Towards the end he turns off the key and checks the amps again, it shows 33-34 amps in, he's putting in over 40 amps. Still quite a bit of "parasitic draw".

 

I've never liked this guy for that exact reason. He has a mix of excellent helpful info, and some really misleading stuff, like this. Anyway, I think I've explained my opinion well enough, people can draw their own conclusions on what a normal parasitic draw is and the appropriate charge amperage to overcome that when the vehicle sits overnight or for several days/weeks/months etc.

 

Sorry if this has already been pointed out.
But what would be a normally expected current draw for the truck just parked with alarms on?
What is it drawing on average with normal driving?
Why is there not a bigger alternator so battery is not drawn down?
WOuld it be a good idea to put a bigger alternator in?
Is there any benefit to a larger capacity battery or will it just take even longer to charge?
My mind is blown by just How Much Electrical there is!
Steering, brakes even 🤯
I camp and now have installed a backup battery to charge anything else because I don't want to drain truck battery as apparently the truck takes it all and then some. I also carry a HD booster pack.
These modern vehicles are freaking me out. 😑
I worry about being stranded way out in the bush. I got a new vehicle for this reason.....
Thx

 

I got the Forscan software, and changed the battery charge level from the factory setting of 70%, to 100%. I never had an issue , but lots of threads about it and felt it was largely due to the fact that the monitoring of and intentionally charging to less than 100% for gas mileage , was to blame. Had it set this way for nearly a year...no problems to report.

 

2021 f150 lariat 2.7
What do you think might be the issue?
My battery exists in an almost perpetual state of reduced charge.
I am reluctant to change anything via forscan lest I void the extended warranty I got specifically because the truck is a rolling computer.
My truck always starts, the auto start/stop never works. Frequently my passenger door lock fails(it's the next to go), but it always starts.
I just feel so restricted when camping. I freaking bought a 100W solar panel and controller just for the damn truck. Ugh.

 

That's what you get for watching Youtube. They don't know jack and then you share it..
A 1 or 2 A battery tender will charge the battery, it just takes awhile.

My 17 F150 had the battery issue when it was brand new. They ended up sticking a larger capacity battery in it. It's still on that Motorcraft battery today. The truck sits at our vacation house now and stays on a 750ma Battery Tender and it stays fully charged.

 

Yes, a 1 amp, or 0.75 amp, maintainer will work fine for overnight or weekend, or week-long sitting. That's plenty big enough for that. Those small sizes are not quick enough to recharge a depleted battery quickly. I am a battery charger/ maintainer geek, so obviously I have five different chargers for different purposes.....

 

There are no simple fixes to a complex system.
The Battery system is designed to run in the 12.0 to 12.8 voltage range state of charge.
The pre-cranking voltage is usually in the 12.0 to 12.4 range.
Running voltage in the 14.0 to 14.8 range. This voltage level drives Current to re-charge the Battery ...and supply the rest of the vehicle needs. This means the charge is split between the two Current needs, at any given time.
After starting, the drive cycles have to be long enough to get a 'reasonable' Battery re-charge.
The AGM Battery full charge voltage is normally cell voltage of 2.15 times 6 cells = 12.9 volts max.
Ford design usually runs the Battery at a state of charge in the 60% range to increase Battery life.

Next on A S/S : There is a Module called Voltage Quality Monitor.
If the voltage available is more than 1 volt too low, this Module inhibits auto start by design and message sent to start the vehicle manually. There are actual faults on a separate basis with DTC Codes assigned, that inhibit auto start..
Reason is to let the driver know there is a low voltage condition or fault to be evaluated before it lets you set with a no crank condition, somewhere.
.
Drain Current needs to be checked for being excessive.
Charging needs to be checked etc.
The Battery is not always the cause. A replacement will result in the same issues after some time if these parameters ae not looked at and corrected where needed.
.
Some other Charging info: The OEM Battery as an H6 AGM has a 70 amp hour rating when new. Under the charging C rule of .1; that means 70 x .1 = a 7 amp charge rate or lower from Aux charging. The Current charging level, determines how long it takes to go full charge as well as from what "discharge level" it begins at.
If higher charger rates are used it shortens the charge time but shortens Battery life, with it.
This is where vehicle drive time becomes important.
Higher Alternator capacity des not solve any issues. Larger Battery capacity just lengthens the time interval to the same end result, over again.

A lot to throw at you but things need to be said, the operation is not so simple but must be understood to some level if any solution is to be found.
Good luck.