What actually goes wrong with the batteries????
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
Replacing gasoline with solar electric lawn equipment
Tapping into the Wind
Expanding MIMA with the Distribution board ( users projects )
How to stop the aging process DIY
What is Genesis One?
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

Test of accuracy

Test of accuracy
Full power battery charge

Before I send the PC boards to the board house, I wanted to determine how accurately the charger can measure the Current, Voltage, and Temperature.
250V with a 10 bit converter has ~0.2V resolution, and the current has about a 2 ma resolution. The temperature is about 0.3 degrees F resolution.
Also wanted to see how clean the signals were.
After making a few component changes I am satisfied that we have a reasonably accurate system.
Of course I could have put in a dual slope or delta sigma stand alone A/D converter with higher resolution, but that would have added more cost and complexity. This seems to be good enough to do the job.
Will finish up the PC boards with a much higher degree of confidence, and should be sending them out tomorrow afternoon.
I did a thermal test of the Maintenance charger, and saw about a 35 degree F temperature rise, so I will be installing fans in those as well as the Overnight.
The fan I will use is the Sunon MB40101V2-0000-A99.
It has maglev bearings, and is rated at 7CFM.
I ran the two chargers at full power connected to a kilawatt meter, and see that at 120VAC the Maintenance uses about 80 Watts, and the overnight was at ~ 240 Watts.