18650 Cells: Difference between revisions
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*While specs say 250 cycles for 15A discharge - Multiple thousands of cycles are possible when charged to 80% and drained to 30%. - [https://electricbikereview.com/forum/threads/e-bike-battery-guide.24443/] | *While specs say 250 cycles for 15A discharge - Multiple thousands of cycles are possible when charged to 80% and drained to 30%. - [https://electricbikereview.com/forum/threads/e-bike-battery-guide.24443/] | ||
=Cost= | =Sourcing= | ||
=Cost Analysis= | |||
*From <$1 to $7 each - so choose wisely - | *From <$1 to $7 each - so choose wisely - | ||
*Cheapest - [https://www.ebay.com/itm/Lot-100X-UltraFire-3-7V-18650-3000mAh-Li-ion-Rechargeable-Battery-For-Flashlight/152775669854?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D20160908110712%26meid%3D55b6eb4cf8af45d2a3c06c30cd407496%26pid%3D100677%26rk%3D2%26rkt%3D30%26mehot%3Dpp%26sd%3D222653268869%26itm%3D152775669854&_trksid=p2385738.c100677.m4598] | *Cheapest - [https://www.ebay.com/itm/Lot-100X-UltraFire-3-7V-18650-3000mAh-Li-ion-Rechargeable-Battery-For-Flashlight/152775669854?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D20160908110712%26meid%3D55b6eb4cf8af45d2a3c06c30cd407496%26pid%3D100677%26rk%3D2%26rkt%3D30%26mehot%3Dpp%26sd%3D222653268869%26itm%3D152775669854&_trksid=p2385738.c100677.m4598] |
Revision as of 12:49, 22 December 2019
What it it?
General Performance
- 10A discharge, self-protection circuit inside.
- 3.7V
- 3 Ahr
- 18 minutes of 37W
- 10W for 1 hour
- 100 of these give 1 kWhr
- 45g each, so 1 kWhr weighs 4.5 kg.
- At this density, ultra light cars (500 lb total) - will have 30 miles per kwhr.
- 1kwhr ~ 4MJ - so about 1/10 kg gasoline. Given gas is 20% efficient in cars, we have 1/2 kg equivalent. Tbis gets us to about 240 mpg equivalent.
- With 1 kW solar added- that gets us to about 400 mpg equivalent.
Discharge Characteristics
- Can 18650 cells really discharge at 10A rate? Yes! [1] - Panasonic goes up to 20 amp rate. 6S (6 cell) packs are 22v. 10 of 6s cells, if discharged at 20A, give a 200A welder for 6 minutes. See Discharge Rate.
- Crappy ones can be as low as delivering 2.5A each - [2]. With 100 of these, that's still a 250A welder which has a weight of 5 kg for the batteries. Still impressive.
- Discharge rate of 20A yields temp increase to 50C - [3]
Specs
- Note actual spec from a buyer on Amazon - [4]
Reviews
- https://thegunzone.com/best-18650-batteries/
- https://www.18650batterystore.com/Best-18650-Battery-Guide-s/142.htm
Management
- While specs say 250 cycles for 15A discharge - Multiple thousands of cycles are possible when charged to 80% and drained to 30%. - [5]
Sourcing
Cost Analysis
- From <$1 to $7 each - so choose wisely -
- Cheapest - [6]
- Best - Samsung 30Q - 3000 mAh - $3 in bulk - [7]
Links
External Links
- Fantastic forms for recycling old 18650s into DIY Power Walls https://secondlifestorage.com/index.php
- Best rated battery and everything you need to know about 18650s - [11]