600V DC from 12V DC Source

Thread Starter

MGPERF

Joined Jun 8, 2021
17
Hello,

I am out of my wheelhouse here as an educator with no electronics background. I am looking to get 600V DC from a 12V lead acid battery I plan to put a supercapacitor in between to stop any issues with headlights flickering etc. as this will be mounted in a vehicle. What I am trying to do basically is create a rudimentary 600V power source which can give short blasts of ~600V and high currents at high frequencies. I am thinking I would use the supercapacitor in combination with a flyback converter to get ~600V and from there use a switching device such as an SCR to send my ~600 volt blast. Any input on an ideal switching device, wiring/circuitry, ways to get ~600V from 12V etc is highly appreciated.

Thanks,
Jon
 

Delta Prime

Joined Nov 15, 2019
996
Hello,

I am out of my wheelhouse here as an educator with no electronics background. I am looking to get 600V DC from a 12V lead acid battery I plan to put a supercapacitor in between to stop any issues with headlights flickering etc. as this will be mounted in a vehicle. What I am trying to do basically is create a rudimentary 600V power source which can give short blasts of ~600V and high currents at high frequencies. I am thinking I would use the supercapacitor in combination with a flyback converter to get ~600V and from there use a switching device such as an SCR to send my ~600 volt blast. Any input on an ideal switching device, wiring/circuitry, ways to get ~600V from 12V etc is highly appreciated.

Thanks,
Jon
Hello there. welcome to AAC! :)
A 600 volt blast can lower your blood pressure to zero in a microsecond.
May I ask. What is your intended application for this 600 volt blast?
 

Thread Starter

MGPERF

Joined Jun 8, 2021
17
I am doing this to make a rudimentary CDI system. I’m going to hit my ignition coil with 600 volt pulses to make a huge ignition spark.
 

Delta Prime

Joined Nov 15, 2019
996
Springs, weights, cam lobes, and other simple machines worked together to deliver spark at the right time. so you will be bypassing all of this when you employ CDI you're going to need four super caps one for each cylinder, calibration is necessary or misfiring, dead cylinders, backfiring, bizarre tach behavior, and countless other things related to how your engine's running. The problem may get worse as the engine warms up. It might not even hold low revs at all.
Just a consideration . But I like the way you think. ;)
 

SamR

Joined Mar 19, 2019
3,405
Have you looked at Mallory High Energy coils and their other ignition products? Mallory (holley.com) The only problem is keeping the hi voltage in the wires and not dancing all over the place. Hi Voltage tends to find its own path of least resistance and not necessarily where you intend for it to be.
 

Thread Starter

MGPERF

Joined Jun 8, 2021
17
Delta prime, I have the distributor advance tack welded in place and no current runs through the points and they are used as a ground trigger/cam position sensor for a timing computer. It runs awesome! Some kind of CDI is my next move but I want it of my own design of some kind or at least wired by me.
 

Thread Starter

MGPERF

Joined Jun 8, 2021
17
Sam, it has a Mallory dual point in it but I’m not sure if I’m taking advantage of the dual point feature anymore now that no current is running through them
 

Papabravo

Joined Feb 24, 2006
16,107
I cannot recommend this as a beginner project. The impediments are enormous. As a first approximation you should probably purchase what you need rather than trying to design a circuit, fabricate a printed circuit board, assemble the board and test the board. There are several reasons for this and there is no rush in laying out the details. Your primary concern should be safety. You are working with voltage and current levels that are potentially lethal. In fact, I think that purchasing an assembled unit to experiment with would be a better place to start. I think a proof of concept would provide valuable insights as you seem to have a number of unanswered questions.
 

crutschow

Joined Mar 14, 2008
27,188
I am out of my wheelhouse here
Yes, and the project your want to tackle is not something that one who is "out of my wheelhouse" should try.
The is nothing "rudimentary" about it.
It needs someone who is fairly knowledgeable about electronic high voltage design.
 

SamR

Joined Mar 19, 2019
3,405
I used to run a Mallory dual point on a 350+HP 350CI chevy small block. I'd have to take the distributor to a speed shop with a Sun ignition analyzer to have them set up the mechanical advance curve (weights and springs) and adjust the pair of points to open and close sequentially correctly. If it has no current going through it the capacitor in the distributor died. It needs to be a genuine Mallory capacitor (and points) to handle the energy being cycled through it especially if using one of their hi voltage coils. It was a bear in wet weather due to hi voltage leaking all over the place even after lots of sprayed silicone and WD40. Lots of pretty little blue sprites dancing all about under the hood at night in the rain.
 

MrSalts

Joined Apr 2, 2020
280
Are you going to assemble a stack of super capacitors in series? And in parallel? A unit that can handle 200v will set you back $1000 or more. Why do you need so much capacitance (super capacitor). What's your budget?
 

SamR

Joined Mar 19, 2019
3,405
The Mallory dual point distributor is a dwell extender as mentioned in the article and their hi energy coils greatly increase the voltage. Never had any dealings with "transistorized" ignition systems but did hear the term from time to time. But how much ignition do you actually need? Several factors to consider. Compression, cam rise and duration, carb CFM, carb jetting, plug specifications, ignition wiring, just to start with. If you're not getting a lot of hydrocarbons in the exhaust gas at the tailpipe your ignition system is doing the job. Now, with dynamometers and exhaust gas monitors ignition systems can be pretty well diagnosed as to efficiency.
 

Ian0

Joined Aug 7, 2020
2,192
"Transistorised" generally used to mean that there was a switching transistor between the points and the coil. I used a BU208 television horizontal scan transistor with some success. The gain is so low that there is still enough current through the points to keep them clean. Nowadays there are IGBTs designed for the job - OnSemi seems to have quite a selection.
"capacitor discharge" discharged a high voltage from a capacitor into the primary of the coil using an SCR. The coil was used as a transformer rather than a choke (i.e. it wasn't the energy storage component any more).

However, I completely agree that with no unburned hydrocarbons in the exhaust ignition isn't a problem that needs solving!
 

Thread Starter

MGPERF

Joined Jun 8, 2021
17
The IGBT is a big piece of the puzzle as are the articles! Thanks, I am currently having difficulty sourcing something to get to 600 volts but I realize now that I don’t need super high capacitance something in the range of 2.2 uf should be fine. The power supply of most other CDI boxes are no good so I’m thinking I could get the longer duration spark I'm looking for easily with a better power source. Perhaps I didn't explain perfectly I am going back to the drawing board a bit and am now looking to use some kind of high turn ratio transformer to go from my 12V supercapacitor to make 600V pulses but at very low current to make it safer. If the power supply to the coil is unstable that is ok! So long as it is getting some 240-600V pulses of some kind it will easily make very hot sparks and ignite the fuel no problem. Any help on a source for this 50-1 turn ratio transformer is greatly appreciated.
 

Ian0

Joined Aug 7, 2020
2,192
Any help on a source for this 50-1 turn ratio transformer is greatly appreciated.
A bobbin,
https://uk.rs-online.com/web/p/coil-formers/8407339/
and some enamelled wire
(and a calculator)

You can take a big chunk of the circuit away and replace it by a SG3525 and a pair of MOSFETs.

Careful with the "better" power source - if it can supply too much current, it will keep the thyristor conducting and just deliver one spark before it gets stuck!

Have a read of this
https://worldradiohistory.com/UK/Wireless-World/90s/Electronics-World-1997-12.pdf
starting at page 16.
I guess from your alias you might be dealing with a BMC B-series engine, and it is very relevant.
 
Springs, weights, cam lobes, and other simple machines worked together to deliver spark at the right time. so you will be bypassing all of this when you employ CDI you're going to need four super caps one for each cylinder, calibration is necessary or misfiring, dead cylinders, backfiring, bizarre tach behavior, and countless other things related to how your engine's running. The problem may get worse as the engine warms up. It might not even hold low revs at all.
Just a consideration . But I like the way you think. ;)
I think there is also a question of legality- changing fundamental engine characteristics like this is in violation of emissions regulations, if TP is located in the USA.
 
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