my vv mod doing weird things????

[drewk302]

Ok I built my vv mod with with the TI board a while ago right. I use it but no matter what the atty gets very hot fast, even if I put it to 3.5v pre load. Now it has like .2v voltage drop under load no matter what voltage or atty. Now anyway if I put my multimeter on the battery fitting it reads fine, but if the leads slip and touch or even get close when I am pushing the button, it sizzles and I can see elecricity???? Like a freekin tazer? Anyone know why? Is it the caps? I had to use electrolic caps????

 

[Gummy Bear]

Which TI chip are you using?
How old is it? What battery, and all that good stuff.

 

[drewk302]

Its the ti8100, its like a month old or less, 2x 14500 trustfire battys, 510 setup, rad shack project box, 3amp switch. I had to use a 100k ohm pot (works fine) everything to spec, the caps are not tantalum they are electrolic type thats all I had access to and ti data sheet says they can be used, I forget the spec on them though bigger than 100mf and I believe they are 32v also. I tested volts loaded and unloaded they are stable, very low voltage drop under load. I cant test the amps, the fuse is blown in my craftsman multimeter for the side to test over 500ma, but the resistors are all to spec???

 

[clutchjunkie]

Everything you said points to that capacitor being way too beastly. It won't show up as a voltage spike because the cap will only charge up to the voltage being pumped into it, but when you put the full load of the atty on it's going to discharge everything into the atty which is why it heats up so fast. Try getting the exact cap mentioned in the schematic and I bet everything will go back to normal.

 

[drewk302]

I have been researching as much as I can and cant find why the caps I used would cause a problem. I used electrolytic instead of tantalum, and electrolytic is ok to use on the spec sheet. From what I have read its ok as long as the voltage is higher (not extreme) and capacitance is higher. I dunno.