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Old 03-25-2010, 01:20 PM   #68 (permalink)
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Originally Posted by RobertSmalls View Post
Traction battery current. Otherwise my logs will be peppered with enormous increases in driving torque accompanied by modest increases in fuel consumption. Logging that channel would also allow me to study exactly how much energy I recover through regenerative braking, and how much I waste with friction braking.

The Insight's current sensor outputs about 25mA per amp of battery current. Battery voltage varies from ~140V to ~168V at rest, and probably varies more under load. If you log both channels and consult a motor + inverter efficiency map (efficiency is a function of RPM and torque), it should be possible to estimate electric drive torque. Whether that estimate will be accurate enough to be useful, I don't know.
So what this will need is a resistor bridge, followed perhaps by an op-amp in order to have the full range in the ADC.

For safety reasons, the resistor bridge needs to be by the pack, no ifs and or buts. However, I will try to design a pad for an op-amp into the circuit-board so that this kind of voltage can be measured.

Anything else?
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