Is 21700 battery profitable to sell on Amazon United Kingdom?

The niche generates £26K/yr across 11 tracked products. 3 of 6 products launched in the last 360 days are still selling. 90-day search growth is -13.9%. Flapen's verdict: Skip it (40/100).

How competitive is the 21700 battery niche?

7 brands and 11 sellers compete. The top 5 products take 78% of clicks and top 5 brands hold 96% of demand.

What do buyers complain about in 21700 battery?

Top complaints mined from reviews: Charging, Size-Overall, Battery Life. The return rate is 1.0%.

When does demand for 21700 battery peak?

Demand is steady year-round — the busiest month runs 1.4× the quietest.

What does it cost to enter the 21700 battery niche?

Listings span £5.23–£20.40; the average listing price is £14.80 (sweet spot $15–$100). The average incumbent carries 41 reviews — the moat a new listing must climb.

21700 battery

Skip it

A small market ($26K/yr) — this niche doesn't clear our bar today.

Review moat

Incredible41

avg incumbent reviews — the moat a new listing must climb

Quality gap

Incredible3.9★

avg incumbent rating — lower means beatable quality

Returns

Incredible1.0%

return rate — above 5% kills the launch gate

Avg price

Good£14.80

avg listing price — sweet spot $15–$100

Price range

Okay£5.23–£20.40

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

Conversion

Okay2.8%

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

Competition

Bad78%

top-5 click share — a locked-up shelf

Growth

Bad-13.9%

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

Brand share

Bad96%

top-5 brand share — brand-locked demand

Market size

Bad£26K

£26K/yr · 65K searches

Signals Low Review Barrier Quality Gap

According to Flapen's Amazon United Kingdom niche tracking, 21700 battery is a £26K/yr Amazon United Kingdom market (65K searches/yr). The top 5 brands hold 96% of demand. Verdict: Skip it — 40/100.

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

21700 battery market data

Units sold / yr: 3K–3K; avg 100–250/product
Revenue / yr: £37K–£44K; units × avg price
Conversion rate: 2.8%
Avg BSR: #116
Page quality: 0%
Prime: 100%
Sponsored: 27%
Out of stock: 10.8%
Avg brand age: 27 months
Avg seller age: 295 days

Competition & brand share

The top 5 products capture 78% of clicks — a locked-up shelf that new listings rarely crack.

Brands

7 falling

Sellers

Top-5 brand share

96%

Top 20: 100%

Top-5 click share

78%

Top 20: 100%

Open market

Global Rankings31%
JESSPOW27%
VOOPOO19%
Efest12%
VENNERLI6%
fenix3%
Open — no brand owns it (1 brand, 1%)

Demand & seasonality

Weekly Amazon search volume, last 104 weeks — -13.9% search growth over the last 90 days.

No pronounced peak months · busiest ÷ quietest = 1.4×

Open Trend

Top 21700 battery search terms

21700 battery50K/yr -13.3%3.3% conv.
21700 vaping battery6K/yr -6.6%6.3% conv.
217005K/yr -0.4%1.9% conv.
21700 battery 5000mah4K/yr -37.9%2.9% 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★)1 product missing review or click data not plotted

All 11 tracked products in this niche — three views at once, no toggling.

Top sellers

by 90-day click share

3.7 Volt Rechargeable Batteries 5000mAh High Capacity Flat Top Battery for Flashlights Headlamps (Pack of 221 X 70mm)

JESSPOW£15.154.1★25 rev

Molicel P42A 4200 mAh 45A Size: 21.7K High Amp Flat Top Battery No Nicotine

VOOPOO£17.834.0★81 rev

P42A 21/700 4000mah Rechargable Compatible With Vapcell Products - For E-Cigarette Ecig Vape Mods/Kits + 10ml Nightmare Juice Nicotine Free (2 Pack)

Global Rankings£16.462.5★5 rev

21/700 6000mAh Highest MAH Red Compatible With Fogstar Energy Works 10A Rechargeable Cell With Sub Ohm Kit No Nicotine + Band (2 PACK)

Global Rankings£20.403.0★2 rev

4000mAh Green 217/00 Compatible With Fogstar Energy Works With Sub Ohm Kit + Band No Nicotine (2 Pack)

Global Rankings£16.474.1★32 rev

Newest

by launch date

Voopoo Argus XT Vape Kit [Silver Grey] - Available in 5 colours - 3A Fast Charge 18650/21700 Battery (SOLD SEPARATELY) 100W - Compatible with MAAT Tanks & TPP Coils - No Nicotine

Survival Boyz£16.3655 rev

5mo ago

EFEST 3000 Rechargeable Battery with Protective Case [Single]

Efest£7.860 rev

6mo ago

3.7 Volt Rechargeable Batteries 5000mAh High Capacity Flat Top Battery for Flashlights Headlamps (Pack of 221 X 70mm)

JESSPOW£15.1525 rev

6mo ago

VENNERLI Rechargeable Lithium Batteries with USB-C Cable Fast Charging Battery 3.7V 7400mWh High-Capacity 2000+ Cycles Ultra-Long Lasting Time Durable Cycle Smart Charging LED Indicator (2-Pack Set)

VENNERLI£13.0336 rev

7mo ago

21/700 6000mAh Highest MAH Red Compatible With Fogstar Energy Works 10A Rechargeable Cell With Sub Ohm Kit No Nicotine + Band (2 PACK)

Global Rankings£20.402 rev

8mo ago

What buyers say about 21700 battery

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

What buyers love

Battery Life24%

“Great batteries”

Charging23%

“Brilliant Charger”

Quality-Overall12%

“Good quality”

Value For Money6%

“great value for money”

Durability5%

“The brand highlights durability”

Ease Of Use3%

“Easy to use”

Size-Overall3%

“they fit perfectly”

Advertised Vs Actual Product3%

“As Described”

Strength2%

“they feel sturdy”

Storage Capacity2%

“Good capacity”

What buyers complain about

Charging14%

“will not charge”

Size-Overall9%

“they are an odd size”

Battery Life8%

“cost a fortune in different batteries”

Advertised Vs Actual Product7%

“This should really be stated clearly in the listing to avoid confusion”

Storage Capacity4%

“Not as good in capacity as the normal ones”

Measurement/Reading Accuracy4%

“Mah not accurate”

Value For Money2%

“These batteries are a little higher in price than average”

Adhesion/Stickiness2%

“Not for vape covered with a sticky lable”

Functionality-Overall2%

“Worked great until the insulation came off the positive end”

Touch/Button Controls2%

“Not many controls”

Top return reasons

Size-Overall61%

Charging11%

Compatibility-Overall8%

Functionality-Overall7%

Battery Life4%

Advertised Vs Actual Product3%

Defective Material/Parts3%

Durability2%

Thickness1%

Adhesion/Stickiness0%

Common questions

Is 21700 battery profitable to sell on Amazon United Kingdom?: The niche generates £26K/yr across 11 tracked products. 3 of 6 products launched in the last 360 days are still selling. 90-day search growth is -13.9%. Flapen's verdict: Skip it (40/100).
How competitive is the 21700 battery niche?: 7 brands and 11 sellers compete. The top 5 products take 78% of clicks and top 5 brands hold 96% of demand.
What do buyers complain about in 21700 battery?: Top complaints mined from reviews: Charging, Size-Overall, Battery Life. The return rate is 1.0%.
When does demand for 21700 battery peak?: Demand is steady year-round — the busiest month runs 1.4× the quietest.
What does it cost to enter the 21700 battery niche?: Listings span £5.23–£20.40; the average listing price is £14.80 (sweet spot $15–$100). The average incumbent carries 41 reviews — the moat a new listing must climb.