Edit: now sorted guys
Thanks
Art

 

Beside you come short current beside transistor. The low voltage of the feeding the opa-amp is Got (DC current transfer ratio min=20% Typ=50%). There is two ways of the improvement:
1. Reduce current of the consumption R12=1kOhm
2. Enlarge the current of management
Forgive for my English.

 

Beside you come short current beside transistor. The low voltage of the feeding the opa-amp is Got (DC current transfer ratio min=20% Typ=50%). There is two ways of the improvement:
1. Reduce current of the consumption R12=1kOhm
2. Enlarge the current of management
Forgive for my English.

sorry to be a hassle could you explain that again? Why would changing R12 have an effect on the transistor?

 

I advise you to use Spice-program. The transistor has to operate as a switch, ie to be in saturation. this transistor current must feed an operational amplifier (I hope it consumes little, I do not have datasheet on it) is enough to consume a lot of reference diode through resistor R12.
The third option is to take the best improvement optocoupler (with a large transmission ratio).

 

By "cell" I assume you mean battery. If so, using a reference designator is "C" is confusing. I suggest "B".

When a circuit turns on its FETs, those FETs short out the power to the circuit.

To inure an optocoupler from random action, connect the base pin to GND with a 1 M resistor.

ak

 

By "cell" I assume you mean battery. If so, using a reference designator is "C" is confusing. I suggest "B".

When a circuit turns on its FETs, those FETs short out the power to the circuit.

To inure an optocoupler from random action, connect the base pin to GND with a 1 M resistor.

ak

hi thanks for your explanation, with this circuit I do not have a GND anywhere could you suggest what I could do then?

 

By "cell" I assume you mean battery. If so, using a reference designator is "C" is confusing. I suggest "B".

When a circuit turns on its FETs, those FETs short out the power to the circuit.

To inure an optocoupler from random action, connect the base pin to GND with a 1 M resistor.

ak

and yes sorry I meant a battery

 

hi thanks for your explanation, with this circuit I do not have a GND anywhere could you suggest what I could do then?

The emitter will work, pin 6 to pin 4.

ak

 

I see no obvious way the opto can turn on with no input.
Are you sure the opto is actually turning on when it shouldn't?
Is its input at 0V?

 

I see no obvious way the opto can turn on with no input.
Are you sure the opto is actually turning on when it shouldn't?
Is its input at 0V?

yep definitley at 0,

 

I see no obvious way the opto can turn on with no input.
Are you sure the opto is actually turning on when it shouldn't?
Is its input at 0V?

There is only in theory 5V at the emitter of the BJT part of the optocoupler but for some reason there is approximatley an equal voltage at the collector also turning on the op-amp and then also turn on the FET's which I don't want

 

If the opto Vce is near 0 V and the LED current is 0 mA, then the opto might have failed. At less than 10 mA, the drive current is a bit light. What is the static current of the opamp?

ak

 

If the opto Vce is near 0 V and the LED current is 0 mA, then the opto might have failed. At less than 10 mA, the drive current is a bit light. What is the static current of the opamp?

ak

sorry what do you mean by static current? Is this something I can find out from a datasheet?

 

If the opto Vce is near 0 V and the LED current is 0 mA, then the opto might have failed. At less than 10 mA, the drive current is a bit light. What is the static current of the opamp?

ak

Can you provide any suggestions of how I can improve the circuit would you select a different opto then?

 

What op amp are you using?
I could find no info on a TSU621.

 

start with one cell and one circuit only. Verify what is going on, then add a 1meg resistor between pins 4 an 6 of the opto like others have suggested to keep it off.
Come back with the results.

 

What op amp are you using?
I could find no info on a TSU621.

I think it is TSV621
http://www.st.com/en/amplifiers-and-comparators/tsv621.html

 

start with one cell and one circuit only. Verify what is going on, then add a 1meg resistor between pins 4 an 6 of the opto like others have suggested to keep it off.
Come back with the results.

I have added the resistor as suggested after adding it there is now a voltage present at the base of the optocoupler and they are still turning on.

 

Did you completely disconnect the diode of the opto?

 

Did you completely disconnect the diode of the opto?

yes nothing on the diode end