Bests & Worsts Reviews from Amazon

I did not purchase this particular battery, but here's some info that is good to know when looking to buy any portable battery charger. 1. The batteries that make up these battery packs are if the 18650 type. They have a maximum output of 3000mah. 2. Based on the dimensions of the pack itself, the maximum amount of batteries would be 5 or 6, limiting the maximum capacity to 15 to 18,000mah. 3. From the multiple different packs I've personal taken apart, there's only 4x18650 batteries inside, making a maximum potential of 12,000mah. 4. The batteries in the packs I've purchased actually measured out with a range of 1,800-2,200mah. Making the claimed 10-40,000mah packs nowhere near the capacity. 5. I bought a Uni-Yeap with a claimed 11,000mah battery, that appears to be accurate. It doesn't use the 18650 batteries, but a LiPo pack, which is more consistent in its specs. So, be sure to research the design and read the feedback from purchasers before spending money on a battery pack. Most are grossly overrated and not worth a plug nickel!