Raptor Flip-Top VV Mod with 20A, 120W dc/dc converter...

[markbarnaby]

Crap, i wired the 93PR200LF the wrong way.. So 0 puts out 6v and 100 puts out 3.4v lol!

 

[Greg Figlar]

Ok whats the lowest volts your batteries can go down to (battery voltage) before they are too low to fire and what is considered time to swap-out.

 

[KurrptSenate]

you'd have to look at the data sheet and what the minimum input voltage is

 

[Greg Figlar]

you'd have to look at the data sheet and what the minimum input voltage is

Ok yeah the data sheet for the chip is 4.5 min and let's say the vtc 4 the data sheet says the minimum discharge is 2.5 vs but the batteries are wired in series so would that be 5volts or higher because the lead battery discharges faster or am I thinking way to far

 

[KurrptSenate]

if you soldered in a zener diode, that would take all the guess work out of it

most people use a 5.6 volt zener

 

[Greg Figlar]

here are my fet and fuses

 

[Greg Figlar]

here is my chip

 

[juggalofisher88]

Awesome job man those look great!
How do you position it in the box?

 

[Greg Figlar]

bottom left corner

 

[juggalofisher88]

bottom left corner View attachment 382020

The fet and board side by side, or is fet laying on bottom, with board sitting on it. Also what's that you covered the inside the box with? Is it epoxy to stop shorts?

 

[Greg Figlar]

Side by side withe the chip on the outside and I coated it with liquid e tape

 

[markbarnaby]

is a .3v voltage drop when loaded normal? what can i do?

 

[jayD]

Use batteries with a higher amp rating, lower the output voltage, use a higher resistance coil, connect the sense pins. One of these is sure to work.

 

[markbarnaby]

Use batteries with a higher amp rating, lower the output voltage, use a higher resistance coil, connect the sense pins. One of these is sure to work.

Batteries, check; lower output voltage, same drop; higher res coil, same drop;
Connecting the sense pins, not tried it yet but i guess ill have to give it a go..thanks! Moreover, is the voltage under load the real voltage you are getting to your atty?

 

[juggalofisher88]

Batteries, check; lower output voltage, same drop; higher res coil, same drop;
Connecting the sense pins, not tried it yet but i guess ill have to give it a go..thanks! Moreover, is the voltage under load the real voltage you are getting to your atty?

Yeah the voltage out under load Is what your atty is actually getting.
With my vtc5s and the sense pins hooked to 510 i had a .04v drop.

I had a pair of noname 10a ICR, i didn't have the sense pins hooked up. The battery sag was ridiculous, i didnt measure it that time but you could tell a huge difference, compared to the same atty/coil with my vtc5s in the mod.
Still need to re attach my sense pins...

 

[markbarnaby]

View attachment 381934

 

[Greg Figlar]

I noticed you don't have your sense pins connected, what's the voltage drop on yours loaded?

maybe 0.2 tops 0.3 but I use silver solder

 

[markbarnaby]

maybe 0.2 tops 0.3 but I use silver solder

Thanks! I've connected the sense pins, a bit of improvement on a .6ohm build but on a .3ohm build my loaded Vout is 5.5v - no difference Oh well not that I would vape that high all the time anyway. I was just not expecting it. Maybe my voltmeter is off? I'm using this one for now. Still waiting for the actual voltmeter in the mail.

 

[markbarnaby]

It turned out I didn't have much voltage drop after all. My voltmeter came in and I hooked it up and all is good. Thanks all and sorry for the mess!

 

[airbrushaddict]

I ordered some 22uf 16v caps, but got 22uf 50v caps instead. Can I still use these or do I need to send them back?