Mostly I just want to charge phone, cam batteries, little stuff like that.
If that's all you have in mind, dan filipi, I refer you to a lithium jump-start battery.
These electrical wonders, about the size of cell phone, can start your bike with 200 cold cranking amps, when necessary. Further, at any time, these little auxiliary power packs can charge any and all the devices you mention with the wiring harness and connectors included.
Further, the battery itself can be charged from the 12 VDC on your bike (automobile lighter plug included).
Did I mention the LED flashlight, strobe, and SOS modes?
Get yourself one of these little wonders, and you won't have to fool with inverters and stuff like that:
The auxiliary battery might come in handy, fetched from the glove compartment of your daily driver sometime, too!
Summary of features of one model (many similar):
Dimensions: 6.75 L x 3.25 W x 1H
200 Amp- 400 peak amp jump starting ability
12000mAh of power
Jump start port
19v port for laptops
12v standard port for all 12v accessories
5V/1A USB charging port
5V/2A USB charging port
Hi-power LED flashlight with 3 modes: flashlight, strobe, and S.O.S
Battery level indicator
Built-in over-charge and over-discharge protections for long battery life
Automatic shut-off when not in use
Micro-Start XP-1 Unit
Simulated leather carry case
Mini jumper clamps
Universal Cable with 8 different detachable tips to fit all the different brands of laptop charging ports
Universal Cable for all 12v accessories such as mobile DVD players, or other 12v accessories
4-in-1 USB cable with Micro USB, Mini USB, Apple 30 pin and Apple Lightning 8 pin connectors
Wall outlet charger
Cigarette lighter charger
FULL DISCLOSURE: No financial interest in Cycle Gear; this is the model I own (now on SALE!):
Have started V-6 with it; oughta handle V-8s as well.
EDIT: Oh, yes! 10 % off EVERYTHING at my friendly local Cycle Gear; today only!