After I killed my odyssey from not driving, I installed a small 50 watt panel on my roof with a renogy charge controller. This does two things. First and foremost, keeps my almost 2 amp parasitic draw from killing another and second, it tops off my battery after driving. My vehicles alternator only does a fair job of charging AGM's. This is the little extra, keeps the state of charge my battery needs. The controller can be accessed with Bluetooth from my phone.
If the vehicle had to sit for a long time, I have a Genius 4amp onboard charger left over from when I had my TJ. I didn't have a spot for a panel on that vehicle so I mounted the charger under the hood.