Battery Question

[Greg2060]

I typically take only short drives, 3-4 miles several times a week with and occasional trip 10-12 miles. So when the ASS stopped working I contributed it to the battery not being fully charged. The voltage gauge would always be in the 14.2-14.8 range, but lately it has been up to 15.2.

I picked up a battery charger/maintainer on Amazon during their black Friday sale to fully charge the battery (NOCO genius 5) but after charging it I see no difference in the voltage reading and the ASS is still not working. Attached photo shows how I hooked up the charger being mindful of the BMS and attached it to the tab off the negative battery terminal.

It only took about 20-30 minutes for the charger to indicate that it was fully charged but I left in on overnight.

Is there something else going on here or did I do something wrong? I was expecting the voltage to drop and the ASS to be functional again. Is there a way to tell if the battery is at 100%? Any insight would be appreciated.

Thanks.

Sponsored

 

[BigHoof]

Is it colder now where you live? Maybe the engine is not getting up to temp with such short trips? ASS has many reasons to not activate in addition to a low battery.

 

[BAUS67]

Not sure where to start. A tender only reads surface voltage. (whats on the post) This is not the true voltage in the battery. Once this surface charge reaches 12Vthe tender will turn off. If you go and take the negative(black) clamp off and re-connect it, more times than not, it will start a charge cycle again. AGM batteries are hard to load test. in other words you can load test it and it will show fine, but still have issues with the battery. Fully charged should be around 12.8 Most times if I have to charge a battery I disconnect the negative terminal end. This way all the charge goes in the battery not into something that is still "on".


One piece of advice I can give you. When you know you are going somewhere go out and start the Bronc 15-20 minutes before you leave. All accessories off/unplugged, no radio, no heat, etc. When the ECM sees the car is not moving it will send the extra juice into the battery. Batteries in todays cars do not charge while driving them. They have way to much draw on them while driving to charge the battery.


Just for the record. I drive 7 miles to work 6 days a week. (about 10 minutes) My Bronc sometimes sets for 3/4 weeks in between drives. I use the described method above and have not had an issue in the 2 years I have owned it.

 

[Greg2060]

Is it colder now where you live? Maybe the engine is not getting up to temp with such short trips? ASS has many reasons to not activate in addition to a low battery.

The ASS stopped working several months ago, but I considered that a good thing. I always manually shut it off anyway. So I don't believe it is temperature related. My main concern is that I am shortening the batteries life by running below full charge for extended periods.

Batteries in todays cars do not charge while driving them. They have way to much draw on them while driving to charge the battery.

Thanks for the insight, but if the battery is not charging while driving, when does it charge?
I'll try running the engine longer before leaving to see if that helps.

 

[Brian_B]

Thanks for the insight, but if the battery is not charging while driving, when does it charge?

Well, anytime you see the voltage over 12.8 on the console, there's some charge going to the battery. Just a matter of how much it making it into the battery and how much is feeding all the rest of the stuff running on the Bronco.

You aren't going to shorten your battery life doing anything you are doing. Keeping the tender on it if you aren't going to be driving it for a few days is a great idea, but you don't need to leave it on every night. The Bronco BMS system is gonna do it's thing to the battery based on SOC, temperature, what the vehicle is doing, and a heap of other things - it's actually fairly sophisticated. Perfectly normal to see voltage fluctuate from high 12's to low 15's while it's running.

Just for reference, I have a Noco 10 that I use a lot. When I'm doing something like Forscan with Key On Engine Off - the Noco will show the battery almost dead. That's because there's a lot of draw on it from the computers and stuff, so the voltage is a bit lower. Soon as I turn the key back off - maybe 5 minutes later it goes all the way up to full charge. I can watch it bounce back and forth all day long as I toggle the key.

From the factory, the Bronco targets to keep the battery at 80%. So the tender only taking a little bit to top it off is actually fairly normal.

Just ASS being off I wouldn't worry to much, @BigHoof is correct, there's a bunch of things that can deactivate ASS - low battery SOC is only one of them. If you start to see the Deep Sleep messages, that's when it's time to get serious.

This is what a quick Google Search popped up:

Bronco Auto Start Stop Conditions

Based on the provided search results, here are the conditions under which the Auto Start/Stop (AS/S) feature on the Ford Bronco operates:

1. Initial Speed: The vehicle must exceed an initial speed of 3 mph (5 km/h) after starting.
2. Stopped Vehicle: The vehicle must be stopped, with the transmission in Drive (D) and the brake pedal pressed.
3. Driver Door Closed: The driver’s door must be closed.
4. Adequate Brake Vacuum: There must be adequate brake vacuum.
5. Interior Compartment Temperature: The interior compartment must have cooled or warmed to an acceptable level.
6. Front Windshield Defroster: The front windshield defroster must be off.
7. Steering Wheel Not Being Turned: The steering wheel must not be being turned.
8. No Steep Road Slope: The vehicle must not be on a steep road slope.
9. Optimal Battery Conditions: The battery must be within optimal operating conditions, including state of charge and temperature range.
10. Engine Coolant Temperature: The engine coolant must be at operating temperature.
11. Ambient Temperature: The ambient temperature must be moderate (not extremely hot or cold).

 

[Greg2060]

Thanks. Haven't seen any Deep Sleep warnings yet. With all those conditions where ASS could deactivate, I'm surprised it ever works at all!

 

[BAUS67]

The ASS stopped working several months ago, but I considered that a good thing. I always manually shut it off anyway. So I don't believe it is temperature related. My main concern is that I am shortening the batteries life by running below full charge for extended periods.



Thanks for the insight, but if the battery is not charging while driving, when does it charge?
I'll try running the engine longer before leaving to see if that helps.

Like Brian B said it is only a small amount of the alternator output is going back to the battery when driving. Larger amounts when not driving. That is why they use an AGM battery not a flooded battery. They can handle the low charge conditions. The problem when the charge gets low the computers start freaking out. Some vehicles will "lock you out" if charge is too low. Then people think they need a battery but it just needs charged. I have seen todays cars start on 7/8 volts. It does not take much to start a car. It is just the ECM starts to shut down when the charge starts to fall off.

 

[Fmuguira]

My ASS and everything is working fine but I often don’t drive my Bronco for 5-6 days… when I do it’s showing 15.2 amps charging and if I drive 20-30 miles it ll go down to 14.8 or maybe 15.0. It takes an hour or two drive for it to typically get low 14 or high 13 range …. Are others seeing same behavior? Any problems pending with such useage?

Thx for input

 

[Ducati1098]

My ASS and everything is working fine but I often don’t drive my Bronco for 5-6 days… when I do it’s showing 15.2 amps charging and if I drive 20-30 miles it ll go down to 14.8 or maybe 15.0. It takes an hour or two drive for it to typically get low 14 or high 13 range …. Are others seeing same behavior? Any problems pending with such useage?

Thx for input

Sounds pretty normal. Unless you're having an issue, it's really not something you need to worry about.

 

[Brian_B]

My ASS and everything is working fine but I often don’t drive my Bronco for 5-6 days… when I do it’s showing 15.2 amps charging and if I drive 20-30 miles it ll go down to 14.8 or maybe 15.0. It takes an hour or two drive for it to typically get low 14 or high 13 range …. Are others seeing same behavior? Any problems pending with such useage?

Thx for input

The BMS will charge not only off low battery - there are other conditions. One example: if you are engine braking down hill, for instance - it will throw more amps into the battery while it can for "free". I have a good stretch of down mountain in my commute - my volts will be at 13.xx and as soon as I start going down hill it will sit at 14.8 to 15.3 the entire ride down the mountain.

 

[Greg2060]

One piece of advice I can give you. When you know you are going somewhere go out and start the Bronc 15-20 minutes before you leave. All accessories off/unplugged, no radio, no heat, etc. When the ECM sees the car is not moving it will send the extra juice into the battery. Batteries in todays cars do not charge while driving them. They have way to much draw on them while driving to charge the battery.

I took @BAUS67 advice and let the car idle for 15 minutes this morning with headlights/radio/heat off. I saw no change in the voltage gauge, still read 15.2. Took a 4 mile trip to the store and on the way back the ASS started functioning again. The voltage dropped to 14 when the engine cut off and then jumped back up to 15 when it restarted. I guess that the battery wasn't really that low on charge after all.
Thanks for everyone's input

Sponsored