12V 60A car battery , maybe dead?

[Richdes]

Yes I m trying to hit the battery with the high voltage spikes at the resonance frequency of the sulfate the transistors what I burned was just 600v rated and yes sometimes my circuit run without load and burned it for that reason I will get 1700v transistor the spikes will never burn it. by the way you say that this circuit runs on several mhz?. I read the frequency with a multimeter that read till 30mhz and just I can read with your large coil just several khz. so I  guess that you must read several mhz in the crest of the spikes? But I cant read the frequency there, cause I don't have scope. In  my tests with a few tuns is the only way to get in the range of mhz for that reason now I m thinking 9 turns for primary 200 turns for secondary (step up transformer) to get the rigth frequ

[Groundloop]

Yes I m trying to hit the battery with the high voltage spikes at the resonance frequency of the sulfate the transistors what I burned was just 600v rated and yes sometimes my circuit run without load and burned it for that reason I will get 1700v transistor the spikes will never burn it. by the way you say that this circuit runs on several mhz?. I read the frequency with a multimeter that read till 30mhz and just I can read with your large coil just several khz. so I  guess that you must read several mhz in the crest of the spikes? But I cant read the frequency there, cause I don't have scope. In  my tests with a few tuns is the only way to get in the range of mhz for that reason now I m thinking 9 turns for primary 200 turns for secondary (step up transformer) to get the rigth frequ

Richdes,

The actual fundamental frequency of the circuit is low, in the KHz area, but as you say, the leading edge
of the pulse is sharp and that creates many over harmonics frequencies. You are also correct when you say
you need fewer turns on the primary coil to get higher frequencies. Good luck in you research.

GL.

[Jes114]

Hi Groundloop,

Firstly thank you for posting this circuit, I was waiting to build one for a long time and when I saw this one I went for it.
I have a few questions though please because I am not sure it is working correctly:

1- I did not twist the 1mm wires together before winding them on a 100mm former, I didn't read that I needed that so I wound them just together; will this be enough do you think?
2- the first battery I tried is a 12V 9AH sealed Lead acid which has been dry for a long time: I opened the caps and added distilled water twice before connecting it to the charger. Voltage was at 2.77 and remained static after it was connected for an hour or so; is this right behaviour?
3- The charger is being fed by a bench power supply, currently at 9V, drawing 0.74A and the BUX80 is only slightly warm; is there a way to find out for sure if it is oscillating without an oscilloscope? The closest I have is a frequency measuring multimeter

I checked the circuit carefully and it looks ok, I even labelled the coil ends to make sure the 3 ends at top of circuit are all from the same side of it, ie they're not swapped.

Thank you for your help.

[Groundloop]

Hi Groundloop,

Firstly thank you for posting this circuit, I was waiting to build one for a long time and when I saw this one I went for it.
I have a few questions though please because I am not sure it is working correctly:

1- I did not twist the 1mm wires together before winding them on a 100mm former, I didn't read that I needed that so I wound them just together; will this be enough do you think?
2- the first battery I tried is a 12V 9AH sealed Lead acid which has been dry for a long time: I opened the caps and added distilled water twice before connecting it to the charger. Voltage was at 2.77 and remained static after it was connected for an hour or so; is this right behaviour?
3- The charger is being fed by a bench power supply, currently at 9V, drawing 0.74A and the BUX80 is only slightly warm; is there a way to find out for sure if it is oscillating without an oscilloscope? The closest I have is a frequency measuring multimeter

I checked the circuit carefully and it looks ok, I even labelled the coil ends to make sure the 3 ends at top of circuit are all from the same side of it, ie they're not swapped.

Thank you for your help.

Hi Jes114,

Sorry, I did not see this post before now. Your coil will probably do fine without the twisting.

Connect a 12 Volt 10 Watt car lamp to the output to check if the circuit is oscillating. If you get
light in the bulb, then the circuit is oscillating. If, not swap the base trigger coil ends and try again.

Now you battery, if one or more cells in the battery is shorted, then trow battery into the recycle bin!

If the battery voltage really jumps up to a high voltage when you switch on the circuit, then the battery
is probably OK. Just charge the battery and watch the voltage go down when the sulphate is being
reduced in the battery. After a while (depending on the size of the battery) the voltage will reach its lower
point (normally around 11 Volt or so) and will start climbing. Continue charging until the battery is at
approx. 13,5 Volt. Then use a 12 Volt 10 Watt (or so) light bulb and drain the battery down to 12 Volt.
After that you just charge the battery up again. Repeat process at least 3 to 5 time. After that you can
use a regular (factory made) lead acid battery charger and fully charge the battery.

If you connect a lead acid battery to the circuit and the voltage does not climb, or the battery gets warm
or the battery smell funny, then the battery is defect and must be recycled.

Hope this help.

GL.

[Mars67]

Hi Groundloop

Thank you for the circuit and all the information you have been providing. I am in the process of getting the necessary parts to build this charger with the air-core coils. I have some larger batteries that I want to try and condition. As I am quite a newbie I have a few silly questions to ask if you will pardon my ignorance.

1. On the first circuit you posted I assume that the 220nF Cap must be 1000v too?
2. I do not have access to an oscilloscope so was wondering if there is a way to ensure that one connects the coils the correct way around from the onset.
3. What is the resistance of the 50R 5W resistor. 5 Ohms or 50 Ohms?
4. What would be the easiest way to twist the three 18 gauge wires together?
5. How do I know to what value to set the pot initially?
6. Will a 9v 1A DC power supply be sufficient for the circuit?
7. Out of curiosity. What causes the circuit to self oscillate?

Thank you