12V 60A car battery , maybe dead?

[Mars67]

I forgot to mention tha I swapped out the 220nF cap with another braand new one and the heating issues remain the same.

[Groundloop]

I forgot to mention tha I swapped out the 220nF cap with another braand new one and the heating issues remain the same.

Mars67,

Thank you for taking time to do the measurements. The clamp meter do measure pulsed DC and your DC ampere meter
measures just current (DC), that is the difference.

I looked at your numbers and can't see that there is any large problems there. The DC bias to the base of the
transistor seems a bit high. One last try, solder your two 100 Ohm resistors in SERIES (instead of parallel) so
that you get 200 Ohm in series with the pot-meter. Connect your test bulb to the output and give it a try.

GL.

[Mars67]

Hi GL

Unfortunately I did not have time to change the circuit last night but what I did was to undo one resistor. With 100 Ohms I must open the pot fully to get 500mA current draw from the circuit. i.e. with the ammeter in serial with the 12v input into the circuit.
This is with the circuit connected to a 100Ah Deep Cycle battery I am trying to recover. It was not possible to say if D5 or the pot got hot because the 100 Ohm resistor got very hot very quickly. I will change the circuit this evening and see what happens. Thank you again for all the help and information.

Marnus

[Groundloop]

Hi GL

Unfortunately I did not have time to change the circuit last night but what I did was to undo one resistor. With 100 Ohms I must open the pot fully to get 500mA current draw from the circuit. i.e. with the ammeter in serial with the 12v input into the circuit.
This is with the circuit connected to a 100Ah Deep Cycle battery I am trying to recover. It was not possible to say if D5 or the pot got hot because the 100 Ohm resistor got very hot very quickly. I will change the circuit this evening and see what happens. Thank you again for all the help and information.

Marnus

Mars67,

It looks like you have a lot of bias current and almost no pulsed current from the L1 coil.
So something is not right in your circuit. Do you have a close up photo of the 220nF capacitor
you are using? Try a larger capacitor 470nF or something like that. Also double check that
your circuit is soldered correctly.

GL.

[Mars67]

Just to add. I put the two 100 Ohm resistors in serial. With the pot fully open the circuit draws 150mAmps. It does not seem as if the other components are getting hot but the two resistors went up to 120 Degrees F and stays there.

I will check the circuit closely to see if there are any issues.

The charger does seem to work as the battery could only hold a charge of 1.2 Volts but can hold a charge of 10.5 Volts after about two weeks.