High count voltage sensor

Discussion in 'General Electronics Chat' started by vwdevotee, Jul 22, 2009.

  1. vwdevotee

    Thread Starter New Member

    Jul 19, 2009
    I need to measure the individual battery voltage in a pack. now, I can see that I need n+1 leads (for n batteries), but is there a way to set a microcontroller to take the difference between each analog I/O? Or would this really be a MCU specific question? The potential across any given battery cell should never go above the usual 5V range, so I don't think I would need to worry about blowing the controller if it's doable.

  2. millwood


    the quick answer is no: no one has been able to solve that problem. when you do, you stand to make tremendous amount of money.

    the long answer is maybe: through a series of mux, you can do that, though the results may not be consistent.
  3. russ_hensel

    Distinguished Member

    Jan 11, 2009
    Put a differential amp on each adc input.

    Or just measure the total series voltage as each cell is added and get the individual cell voltage by taking the difference, as in differential ( not the calculus sense )
  4. BruceAllan

    New Member

    Nov 23, 2009
    I recently had a problem like this and came across the following website:
    Using opto-isolators, it is possible to measure the voltage on many batteries in series. Also, the digital ground of the MCU is effectively isolated from the batteries, so that noise from motors etc will not disrupt your digital circuit.
    Hope this helps!