I am developing a battery monitoring system for duel batteries in my 4x4. Using an Atmel AVR micro I intend to monitor the discharge/charge current going into the batteries so I can calculate the remaining charge in the batteries to maximise their usage. (When hundreds of Km from anywhere it is important to keep the 12v system healthy) The code for the micro is the easy bit, the problem I am encountering is getting the data into the micro.
I have a current shunt that gives me current flow readings from 0 50 amps in millivolts 0 50 mv. 50mv being 50A through the shunt. I require a DC amplifier to increase the shunt voltage into the ADC on the micro to around 5v (a 100x amplifier). Whilst this does not seem too difficult the big hurdle for me arrises when I have to monitor current in and out of the system. For instance if 10 amps is being drawn out of the battery I will have a positive 5 mv being read across the shunt, but if 10 amps is being delivered to the battery from the cars charging system I will register negative 5mv.
What I am asking help with is building a DC amplifier that sits at 2.5v when there is neither current being delivered or drawn. So if I am using 50A I will get 5v Dc into the micro but when I am charging the batteries I will get a reading below 2.5 volts. Can this be done using a single rail supply Op Amp? Any help would be appreciated.
Thanks in advance.
H man...
I have a current shunt that gives me current flow readings from 0 50 amps in millivolts 0 50 mv. 50mv being 50A through the shunt. I require a DC amplifier to increase the shunt voltage into the ADC on the micro to around 5v (a 100x amplifier). Whilst this does not seem too difficult the big hurdle for me arrises when I have to monitor current in and out of the system. For instance if 10 amps is being drawn out of the battery I will have a positive 5 mv being read across the shunt, but if 10 amps is being delivered to the battery from the cars charging system I will register negative 5mv.
What I am asking help with is building a DC amplifier that sits at 2.5v when there is neither current being delivered or drawn. So if I am using 50A I will get 5v Dc into the micro but when I am charging the batteries I will get a reading below 2.5 volts. Can this be done using a single rail supply Op Amp? Any help would be appreciated.
Thanks in advance.
H man...