Zak
Legend
I have accumulated a collection of Ryobi 40V lithium rechargeable battery packs. You would think that these batteries would have a USB port so that they can be used as power banks. Lo and behold, Ryobi sells an adapter for that purpose (the adapter also serves as a slim charger for the batteries).
I just received it and am using it now to charge my cell phone. I think it might be very useful for car camping.
RYOBI 40V Lithium-Ion Charger with USB Port OP403A - The Home Depot
Charge your 40V lithium-Ion batteries with this charger from RYOBI. Compatible with all RYOBI 40V batteries, this charger is equipped with a USB power source to charge your small electronics while plugged
www.homedepot.com
I just received it and am using it now to charge my cell phone. I think it might be very useful for car camping.