First I need a voltage divider I know that is two resistors but I’m a little unclear on how that would be wired to an adc
Second I need a circuit that can measure charging current based on an adc while it’s still isolated from the adc I can’t have the 1 amp going to the adc pin, but I can’t restrict the current flow to the charging cells.
Third I need to learn how I could switch what is coming in to an adc pin so I can measure 4 independent voltages with one pin. What I mean is the following let me see if I can make a small schematic with my keyboard
| + cell one - |+ cell two -|+ Cell three -|+ cell four -|
| | | | |
1 2 3 4 5
well the thing it if I want to measure the individual cell voltages, how could I do that I mean they can’t have a common ground and still be wired in series for charging and output or can they? Anyone got a solution to this doozy because quite frankly I’m at my wit’s end with this one. I mean series and parallel at the same time anyway I see it just adds up to one giant short circuit to me :s the only way I could see doing it is probing one and two then 2 and 3 then 3 and 4 and the 4 and 5 in succession but the nightmare there is that I don’t have a common ground and I need to switch both the ground and the positive every probe time which means either micro relays which eat up lots of energy compared to transistor switches and add components I think
A. I would need transistors driving the relays to amplify the switch current from the PIC port B pins.
B. What I wanted to do is have two pins switch the adc cell probe pin like this. : both pin 1 and 2 high = cell one, pin 1 high and pin 2 low cell 2, pin 1 low and pin 2 high cell 3 and pin one and 2 low would equal cell four. But the more I think about that I see per switch state I would need either relay for both the positive and negative testing points or I would need to use both a pnp and an npn as switches this is turning out to be a nightmare anyone got a more elegant solution. I know I can use a transistor as a switch but this is also a problem since I need to switch both rails. Anyone got a solution for me here.
terramir
Second I need a circuit that can measure charging current based on an adc while it’s still isolated from the adc I can’t have the 1 amp going to the adc pin, but I can’t restrict the current flow to the charging cells.
Third I need to learn how I could switch what is coming in to an adc pin so I can measure 4 independent voltages with one pin. What I mean is the following let me see if I can make a small schematic with my keyboard
| + cell one - |+ cell two -|+ Cell three -|+ cell four -|
| | | | |
1 2 3 4 5
well the thing it if I want to measure the individual cell voltages, how could I do that I mean they can’t have a common ground and still be wired in series for charging and output or can they? Anyone got a solution to this doozy because quite frankly I’m at my wit’s end with this one. I mean series and parallel at the same time anyway I see it just adds up to one giant short circuit to me :s the only way I could see doing it is probing one and two then 2 and 3 then 3 and 4 and the 4 and 5 in succession but the nightmare there is that I don’t have a common ground and I need to switch both the ground and the positive every probe time which means either micro relays which eat up lots of energy compared to transistor switches and add components I think
A. I would need transistors driving the relays to amplify the switch current from the PIC port B pins.
B. What I wanted to do is have two pins switch the adc cell probe pin like this. : both pin 1 and 2 high = cell one, pin 1 high and pin 2 low cell 2, pin 1 low and pin 2 high cell 3 and pin one and 2 low would equal cell four. But the more I think about that I see per switch state I would need either relay for both the positive and negative testing points or I would need to use both a pnp and an npn as switches this is turning out to be a nightmare anyone got a more elegant solution. I know I can use a transistor as a switch but this is also a problem since I need to switch both rails. Anyone got a solution for me here.
terramir
because no cell should drop below 2.8V it could harm them! before once every few program cycles is fine.
