Here goes, I have a 2005 Grand Caravan SXT 3.8 V6. A few days ago my wife was driving and all of the gauges started to flip back and forth dash flickering,all at the same time. She then stopped for gas and it wouldn't start, No lights, radio, anything. like the battery was completely dead.Then it just started and every thing was fine until this morning..no start. I put my meter on battery volts were at 12.8 then dropped to 6.5...when i tried to start..after 15 mins i had very little power enough to turn key...decided to put battery on charger..( 2 years old) When i put on charger jumped back and forth from 50% charge to done..Put on trickle charge and it has been around 70% for a few hours.. i checked grounds, cleaned battery connections and cables..found no loose wires..Gravity tested battery cells all is good. Took off charger car starts right up left running for 30 mins no voltage drop..when running has around 14 volts..My concern is if charger is reading low battery but my meter and hydrometer say otherwise is the battery junk? What could cause gauges to jump around? seems fine now but i know this is gonna be a problem and leave me on the side of the road..any advice would be appreciated.
Thanks.

 

I've seen several of these posted on several forums but no one states a verified fix. Erratic instruments is an initial sign of weak power be it the battery or battery cables. Add the dead starts and it gets more complicated.

I would start off by getting that battery load tested. That 6v drop is excessive. Usaually, if it drops below 9 volts it's considered a failed load test. Most auto parts stores like AutoZone will test it for free.