XTPower MP-30000 Power Bank - High Capacity External Battery with 31200mAh - DC and USB Charger for Laptops, Notebooks, Tablets and Smart Phones, etc. - 2 USB 2.1/1A and DC 9V to 20V max. 4A or 80W

I tested the capacity by discharging it at 19 V and 18 W. It stopped after 73.5 Wh --- this is 65 % of the nominal 115 Wh.The Power Bank switched off when the capacity meter still showed around 30 %. Of course, you cannot fully discharge a lithium ion battery, and the conversion to 19 V has some losses. Still, I was expecting 10 or 20 % more actual capacity.

FANSTASTIC charger! Used during a recent storm which knocked out our power temporarily. I was able to charge 2 phones and my laptop with the adapters provided in the box.

I used this to light LED on costumes. It survived snow and cold and held up well. It recharges quickly and seems to hold that charge even in cold conditions.

Battery was inferior. Expected new battery to charge 100%. After 2 attempts battery only charged to 76%.

pretty good

This product does not last long and the company doesn't respond. I bought this for my daughter to carry to school because they need to use their laptops. She used it happily for about a month and then it stopped working. The lights light up and it says that it's fully charged, but she can no longer charge her laptop with it. I tried to contact the seller and they never responded.

Good

It fully charged when i first got it and hasn't been above 6% since.