Item 1 of 2
Item 1 of 2
frontpageiconian | Staff posted Jul 11, 2025 4:25 PM
Prime: 20,000mAh BooKoo A9 2000A Car Battery Jumper w/ QC 3.0 & 18W PD
$22
$70
68% off
+ Free Shippingat Amazon
+ Free Shippingat AmazonDeal Details
Update: This popular front page deal is available again for slightly less with a new promo code.
BOOKOO via Amazon has for Prime Members: 20,000mAh BooKoo A9 2000A Car Battery Jumper w/ QC 3.0 + 18W Power Delivery for $36.79 - $14.72 w/ promo code TYLQ6GNL at checkout = $22.07 --> Now $21.89. Shipping is free.
Thanks to Deal Editor iconian for sharing this deal.
Product Details:
BOOKOO via Amazon has for Prime Members: 20,000mAh BooKoo A9 2000A Car Battery Jumper w/ QC 3.0 + 18W Power Delivery for $36.79 - $14.72 w/ promo code TYLQ6GNL at checkout = $22.07 --> Now $21.89. Shipping is free.
Thanks to Deal Editor iconian for sharing this deal.
Product Details:
- 74Wh portable lithium car battery jump starter can safely jump start a low volt,drain or dead car battery in seconds with this 2000A car starter, rated for gasoline engines up to 8.0L and diesel engines up to 6.5L.
- 3 LED lights modes: Flash Light, Strobe Light, and SOS Light
- 20000 mAh large capacity battery backup can start dead battery over 30 times
- IP66 Water Resistant
- USB-C Input
Editor's Notes
Written by persian_mafia | Staff- About this Deal:
- Limited time deal, while supplies last.
- About this Store:
- Don't have Amazon Prime? Students can get a free 6-Month Amazon Prime trial with free 2-day shipping, unlimited video streaming & more.
- If you're not a student, there's also a free 1-Month Amazon Prime trial available.
- You can view Amazon's Return Policy here.
- Additional Notes:
- Please see the original post for additional details & give the WIKI and additional forum comments a read for helpful discussion.
OEGAZA8E
Community Notes
About the Poster
Deal Details
Community Notes
About the Poster
Update: This popular front page deal is available again for slightly less with a new promo code.
BOOKOO via Amazon has for Prime Members: 20,000mAh BooKoo A9 2000A Car Battery Jumper w/ QC 3.0 + 18W Power Delivery for $36.79 - $14.72 w/ promo code TYLQ6GNL at checkout = $22.07 --> Now $21.89. Shipping is free.
Thanks to Deal Editor iconian for sharing this deal.
Product Details:
BOOKOO via Amazon has for Prime Members: 20,000mAh BooKoo A9 2000A Car Battery Jumper w/ QC 3.0 + 18W Power Delivery for $36.79 - $14.72 w/ promo code TYLQ6GNL at checkout = $22.07 --> Now $21.89. Shipping is free.
Thanks to Deal Editor iconian for sharing this deal.
Product Details:
- 74Wh portable lithium car battery jump starter can safely jump start a low volt,drain or dead car battery in seconds with this 2000A car starter, rated for gasoline engines up to 8.0L and diesel engines up to 6.5L.
- 3 LED lights modes: Flash Light, Strobe Light, and SOS Light
- 20000 mAh large capacity battery backup can start dead battery over 30 times
- IP66 Water Resistant
- USB-C Input
Editor's Notes
Written by persian_mafia | Staff- About this Deal:
- Limited time deal, while supplies last.
- About this Store:
- Don't have Amazon Prime? Students can get a free 6-Month Amazon Prime trial with free 2-day shipping, unlimited video streaming & more.
- If you're not a student, there's also a free 1-Month Amazon Prime trial available.
- You can view Amazon's Return Policy here.
- Additional Notes:
- Please see the original post for additional details & give the WIKI and additional forum comments a read for helpful discussion.
OEGAZA8E
Community Voting
Deal
Score
+130
Good Deal
Bad Deal
Top Comments
Based on extensive testing, most of these devices only deliver about one-third of their advertised capacity. In reality, you're likely getting around 12,000 to 16,000mAh of usable energy.
High amp ratings like "1500A peak" are common, but they don't tell the full story unless:
- The boost circuit is well-designed,
- The battery cells can sustain high discharge current,
- The wiring and connectors are thick and efficient.
My 3.0L German diesel engine requires approximately 800 amps for 3 seconds during startup.
Power Calculation: 12V × 800A × (3 sec / 3600 sec) ≈ 8 Wh
So, a single crank uses about 8 watt-hours. If your jump starter is rated at 30Wh, you'll get maybe 2–3 cranks total, especially after accounting for energy lost during voltage conversion.
- Cheaper units lose 20–25% energy in the process.
- High-quality brands like NOCO typically lose 15–20%.
How to Accurately Test a Jump Starter:
1. Charge the jump starter to 100%. Use a USB power meter to ensure it's no longer drawing current.
2. Discharge it completely and record the watt-hours (Discharge Wh).
3. Calculate actual capacity in mAh: Real Capacity (mAh) = Discharge Wh ÷ 3.7V
4. Charge the device back to 100% and record the input watt-hours (Input Wh).
5. Calculate energy loss: Loss Wh = (Input Wh - Discharge Wh)
6. Calculate efficiency: Efficiency % = 100 - (Loss Wh ÷ Input Wh × 100)
Join The Conversation
Share your experience with the Slickdeals community
Share information with the community. Please follow our Community Guidelines and be kind!
99 Comments
Sign up for a Slickdeals account to remove this ad.
Technically, can you jump start by plugging it into cigarette lighter - if it has the adapter?
Solar chargers plug into the cigarette lighter - so it must be?
Solar chargers plug into the cigarette lighter - so it must be?
https://m.media-amazon.com/images...HEGtgL
Sign up for a Slickdeals account to remove this ad.
Our community has rated this post as helpful. If you agree, why not thank Oil_Burner
Based on extensive testing, most of these devices only deliver about one-third of their advertised capacity. In reality, you're likely getting around 12,000 to 16,000mAh of usable energy.
High amp ratings like "1500A peak" are common, but they don't tell the full story unless:
- The boost circuit is well-designed,
- The battery cells can sustain high discharge current,
- The wiring and connectors are thick and efficient.
My 3.0L German diesel engine requires approximately 800 amps for 3 seconds during startup.
Power Calculation: 12V × 800A × (3 sec / 3600 sec) ≈ 8 Wh
So, a single crank uses about 8 watt-hours. If your jump starter is rated at 30Wh, you'll get maybe 2–3 cranks total, especially after accounting for energy lost during voltage conversion.
- Cheaper units lose 20–25% energy in the process.
- High-quality brands like NOCO typically lose 15–20%.
How to Accurately Test a Jump Starter:
1. Charge the jump starter to 100%. Use a USB power meter to ensure it's no longer drawing current.
2. Discharge it completely and record the watt-hours (Discharge Wh).
3. Calculate actual capacity in mAh: Real Capacity (mAh) = Discharge Wh ÷ 3.7V
4. Charge the device back to 100% and record the input watt-hours (Input Wh).
5. Calculate energy loss: Loss Wh = (Input Wh - Discharge Wh)
6. Calculate efficiency: Efficiency % = 100 - (Loss Wh ÷ Input Wh × 100)
Sign up for a Slickdeals account to remove this ad.
Join The Conversation
Share your experience with the Slickdeals community
Share information with the community. Please follow our Community Guidelines and be kind!