Details are a tad sparse on said brand's website. But if we assume their 5Ah bank has nominal Li-Ion voltage of 3.6 then that's 18Wh, charged 0-100% in 18 minutes is a neat 0.3 hours meaning it nets 60W of draw from the power supply.
Just got the Nitecore 21700 Intelligent Battery System. It's a compact kit with a magnetic power bank and battery charger, high cri 80 lumen magnetic lantern, and 21700 I series battery. It's hard to beat the compact size of the 2 amp power bank and you can't beat how fast it is to swap out the 5 amp battery. Despite both contacts on one end of the battery, they made it backwards compatible with other lights by having a regular negative terminal on the other end. The 15 amp rated battery works with my E4K and MH10 v2 which are not I series lights. The lantern has no moving parts to wear out (no switch) as it turns on when connected with the battery. For $6 more than a 15 amp rated 5 amp battery with a built in USB port, seems well worth it to get a power bank and lantern as well as a backup battery for a light like the E4K.
About September 2020 I bought a LiIon 8000 mAh car battery jump starter, at Costco. It is the Type S brand. It worked fine on my 9 HP lawn mower, but I couldn't test it on my 4.6L 8 cylinder engine (its battery was fine).
After not being used for a month or more, the battery in my car became stone cold dead. I tested this LiIon battery and it cranked the engine as quickly as the new replacement battery did. Despite, not topping the LiIon cell off since I got it, it was still at 100% charge, and after cranking and starting the car's engine, it was still at 95%.
I am pleased to give it a passing grade.
It comes in a convenient zip up container, has a flashlight, and can be used as a power bank.
I like Anker power banks too but I think water proofing them would not necessarily be a good thing as in charging them pressure could build up and have nowhere to vent plus having rubber caps over all the ports is a mess as often there are 3 ports on larger power banks. What would be nice is custom fitted ziplock type bags that are thicker than food bags.