Lithium Ion Battery

• $56 for 100 of 20Wh batteries - 3.7V, 5.8Ahr. 2000Whr for $56? [1]
• $3.50 per cell - PKcell - [2]

Review

This is a good review. Standard is 2200 Ah for 16850 cells, 3.7 v - 8 Wh of power. [3]

• Ultrafire at 1 Ah and 4A is worth the $1.2. Cheaper than all others, for half capacity.
• Further - if it's 1 Ah and 72 cents - it appears to be 370W for $67, or under $200 per kW? Definitely would be worth it.

Protection

• Protected vs unprotected - [4]

Not High Drain

• 2600 advertised - [5]