---
title: "21700 Battery — $72K/yr Amazon US Niche (2026) - Flapen"
canonical_url: "https://flapen.com/research/us/electronics/21700-battery"
last_updated: "2026-08-11T02:28:06.652Z"
locale: en
meta:
description: "Niche score 54/100 · $72K/yr market · 277K searches/yr · $22.47 avg price. Weak search conversion (1.2%) keeps it on the watch list. Data updated Jul 2026."
"og:description": "Niche score 54/100 · $72K/yr market · 277K searches/yr · $22.47 avg price. Weak search conversion (1.2%) keeps it on the watch list. Data updated Jul 2026."
"og:title": "21700 Battery — $72K/yr Amazon US Niche (2026) - Flapen"
---
# **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.
Market size 18Growth 34Conversion 14Competition 50Returns 91Price range 87Avg price 94Brand share 73Review moat 80Quality gap 81
**Avg price**
**Great****$22.47**
avg listing price — sweet spot $15–$100
**Returns**
**Great****1.2%**
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**
**Great****4.2★**
avg incumbent rating — lower means beatable quality
**Review moat**
**Great****404.96**
avg incumbent reviews — the moat a new listing must climb
**Brand share**
**Good****61%**
top-5 brand share — brands hold most of the demand
**Competition**
**Okay****55%**
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**
**Bad****1.2%**
search→purchase rate — share of searches ending in a sale
**Signals**[** No Dominant Brand**](https://flapen.com/research/niches?market=us&signal=no_dominant_brand "Top brand's click share < 20%") [** Low Review Barrier**](https://flapen.com/research/niches?market=us&signal=low_review_barrier "Top brand's reviews < 500")
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 ~~](https://flapen.com/research/methodology)
## **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**
**23**
**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.
7K5KHoliday '24Prime Day '25Spike '25 seasonSepDecMarJunAugNovMarMay
No pronounced peak months · busiest ÷ quietest = 1.2×
[**Open Trend **](https://flapen.com/research/us/electronics/21700-battery/trend)
## **Top 21700 battery search terms**
- **21700 battery**166K/yr-2.3%0.8% conv. - **21700 rechargeable battery**46K/yr+34.2%0.9% conv. - **21700**22K/yr+4.0%0.4% conv. - **21700 battery 5000mah**11K/yr+31.5%0.5% conv. - **21700 batteries**6K/yr+30.8%1.0% conv. - **olight 21700 battery 5000mah 3.6v**4K/yr+39.4%2.1% conv. - **21700 battery samsung**5K/yr+12.4%0.1% conv. - **20700 battery**5K/yr+14.0%0.1% conv. - **21700 flat top battery**4K/yr-13.6%0.6% conv. - **olight 21700 battery**5K/yr-16.2%1.1% conv. [**All search terms **](https://flapen.com/research/us/electronics/21700-battery/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.
0%4%$3K8%$6K12%$9K16%$12K1101001K10K Reviews — right = deep review moatMarket share (90d) ≈ est. sales
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
[1**BFHB 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry2-Pack**BFHB**$18.76**4.3★9 rev](https://www.amazon.com/dp/B0H37BPQXP) [2**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**$19.33**4.7★12 rev](https://www.amazon.com/dp/B0GSYN5R6L) [3**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**$23.07**4.5★11 rev](https://www.amazon.com/dp/B0D9LBVF9D) [4**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**$14.97**4.2★74 rev](https://www.amazon.com/dp/B0BVQXLH6R) [5**Protect Your Power - Slimline 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry 2-Pack (Holds 2 Batteries)**Protect Your Power**$16.93**4.6★250 rev](https://www.amazon.com/dp/B09XRBR991)
**~~View all top sellers →~~**
### **Newest**
by launch date
[**BFHB 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry2-Pack**BFHB**$18.76**9 rev1mo ago](https://www.amazon.com/dp/B0H37BPQXP) [**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**$9.72**42 rev3mo ago](https://www.amazon.com/dp/B0GVBQ79HV) [**XONBDNOX 217 Rechargeable Battery Case Set 2-Pack: 5000mAh High-Capacity 3.6V 217 Flat-Top Batteries Suitable for flashlights headlamps and More.**XONBDNOX**$19.45**7 rev3mo ago](https://www.amazon.com/dp/B0GV3V166Q) [**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**$19.33**12 rev4mo ago](https://www.amazon.com/dp/B0GSYN5R6L) [**ABCTOY 6 Pack 3.7V 9900 mAh Rechargeable Battery Flat Top Upgrade Capacity Batteries for Flashlights Solar Lights Headlamp Remote Control**ABCTOY**$23.81**20 rev5mo ago](https://www.amazon.com/dp/B0GMQL1N6F)
**~~View all new products →~~**
### **Trending**
90-day click momentum
[**XONBDNOX 217 Rechargeable Battery Case Set 2-Pack: 5000mAh High-Capacity 3.6V 217 Flat-Top Batteries Suitable for flashlights headlamps and More.**XONBDNOX**$19.45**4.4★**▲ 103%**](https://www.amazon.com/dp/B0GV3V166Q) [**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**$19.33**4.7★**▲ 103%**](https://www.amazon.com/dp/B0GSYN5R6L) [**BFHB 21700 Battery Case Compact Durable TPU Organizer for Travel Flashlights & Everyday Carry2-Pack**BFHB**$18.76**4.3★**▲ 103%**](https://www.amazon.com/dp/B0H37BPQXP) [**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**$23.07**4.5★**▲ 103%**](https://www.amazon.com/dp/B0D9LBVF9D) [**FITHOOD Battery Replacement for Welch-Allyn 21700 11720 71050 11730 71051 18200 74054 71022 71150 WA-72200 71055 74710 71054 78904586 (750mAh/3.6V)**FITHOOD**$27.97**3.9★**▲ 102%**](https://www.amazon.com/dp/B083BLQ873)
**~~View all trending →~~**
## **What buyers say about 21700 battery**
What buyers praise and complain about, mined from review topics.
### **What buyers love **
**Charging**30%
*“They charge good”*
**Battery Life**14%
*“Great battery”*
**Quality-Overall**9%
*“Nice quality”*
**Value For Money**7%
*“Good Value”*
**Advertised Vs Actual Product**7%
*“As advertised”*
**Ease Of Use**6%
*“Easy to use”*
**Size-Overall**3%
*“the case is a good size”*
**Durability**2%
*“for one of the less expensive options it has a durable”*
**Portability**2%
*“and it's easy to carry around”*
**Efficiency**2%
*“works great”*
### **What buyers complain about **
**Charging**31%
*“Useless charger”*
**Battery Life**10%
*“Batteries are too short”*
**Compatibility-Overall**6%
*“AA and AAA don't fit”*
**Size-Overall**5%
*“one slot could not take the larger one”*
**Functionality-Overall**4%
*“Did not work”*
**Instructions/User Manual/Troubleshooting**3%
*“No manual or instructions included”*
**Advertised Vs Actual Product**3%
*“Fake ad”*
**Durability**3%
*“Happened several to times”*
**Heating**3%
*“Also when I used these the battery compartment got really hot”*
**Quality-Overall**2%
*“Looks cheap”*
### **Top return reasons **
**Charging**37%
**Size-Overall**15%
**Battery Inclusion**13%
**Advertised Vs Actual Product**6%
**Functionality-Overall**5%
**Compatibility-Overall**5%
**Battery Life**4%
**Defective Material/Parts**3%
**Value For Money**2%
**Brightness/Shine/Glow**2%
## **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.
## **Related niches in Electronics**
- 69 [**power strip long cord**](https://flapen.com/research/us/electronics/power-strip-long-cord)$510K/yr+50.2%**Worth a look**- 70 [**airpods pro charging case**](https://flapen.com/research/us/electronics/airpods-pro-charging-case)$798K/yr-5.3%**Worth a look**- 70 [**starlink mini tripod**](https://flapen.com/research/us/electronics/starlink-mini-tripod)$478K/yr+62.3%**Worth a look**- 70 [**luggage tracker**](https://flapen.com/research/us/electronics/luggage-tracker)$716K/yr+29.5%**Worth a look**- 70 [**canopy fan**](https://flapen.com/research/us/electronics/canopy-fan)$298K/yr+135.4%**Worth a look**- 70 [**spypoint battery pack**](https://flapen.com/research/us/electronics/spypoint-battery-pack)$379K/yr+67.4%**Worth a look**[**All Electronics niches **](https://flapen.com/research/us/electronics)