Lowes offers Craftsman V20 20V Lithium-ion 6 Ah Battery for $84 (reg $139) with free shipping.

Product Description:
This V20* 6.0Ah Lithium-Ion Battery provides up to 4.5x the capacity versus the standard V20* MAX Lithium-Ion Battery. It is compatible with all CRAFTSMAN® V20* tools and equipment. Each pack is equipped with a 3-LED state-of-charge indicator for immediate battery charge information. No memory and virtually no self-discharge means this battery is ready when you are.

• V20* 6.0Ah high-capacity lithium ion battery provides up to 4.5x the capacity versus the standard V20* lithium ion battery CMCB201 (1.3 Ah) lithium ion battery (included in kits only)
• Extreme runtime for heavy-duty jobsite applications Professional-grade, high-energy cells
• 3-LED state-of-charge indicator for immediate battery charge feedback
• No memory and virtually no self-discharge for maximum productivity
• Includes (1) V20* 6.0 Ah lithium ion battery
• Disclaimers: *Versus V20* CMCB201 (1.3Ah) Lithium Ion Battery; Battery only, charger not included