dbunch304 Posted June 17, 2019 Report Share Posted June 17, 2019 2013 C Max Hybrid. We had the battery replaced a few months ago and its been running great until the last week. I've had to charge the battery twice because the 12V was dead.It takes forever to charge at 6 amps.But the last time I recharged it a couple days ago it charged all the way. I charge it under the hood.20 hours later I get in the car and the battery is dead. I don't see anything that is on and I have been making sure that I am turning the car off before I get out. My next step is to charge the battery up and take it to Advanced Auto and let them test the battery.The Ford shop is about 45 minutes away. Anyone have any input on what to look for or do? Quote Link to comment Share on other sites More sharing options...
plus 3 golfer Posted June 17, 2019 Report Share Posted June 17, 2019 (edited) You may simply have a defective battery. Whether defective or not, reset the battery age (as I have said this probably a 100 X) when you replace the battery. If you don't, the charging algorithm will continue to use the every degrading Ah capacity of the old battery which is computed by the "coulomb counting" routine and hence will only charge the battery to a very low State of Charge. If the age was never reset since the car was new, I doubt you will ever get much above a 20% SOC and only after driving the car for maybe 45 minutes or so. Even if you charge with an external charger to a 100% SOC, the car's charging algorithm will not maintain the level. Also, even Ford dealers will neglect to reset battery age. ;) One way to tell if the age was reset, is to leave radio on, turn car off, don't open any doors and time how long it takes for the system to shut down. When reset, the algorithm (assuming battery charge is high enough) will shut down the system to conserve power after exactly 10 minutes. As the battery loses capacity over time, this energy saving feature will continually decrease the time until shutdown. Edited June 17, 2019 by Plus 3 Golfer JAZ and C-MaxA2 2 Quote Link to comment Share on other sites More sharing options...
dbunch304 Posted June 17, 2019 Author Report Share Posted June 17, 2019 Thanks.. I will try your test.. My gut feeling is they didn't reset it.. I had my radiator flushed and after a week I had the hood up and it was over an inch below. And yes I read the manual on how and when to check it and I was on level ground. And they've flubbed up a few times before... You may simply have a defective battery. Whether defective or not, reset the battery age (as I have said this probably a 100 X) when you replace the battery. If you don't, the charging algorithm will continue to use the every degrading Ah capacity of the old battery which is computed by the "coulomb counting" routine and hence will only charge the battery to a very low State of Charge. If the age was never reset since the car was new, I doubt you will ever get much above a 20% SOC and only after driving the car for maybe 45 minutes or so. Even if you charge with an external charger to a 100% SOC, the car's charging algorithm will not maintain the level. Also, even Ford dealers will neglect to reset battery age. ;) One way to tell if the age was reset, is to leave radio on, turn car off, don't open any doors and time how long it takes for the system to shut down. When reset, the algorithm (assuming battery charge is high enough) will shut down the system to conserve power after exactly 10 minutes. As the battery loses capacity over time, this energy saving feature will continually decrease the time until shutdown. Quote Link to comment Share on other sites More sharing options...
lutznvicki Posted June 25, 2019 Report Share Posted June 25, 2019 We have had the dead battery issue as well. What worked (most of the time) was to TURN OFF the climate control, TURN OFF the radio.If we've somehow turned off the car when the AC was still on, the car would be dead when we returned to it.A handy item to have is the quick chargers sold at Costco. It's a pre-charged box with a couple of jumper cables. Hook one up to the battery under the hood and the other to a ground, jump into the car, hit the start button, and off you go. They run about $70 and it's a life saver.We've towed the car behind the motor home, and the car's been dead when we get to our destination. Pop the charger on, and poof! the car starts!.I hope this helps some of you. Quote Link to comment Share on other sites More sharing options...
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