|
Testing temperature update!
My probe thing is whacked!
I brought out the rice cooker filled with water and put in a temp probe from my handy clamp meter and the 4th unused probe from my hacked together POS, turned it on and recorded the two values as the water temp rose.
at an actual temp of 58C, my probe read 102C
at an actual temp of 75C, my probe read 152C
I knew it was a little off at lower temperatures, but it's way off at higher temps!
So, firstly, if the top of the mosfet cases are only ~60C, and maybe it's a bit warmer at the junction, that might be ok. It was only a 4 mile trip around the block, so we'll have to see what happens on longer runs or harder accelerations.
secondly, i'd like to fix my frickin code! I didn't necessarily plan my circuit too well and ended up with quite a ridiculous ADC to Temp curve that's 3rd order. Straight from excel, I was using this:
tempfine=0.00000041*(ADC^3) - 0.00055497*(ADC^2) + 0.35803595*ADC - 6.14221231;
where tempfine was initialized as float. I'll admit that I really don't know how this works for microcontrollers - I initially coded it up and loaded it, saw a value that was roughly room temperature, then squeezed a probe in my hand and saw another number that was roughly body temp and concluded it was good! Obviously it isn't!
Any ideas?
|