well you seem to know more than 90% of the vapers out there. Love the star trek reference extra points for that
Thanks for the vote of confidence.
mooch's tests are more centered towards pushing batteries to their max potential, because its about what is safe usually. He doesn't focus on the minimums
In the main that's true. It niggles me a little when he starts criticising the labelling of a battery and than assigning his own capacity ratings but he hasn't actually tested it in line with what those ratings actually stand for.
I appreciate its only a very small part of what he does and establishing how hard you can really work a battery is invaluable stuff. Bearing in mind how long it will be taking him to discharge a battery with all the different loads on them, and the number of batteries he tests he is putting a lot of time into doing it so you have to admire the effort as well as the intent behind it.
I think Mooch cuts off at 2.9ish V on his charts because I BELIEVE and I may be wrong he has stated running them down to 2.5 puts more strain on the battery and shortens their life. But I do get what you are saying about why the charts should go that low. PLUS MOST mods that have low battery cutoff stop at 3.0ish volts per cell. I think this is done to limit amp draw on the battery in a VW device
For Li-ion batteries they are fine to 2.5V. If you take them below 2.4 you start to damage them and definitely shorten their life. There really isn't a lot of merit taking a cell much below 3V in practice so like you say, It kinda makes sense to call it quits just under that. Personally I would like to see him test all cells at 0.2 X its Acont rating down to 2.5 and then do his 5, 10, 15 tests and I'd like him to plot V against Time, but hey, I'm not paying the guy for spending his time doing all this work. If you think about it the VW point isn't really valid because you can't change I=V/R and P=IV. As the batteries voltage is dropping as it is discharging I is going to go down and V is going down.So, your W is going to go down whatever you do to your W setting.
Mooch is more interested in safety then what a cell can do or was designed to do. He approaches it as what will vapers do with this battery and people will push the limits of safety and do stupid stuff. So I think he presents his data is a way to show you what's the most or worst you should do to a battery and still be safe-ish since most things concerning safety on a cell revolve around amp draw and temperature
For sure, though he pushes cells to limits I wouldn't dare to as part of doing that. I'd be very interested to see how his rig is set up. A battery sled attached to some nice thick high amp cable so he can keep them behind some decent shielding, well away from his gear - and himself! just in case they go bang I would hope.
When you say PWM...i understand that most mods are pulsing regardless of how they are designed. However in the vaping world PWM is a specific style of mod used MAINLy but not always with a potentiometer. there is no wattage adjustment. I get that VW mods are still pulsing but PWM mods and VW are different animals in the vaping world and the calculations I was taught to determine amp draw on the battery is different P=IV vs W/V/Efficiency.
Ahh OK. When I've been saying PWM, that includes VW, VJ, VV and even most low powered fixed W devices, because they are all doing that in reality. Whether its via you adjusting a pot, Moving a W/V setting on a display or have no control over settings, they all basically do the same thing. I didn't realise there was a special class of mods which attract the PWM moniker. To be fair that sounds like another typical misnomer that doesn't help anyone. Its a bit like everyone calls the little thing they plug into the wall to charge their phone a phone charger. It isn't at all, its a power supply is all. The 'chargers ' or more accurately charging circuits are actually built into the phones.
I'll be the first to admit I do not understand exactly what is going on in the chips. I just research and do my best.
Thats all you can do really. I just wish manufacturers of electronic gear put a little more technical information in their information sheets and literature so we were more informed and could make better decisions as a matter of course. The only reason I know my mod has a 1.4A charging circuit for example is because I tested it. If the cells are balanced I know there is no chance I will be doing any damage by charging them using it from a current perspective. when I connect the USB up to a 5V supply it cuts off charging at 4.15V so I know its not going to overcharge my cells when I hook it up to a 5V supply. I only know that because I tested that too though. This sort of info should be readily available in the sodding instruction manual for everyone to know.
In terms of my own setups I use 2x18650s PWM mods in series that at 50% on the potentiometer simulate more like 50 watts on my .8ohm coils
I know the V of the batteries because my charger tells me that when I put them in so I know it's around 3.1 per cell where my PWMs start lacking even if I start turning the potentiometer up
That's interesting. If you are using 2X18650s in series and your charger is telling you they both have 3.1V when you take them out you are taking that battery from 8.4V to 6.1V. The information we don't have is what average voltage is being seen across your coils at full charge and when you call it quits because we don't know what the pot is doing to the PWM i.e when you turn it right up is it it pulling low for 0 time giving you the full V that the battery has, or is it still stepping the V down a touch. Similarly when it is set to "50%" is that as low as it will go or is it actually at 50% of the range that it can be turned. Does the 50% represent 50% time at 0V = Time at Vmax when it comes to pulse width, so at full charge is setting giving you 4.2% across the coils dropping very rapidly towards 3.6V unless you adjust.
Based on what you have said I would suspect you might get the same or better run time on the vtc6 at the 2.4-3.5 amp draw you are proposing
Not likely. Based on those graphs you posted earlier I'd say with some degree of confidence you would be looking at around 3.3Ah on the LG's before it hit 2.8V and then on the MJ1s you should just about hit the 3Ah it is rated at. On the voltage, going by the graphs you might see maybe 100mV or so higher V on the MJ1s reducing to no more than 50mV mid discharge and by 3/4 discharge the LG's would then be starting to show a slightly higher V than the MJ1's.
The MJ1's would be slightly harder hitting initially, but that would fade away and by the time you got to 3/4 discharge the more satisfying vape would be coming from the LG's. The LG's would go on longer and give just around 10% more run time than the MJ1's. So say we all.
Having done a little more digging there is a sneeky little cell out there in the 3500 class that might just be worth taking over the LG. The Sanyo NCR18650GA. Its officially rated as a 3300 cell but bucking the trend, it seems Sanyo may have actually understated its capacity.
Your concept is A Typical I feel. I am still not sure the advantage of carrying around a big ass mod that is 6x 18650s vs a 2x18650 and carrying extra batteries.
Well the advantage of having all 6 in the device rather than running them in pairs is the reduced load on each individual cell. This will reduce Vsag and you will get less of a Vdrop under load. It will mean each cell is working less hard, generating less heat and will increase overall runtime.
The downside is the big ass mod, but then I'm already fixated on modding an original gameboy or similar so going there is going to give me a big ass mod anyway.
But everyone has their own unique situations. SO you should do what works best for you. BUt with 6 cells I am not really sure there is going to be much if any runtime difference using the MJ1 and a VTC6. Maybe a few hours. But since your goal is 2 or 3 days a couple hours may not make much of a difference or it could mean all the difference.
Thats the beauty of building your own kit from scratch I suppose, the ability to make things just the way you want it. (The smart money would say 10% additional run time as above.)
I would look at big al's Ipwm board it lets you set a memory voltage and maintain a steady voltage across the discharge so you do not have to adjust a potentiometer. This is the board I plan to use on my first build for that very reason. because 85-45 watts is a big range for some people
That is a great tip. I will look into that. the idea of actually regulating voltage in that way interests me a lot. My thoughts were to use a buck regulator setup to achieve that sort of thing. I'm fascinated to see how someone else has approached it.