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It's only firing below last voltage when there is a last voltage to fire -- regulation has kicked in at that point. This is only when changing batteries, and only upon the first firing of the carto after inserting new batteries. (Not when turning it on -- after having a think about it I realized that it only loses settings after a battery change.) That is the only time when it will send unregulated current through the carto.
Well, I made a new coil, metered at 1.3 ohms on the Vamo.
Test:
2.7 ohm atty using a 18650 battery at VW 10 watts rms mode. Fired the device --- all good.
Replaced 2.7 ohm atty with 1.3 ohm atty and inserted stacked 18350s. Powered on the device and hit the fire button. It fired up and blew up the coil.
I guess that this test confirms that there is a problem with the Vamo ...
Test:
2.7 ohm atty using a 18650 battery at VW 10 watts rms mode. Fired the device --- all good.
Replaced 2.7 ohm atty with 1.3 ohm atty and inserted stacked 18350s. Powered on the device and hit the fire button. It fired up and blew up the coil.
I guess that this test confirms that there is a problem with the Vamo ...
Getting a little confused now ... lol
When you replace the batteries, voltage setting is reset but wattage setting remains.
So your suggesting that it will fire a different device based on the previous device voltage calculations for a second correct?
In such a case, you should beable to fire under 1.2 ohms as well ... as the base problem you are suggesting is that it takes a second for the vamo to read the new resistance and modify the the voltage accordingly.
Am I understanding you correctly? Obviously the best way to confirm this is going to be with a meter or scope.
When you replace the batteries, voltage setting is reset but wattage setting remains.
So your suggesting that it will fire a different device based on the previous device voltage calculations for a second correct?
In such a case, you should beable to fire under 1.2 ohms as well ... as the base problem you are suggesting is that it takes a second for the vamo to read the new resistance and modify the the voltage accordingly.
Am I understanding you correctly? Obviously the best way to confirm this is going to be with a meter or scope.
Yes, that's pretty much what I'm getting at -- a 1.2ohm coil should theoretically fire, at least for a brief moment, when you attach it after having previously attached a higher resistance device.
Generally though that wasn't really my primary concern -- I'm pretty sure tests will prove it out at any rate -- but my main concern was with the device spitting out raw, unregulated current in stacked mode after inserting the batteries, turning it on, and firing a carto for the first time after powering it up. This is the dangerous part.
So this is an interesting find and I wonder how many devices do this. Most of us immediately check our ohms when we place a new device on it so it makes sense that no one found this until now.
What happens if you put the batteries in and adjust the wattage up or down? Any effect on the stuck voltage?
What happens if you put the batteries in and adjust the wattage up or down? Any effect on the stuck voltage?
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This is the first device I've come across that doesn't limit its current while it's doing an ohm check. It's a pretty bad design oversight frankly if it's designed to take stacked 18350s.
Nope. Regulated current at any level doesn't even enter into the picture until it's gotten its ohm reading -- the regulator isn't even engaged until it does. (Again, this is only in VW mode, not VV; it doesn't do a resistance check on power up or carto change.)
Unless I missed the answer to this being said previously, what happens when you do an ohm check before firing? Does the Vamo still have to "recheck" the ohm setting after you've already checked it once?
To simplify, in stacked 18350 mode, using under Variable Power mode, fire a >3.0ohm coil, then replace with a 1.5ohm coil. Perform an ohm check on the Vamo (holding down the + button), then fire. Would it still 'burst' the higher voltage for a second even when you've already performed a check?
To simplify, in stacked 18350 mode, using under Variable Power mode, fire a >3.0ohm coil, then replace with a 1.5ohm coil. Perform an ohm check on the Vamo (holding down the + button), then fire. Would it still 'burst' the higher voltage for a second even when you've already performed a check?
But the regulator does kick in after the initial firing correct? So if I put in batteries, check my ohms, fire ... then screw on a new device ... it will check the ohms and work fine.
So basically vamo users who use vw need to recheck their ohms on a new battery.
So basically vamo users who use vw need to recheck their ohms on a new battery.
I did another test with a sub par atty 1.0 ohms ...
The vamo did not fire the atty, lo ohms indicator displayed when I hit the fire button.
The vamo did not fire the atty, lo ohms indicator displayed when I hit the fire button.
larktdl:8086796 said:
And you did this after putting the battery back in correct? That's very weird. That would suggest its reading the resistance just fine, however the voltage isn't changing fast enough on the first fire.
That's a good question. I didn't even think to try that to be honest -- I haven't used it stacked since the last carto half blew on it, but that might be a good test to try.
That's very possible. Could be a good workaround.
I'm going to risk a third carto now (just dumped the old one). New carto meters out at 2 ohms even.
Hope this works...
[changes out 18650 for 2x18350]
Power on...
Meters out at 2.2ohms (for some reason -- it just metered out at 2ohms before).
Adjust wattage to 10...
Fire...
Hmm. Brief blast warmer than it should be but not hot. Still meters at 2.2ohms. So it looks like this might be the workaround for stacked mode. Still annoying that this has to be done though.
This could be a possibility, but then it brings up the question, why is it taking so long to change the voltage? What's it doing in that first half to three quarters of a second that it's not using to change the voltage?
Another test ...
Using Vamo with stacked batts in VW rms mode 3.5 watts.
Connected 2.7 ohm atty, fired okay.
Connected 1.3 ohm atty, fired okay.
Removed batts, powered on device, fired okay
Removed batts, inserted single 18650, 2.7 ohm atty connected to device
Set wattage to 10, hit fire button, no problems
Removed 2.7 ohm atty and attached 1.3 ohm atty, hit fire button, no problems
Replaced batteries with stacked 18350s - powered on device, hit fire button - the atty did not blow up.
The only difference this time around is the output voltage dropped from 8.3 to 8.2 volts.
Using Vamo with stacked batts in VW rms mode 3.5 watts.
Connected 2.7 ohm atty, fired okay.
Connected 1.3 ohm atty, fired okay.
Removed batts, powered on device, fired okay
Removed batts, inserted single 18650, 2.7 ohm atty connected to device
Set wattage to 10, hit fire button, no problems
Removed 2.7 ohm atty and attached 1.3 ohm atty, hit fire button, no problems
Replaced batteries with stacked 18350s - powered on device, hit fire button - the atty did not blow up.
The only difference this time around is the output voltage dropped from 8.3 to 8.2 volts.
So perhaps it's intermittent? Maybe a bug or something? It seems be a problem that's reproducible, but maybe not reilably.
Maybe the initial resistance check is interfering with the output voltage?
I mean ... something has to be causing that delay whether its interference or some kind of bug in the software that only applies on a hard reset.
I mean ... something has to be causing that delay whether its interference or some kind of bug in the software that only applies on a hard reset.
How fast are you guys performing the tests? As in ... were your initial test very quick while the last test you took more time?
My only reasoning for asking this is because ... perhaps ... you need to wait 3-4 seconds after changing batteries before the resistance check is complete on start up. If you fire right away, it uses the last known setting until it can determine the new resistance. (which takes a few seconds on any device)
That could definitely explain a lot.
My only reasoning for asking this is because ... perhaps ... you need to wait 3-4 seconds after changing batteries before the resistance check is complete on start up. If you fire right away, it uses the last known setting until it can determine the new resistance. (which takes a few seconds on any device)
That could definitely explain a lot.
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The SS ones I received today do remember the watt setting (still not the Volt however). Are you suggesting the problem has been addressed?
Very exciting thread!
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