Thanks for the reply, just ordered the E5. You guys are the best!
I've had several Anker brand battery backups and have been very pleased with them. Just check out Amazon and see which size has the best value at the moment. The Crafty battery is 2600 mAh I believe, so you can use that number to determine how many charges you can get out of the pack. Example, a 10,000 mAh battery pack could recharge the Crafty ~4 times (10,000/2,600).
I'd currently recommend the Anker E5. Great price, reliable, fast charging. Hard to beat. The E4 has 16,000 mAh battery, so you should get 5, maybe 6 charges from it.
I use these at festivals for power for my phone/vape all the time. Life savers.