12V 60A car battery , maybe dead?

[Groundloop]

Hi
I put a heat sink on the transistors.
Can not find NTE2354, but I find that some of BU transistors are alike and I can buy them.
(2508A, 2508AF, 2520D, 2520DF, 2525A what do you think abot them)
I dont have osciloscope.
What does it mean "swapping"?
Transistors 2N3055 are OK. They are not from same manufacturer so they might not be the same quality.
Battery is 12V/6Ah.What is the limit for this carger?

zeljkoc,

Use 1 transistor onto a heat sink:

BU2508A        OK to use in your circuit, recommended. :-)
BU2508AF      OK to use in your circuit. :-)
BU2520D        NOT OK to use. :-(
BU2520DF      NOT OK to use. :-(
BU2525A        OK to use in your circuit, recommended. :-)

Swapping means disconnecting the two wires on the trigger coil (L1, the one connected to the BASE of the transistor etc.)
and then put the other ends of the wires back into the circuit again. If the wires on the trigger coil is wrongly
connected, then all you get is a positive voltage on the base of the transistor, turning it on, transistor heats up, but
no oscillations in the circuit. No oscillations = No output to charge a battery.

The 12V/6Ah battery is OK to be charged on this circuit. The circuit will charge ANY lead acid battery, but
the larger (bigger) the battery, the longer time it will take to charge.

I have updated the drawing for you and attached the drawing here.

GL.

[zeljkoc]

Groundloop,
The minute I send a reply I realize what do you mean when you wrote "swapping". When I read Rodelu`s post I was sure what to do. I change positions of the ends of L1 and it`s working.
Thank you.
2N3055 is slow but it works. When I replace him with BU2508A charger will run much efficiently.
Something strange happened when I connect power supply and start to rise input voltage. Everything was OK till input voltage reach about 5.4 V and current 0.4 A. Afther that voltage jump to 7 V, current drop to 0.15 A and charger stop. I turn off charger and start again but it repeats so I leave charger at 5.4 V to see does it work.
Thank you for drawing update and suggestions.
                                                                                            zeljkoc

[Groundloop]

Groundloop,
The minute I send a reply I realize what do you mean when you wrote "swapping". When I read Rodelu`s post I was sure what to do. I change positions of the ends of L1 and it`s working.
Thank you.
2N3055 is slow but it works. When I replace him with BU2508A charger will run much efficiently.
Something strange happened when I connect power supply and start to rise input voltage. Everything was OK till input voltage reach about 5.4 V and current 0.4 A. Afther that voltage jump to 7 V, current drop to 0.15 A and charger stop. I turn off charger and start again but it repeats so I leave charger at 5.4 V to see does it work.
Thank you for drawing update and suggestions.
                                                                                            zeljkoc

zeljkoc,

The oscillator stops at higher input voltage because the bias voltage to the base of the transistor
will keep the transistor conducting current and the pulse from the trigger coil is too small to switch
the transistor. There are several ways to avoid this. 1 - Avoid higher input voltages. 2 - Increase the
resistance of the resistor. 3 - Increase the number of turns on both coils. 4 - Use a bigger Ferrite core.

GL.

[zeljkoc]

Groundloop
With BU2508A I can reach 12V of input voltage and 0.25A of input current without problem. 2N3055 is realy slow.

[Groundloop]

Groundloop
With BU2508A I can reach 12V of input voltage and 0.25A of input current without problem. 2N3055 is realy slow.

zeljkoc,

OK. Good work. :-)

GL.