Battery dead in mornings, once a month

[Robbie2618]

My 2007 Explorer limited 4.6 v8 2wd has a intermittent dead battery in the morning. It happens about once a month, the battery is dead to where it won't even crank. I will get a jump and it's fine for another month, I drive it daily. Alternator was tested put out 14+ volts, I replaced the battery after the first time thinking it was an old battery. Has done it 6 times since spring. Dealership can't find a problem, I check the battery voltage now and then it's always full charged. Then boom dead as can be after a month or so. Never seen any lights on at night, positive they aren't coming on like an interior light. Checked the glove box light switch seems positive and engages well before the door's latched so not the glove box light. I'm guessing something other than lights staying on and draining battery because if intermittent charging the battery should also be dead at the store or when I leave work. Always in the morning and very dead. Anyone every heard of this or have ideas?

 

[974X4BLACKSPORT]

You say the battery is "dead" because car wont start, but have you checked the voltage at the battery terminals when this happens? Anyway, I would start by checking all the main wiring and ground strap locations for looseness or corrosion.

 

[rmcalis]

I have the same problem with my '10 Sport Trac 4.6L. New battery and alternator. No problems with lights or other drains that I can find. I put a voltage monitor on the battery for a while, it showed a slow, normal drain, then suddenly a big voltage drain to a dead battery. I changed the relays in the fuse box thinking one might occasionally stick closed, but it didn't seem to help. It went about six months one time without a problem and I thought the problem had gone away, then suddenly it struck again. I keep a hand held portable jumper in the vehicle just in case. I think it is a gremlin that will not/cannot be found. If anyone finds a solution, please help.

 

[Robbie2618]

Update. The problem was always in the morning so thought it was something staying one at night. It just did it during the day after driving it 20 minutes. Now I'm suspecting the charging system. After starting the voltage at the battery is 14.2, the alternator has passed three checks, autozone, advanced Auto and lastly at the dealer. Advanced Auto also did it with lights and heater on and still passed but I didn't see the voltage myself. After it did it this last time I did some checks. After starting the alternator puts out 14.2 volts but shortly after goes down to 13.6. That seems low, with lights, wipers and heater fan all on volts drops to 13.3 from what I've read it should not drop that low. I've also noticed the battery is never above 12.7 with no load disconnected. I've read a charged battery should be 12.9 my battery after it has been disconnected for a few hours reads 12.6 it is a new battery the old one was doing the same. I'm now suspecting the charging system is not fully charging the battery. Even though it passes everyone's tests. But if it puts out 14.2 volts after starting why would it lower to 13.6 and even go down to 13.3 with heavy load when the battery is not yet fully charged? Does this sound like a bad alternator or voltage regulator? I'm guessing regulator since it can put out over 14. Can the regulator be changed separate on these alternators?

 

[Scott E]

Dealing with some of your same issues... see my new post... perhaps we will connect...

Luck..
Scott

 

[Robbie2618]

Hi Scott, I never found the problem. After probably finding the car dead a dozen times or so I bought a portable jumber battery pack. Used it once then the problem mysteriously just went away on its own. Havent had a dead battery since November. Hope you track your problem down. I know how frustrating it is.

 

[Robbie2618]

Hi Scott, I never found the problem. After probably finding the car dead a dozen times or so I bought a portable jumber battery pack. Used it once then the problem mysteriously just went away on its own. Havent had a dead battery since November. Hope you track your problem down. I know how frustrating it is.

 

[Scott E]

Hi Scott, I never found the problem. After probably finding the car dead a dozen times or so I bought a portable jumber battery pack. Used it once then the problem mysteriously just went away on its own. Havent had a dead battery since November. Hope you track your problem down. I know how frustrating it is.

we will see... yup you are right... past frustrating lol... but persistance has to pay off....

Glad yours is resolved.. thanks for replying
Scott

 

[rmcalis]

Scott, I feel your pain. I am/was dealing with the same problem, but very intermittent, not on a regular interval. A major electrical upgrade was done when I had a supercharger installed (much new wiring with new grounds, battery moved to other side of engine compartment, new alternator and battery) didn't seem to change anything. Bought a portable jump starter (the $80 Li-Ion kind) and jumped my '10 4.6L when needed. It happened several times, the last was twice in a two week period the first of last year (2018), but it hasn't happened since (I bet I just jinxed myself).
I think it is an annoying gremlin we just have to live with.

 

[Scott E]

Scott, I feel your pain. I am/was dealing with the same problem, but very intermittent, not on a regular interval. A major electrical upgrade was done when I had a supercharger installed (much new wiring with new grounds, battery moved to other side of engine compartment, new alternator and battery) didn't seem to change anything. Bought a portable jump starter (the $80 Li-Ion kind) and jumped my '10 4.6L when needed. It happened several times, the last was twice in a two week period the first of last year (2018), but it hasn't happened since (I bet I just jinxed myself).
I think it is an annoying gremlin we just have to live with.

what a royal pain... we shall overcome!

 

[mweiss]

I'm having the same problem.. started happening a few months after installing a new battery. Sadly, it seems others have the same random problem and no cause found.