Agree,
Protected cells would protect the vaper from an unsafe unbalanced battery condition.
Would have to be a pair of protected 3.7 volt cells as a pair of 3.0 volt cells would not get to 6.4 volts.
The little bugger does have a pretty high temp coef though. Lets see, 7.4 - 5 = 2.4 volts, maybe 2 amps = 4.8 watts dissipated at a junction TC of 12C per watt=+58C over ambient, + TC of heat sink =??
How warm do you think the little tube would get?
Heat input would be from conduction from atty? and from regulator?
At least hotter than the atty shell by itself.
They have these little press on radial transistor heat sinks that would look absolutely cool on this idea. Anodized in an matching color, and they are pretty cheap.
You may be on to something. Dead atty for case and one connector. Dead battery for the other connector. One off prototype would be cheap.
And warn people not to try this with unprotected cells, because this regulator will keep trying all the way down to 1.5 volts input.
R
A little guess work on thermal effects
just a guess)
The junction resistance for the smaller of the cases for this regulator is 12C/W
A joye 510 at 5 volts would be at least 2.2 amps, and a pair of 3.7 volt cells would give 7.4 for a while giving a component dissipation of 5.3 watts. If the tube (about 10mm in diameter and 25mm long) was copper then the still air thermal resistance would be about 40C/W. But that would be for continuous heat input. If we assume
a 10% duty cycle (about two 3 seconds vapes a minute) then we could use 4C/W (disregarding spreading resistance and heat input from the atty (it does get warm) then we add about 21C. On a warm day, vaping, and holding this in our hands then ambient could be at least 30C.
Our junction temperature would be at least 111C. This is getting pretty close to the 125C specification and we left out some of the heat sources.
Heat kills. Current ratings not withstanding, junction temperature will heat up the device case and let all the smoke out. Once that happens it quits working.
Regulator in a plastic box? Indeed
Does anybody remember the old Pentium 60mhz Cpu (that was a little before the Pentium 4) and the heat sinks that Intel supplied that weren't good enough so they went to forced air?
The Pentium 60 dissipated about 12 watts.
Without the heatsink the CPU would overtemp in about 30 seconds.
486/50 only dissipated 5 watts, but that was before dirt was even invented.