Battery checker

[Acetronics2]

Hi,

I think ( ! ) a look to the '88 Datasheet ( ADC config ) could help you a bit ...

Alain

PS: common diodes as voltage refs ... that's a bit rock and roll ...

[lerameur]

I just changes the circuit a bit. I have new ideas this morning. night was good.
I am getting 1.06v steady on the diode as reference. My voltage divider shows me 0.7, but I am getting zero as output now.
Is it the hardware or the programming ?
I posted a new pic.
http://www3.sympatico.ca/lerameur/
also changed this line:
ADCON1 = %10010010


ken

[brianwu]

but I am getting zero as output now.
Is it the hardware or the programming ?
I posted a new pic.
http://www3.sympatico.ca/lerameur/

ken

Picture show you have both input connected to same place (ref. diode), resistor divider left unconnected.

[lerameur]

I got it going somehow. I dont even know what I was doing wrong...
maybe I am still sleeping
k

[lerameur]

Ok I think I know where lies the confusion.
Ihave two batteries I want to check.I can check the battery that powers the microcontroller with voltage reference. I am trying to check the second battery . There is no common ground and I dont want one because of the isolation I want to have. Therefore I think when I do an A/D, is reads as a floating value.
How do I go around this ?

[Dave]

lerameur, Why not just read the total voltage of the series connection and then the lower cell voltage. Then subtract the lower voltage from the total voltage to get the upper cell voltage? That way you only have 1 ground connection.

Dave Purola,
N8NTA

[lerameur]

the batteries are not in series. One 12v battery for the controller, and a 24v (well 2 12v battery in series) for the motors. That is if I understood you correctly
k