2011 Odyssey "battery charge low..." dash message

hnguyen2

I got this message "Battery charge low. Switch off all lights and electrical devices." every time I took my key out of ignition. It started about 2 months ago. Then a couple weeks after, battery died. That battery was 1 year old so it shouldnt have died. Brought my car to Honda dealer. They replace the battery, charged me $135. A few days later, the message came back. Called them and took my car there again 2 times more for software update. After the third time, they told me they did every thing and tested everything. If message would come back, I could either ignore it, or brought my car back and left it there so they could get to the bottom with Honda. Well, message did come back. Not just that, brand new battery died in less than a month. Took my car back. This time they found out negative cable was loose. They told me that was it, that had been the problem all along. Okay, I paied $135 and wasted many hours to get a cable tighten. No problem though, because at last problem was found. But wait, the very next day, the freaking message showed up again. Battery is still ok but with the message keep showing, I think battery will die again.
So, anyone here has ever experienced something like this? Please help!!!