12V 60A car battery , maybe dead?

[Groundloop]

Thanks for the great advice guys. I live in South Africa so it is a challenge to buy stuff off e-bay as many suppliers don't ship here and our postal services are so bad that you are very likely to lose any items of perceived value.

As far as the circuit is concerned I reversed L1 and it does not work. I wonder if the layout of my circuit could have anything to do with the heat issues?

Mars67,

OK. Put the L1 coil back as it where.

What is the type number of your 5 Watt 500 Ohm pot-meter?

GL.

[Mars67]

Hi GL

Unfortunately I do not have the info on me at work. I will post the details as soon as I get home this evening.

Mars

[Mars67]

The following info appears on the pot. WX-050 500 Ohm.

I had a 5 Amp ammeter connected in serial on the positive wire of the power input into the circuit and adjusted it to 0.6 Amps as in the photos I posted. Today I got a clamp meter and measured the same wire and got over 1 Amp. I then adjusted the pot for the clamp to read 0.6 and now the regulator is much cooler and D5 is not getting hot. The side of the pot is still warm to the touch.

[Groundloop]

The following info appears on the pot. WX-050 500 Ohm.

I had a 5 Amp ammeter connected in serial on the positive wire of the power input into the circuit and adjusted it to 0.6 Amps as in the photos I posted. Today I got a clamp meter and measured the same wire and got over 1 Amp. I then adjusted the pot for the clamp to read 0.6 and now the regulator is much cooler and D5 is not getting hot. The side of the pot is still warm to the touch.

Mars67,

I did check the data sheet for your pot-meter, and did find that it is a 5 Watt type, so no problem there.
So it is a mystery to me why your pot-meter gets warm. I currently have no idea on how to fix that.
Is it possible for you to take a close up photo of your PCB top and bottom and post here?
Also you should check that the capacitor is OK. If the capacitor is leaking DC current to ground,
then that could explain why there is too much current through your pot-meter. Can you put
your ampere meter in series with the pot-meter and measure the current?

GL.

[Mars67]

OK so I eventually got some time to measure the currents. With the pot set to where it was when getting quite hot (with the analogue ammeter in serial with the 12v positive input into the circuit) I am measuring 1.03 Amps over the same wire with the DC clamp meter (I don't understand why there is that difference) and it measures 94mA over the pot (ie in serial with the pot). The clamp meter over the same wire measures 43mA.

When I increase the resistance in the Pot to and .60 Amps as indicated by the clamp meter over the 12V input into the circuit I get 36mA through the pot with my multi-meter connected in serial.

Here are some close-up pics of the Veroboard.