Bat. or Alt. help. FML

Go to get in and leave work. Car is dead. So dead it doesn't even turn over. Do battery test. 12.8 volts and upon trying to start car drops to 3.5. Seems like battery to me. turned car off. Car is back in uber dead state. While driving tho if i turned on the headlights the car would "restart" but not shut off. Radio would flick off and on, lights on dash would flicker like I just started it up. Car remote wont even lock the car. Luckily I made it home tho. Any suggestions. Yes it has been awhile since i replaced the battery but its started up this morning fine and after work it just died. Don't know if i left lights on. wasnt paying attention.

Bad cell in the battery. It happens. Replace it youll be good.

If your battery has caps on top of it take it to an Auto Zone, Kragens or Sears automotive and have them check each cell with a hydrometer. That will tell if a cell is bad. If the cells are all good have them charge it and then do a load test to tell it's overall condition.

Kinda funny story. Turns out it did have a bad cell. No biggie. So i get a replacement battery from Advance and apparently there is a 51 and 51R series battery. Dude gives me the regular one with reversed terminals and i hook it up wrong since i was in a rush. I blew the 80 amp battery fuse haha. So i had to take it back and gt the R series battery. Damn Honda batteries. Oh well tho. Honda has one for $6.38 so I'll pick it up tomorrow on my way home and if all goes well i won't be back for more help