Bigboat

At high rpm, the capicitor don't discharged to the bottum.
Only at low rpm your using the max current.
The spark is also better at low rpm as high rpm

@Tung,

Was't better when I set the POP to 35 or 30 or 25 ?
I have to choose a number for the POP and I choose 40.
But you can change anything as you like into the Exelsheet.
Set yours to 36 and draw the curve between 27 and 15.

Futterama

Bigboat, my question is still unanswered - at which RPM does the CDI work for 6 hours with a 2000mAh 6V battery?

Bigboat

At high rpm, but I can't given you the exact rpm.
Why, I dont know the conditions of your HV-board.
Put your digital multi meter between the leads and you know more then I do.

Futterama

Bigboat, I'm just trying to compare efficiency between the 2 different kind of HV circuits.

Bigboat

I understand, but there are to many undeffind values.
Wat is the ocsilatortime of your HV-board, wat is the condition of your capacitor, wat is the laodtime of the capacitor, wat......aso.
Buy 100 cars of the same brand and drive them behinde each other on the road at the same time, same speed and every car is differend in consuming petrol.
You have to test it your self how long your batteries will live.

Futterama

Bigboat, I'm not trying to make you tell how my HV circuit will perform. I'm trying to compare which is most efficient. If my circuit will run for 2 hours on a 2000mAh 6V battery, then you'r circuit is 3 times more efficient and something needs to be changed in my circuit. You see?

Bigboat

I understand, but you don't know befor you have try yours.
Maybe it's better, maybe it's whors......I don't know.

Phatburner

Hi Bigboat;

6 Hours on a 2 Ah battery means an average current of 333 mA. On 6 volts 330 mA is 2 Watts right? This seems to be a decade lower than the value I figured before. Did I make a mistake on the math? Joules = wattsxseconds. 12000 rpm would be one spark every 5 msec. 90 mJ per spark means that 0.09 J / 0.005 sec = 18 W?? What did I miss here?

J

Ricky1765

Can some one tell me where I can find the latest RC CDI Ingition Circuits and parts list. This looks like a great project, cant wate to get involved.
Thanks

Kymmy

The more upto date version (electronics by BIGBOAT and code by JMJ is [link=http://www.rcuniverse.com/forum/m_4344316/tm.htm]HERE[/link] Though I think that all the project links are down atm due to server issues

Bigboat

This week we are back on line.....they promise us !

Phatburner

Anybody made any progress on the inverter using LT3750 yet? I got my parts now but I didn't realize the FET I bought is impossible to solder by hand. All the connections are on the bottom. How do they solder those?? Anyways I am trying to get a different FET that meets the requirements. Vds ~100v and Rdson ~20mOhm. Not so easy.

Kymmy

If not let me know and I can give you some temp space until yours is sorted..

Phatburner

I found the following device available in small quantities from digikey FDD3672 made by Fairchild. Vds 100v rdsON 28mOhm at 44 amps with Vgs 10v. I know the Vgs isn't great for you guys who want to run on 5 v but I am running on 12v so it is fine for the LT3750 which drives the gate to Vcc-2v during normal operation.

BTW I have my inverter built from your desigh BIGBOAT, it is running and I'm getting plenty of output voltage with it running at about 30KHz but the efficiency is not too great. It might be due to the core I am using which is an amidon FT-82-43. the -77 material would probably be better at 100 KHz or lower but all I had was the -43 material.

Let's see what the LT3750 can do. It is supposed to deliver 90% eff or so......

Mitty

Bigboat,
Thank you for the time and effort you put in this project development.

I can give you a server space if your hoster isn't dependable enough.Mine's at 99.99% uptime . If you would like it pm me or email and I'll set the ftp access for you.

Bigboat

It looks like Murphy was here, also my second provider have problems.
This time the have also the dsl-line disconnect.
Now they must install the complete dsl-line and internet......**** happens.
I can't send or upload big item, I use the line at work.
I think (hope) within one or two week i'm back online.

Kymmy

Rob,

ThanX for the update..hope you;re back to normal soon

Kymmy

Bigboat

I'm back !!
To day they make the dsl-connection and the servers are back online.

bluejets

New to forum and would like to have a couple of details clarified. The new cdi page is shown as being at http://www.modelbouw.gompy.net/newcdi/newcdi.htm ....... correct?

So I went there and downloaded project details at the bottom of the page.

Also downloaded circuit diagram that shows the microcontroller as being 16F628.
There are many different ones so which one is the correct one for the project to work with the code downloaded?
Some are............. 16F628-04/P..... 4 meg speed
16F628-20/P..... 20 meg speed
16F628A-I/P .... 20 meg speed
I took a peek inside the Testfunction C.zip and found reference to the following

100uS loop time
// ; 4MHz clock / 4 = 1MHz instruction cycle
// ; cycle time = 1/1MHz = 100uS
// ; 100uS/100uS = 100 cycles
// ; prescaler set to divide by 4

To me, this appears as though I should be using the 16F628-04/P, however, the parts list included in Layo1 folder under CDI1b_BOM.txt, shows the controller as being 16F628A. I have seen reference to this question before, allbeit in a slightly different form, however , there appeared to be no clarification at that time either. I have read through masses of pages refferring to this latest cdi and the older units but have found no answer.

I am not into modifying code or changing timing within so would have no idea where to even begin.
Also, there is a folder to download called testfunc_hex.zip. Firstly ,is this the program that has to be loaded into the chip?
Secondly, if so, then am I correct in assuming there is no longer a requirement to download MicroC program and copy and paste C code into it to retrieve hex file?

Can someone help?

Thanks.....

Kymmy

I used the 16F628A (it is referenced somewhere in the thread) and it worked fine.

As for the MicroC program, the PIC when programmed (with the default HEX file - testfunc_hex.zip) via PIC programmer has a very basic ignition map/curve on it... This won't suit all motors so to program your own curve you will need to alter the spreadsheet, use MicroC to compile the new program to a new HEX file and then again use a PIC programmer to put the HEX file onto the PIC

Now when I have time all I need to do is work out how to wind the final HT coil and I'm fully up and running

bluejets

Thanks for info on using 16F628A chip.

Your reference to reprogramming chip using MicroC to produce new hex file with a revamped timing curve has raised another question, or rather another conformation.

Do I then get my new curve details out of the spreadsheet, copy and paste just this into MicroC to produce new hex file. If so, when I use this info to re-program the chip, will this not be the only data in the chip? As I understand it, the re-programming will erase any previous program. Rather, do I have to dig into previous file and re-hash to remove old timing data and replace with new info? As I said previously, I have no experience with re-writing of program details, and I can't just duck down to the nearest high school and get someone to do it for me. Prepared to give it a go given correct and complete directions though.

Futterama

Try opening the .c files in MikroC, and try opening the spreadsheet. You will se that you need to copy-paste data from the spreadsheet to MikroC. You then use MikroC to compile/produce the .hex file that you will load into the PIC using a PIC programmer.

bluejets

Hello Denmark (place of my grandfathers origin)

Thanks for the help. I think I know what you are referring to so I will try it and see how I fair.

Did you use the 20 meg chip also? ...... 16F628A

bluejets

OK....did what you instructed within MicroC and can see where to replace data.

Many thanks .......

Bigboat

We start the topics in 2005 and still people are interst into this topics, great !
If I count both topics together, we are number two with the hits (106620) of the topics.



The only thing I missing are pictures (or story's) of sucsesfull built CDI's.