Minimal car use to maintain battery charge

[cqcq42]

In an effort to reduce my carbon footprint and help the planet, I have started shopping more locally and walking or bicycling more often. I probably didn't help the planet much, but I was 'rewarded' with a dead battery.
My 2013 Honda Accord has electronic entry so the car is always on for at least that, plus the clock, plus the engineers probably decided the computer should be on as well.
Given that drain, what is the minimal running time per week that's needed to maintain a battery charge?
Also, is there an add on that can help? It should warn me that if I shut the car off now, the battery may not last another week or so. (I sure don't want something contributing to drain with the engine off!)

[shorod]

Do you park somewhere that you can use a plug-in battery maintainer? These don't take much power but will keep the battery topped off and ready to go when you need to drive the car somewhere.



The starter draws quite a lot of current to start the engine so if you were to start the car to keep the battery charged, you'd probably need to drive it for 5 or 10 minutes, preferably at a time that headlights are not required and with minimal stop and go traffic (to reduce brake light use and idle speed).


-Rod