Hello good day to everyone here - I am trying to build a solar powered fence charger to keep out animals and humans -
I have attached an image of a cdi ignition module based fence charger but it works with mains voltage - I would like to use a solar
panel to power the circuit but without batteries as its only going to be used during the day - A cdi module wont be hard to source
out here in jamaica so i was wondering if anyone could tell me what to change on the circuit considering the input will be 12Volts.

 

Build a circuit using a flyback, Kettering-type ignition-coil circuit that is designed to operate from 12V, such as this.

 

Thank you very much- the flyback is t1 i assume

 

Hello good day to everyone here - I am trying to build a solar powered fence charger to keep out animals and humans -
I have attached an image of a cdi ignition module based fence charger but it works with mains voltage - I would like to use a solar
panel to power the circuit but without batteries as its only going to be used during the day - A cdi module wont be hard to source
out here in jamaica so i was wondering if anyone could tell me what to change on the circuit considering the input will be 12Volts.

That circuit is not a "fence charger"by any stretch! It is a mains powered shocking circuit. It is also much more complex than any electric fence charger that I have seen.

 

Thank you very much- the flyback is t1 i assume

Yes, T1 is a standard old vehicle ignition coil.

 

Thanks to "C" for providing an actual fence charger pulse circuit that was clearly laid out and easy to follow. It may still require an actual battery, or a super-capacitor, to supply the pulse current, which will not be small.
A power transistor, Q2, driving a power transistor, Q3 is a bit unusual but it makes perfect sense in this circuit.
I wonder about the source of that circuit we see in post #1, as it is quite complex for the function it is claimed to provide.

 

It may still require an actual battery, or a super-capacitor, to supply the pulse current

Yes, my sims indicate it would require about 5mF to generate a 5ms, 5A peak pulse into a standard ignition coil if powered by a low-current solar panel.

 

OK, a 5 mF capacitor with zero internal resistance may be a challenge to find, but for the low voltage that the circuit uses, and considering that size is probably not a big issue in this project, even a 470Mfd capacitor should fit very well.
An interesting variation would be to replace the timer trigger with a capacitor voltage sensing trigger, so that on a sunny day the pulses could be much more frequent, while on an overcast day the pulses would be less frequent, but still the same amplitude. Since the 555 timer uses a comparator to trigger the time cycle ,that should only require a minor circuit adjustment.

 

crutschow i thought of using a tv flyback to power this as i already obtained one - i have not been able to obtain an ignition coil out here as when i ask they dont know what im talking about

 

crutschow i thought of using a tv flyback to power this as i already obtained one - i have not been able to obtain an ignition coil out here as when i ask they dont know what im talking about

No, a tv flyback transformer will not likely work well.

Use one like this:
You should be able to find one in an automobile junk yard, if there's one near you.

 

Just as a side note and something you want to consider. Solar panels are rated using their maximum output as in bright sun directly overhead. On an overcast day good luck. Thus you want a battery. You can work it so the fence is only powered during daylight hours.

Ron

 

No, a tv flyback transformer will not likely work well.

Use one like this:
You should be able to find one in an automobile junk yard, if there's one near you.
View attachment 335727

In quite a few parts of the world there is no such thing as an automotive junk yard. And in some other parts of the world there are not many who know anything about replacement parts on cars.

 

In quite a few parts of the world there is no such thing as an automotive junk yard. And in some other parts of the world there are not many who know anything about replacement parts on cars.

And likely those that live in those areas would not be asking how to build an electric fencer.

 

Really, it would be in some of those areas where an electric fence charger would be most needed!!

 

In quite a few parts of the world there is no such thing as an automotive junk yard.

I would have said 'Very few parts of the world without one" !!
I used the more modern waste spark coil for mine, the older style maybe getting rarer!

 

evidently our experiences differ.

 

Really, it would be in some of those areas where an electric fence charger would be most needed!!

If they can figure out how to obtain the electronic parts for an electric fencer, than I would think they would also be able to obtain an ignition coil.

 

Parts availability varies in different parts of the world. Also the technical knowledge and abilities of those folks representing that they have the ability to diagnose and repair things. And that lack of insight certainly extends to those merchants selling stuff.

 

With a brief search, It would appear there is not a shortage of scrap auto parts in Jamaica!!

 

Here's a thought:

Yardy - where are you located?

ak