Is 21700 battery profitable to sell on Amazon United States?

The niche generates $72K/yr across 27 tracked products. 0 of 11 products launched in the last 360 days are still selling. 90-day search growth is +7.0%. Flapen's verdict: Worth a look (54/100).

How competitive is the 21700 battery niche?

21 brands and 23 sellers compete. The top 5 products take 55% of clicks and top 5 brands hold 61% of demand.

What do buyers complain about in 21700 battery?

Top complaints mined from reviews: Charging, Battery Life, Compatibility-Overall. The return rate is 1.2%.

When does demand for 21700 battery peak?

Demand is steady year-round — the busiest month runs 1.2× the quietest.

What does it cost to enter the 21700 battery niche?

Listings span $9.01–$67.48; the average listing price is $22.47 (sweet spot $15–$100). The average incumbent carries 405 reviews — the moat a new listing must climb.

21700 battery

Worth a look

Shows a sweet-spot price point ($22.47 avg), but weak search conversion (1.2%) keeps it on the watch list.

Avg price

Great$22.47

avg listing price — sweet spot $15–$100

Returns

Great1.2%

return rate — above 5% kills the launch gate

Price range

Great$9.01–$67.48

cheapest to priciest tracked listing — scored on the share inside $15–$100

Quality gap

Great4.2★

avg incumbent rating — lower means beatable quality

Review moat

Great404.96

avg incumbent reviews — the moat a new listing must climb

Brand share

Good61%

top-5 brand share — brands hold most of the demand

Competition

Okay55%

top-5 click share — leaders hold, buyers still browse

Growth

Okay+7.0%

90-day search growth — must beat 0% to launch

Market size

Bad$72K

$72K/yr · 277K searches

Conversion

Bad1.2%

search→purchase rate — share of searches ending in a sale

Signals No Dominant Brand Low Review Barrier

According to Flapen's Amazon United States niche tracking, 21700 battery is a $72K/yr Amazon United States market (277K searches/yr). The top 5 brands hold 61% of demand. Verdict: Worth a look — 54/100.

Data updated Jul 22, 2026 · scored weekly · How we score niches

21700 battery market data

Units sold / yr: 10K–13K; avg 250–500/product
Revenue / yr: $225K–$281K; units × avg price
Conversion rate: 1.2%
Avg BSR: #3,989
Page quality: 0%
Prime: 85%
Sponsored: 81%
Out of stock: 6.4%
Avg brand age: 34 months
Avg seller age: 181 days

Competition & brand share

The top 5 products take 55% of clicks — established leaders, but buyers still shop beyond them.

Brands

21 rising

Sellers

Top-5 brand share

61%

Top 20: 99%

Top-5 click share

55%

Top 20: 93%

Open market

32%

MLKJHZ15%
BFHB15%
Sinyeeho13%
DIVTEK10%
OLIGHT9%
Protect Your Power7%

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — +7.0% search growth over the last 90 days.

No pronounced peak months · busiest ÷ quietest = 1.2×

Open Trend

Top 21700 battery search terms

21700 battery166K/yr -2.3%0.8% conv.
21700 rechargeable battery46K/yr +34.2%0.9% conv.
2170022K/yr +4.0%0.4% conv.
21700 battery 5000mah11K/yr +31.5%0.5% conv.
21700 batteries6K/yr +30.8%1.0% conv.
olight 21700 battery 5000mah 3.6v4K/yr +39.4%2.1% conv.
21700 battery samsung5K/yr +12.4%0.1% conv.
20700 battery5K/yr +14.0%0.1% conv.
21700 flat top battery4K/yr -13.6%0.6% conv.
olight 21700 battery5K/yr -16.2%1.1% conv.

All search terms

Top 21700 battery products on Amazon

Each bubble is one product — market share against review moat; bubble size tracks estimated sales, color grades how beatable the incumbent looks.

Beatable (≤4.3★) Contested Strong incumbent (>4.7★)

All 24 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

BFHB 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry2-Pack

BFHB$18.764.3★9 rev

2-Slot Battery Charger Flap Top Set for Flashlights Universal 3.7V Li-ion Batteries Charger for 18650 26650 21700(No Suitable for nimh and 1.5V Batteries)

MLKJHZ$19.334.7★12 rev

2-Slot 21700 Battery Charger Set 2pcs 5000mAh Button Top Universal 3.7V Li-ion Batteries Charger for Doorbells Flashlights Headlamps Cameras Toys(No Suitable for nimh & Other 1.5V Batteries)

Sinyeeho$23.074.5★11 rev

18650 to 21700 Battery Adapter Converter Adapter for 21700 Flashlight Cases with Metal Contacts 18650 Sleeve Batteries Protective 21700 Battery Adaptor Holder Accessories (2 Battery Converters)

DIVTEK$14.974.2★74 rev

Protect Your Power - Slimline 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry 2-Pack (Holds 2 Batteries)

Protect Your Power$16.934.6★250 rev

Newest

by launch date

BFHB 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry2-Pack

BFHB$18.769 rev

1mo ago

18650 Battery Charger 2 Bay LCD Display Universal Charger for 3.7V/3.6V Li-ion Batteries 26650 21700 18650 16340(RCR123) 14500 10400 1.2V Ni-MH/Ni-Cd AA AAA Batteries(Battery not Included)

MLKJHZ$9.7242 rev

3mo ago

XONBDNOX 217 Rechargeable Battery Case Set 2-Pack: 5000mAh High-Capacity 3.6V 217 Flat-Top Batteries Suitable for flashlights headlamps and More.

XONBDNOX$19.457 rev

3mo ago

2-Slot Battery Charger Flap Top Set for Flashlights Universal 3.7V Li-ion Batteries Charger for 18650 26650 21700(No Suitable for nimh and 1.5V Batteries)

MLKJHZ$19.3312 rev

4mo ago

ABCTOY 6 Pack 3.7V 9900 mAh Rechargeable Battery Flat Top Upgrade Capacity Batteries for Flashlights Solar Lights Headlamp Remote Control

ABCTOY$23.8120 rev

5mo ago

What buyers say about 21700 battery

What buyers praise and complain about, mined from review topics.

What buyers love

Charging30%

“They charge good”

Battery Life14%

“Great battery”

Quality-Overall9%

“Nice quality”

Value For Money7%

“Good Value”

Advertised Vs Actual Product7%

“As advertised”

Ease Of Use6%

“Easy to use”

Size-Overall3%

“the case is a good size”

Durability2%

“for one of the less expensive options it has a durable”

Portability2%

“and it's easy to carry around”

Efficiency2%

“works great”

What buyers complain about

Charging31%

“Useless charger”

Battery Life10%

“Batteries are too short”

Compatibility-Overall6%

“AA and AAA don't fit”

Size-Overall5%

“one slot could not take the larger one”

Functionality-Overall4%

“Did not work”

Instructions/User Manual/Troubleshooting3%

“No manual or instructions included”

Advertised Vs Actual Product3%

“Fake ad”

Durability3%

“Happened several to times”

Heating3%

“Also when I used these the battery compartment got really hot”

Quality-Overall2%

“Looks cheap”

Top return reasons

Charging37%

Size-Overall15%

Battery Inclusion13%

Advertised Vs Actual Product6%

Functionality-Overall5%

Compatibility-Overall5%

Battery Life4%

Defective Material/Parts3%

Value For Money2%

Brightness/Shine/Glow2%

Common questions

Is 21700 battery profitable to sell on Amazon United States?: The niche generates $72K/yr across 27 tracked products. 0 of 11 products launched in the last 360 days are still selling. 90-day search growth is +7.0%. Flapen's verdict: Worth a look (54/100).
How competitive is the 21700 battery niche?: 21 brands and 23 sellers compete. The top 5 products take 55% of clicks and top 5 brands hold 61% of demand.
What do buyers complain about in 21700 battery?: Top complaints mined from reviews: Charging, Battery Life, Compatibility-Overall. The return rate is 1.2%.
When does demand for 21700 battery peak?: Demand is steady year-round — the busiest month runs 1.2× the quietest.
What does it cost to enter the 21700 battery niche?: Listings span $9.01–$67.48; the average listing price is $22.47 (sweet spot $15–$100). The average incumbent carries 405 reviews — the moat a new listing must climb.