Charging voltage high 15 on average. Need cold weather feedback (Minnesota) Battery already replaced.

[BroncoDave24]

Just from my observations - the Bronco BMS has four states that it cycles through:

15V+ “High Charge” - you see this if the battery SOC is really low (I don’t know the exact figure, maybe 50%?), or during “regenerative braking” events, or sometimes immediately after starting the engine

~14.5V “Charge” - this is when the BMS is just topping off the battery trying to hit that 80% SOC with a slow and steady charge rate

~13.5V “Float” - alternator is carrying all the vehicle load but not actually charging the battery. Means you are right around that 80% SOC mark

~12.5V “Battery Only” - you will see this mostly when ASS kicks in (obviously since alternator isnt spinning) but it can also pop up while driving, Bronco shuts off the alternator and lets the battery draw down some because it has exceeded 80% SOC

Interesting... That makes perfect sense! I will add one more comment:

It may help to understand the job of the "smart shunt" sensor that connects to the negative battery post. It sends a lot of info to the ECU so the regulated voltage is always optimum. This includes the exact temperature of the battery, the exact voltage at the battery, and the net current flowing in or out of the battery.

I also can agree with @dougcjohn about using the factory battery, or at least using a battery that has specs IDENTICAL to the factory battery, and that's not always easy to find. The algorithm that the ECU uses to calculate optimal charge is based on a set of exact specifications of the battery, which the factory battery would definitely match. If you change the specs of the connected battery, say the float voltage/temperature ranges are different, or more commonly, the CA or CCA is increased, the algorithm can't do it's calculations correctly. I'm not saying it won't work, it's just not optimized!

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[idontknow]

Appreciate all the feedback guys. Seems the battery was definitly on the low side. I only have a smaller tender that I use for charging the batteries for my kayak fish finder. It is a car battery tender but definitly not a fast one. I hooked that up last night.. was still charging this morning after 12 hours.

Started the car up…slowly went up to 15v charging.. then after i pulled out of my garage it settled out To 13.9 my whole way here. Gonna toss it on a charger again tonight and also take it for a “scenic drive” this weekend. Thanks again!

 

[Area51BS]

First time driving in very cold temps for me today. 15.1v. Never seen it that high before. Return trip after parking was normal 14’s.

 

[LSW]

I just watched my volts on my 20 minute/15 mile commute today. Last drive was 2 days ago for 1 hour+ so it should’ve been close to fully charged. Temp was 25 degrees and it had been garaged overnight in 65 degrees. Volts stayed at ~15.1 until about 10 minutes into the drive and which point they decreased to ~14.8. They fluctuated up & down between 14 and 15 a few times but mostly stayed in the 14 range after the initial 10 minutes. This is pretty typical in what I’ve observed in my 3 years of Bronco driving.

 

[HoosierDaddy]

Just from my observations - the Bronco BMS has four states that it cycles through:

15V+ “High Charge” - you see this if the battery SOC is really low (I don’t know the exact figure, maybe 50%?), or during “regenerative braking” events, or sometimes immediately after starting the engine

~14.5V “Charge” - this is when the BMS is just topping off the battery trying to hit that 80% SOC with a slow and steady charge rate

~13.5V “Float” - alternator is carrying all the vehicle load but not actually charging the battery. Means you are right around that 80% SOC mark

~12.5V “Battery Only” - you will see this mostly when ASS kicks in (obviously since alternator isnt spinning) but it can also pop up while driving, Bronco shuts off the alternator and lets the battery draw down some because it has exceeded 80% SOC

Awesome description for us knuckle draggers! LOL

FWIW to add to the discussion, we have been pretty cold here for a week or two and forecasted the same for another week.
Meaning:
Overnights of below zero/single digits and highs just reaching the teens (F) (-18*C to 7.2*C) .... the few times I have driven the Bronco, I noticed the voltage reading in the 15v range.

2021 Base 2.3 manual ... 45k miles ... original OEM battery. Sits outside this year.

I cycled it with a BatteryTender® last summer, we'll see how far I can make it last.

 

[dejones64]

2022 2.3 7mt, replaced the battery last July while on a cross country trip, because to voltage displayed 12.2-12.8 or lower. Seemed low to me but I was just starting out on a backcountry adventure and didn't want trouble. Dealer ran diags and thought it was low too, also had the alternator replaced (under warranty, battery out of pocket).

This winter I've noticed a majority of the time at 15-15.2, sometimes 14.5-14.9. I attribute to the cold weather.

Dealer said not to worry, Ford says the range is 12.2-15.2. Once in awhile I'll see 15.3.

I haven't had issues, will see once it warms up I guess.

Edit: I drive about 60 miles a day.

 

[Area51BS]

We are now back at normal temps. I’m still seeing 15.1 volts for better part of a day. Then at some point it goes back down to 14. Never any warnings. Interior lights do go to sleep when parked for the week. Might be nearing battery time. No other indicators.

 

[AZMikeL]

Sounds like your battery is long in the tooth. I was pegged above 15 for several months on mine. I really didn't even notice it until my ASS quit working after A/C season (8 months here!) and then got deep sleep warnings a week into a work trip to India.

Bought a replacement at Costco for $179 and used the BMS cheat code to reset.

Wife's 10 YO BMW battery needed replaced a couple of months later. Dealer price - $850, trusted shop price up the road - $630. You have to reset the BMS on those cars via OBD programming. Wish they would get with the program like Ford and offer a cheat code to do it!

 

[dejones64]

Had a few warmer days here in MN. My voltage has dropped down, I've seen 12.9-14.9. Granted my battery and alternator (2nd ones), are only about 8 months old. I do see fluctuations as I'm driving, letting off gas, giving it gas, manual shifting, seems to level off in the 13's.

 

[idontknow]

Had a few warmer days here in MN. My voltage has dropped down, I've seen 12.9-14.9. Granted my battery and alternator (2nd ones), are only about 8 months old. I do see fluctuations as I'm driving, letting off gas, giving it gas, manual shifting, seems to level off in the 13's.

Same here. Been chilling around low 13.x most days with slight variability. Was 15 when I left work just now and was backdown to 13 by the time I got home.

How much snow did you end up with where you are at? We got about 14” from that storm a couple weeks ago.

 

[dejones64]

Same here. Been chilling around low 13.x most days with slight variability. Was 15 when I left work just now and was backdown to 13 by the time I got home.

How much snow did you end up with where you are at? We got about 14” from that storm a couple weeks ago.

I'm in the Elk River area and I think we got a few inches of snow, wasn't a lot, in my opinion. Storms seem to go north and south of the Twin Cities, the brunt of it.

 

[Easy-v]

I noticed my hitting 15 and above this past winter as well. With nicer weather it goes back down at least that’s what I’ve been seeing for the last few weeks.

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