Good reminder/point about charging lights.  And, I too have found the bike computer battery to last a few days, taking the workload off the phone. 

+1 for Ron's comment on the Anker powerbank.  I have a 5200Ah unit, now 11 years old.  It's small, reliable, & unobtrusive.  Mine can be charged while it's powering another device.  Depending on the terrain & wind (hence my speed), the Anker is recharged in 3- 4 hours. (I have a SON 28 hub dynamo on my Thorn touring bike, hooked up to a Sinewave Revolution charger.)

My requirements are usually limited:  my iPhone (I use the Osmand Maps app, which runs offline, so I usually keep the phone in Airplane Mode during the day); occasional recharging 2 AAA batts in my rear lights and 3 in my headlamp; and ditto my bike's Cygolite handlebar light.

All of these work with a USB male plug, so I use a "splitter", a very handy Y-shaped device with a single male plug that goes into the Anker's female USB outlet, and two female plugs that can accept both the phone's male USB charger, and that of the the battery charger.