New consulting relationship with GreenTecAuto begins
What actually goes wrong with the batteries????
A look at todays Hybrid and EV battery packs
Battery packs exposed
Keeping Warm In New England
Plugging into the SUN
Making a small solar concentrator
Building MIMA and the plug in adapters
Converting a telephone truck to electric
DIY dual pulse Capacitor Discharge Spotwelder
Getting in shape while making electricity
Replacing gasoline with solar electric lawn equipment
What is Genesis One?
How to stop the aging process DIY
MIMA Install Day 2005 a Big Success!
Building a hybrid car grid charger
Assembling the bases
building it bigger 4.5A
Calibrating the temperature
Calibration and test of components and boards
Charger # 1 goes into beta testing
Discharger # 1 / gridcharger cycler accessory
Fan and temp boards
Getting serious
Harnesses for the Insights are nearly finished
Helpers make it go much faster
Inside the overnight charger
Modified overnight boxes
More thermal testing
Moving towards the goal line
PTC strip monitor and charger shutdown circuit
Temp volts and current calibration fixture
Test of accuracy
The code
Thermal testing.
The weather slows us down
Tapping into the Wind
Expanding MIMA with the Distribution board ( users projects )

Calibrating the temperature

Calibrating the temperature
Clothespins ballons and thermos liner

Yes sometimes it takes several tries to get a fixture to do it's job as desired.
The thermal calibrator was one of those.
I start with a simple temperature controlled aluminum box, took to long for the air to heat the probes, as the leads were outside the box, and air could escape through the opening.
Second fixture has aluminum heat sink with bent fins to make direct contact with the temperature probe chip, but due to the curved contact area, the position of the probes was very critical, and even with some thermal grease, was all over the place.
After some thought, we made a water bath, with balloons to keep the probes dry, clothespins to hold the probes in position, and a heater to get the bath up to the required 120F that I want to do the calibration at. Warm up with the small heater takes a while, but once up to temp, I turn off the heater, and the thermos holds the temp very well, with only a 1 degree drop every 5 minutes. With the heater off, and some stirring, the bath is a very uniform temperature, so we can calibrate the inlet and outlet probes to be at the exact same reading.
Since the probes are to measure the inlet to outlet temperature rise of the pack, it is important that they are matched.