Last Updated on December 13, 2017 by Team Spinfuel

This has been an eventful few weeks for me reviewing devices. First, I had to lead off my Reuleaux RX2 20700 review with a retraction, and now this. This Sigelei Fuchai Duo-3 review represents the first-ever time I’ve had to borrow a piece of hardware to complete the job.


You see, I was tasked with reviewing the new version of the Duo-3, which has three-battery capability, but the version I received only had the two-battery setup (which we already reviewed here). Once again, this was my oversight, so I called a few local shops, borrowed the necessary battery door, and was soon ready to test the mod as intended.


Legwork aside, I’m glad I made the effort, because not only is the Fuchai Duo-3 a more powerful device with three batteries, it’s also a better one. And I look forward to using it for a long while (provided Spinfuel VAPE doesn’t confiscate it and fire me for confusing the heck out of these recent reviews).

Sigelei Fuchai Duo-3 Mod (3-battery configuration) Review – Spinfuel VAPE Magazine

Initial impressions of the Sigelei Fuchai Duo-3 mod (3-cell)


As we noted in the preview, the Fuchai Duo-3 represents a reinvention of the usual Fuchai design and format, most notably with the more-compact style and full-color TFT screen. It’s a completely new look and feel, and – in this writer’s humble opinion – a vast improvement over the previous rendition.


Now, we covered the two-battery version back in June, and our staff agreed it was a compact, powerful mod that more than delivered for the price. Well, I’m happy to say the three-battery configuration doesn’t affect the look and feel. Yes, it’s obviously wider and heavier with an extra cell, but the Fuchai Duo-3 remains compact and great in the hand.


The ample device width allows vapers to use tanks up to 32mm, giving all you Modfather fans reason to celebrate. But again, the device still feels compact – especially when compared to other three-battery mods on the market.


In my preview, I had some slightly critical feelings about the color screen, which seemed to have too many colors onscreen at one time. However, after spending more time with the mod, I learned to appreciate how the different hues made it easy to see the information I needed, even on a slightly busy 1-inch display.


Finally, the extended battery door fits well, with no play or wiggle, which is nice considering the original two-battery door had some slight fit issues.

Operating the Sigelei Fuchai Duo-3 mod (3-cell)

In fact, I’d argue the larger configuration makes the Duo-3 more balanced and less wobbly when using larger atomizers, like the SMOK TFV12 Prince, or larger RTAs, like the Digiflavor Pharaoh. The slightly wider footprint makes the whole setup feel sturdier, as well.


The oversized zinc alloy fire key makes for a comfortable firing grip, even with the wider circumference. I have smaller hands, and had no problem reaching any of the operation keys, with any style of grip.


Sigelei made some significant upgrades to its proprietary chipset with the Fuchai Duo-3, most notably with the laser-perfect temperature control – a far cry from the dreadful TC disaster of the Fuchai 213. Here, the full TC suite includes adjustable TCR and TFR (temperature factor of resistance) modes. TCR settings work as expected, and came in handy when using complicated coil builds.


TFR was more of a question mark for me. Though the idea of implementing DNA-style levels of customization, specific to types of wire and their resistance, I had a very difficult time determining the advantage over using this mode, versus standard TC or TCR settings. But, it’s nice that Sigelei responded over and above the call of duty to deliver precision temp control to its customers.


Navigating the simplified menu system is a breeze, even with the standard hold/press interface. I found the buttons and keystrokes to be extremely responsive, and before long, I was making adjustments with ease.


The mod also features an advanced series of preset modes to ease new users’ transition to the device. And the preheat settings also provided notable distinctions in vape quality.


One item of note – the Fuchai Duo-3 display only features one battery level bar. I had hoped the display would have individual battery power indicators, with the screen changing from two to three bars with the extended door installed. However, the meter is fairly accurate, and I never found myself suddenly left with limited power from inaccurate readings.

Element Vape

Vaping the Sigelei Fuchai Duo-3 mod (3-cell)

Power is the primary focus here. In its three-battery setup, the Fuchai Duo-3 is listed with a potential of 255 watts. And, it gets REALLY close before things get a little dodgy. Though it’s not a dealbreaker, the Fuchai Duo-3 started to throw warnings above 240 watts. There are a lot of reasons this could have happened, and the device performed admirably up until this point, so for once, I’m going to let it slide.


At less-extreme wattages, the Fuchai Duo-3 shines. Smooth, pulse-free power provided a wonderful vape experience with both MTL and sub-ohm atomizers. I found the mod to really hit its stride around 70-90 watts, and I imagine many of Sigelei’s target audience live in that range, as well.


In temperature control, it was clear this was an all-new Fuchai. The Duo-3 offered a flawless TC experience, regardless of which wire type I chose. I found a lower-resistance (0.2-ohm) titanium coil to work best on the mod, as it was the most reliable, fastest-ramping of the builds I tested. The Duo-3 never once faltered in reading coils, and the precise TCR adjustments made my more-complicated wire types a seamless experience.


Battery life on the original setup of the Fuchai Duo-3 was pretty good, but adding the third cell turns it into an all-day device. Using it at 85 watts, with countless adjustments and menu tweaks, I still enjoyed nearly seven hours of fault-free vaping before having to swap cells or recharge.


One item to notein the two-battery configuration, the Duo-3 had onboard 2.5-amp charging via the included USB cable. However, it’s not clear if the three-battery setup gets the same charging input. But I CAN say it charges well via USB, though not as efficiently as with using an external charger.

Wrapping up … and Score …

So, it wasn’t the easiest way to review a mod, but I’m glad I decided to track down the necessary battery door extension, rather than sending my editors a lame email about getting the wrong device. Because the Sigelei Fuchai Duo-3 is a contender for best three-battery mod available.


Yeah, that’s a bold statement in a world of Reuleauxs and Prisms. But even with this stiff competition, the Duo-3’s fantastic temp control, outstanding form factor and overall power performance make this an outstanding triple-18650 device at an amazing price point.


Score: A

Fuchai Duo-3 Specs and Package Contents

Sigelei Fuchai Duo-3 175W TC Box Mod specs:

  • Dual 18650 High-Amp Battery – Not Included
  • Wattage Output Range: 10-175W (2-battery) 10-255W (3-battery)
  • Voltage Output Range: 1-7.5V
  • Min Atomizer Resistance: 0.1ohm
  • 1-Inch OLED Display – Full Color Resolution
  • Ni200, Titanium, and Stainless Steel Compatibility
  • Temperature Coefficient of Resistance (TCR) Adjustments
  • Temperature Factor of Resistivity (TFR) Adjustments
  • User-Friendly Preset Modes
  • High-Grade Zinc Alloy Construction
  • Three-Button Operation
  • Large Oversized Firing button
  • Removable Battery Cover – Lock Switch (2- and 3-battery doors included)
  • Reverse Battery Protection
  • Low Resistance Protection
  • Battery Imbalance Protection
  • Low Input Voltage Warning
  • Short Circuit Protection
  • Overheat Protection
  • MicroUSB Port – Firmware Upgrades
  • Spring-Loaded 510 Connection


Sigelei Fuchai Duo-3 175W TC Box Mod Package contents:

  • 1x Sigelei Fuchai Duo-3 Mod
  • 1x USB Cable
  • 1x Battery Cover
  • 1x English User Manual