Revision as of 12:49, 22 December 2019

What it it?

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.

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]

While specs say 250 cycles for 15A discharge - Multiple thousands of cycles are possible when charged to 80% and drained to 30%. - [5]

These appear to be on spec at 3000 mAh - [8].
Cycle life and specs - [9] - 250 cycles to 70% of rated
1000 cycles at 6A discharge rate bottoming at about 60% capacity for 2000 cycles? - [10]. So these last pretty long.

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]

@@ Line 29: / Line 29: @@
 *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 -
 *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]