Auto start-stop and battery voltage

I don't mind the auto start-stop but I am wondering if it's causing my battery voltage to run low. A couple of times when I was working with forscan, forscan said "battery voltage below 11.5 cannot write try again later" or something like that. And today, as I was walking up to the truck (it was locked) with key in my pocket (802 keyless), I saw the mirror and hazard lights flashing randomly. Was weird, and a google suggested that might be because of a weak battery?

Anyone know if auto start stop especially in summer when AC is mostly going full tilt causes battery to run low?

It is possible but not 11.5v. That is very low. One of the things the auto start stop system does is disable itself when the voltage drops too low, and if the temp between the outside and cabin is too great. Disable auto start for a week and see if your battery will come to a full charge. 11.5v sounds like a defective battery.

pjones said:

It is possible but not 11.5v. That is very low. One of the things the auto start stop system does is disable itself when the voltage drops too low, and if the temp between the outside and cabin is too great. Disable auto start for a week and see if your battery will come to a full charge. 11.5v sounds like a defective battery.

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Interesting. I have been driving the truck quite a bit, you would think that the battery would have been topped up by now. Unless I have some sort of a major battery discharge while parked issue.

So far, the truck has started right up every time though.

Possible that forscan is reading the voltage wrong? Put a multimeter and see if it really is 11.5v.

I've been have a battery issue as well. My code keeps popping high stop light drawing too much

I use auto stop start and have parking lights and low beams on while driving no issues with battery.

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pjones said:

Possible that forscan is reading the voltage wrong? Put a multimeter and see if it really is 11.5v.

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I might just do that. Good point, the cheap Chinese adapter could be reading the voltage incorrectly. Will keep you guys posted.

How long are you using accessory power?

I washed my truck and put some wax on a while back, listening to tunes from the truck, which is running an 8” Kicker sub at 300w. It shut down with the dire battery voltage warning x2 before i was done. I figured - WTF. it’s brand new, my last F150 battery lasted 8 years. I took the truck out the next day, and for about 25 minutes, the auto start / stop was suppressed for voltage or battery or whatever the message is in the menu.

I think if you were really under 12v you’d notice when you tried to start the truck.

11.5v means a fully discharged battery. Check this for "State of Charge"

http://www.mmbalmainauto.com.au/PDF/State_of_charge_12_volt_batteries.pdf

My battery died today. Got a jump, drove it to the dealer and they tested it. Said it was bad and replaced it. Couldn't find any other issues.

Not sure what happened, but I've had no problems up to this point. Truck has less than 2k miles.