Stoney ECDmeter - Page 21
just so you guys don;t have to blow it up to see what it can do I thought I better try first..
firstly, hit a snag in testing, giving it a good thrash has made me aware I do not have a single
mod capable of more than 3A.
tried the old indulgence .. fresh imr, .. get to about 3.2A out before the output voltage is no longer sufficient to turn the display on, 0.52ohms ..
i have the crappy no-ego's .. they would die .. I have nothing capable of over 3A, bit sad really.
will have to hack something up now..
(10 minutes later .. )
there we go, seems to be handling 5.6A no probs
enough to get 8 strands of 34 gauge glowing orange.
... onwards ..
swapped to 32 gauge 8 strands, allowed me a longer length so its less likely to blow the kanthal,
ended up testing to 16 strands, alligator clips attached to heavy wires and holding the clips on a AW imr.
the maximum the shunt should be capable of continuously is 3.5A, should cover all ecig applications, what I am testing is what will happen on a shorted line on a mechanical
mod (yes I am looking at you RC)
I had come to the conclusion that 5A short term should be ok and designed the board to help the current shunt as much as possible, its near a big heatsink ( the connector) has lots of track top and bottom and vias thru the board to help heat transfer .. seems to have done the job as I can get it smoking and its cool to the touch within a few seconds.
anyway .. 5.5A is no problem for 5 seconds, did not try much longer, thats long enough for most kanthal to blow unless you are using multiple strands.
at 7.5A the shunt starts smoking at 5 seconds, retained its accuracy though.
ended up running a dead short, just the resistance of the multimeter and the wires, 11.7A .. shunt smokes within a half second (its now 1200% over its rating) got a discoloured band but still retains its accuracy.
over 9.99A the first digit of the meter shows a wierd graphic character, its because I did not program the thing to cope with that and have no intention of doing so, the last 2 characters where still correct to my meter though x.76A .. I may revisit later if anyone really needs it and a lower resistance shunt is fitted..
I still foresee a dead short, say a wick on a line shorting to both posts, with a good unprotected battery and a solid mechanical mod has the capability of blowing the shunt but confident now that not much else will. What I can do is swap out the shunt for anyone that manages to blow it for a 0.05 ohm job, it means that it will lose the resolution on current and resistance but should then be safe for 10A in short bursts. It will not damage the meter permanently, think of it as a fuse.
So in summary ..
3.5A continuous is no problem at all.
5A is safe for 5 seconds at least
7.5A is safe for 1 second
10A plus .. you are on your own..
I think I should add a flashing display on anything over the 3.5A rating, if you where looking at voltage you may not know its spitting out a massive current until its too late.