Megasquirt Support Forum (MSEXTRA)

neverlift19 wrote:on my board I have tip126 and a quick google search shows them to be in the same family, just slightly different ratings. Am I justified to say its safe to do the modification?

Yes, it's safe to do this modification.

thanks I will report back later!

Couldn't find a 50v 470uf cap but I did dig a 25volt off an old brushless speed controller, curious if the voltage is really important?

Thanks
Joshua

You're trying to control flyback voltage, which will be significantly higher than 25v. Are you sure you want a 470uF? The others have been talking about 47, or 0.47 ...

Honestly I dont know, I see some using 47uf some using 330uf .47uf I am honestly not sure and some of the links are dead I didnt get to go far on my test run... no log..

neverlift19 wrote:Couldn't find a 50v 470uf cap but I did dig a 25volt off an old brushless speed controller, curious if the voltage is really important?

The flyback voltage is clamped to 36V, so you really need a 50V+ rated capacitor.

ok will get on that tomorrow. So whats the uf rating I 'should' be getting or is that a test and tune type of thing?

FWIW.......

I have been using a 47uF/63v without issue......

Ken

Again, I'm using a 47uF 50V polarized (NOT bipolar) capacitor. Solved all of my noise issues.

grr my radioshack is weak, a bunch of non helpful people work there. Almost blank faced when I asked about a polarized 50v 47uf cap... highest they had in stock was 35v so I guess I need to order online or see if anyone has one laying around, still getting voltage spike and sag however its a lot lower! msq below.

RadioShack carries a 100uF/50V capacitor (P/N 272-1044) that should work fine.

I'll try that out next! The 47uf smoothed out the intensity a LOT down to within a 2 volts of swing vs 11 volt swings

,6 volt swing I can completely live with THANKS YOU GUYS

Great! Thanks for reporting back!

after more logs the 100uf has much larger swing than I originally saw, it is closer to a 3 volt swing, found a 47uf 50volt cap I am going to try out today. Update later.

neverlift19 wrote:after more logs the 100uf has much larger swing than I originally saw, it is closer to a 3 volt swing, found a 47uf 50volt cap I am going to try out today. Update later.

Did you ever perform the sensor ground test?

yes passed that, as soon as I read that I went and checked took 30 seconds

have not logged to see if its smoother yet, been doing wiring and adding stuff

should I add this mod to the idle pwm too? have yet to set pwm for idle but its on the list for tomorrow morning.

ok after a few logs this is way worse. Its a very shaky swing of over 4 volts now. Undrivable at night with any electrical load

I added a 47uf 35v polazided on the center legs of Q3 to Q9 with the negative side on Q3. none of the legs where lifted. is this right? this is on a v3.57

I have been using it like this and still get noise. I have my grounds done the correct way too.