My latest EV project

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Regular Member

Joined: 12/08/2016
Location: Australia
Posts: 94
Posted: 10:15pm 01 Nov 2021      

Last night I started a trial run using an Arduino to run a series of temp sensors. The sensors are a safety feature. If the batteries get to a certain temp I need to ease off on the accelerator. The sensors I am using can be run in series and provide a digital signal. I purchased 2 sensors for the trial run but my hope is to use 45 to have a sensor for each set of battery cells. I need to prove that 45 will work in series and drive some form of visual output. I successfully got 1 sensor working but couldn't get the second one working. I thought I either had the wiring or programming wrong. But then I swapped the sensors over and still couldn't get the second one working. So I am fairly sure it is a faulty sensor. I plan to purchase a couple more sensors and some other items to continue the trial tonight. I need to decide on the best way to display the result.

I think displaying the individual temps for 45 sensors would be way too difficult and would also be an eye sore in the car. I was thinking of 2 x 7 segment displays to provide the highest temp rounded to the nearest digit. But even that would be an eye sore. My current thinking is to have a single bar of 10 LEDs with 7 green and 3 red. Each LED would represent 10 degrees. Before driving it should sit at 2-3 LEDs. Normal driving might see 3-4 LEDs. If it gets to 5-6 it's time to back off. Any higher than that would be cause for concern and time to stpp driving entirely. The LED bar is only 61mm long and 5mm high so I think it will be the neatest solution.

I also need to modify the code so that it drives another LED to warn if any of the sensors go off line.

As a side note the motor controller also has a temp sensor for the motor and can drive the standard temp gauge in the cluster.