Overview
The Yocan FLAT Series represents a thoughtful approach to 510 battery design, addressing one of the most common frustrations with pen-style batteries: the tendency to roll off tables and surfaces. With its distinctive square profile, the FLAT Series stays put where you leave it while delivering reliable performance for your 510 cartridges.
The series includes multiple variants, with the FLAT Mini and FLAT Slim being the most compact options. Both feature the same core functionality including variable voltage, preheat mode, and USB-C charging, differing primarily in size and battery capacity.
Design & Build Quality
The standout feature of the FLAT Series is immediately apparent: the square cross-section. This isn't just an aesthetic choice—it's a practical solution to a real problem. The flat sides ensure your battery won't roll away when set down on any surface.
FLAT Slim vs FLAT Mini
| Feature | FLAT Slim | FLAT Mini |
|---|---|---|
| Battery Capacity | 350mAh | 400mAh |
| Dimensions | 12 x 12 x 84mm | 15 x 15 x 71mm |
| Weight | 0.77 oz | 0.95 oz |
| Form Factor | Taller, thinner | Shorter, wider |
The FLAT Slim is the more discreet option, with a narrower profile that slides easily into pockets. The FLAT Mini, despite being "mini" in name, actually has a slightly larger footprint but shorter height, making it feel more substantial in hand.
Both models feature a sturdy zinc-alloy frame with a rubberized coating that provides grip and durability. The construction feels premium despite the affordable price point. Available gradient colors include Black, Silver, Blue Pink, Green White, Purple Pink, and Red Teal, giving you plenty of options to match your style.
Features
Variable Voltage
The FLAT Series offers three voltage settings to customize your vaping experience:
| Voltage | LED Color | Best For |
|---|---|---|
| 2.6V | White | Maximum flavor, delicate terpenes |
| 3.2V | Green | Balanced flavor and vapor production |
| 3.8V | Red | Maximum vapor, thick oils |
Click the power button three times to cycle through voltage settings. The LED color provides instant feedback on your current selection.
Preheat Function
The 10-second preheat function at 1.8V gently warms your cartridge without burning the oil. This is particularly useful for:
- Cold weather use
- Thick or viscous oils
- Cartridges that have been sitting unused
- Getting maximum efficiency from your last drops
Double-click the power button to activate preheat mode.
Safety Features
Yocan has included essential safety features across the FLAT Series:
- 15-second safety cutoff: Prevents overheating during extended draws
- 5-click on/off: Prevents accidental activation in pockets
- Resistance protection: Only works with cartridges >0.8 ohm
USB-C Charging
All FLAT Series batteries feature USB-C charging, a welcome upgrade from older micro-USB designs. Charging is fast and convenient, with the smaller models reaching full charge in under an hour.
Performance
Vapor Production
At the lowest 2.6V setting, the FLAT Series produces smooth, flavorful vapor ideal for terpene preservation. The middle 3.2V setting offers a nice balance for everyday use, while 3.8V delivers satisfying clouds for those who prefer more vapor production.
The voltage range of 2.6V to 3.8V is somewhat conservative compared to some competitors, but it covers the sweet spot for most 510 cartridges. The absence of ultra-low or ultra-high voltage options means you won't accidentally burn your oil or get wispy hits.
Battery Life
Battery life varies significantly between models:
FLAT Slim (350mAh): Expect 100-150 puffs per charge, suitable for light to moderate daily use. Power users may need to charge daily.
FLAT Mini (400mAh): Offers roughly 120-180 puffs per charge, providing a bit more runway between charges while maintaining a compact form factor.
If battery life is your priority, consider the larger FLAT (650mAh) or FLAT Plus (900mAh) variants in the same series.
Cartridge Compatibility
The standard 510 threading works with virtually all oil cartridges on the market. The magnetic connection provides a secure fit without the hassle of screwing cartridges in. The >0.8 ohm resistance requirement means the FLAT Series is optimized for oil cartridges rather than low-resistance atomizers.
Pros & Cons
Pros:
- Square design prevents rolling—a surprisingly useful feature
- USB-C fast charging across all models
- Excellent value at under $20
- Multiple size options for different preferences
- Stylish gradient color choices
- Solid build quality with zinc-alloy construction
Cons:
- Smaller models (Slim/Mini) have limited battery life for heavy users
- Voltage range is narrower than some competitors
- No digital display for precise voltage reading
- Only compatible with higher resistance cartridges (>0.8 ohm)
Verdict
The Yocan FLAT Series delivers exactly what it promises: reliable, stylish 510 batteries at an excellent price point. The square design isn't just a gimmick—it genuinely improves the daily user experience by keeping your battery where you put it.
For most users, the FLAT Mini offers the best balance of portability and battery life. Choose the FLAT Slim if maximum discretion is your priority and you don't mind charging more frequently.
At under $20, the FLAT Series is an easy recommendation for anyone looking for a dependable cartridge battery. The combination of practical design, solid construction, and thoughtful features makes this a standout value in the 510 battery market.
Related: Yocan FLAT Series Manual