Measuring 2 Volt Cells in Parallel

[bryan1]

G'Day Guy's,

The main problem with measuring 2 volt cells with a common ground is each cell will rise 2 volts on average so that causes a major problem using ADC on a pic. I have been talking with a mate over this issue and we came up will a possible solution that uses a RFpic say a RF12f675. Now by doing it this way each pic can measure 2 cells and have a IR sensor to be signalled when a packet needs to be sent. Each pic can be powered by 2 cells so power won't be a problem.

This is one complicated idea but if any guy's have any easier way chime in as this is one project I want to do.

Cheers Bryan

 

[Nigel Goodwin]

I'm a bit confused about exactly what you're trying to do?.

Do you mean you've got a number of lead/acid (2V) cells in series, and you want to individually measure the voltage of each cell?.

Simply use a DPDT relay for each cell, and switch both ends of the individual battery you're testing to the PIC monitoring circuit.

 

[nickelflippr]

Any modern PIC of say 18 pins is going to have 12 adc (e.g. 16f1827) and up from there to 30 channels on a 40 pin device (e.g. 18f46k22). Hook them up, and just subtract the previous reading from the next one up the ladder of 2V battery cells.

EDIT: Of course you would have to use a voltage divider to cover the range of the overall battery pack

 

[alec_t]

If the 2V cells are in parallel, as the post title states, then they will all have the same terminal voltage; so a single-channel ADC will suffice.