Compare Cell Phone Battery Deals

For new customers, Caloby via Vault offers the Unu Enerpak Vault 11,000mAh Dual Port External Battery Pack for $34 with free shipping via the directions below. That's $11 under our mention from last week and the lowest total price we've seen for this model. (It's a current price low by $11.) It features an LED battery capacity status indicator, two USB ports, and more. To get this deal:

1. Click "Become a Member" to sign up and receive a $15 credit
2. Search "11000MAH" to see the Unu 11,000mAh External Battery Pack for $49
3. Add to cart for a final checkout price of $34

eXpansys offers the Wireless Xcessories Power Case for Samsung Galaxy S4 in Black (pictured), model no. GS4POWRPKBK, or White, model no. GS4POWRPKWH, for $39.99 plus $3.99 for shipping. That's the lowest total price we could find this case. It features a 3,000mAh built-in battery, protective IC circuit, LED indicator, and more.

GearXS via eBay offers the Soundlogic 5,600mAh Portable Backup Battery, model no. BB56-24/5723, for $19.99 with free shipping. That's tied with our mention from three weeks ago and the lowest total price we could find by $3. It charges and provides backup power to USB input-compatible devices, including iPhone, iPod, and most other current smartphones. Deal ends June 7 at 11 am ET.

newegg offers the uNu Enerpak Vault 11,000mAh Portable Battery Pack for $44.99 with free shipping. (Groupon charges the same.) That's tied with our mention from a month ago and the lowest total price we could find by $29. It's compatible with smartphones, tablets, and any other devices that have USB connections.

Update: newegg has sold out; however, Groupon still offers it for $44.99 with free shipping.