DEEPOWER QS7

On paper this is one of the better-equipped bikes in the retro fat-bike format. The rear suspension is a genuine shock: DEEPOWER's product page lists an inverted aluminium front fork with 150 mm of travel and a nitrogen rear shock absorber mounted centrally, and its product photos show it. That is a real advantage over bikes like the ASKGO S9, whose "full suspension" turns out to be a front fork and a sprung seatpost. The manufacturer also lists front and rear turn signals, a Shimano seven-speed, mechanical disc brakes with 160 mm rotors, and 90% pre-assembly.

The manual gives a weight of 75 lb for the 20 Ah version, which is heavy but normal for a steel-framed moped-style fat bike, and a 330 lb load limit (the product page says 440 lb; we use the lower figure). DEEPOWER recommends riders from 160 to 195 cm, about 5'3" to 6'5".

48 V x 20 Ah is 960 Wh. Realistic e-bike consumption is 15-30 Wh per mile, and a 75 lb fat-tire bike ridden on the throttle sits at the upper end. The primary listing claims 70 miles pure electric and 100 miles with pedal assist:

• 960 Wh / 70 miles = 13.7 Wh per mile on throttle alone, which a bike this heavy on 4-inch tires will not manage at speed
• 960 Wh / 100 miles = 9.6 Wh per mile, which fails the arithmetic outright
• 960 Wh / 30 Wh per mile = 32 miles; 960 Wh / 20 Wh per mile = 48 miles

DEEPOWER's own manual agrees with the arithmetic rather than the listing. For the 20 Ah pack it quotes 25-30 miles pure electric and 35-50 miles pedal-assist, and the second Amazon listing for the same frame quotes 30 and 70. We plan on about 35 miles of mixed riding. The listing title's "35-180 miles" spans all three battery options; the 180 would need the 60 Ah pack, a different and more expensive configuration.

Under the US three-class framework, Class 1 and Class 2 cap at 20 mph, and Class 3 allows 28 mph with pedal assist only, with a throttle not permitted in most states. The federal definition (15 U.S.C. §2085) is written around 750 W rated output.

The 750 W rated figure comes from DEEPOWER's manual, not the Amazon listing, which only says 2000 W peak. The manual's peak figure is 1500 W, so the listing and the manual may not describe identical hardware. Take the manual at its word and the wattage is inside the cap. Speed is where it breaks down:

• As the manual says it ships, limited to 15.5 mph, it would sit inside Class 2 (throttle, under 20 mph), legal in every state.
• At the 28 mph in the Amazon title, with the throttle the manual shows on the handlebar, it fits no class in most states.
• With the limiter removed, 30 mph, it is above Class 3 and is not a street-legal e-bike in any state. The manual itself warns that lifting the limit "may bring legal risks".

So the bike can be legal, and whether it is depends on a wire under the seat. If you want it for bike lanes and paths, leave the limiter in place, or set the display to 20 mph if it allows. Seven jurisdictions ban Class 3 outright (DC, Kentucky, Massachusetts, Montana, North Carolina, Pennsylvania and South Carolina). Check yours on our street-legal-by-state guide.

The Amazon listing mentions no UL standard. DEEPOWER's product page links two documents labelled "SGS Certified", and we opened both. The UL 2849 report (the complete e-bike electrical system) is a test report from a Shenzhen lab covering DEEPOWER models S7, S7-1 and S7-2. It does not name the QS7 and was not issued by SGS. The UL 2271 report (the battery pack) is a TÜV Rheinland test report for battery models HL4820-M48-G80 and HY4820-M48-Y52, which passed UL 2271:2018. That is a real document, but nothing on the Amazon listing ties those model numbers to the pack you would receive. Our reading: UL 2849 is not documented for the QS7, and UL 2271 is documented for a DEEPOWER battery but not confirmed for this listing. If your building requires UL 2849 for indoor charging, ask DEEPOWER for a report that names the QS7.

The Jasion RetroVolt 330 at $539.99 (as of Sep 16, 12:01 PM EDT, subject to change) was Amazon's best-selling bike in this format in September 2026; it has a smaller 720 Wh pack and publishes no rated wattage, but offers a passenger bench. The TST Fat Retro at $579.99 (as of Sep 16, 12:01 PM EDT, subject to change) also quotes peak watts only and no top speed. The DTTZH F6 at $469.98 (as of Sep 16, 12:01 PM EDT, subject to change) prints its 750 W rated figure on the listing itself and has a slightly smaller 749 Wh pack. Among these, the QS7 has the largest battery and the most complete published hardware list, alongside the least consistent speed claims.

Warranty wording also varies: the Amazon listing gives one year with email support, while DEEPOWER's site describes a two-year period in a paragraph that also mentions a one-year warranty. Assume one year and anything more is a bonus.