I’m not sure what all you need to charge but can make a suggestion if it’s lights and other lower powered items that typically charge via a usb cable. You can purchase a usb hub with 2, 4, 6 or 8 ports on it so you attach multiple devices to it, make sure it does not require power.  Then purchase a battery pack that will attach to the USB hub, it should charge all of your items at least once per battery charge.  You can always take the charger home with you and recharge that battery for use the next time.  You coils probably get both items via amazon for less than $50