I'm looking to build a project that will simulate the monitor a battery box. Similar like what laptops use.
I want to acurately simulalate two 12v 1300Ah batteries in a battery box wired in parralell. Like what you use them in my car with a 500w inverter ( or cell phone and such ) it has a cord with a cig lighter end for charging, and two cig lighter jacks. ( I plug in an external inverter to run my laptop and such )
I currently show a basic voltage display now, but I would like to simualte an intelligent circuit. One that uses the microcontroller, and a LCD display. I would like a button switch that turns on the display ( to save battery power ) when the display is on I would like it to show percent charge. also if the batteries are being drained how much longer the charge will last, if the batteries are being charged how much longer till they are at full charge. I might also like to display the current currently being used ( charging or discharging ) These can either be on one display or scrolled with a push button. I have several 2x16 displays to use.
I'm not sure where to start, but it doesn't seem like it would be that complicated of a project. I figure the battery stats would be coded in so it can figure out the % charge, and time left. Perhaps use the ADC to figure out battery voltage and current draw. I'm a very good programmer, but I'm not sure where to start.
Any suggestions or does any one of a project like that already? Thanks for all your help! Prashish
There are a copule of integrating battery supervisor chips available that may possibly be used (SPI or Dallas/Maxim one-wire interface) and that can measure and integrate time and current. You would at least need a current shunt but might have to scale the voltage too.
The alternative is to build everything yourself, using ADC. But you have to handle negative currents which makes it a bit harder. Just adding an offset and using a single-ended ADC can result in zero current being counted as a weak charge or discharge current because of offset errors.
Linear technology has a dedicated battery monitoring IC LTC6802-1, it can monitor individual voltages even in series stacked battery stacks and has a daisy chainable serial output.
there are intelligent battery chargers for different types for batteries at Texas instruments, u even get free sample for evaluation, there are some ics which even have led connected to show u the actual capacity for the battery and the average time left.
Look on source forge for the open source simulation: I E do a search on open source simualtion c
I think Atmel used to publish battery monitor applications for the AVR? You could see if they are still available...
www.atmel.com/.../search_results2.asp
Have you used it practiciccally? because it seems to be a very handy and efficient way of doing it...