Mobil device charger that uses 18650's

[TX Foilhead]

Does anyone know of a good mobile device charger that uses 18650's? Once I got away from tanks and went to a REO I started using my old mod batteries as a portable device chargers. I'm down to 1 very old e leaf now. Im taking a trip to Disney World in a few weeks and thought I might be handy to have a couple of new portable battery packs to charge things up with and it will be really nice if I could use some of the 18650's that I'm not using in my REO's anymore to power them.

So far all I'm finding is some scetchy looking Chinese stuff on Amazon. One battery can make a real mess if goes wrong and blows up, so having 4 in something makes me very nervous.

 

[Barkuti]

Used this circuitry in a couple of custom built powerbanks:

Dual USB 5V 1A 2.1A Mobile Power Bank 18650 Battery Charger PCB Module Board @ Banggood

Attains quite good efficiency and pulls up to 2A to charge the batteries, which is nice. Such circuit is used in this powerbank kit:

DIY Kit Dual USB 5V 1A 2A Power Bank 18650 Battery Charger Box @ Banggood

Use code SCM15 for absolutely rock-bottom price on the PCB alone right now; the kit is already on sale!

Be careful with the battery polarity on assembly, powerbank PCBs do not usually possess reverse polarity protection logic (smoke signals warning!

).

Cheers