21v lithium ion battery
Worth a lookShows a thin review moat (94 avg reviews), but a small market ($73K/yr) keeps it on the watch list.
Review moat
Incredible94.33avg incumbent reviews — the moat a new listing must climb
Avg price
Incredible$29.19avg listing price — sweet spot $15–$100
Price range
Incredible$17.91–$47.70cheapest to priciest tracked listing — scored on the share inside $15–$100
Quality gap
Good4.4★avg incumbent rating — lower means beatable quality
Brand share
Good71%top-5 brand share — brands hold most of the demand
Competition
Good55%top-5 click share — leaders hold, buyers still browse
Growth
Okay+18.6%90-day search growth — must beat 0% to launch
Conversion
Okay2.6%search→purchase rate — share of searches ending in a sale
Returns
Okay4.4%return rate — above 5% kills the launch gate
Market size
Bad$73K$73K/yr · 96K searches
According to Flapen's Amazon United States niche tracking, 21v lithium ion battery is a $73K/yr Amazon United States market (96K searches/yr). The top 5 brands hold 71% of demand. Demand peaks in Apr–May–Jun. Verdict: Worth a look — 50/100.
Data updated Jul 29, 2026 · scored weekly · How we score niches
21v lithium ion battery market data
- Units sold / yr
- 3K–3K
- avg 100–250/product
- Revenue / yr
- $73K–$88K
- units × avg price
- Conversion rate
- 2.6%
- Avg BSR
- #1,133
- Page quality
- 0%
- Prime
- 100%
- Sponsored
- 78%
- Out of stock
- 13.0%
- Avg brand age
- 23 months
- Avg seller age
- 161 days
Competition & brand share
The top 5 products take 55% of clicks — established leaders, but buyers still shop beyond them.Brands
16 rising
Sellers
20
Top-5 brand share
71%
Top 20: 100%
Top-5 click share
55%
Top 20: 93%
Open market
24%
- S725%
- SHINTYOOL18%
- DNLBBO18%
- YINMAYI6%
- MIMYTH6%
- XGOLD5%
Demand & seasonality
Weekly Amazon search volume, last 56 weeks — +18.6% search growth over the last 90 days.Peak months: Apr, May, Jun · busiest ÷ quietest = 2.1×
Top 21v lithium ion battery search terms
- 21v lithium ion battery29K/yr
- 21v battery13K/yr
- 21 volt battery8K/yr
- 21v battery replacement7K/yr
- 21 volt lithium battery12K/yr
- yunxi 21 v battery4K/yr
- 21v lithium battery5K/yr
- makita 21v battery6K/yr
- mini chainsaw replacement battery4K/yr
- seese 21v battery4K/yr
Top 21v lithium ion 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.
All 24 tracked products in this niche — three views at once, no toggling.
Top sellers
by 90-day click share
S7 21V Lithium Ion Battery 2.0AH Rechargeable Battery with LED Indicator Light Compatible with Mini Chainsaws and Leaf Blowers
S7$17.914.5★413 rev
DNLBBO Mini Chainsaw Battery 21v Lithium Battery - 4.0 Ah Battery with Electric Quantity Display Include Charger Adapter Suitable for Cordless Powe
DNLBBO$26.024.6★59 rev
SHINTYOOL 21v Lithium Battery - 4.0 Ah Battery with Charger Adapter Led Indicator Compatible with Leaf Blower
SHINTYOOL$27.664.4★925 rev
S7 21V Lithium Ion Battery - 4.0 Ah Rechargeable Battery with Led Indicator Compatible with Mini Electric Chain Saw 4 Inch/ 6 Inch Leaf Blower
S7$28.394.6★57 rev
SHINTYOOL 21v Lithium Battery - 2.0 Ah Battery with Charger Adapter Led Indicator Compatible with Leaf Blower and Cordless Tiller
SHINTYOOL$18.804.6★319 rev
Newest
by launch date
Mini Chainsaw Battery 21V 4000mAh Lithium Battery with Charger Adapter
Hguptgw$24.865 rev
Mini Chainsaw Battery 21V 2000mAh Lithium Battery with Charger Adapter
Hguptgw$18.075 rev
DNLBBO Mini Chainsaw Battery 21v Lithium Battery - 2.0 Ah Battery with Electric Quantity Display Include Charger Adapter Suitable for Cordless Powe
DNLBBO$21.959 rev
SHUQY 21V Lithium Battery 7500mAh Replacement Battery Pack Universal Cordless Tool Battery with LED Indicator Compatible with Chainsaw Drill Leaf Blower Lawn Tools
SHUQY$39.5534 rev
Grinsvalley 4 Pcs 21v Batteries Replacement 2400mah Lithium Battery for 18v 20v 21v Power Tools with a Charger Adapter Compatible with Mini Chainsaw Leaf Blower Weed Wacker Power Washer
Grinsvalley$47.705 rev
Trending
90-day click momentum
YINMAYI 21V 4.0Ah Battery with Charger & LED Display for Electric Tools
YINMAYI$37.204.6★
JFOTOY Battery for Portable Cordless Washer 21V 4000mAh with Power Display
JFOTOY$29.530.0★
SHUQY 21V Lithium Battery 7500mAh Replacement Battery Pack Universal Cordless Tool Battery with LED Indicator Compatible with Chainsaw Drill Leaf Blower Lawn Tools
SHUQY$39.554.3★
Vkdemer 21V Lithium Battery 2.0AH Rechargeable Battery Compatible Buffer Polisher Cordless Ratchet Wrench Tiller Cultivator Power Tools
Vkdemer$18.674.0★
Grinsvalley 4 Pcs 21v Batteries Replacement 2400mah Lithium Battery for 18v 20v 21v Power Tools with a Charger Adapter Compatible with Mini Chainsaw Leaf Blower Weed Wacker Power Washer
Grinsvalley$47.704.6★
What buyers say about 21v lithium ion battery
What buyers praise and complain about, mined from review topics.What buyers love
“Great battery life”
“Quick charger”
“Excellent fit”
“Good Value”
“a great many--especially garden tools”
“Performs as expected”
“Compatible”
“should be durable”
“Long lasting power”
“Easy to use”
What buyers complain about
“Not charging”
“Battery didn't last long”
“Last 15 minutes”
“it's a fraction of a millimeter off in size”
“Did not work with my edger”
“Poor quality”
“won't totally different set up”
“slips off all the time”
“pictures don't match the product”
“Little expensive”
Top return reasons
Common questions
- Is 21v lithium ion battery profitable to sell on Amazon United States?
- The niche generates $73K/yr across 27 tracked products. 4 of 17 products launched in the last 360 days are still selling. 90-day search growth is +18.6%. Flapen's verdict: Worth a look (50/100).
- How competitive is the 21v lithium ion battery niche?
- 16 brands and 20 sellers compete. The top 5 products take 55% of clicks and top 5 brands hold 71% of demand.
- What do buyers complain about in 21v lithium ion battery?
- Top complaints mined from reviews: Charging, Battery Life, Durability. The return rate is 4.4%.
- When does demand for 21v lithium ion battery peak?
- Demand peaks in Apr–May–Jun; the busiest month runs 2.1× the quietest.
- What does it cost to enter the 21v lithium ion battery niche?
- Listings span $17.91–$47.70; the average listing price is $29.19 (sweet spot $15–$100). The average incumbent carries 94 reviews — the moat a new listing must climb.