I'm building some 18650 packs. 10S5P, 50 cells each. Low capacity cells, but also extremely cheap. I will use them in a PV system. : 18650masterrace
10S5P Battery Pack with Panasonic B Cells, 16.75Ah, 24.37A, 36V, Cuboid Shape, Customizable - 18650 Battery Pack - Lithium Ion Battery Pack - Voltaplex
18650 10s5p 36v 13ah Rechargeable Lithium Ion Battery Pack With Bms - Buy 18650 10s5p Rechargeable Lithium Ion Battery Pack,Rechargeable Battery Pack,36v13ah Li Ion Battery Pack Product on Alibaba.com
NI-MH Battery Packs 12V 70Ah High Capacity Rechargeable Battery Packs in Smart 5G Coal Mine - BETTERPOWER