Wanted to retouch on the 18650 technical data from an earlier post- This unit isn't as spikey so to say as the vmax, but still the voltage through the pwm still bounces around pretty heavily. Accuracy again isn't the strong suit for the zmax. In voltage mode 3.0v is actually closer to 3.31v on avg, better than the vmax (3.53v or so), but still not 3.0v. Every voltage was off in one way or another, won't post every voltage and what it was unless someone asks, but will go with some main ones- 3.2v- 3.41v on avg, 3.7v- 3.66v on avg, 4.2v- 4.33v on avg, 5.0v- 5.28v on avg, 6.0v- 6.11v on avg. Even with the single battery saw spikes as high as 7.7v on the scope when testing. As for amperage limits in voltage mode, 4.52a was the highest I could push it before getting a lor or wsc error. That's still roughly .3a higher than I could push my vamx (4.19a max), and a full amp higher than the provari. In the output aspect of vv mods, the zmax is the best performer thus far. In wattage mode things were just as off. For one it's not .1w increments as said on CCV, Electronicnicstix, etc. it's .5w on my unit. Not a big deal to me, because I prefer the voltage settings to the wattage (just personal taste). At 3 watts with was getting 2.93w on avg with a 2.5ohm atty (2.71v, 2.5ohm, 1.08a). At 6w same atty was getting 5.89w on avg (3.84v, 2.5ohms, 1.536a). 9w again with that 2.5ohm atty was 9.17w on avg (4.79v, 2.5ohms, 1.916a), 12w was 12.14w on avg (5.51v, 2.5ohms, 2.24a), 15w was 15.37w on avg (6.2v, 2.5ohms, 2.48a). Within tolerances but again quite a few spikes on the voltage under 9w testing saw a spike of 8.1v. Again accuracy isn't the killer aspect of this device.
The voltage/wattage droop when the battery is low isn't nearly as bad as with the vmax, but still there. Right around 3.45v on a single 18650 batt started seeing the voltage be .1-.3v on average lower at the same settings as when the batts was 3.5v or above.
Stacked 18350 tech data- When using the stacked batteries in the Zmax it truly behaves more like it's older brother the vmax. 3.0v was 3.61v on avg. (.8v higher than the vmax tested), 3.7v was 4.11v on avg., 4.2v was 4.92v on avg., 5v was 5.53v on avg., 6.0v was 6.58v on avg. The voltage spikes were even worse than with the single 18650 batt. Wattage was much the same- 3w was 3.87w on avg (3.05v, 1.27a, 2.4ohms), 6w was 7.03w on avg. (4.11v, 1.71a, 2.4ohms), 9w was 9.68w on avg. (4.82v, 2.01a, 2.4ohms), 12w was 12.83w on avg. (5.55v, 2.31a, 2.4ohms), and 15w was 16.12w on avg (6.22v, 2.59a, 2.4ohms). With running two batts throw the accuracy out the window.
Voltage/wattage droop was much like the vmax again, by the time the batts reach 6.9v combined total the voltages are down by -.4-.7v on average from their earlier numbers, and at 6.8v combined seen voltages as high as -.27v off from the voltage setting itself.
So if you prefer accuracy in this device and battery life go with an 18650 high drain (aw, panasonic hybrid, or efest. Find the one that fits best in this device is the aw 1600mah or the efest 1500mah. If you're going with one of the 2000mah+ high drains go with a flat top to put less pressure on the contact pin). If you want pure power go with the 18350's in a stacked form with extension cap (again prefer a flat top and a nipple top combo, flat on top nipple on bottom. This way no chance of the magnet slipping for any reason and causing a potential problem (not to mention possible losing of said magnet when changing batts), and makes it so the least amount of pressure possible is put on the contact pin in the unit).