Hi,
I've used a few of the hall effect current sensors from Pololu for this type of thing also. In a project on a boat I measured solar and generator input as well as total battery discharge using 3 of these modules. I also use them in my benchtop power supply. This +/- 5A one based on Allegro ACS714 will give you the best resolution for the range you're measuring.
Cheers ! Geoff