can then be easily continued into the normal mechanical brakes.  Some more tinkering will be necessary to get the sensitivity right, increasing the "travel" to be about twice what it is now seems like the next step.  It is much more intuitive than the temporary dial potentiometer mounted on the steering column.

The Civic was also taken for a total of 30 miles between charging cycles, split between approximately 5 miles of testing and 25 miles from 12 laps of the nearby Schenley golf course.  Good news is, the pack voltage saw no drops in voltage until lap 10, and the drop was small.  No BMS faults either!  The 25 miles was estimated to deplete the pack approximately from a 90% state of charge to 30% in normal driving conditions with currents up around 300 A.

There have been some interesting problems with the motor torque at low speeds.  We have heard that many other conversions are able to spin their wheels at the start.  Previously, we had very gentle acceleration even when the accelerator was pressed to the floor.

However, our controller and motor came as a package deal, nominally an AC-31.  It turns out that our controller was set to operate an AC-35 motor and the motor was labeled "AC-3501".  However, it seems that the nameplate may be mistaken.  By changing our controller parameters to those suitable for the AC-31 (motor setting 164), we have been able to achieve much better performance, even starting respectably in second gear.  We are anxious to see the effects on our mileage and efficiency!

 

[UPDATE]

The new parameters also strongly affected the performance of regen.  The FSR on the brake pedal seems like it could be potentially dangerous.  The braking is far too strong in first gear, second and third are debateable.  A major problem occurs when changing gears (technically, when you press the clutch), the regen cuts out and suddenly you have to press much deeper on the brakes (to activate the mechanical brakes).  We are still waiting for a spring-loaded thumb-switch potentiometer to arrive, to be installed on the steering wheels near the right hand.

The car will be driven home this weekend by a ChargeCar member, we look forward to calculating efficiencies with the new controller parameters!

Cat News Tag honda

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