Battery saver message

[hybridbear]

First, I don't see any Wiki link. Is this really just the "enhanced" version of a scan tool ?

 

Secondly, while the design of the overall car is different, the battery is still just a battery.

I've been an Electronics Engineering Tech. for about 45 years now so what I am about to say is not idle speculation.

 

A 12 V car battery is NOT designed to sit at 50% charge for long periods. It just isn't. The newer AGMs tolerate that a little better but not much.

 

So I'm pretty sure that you seeing that occasional "BS" message, coupled with the fact that your are seeing a SOC reading lower than 90% for long

periods of time really indicates that you have a problem brewing. All of that is not normal.

 

If you refuse to attach a battery tender during long periods on non-use, it's likely that you will have short battery life and repeated failures.

 

Right NOW your battery has probably been neglected long enough that it needs to be replaced because total failure is probably not far away.......especially without a supplemental charge every now and then.

 

And I am not throwing rocks at you or Ford either. The 12 V battery is a weak spot on a LOT of hybrids......and with a lot of owners too.

 

Ignore this advice if you wish. Your car, your battery and your time.

Others may find the information useful even if you don't.

Post 209 contains the link.

 

I'm not saying that the SOC should be ~60%, I'm reporting what is happening. I also trust the car to manage the SOC without intervention. If the battery dies then Ford will replace it under warranty as they have done for owners with the BS message issues.

 

For comparisons sake, yesterday while over visiting my parents I checked their 12V SOC and their C-Max Energi was reporting a 12V SOC of 99%. This dropped to 98% after making a couple short trips.

 

Perhaps at some point I will use a battery charge to charge the 12V up to full to then see if it sustains that full charge or if it loses it. However, I don't have such a device and don't plan to buy one. Perhaps when I bring my car to the dealer for the eCVT leak I can ask them to check my 12V battery & DC2DC converter charging system to make sure that everything is working correctly.

[larryh]

The commute to work is only 15 minutes. The current to the 12 V battery was near zero during the last five minutes. The SOC went from 82% to 85% during the commute. The resolution of the current measurement is only one amp, so I can’t measure fractions of an amp. I will need to continue to monitor the car to see how the SOC gets down to 55%. So far in the past day it is has mostly gone up, from 55% to 85%.

 

A few weeks ago Sunday, I recorded what the car was doing while charging the HVB. The car charged the HVB for about two hours. The SOC of the 12 V battery was 73% at the beginning and 76% at the end. The car maintained 14.5 Volts to the 12 V battery for four minutes. Then dropped the voltage to 13.3 Volts for the remainder of the time. During the first four minutes, the current dropped from 13 amps to 4 amps. The SOC rose from 73% to 74%. After the voltage drop, the current was less than an amp—the car doesn’t show fractions of an amp. The SOC rose to 76% by the end of the two hours. If the car wanted to aggressively increase the SOC of the 12 V battery, it should have maintained the 14.5 V to the 12 V battery the entire time. But it didn’t. I have no idea why yesterday it decided to aggressively increase the SOC from 72% to 85%, but three weeks ago Sunday, it only decided to go from 73% to 76%.

 

[taullinis]

I am curious for those of you monitoring this are you using Torque? If so are you using a built in monitor or a custom PID, again if so what PID/math?

[larryh]

I am curious for those of you monitoring this are you using Torque? If so are you using a built in monitor or a custom PID, again if so what PID/math?

If you have an ELM 327 scanner and a PC, you can download FORScan to get all the available PID measurements. Go to forscan.org.

 

The latest version of Scan Gauge may also show them. I'm not sure if it is readily available yet. I saw a discussion regarding that at the MyFord Mobile web site recently.

Edited May 27, 2014 by larryh

[Easy Rider]

 

For comparisons sake, yesterday while over visiting my parents I checked their 12V SOC and their C-Max Energi was reporting a 12V SOC of 99%. This dropped to 98% after making a couple short trips.

 

However, I don't have such a device and don't plan to buy one.

Well that's more like what it should be.

 

A small battery tender can be had for about $30 and is useful in several situations.....like leaving something on and running the battery down by mistake.......or finding the battery that you suspected has finally gone flat on that morning that you MUST be at work on time for an important meeting and can't wait for the tow truck......or when you plan to leave the vehicle idle for more than 10 days.

 

It is also a quick rough way to check the battery and charging systems health. You connect the tender after it has sat overnight. If the "green" light comes on within a couple of minutes, it's a good bet that everything is healthy. OTOH, if the green light is still not lit after several hours, you might want to get it checked out. The system really IS designed to keep it almost fully charged all the time.

 

BUT it is your time and your money and YOU that will have to deal with the hassle if it finally fails at a bad time so don't get a charger; no skin off my nose.

 

I encourage you, however, to not wait too long before getting it checked out.

[Easy Rider]

I have no idea why yesterday it decided to aggressively increase the SOC from 72% to 85%, but three weeks ago Sunday, it only decided to go from 73% to 76%.

 

 

SIGH. There is NOTHING in the charging system or it's associated logic that makes changes like that ON PURPOSE.

It has not "decided" to do that.

Something is wrong.

I quit.

[larryh]

Note that I have a Fusion Energi. The SOBDM module controls charging of both the High Voltage Battery and the 12 V battery when the car is plugged into the 120 V or 240 V charging station. It decides when and how much to charge each battery. I have it programmed to charge the car starting around 1:00 am when the electric rates are low. This an excerpt from the following document http://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM1303_HEV.pdf.

 

The SOBDM, also known as the Battery Charger Control Module (BCCM), is an air-cooled component that charges both the high voltage battery and the low voltage (12V) battery when the vehicle is not operating and plugged into a (110V or 220V) EVSE. The SOBDM is known as the on-board charger. Its primary function is to coordinate charging operations and convert AC to DC. The SOBDM incorporates an integrated module that communicates with other modules over the HS-CAN, and is located inside the high voltage battery pack electronics compartment.

Edited May 28, 2014 by larryh

[larryh]

I tried a simple experiment to verify what SOC is measuring. I plugged the car into the 240 V charger with the charger turned off and turned on the car. When I do this, the DC to DC converter is disabled and the entire 12 V power supply to run the car comes from the 12 V battery. The lights, radio, and other accessories in the car consumed 23 amps of power for about 25 minutes. The SOC dropped linearly from 81% to 51% (R^2 = 0.9976, where 1 is perfectly linear). The equation for SOC vs. time was:

 

y = -0.0211x + 80.695,

 

where y is SOC in percent and x is time in seconds. Interpolating (which probably is not accurate), if the SOC were 100%, it would take 100/.0211 = 4739 seconds or 1.32 hours to discharge the battery drawing a current of 23 amps. That means the capacity of the battery is 23*1.32 = 30.2 Ah. The rated battery capacity is 43 Ah. I don't know the actual procedure used to compute battery capacity.

 

At 51% SOC, the car no longer powers the power points after turning off the car. So it definitely recognizes that the 12 V battery is low and is trying to conserve energy.

 

I previously did this unintentionally. The car stopped working after 45 minutes. So extrapolating, the car is completely dead when the SOC is about 25%. I don't intend to repeat this experiment again to determine the actual value.

Edited May 28, 2014 by larryh

[larryh]

This morning, the car charged the HVB and the 12 V battery from 12:56 am to 2:44 am. The SOC of the 12 V reached 72% (it was at 51% last night after my experiment posted above). It then continued to charge the 12 V battery until 4:57 am. The final 12 V battery SOC was 73%--the SOC didn't increase very much during these last two hours. This time, the car provided 14.3 V for the 12 V battery the entire time. How many hours does it take to fully charge a 12 V battery? I will have to see what an external battery charger does. Since the car is plugged in all night every night, I don't see why the car shouldn't be able to maintain the 12 V battery at 100% SOC. It seems very strange that 2+ hours of charging each night can't maintain the 12 V battery at 100% SOC. Either the car is not measuring the SOC properly, the battery is not working as expected (although I have not had any problems with the battery), or the engineers don't think it is important to maintain the battery at 100% SOC.

 

I noticed about 5 minutes into my commute this morning the DC to DC converter changed the 12 V setpoint from 14.4 to 13.3 volts, even though the 12 V battery SOC was 73%.

Edited May 28, 2014 by larryh

[Easy Rider]

I don't see why the car shouldn't be able to maintain the 12 V battery at 100% SOC.

 

the battery is not working as expected (although I have not had any problems with the battery),

 

I don't see why either; it absolutely should.......at least a lot closer than 73%

 

And the readings and experiences that you have stated on here DO INDICATE THAT YOU ***ARE*** HAVING PROBLEMS WITH THE BATTERY, probably.

 

You have now dragged it down to about 50% at least twice.

Once or twice more and your battery problem will become painfully obvious.

 

Why are you so stubbornly still screwing with it when you should be having the shop check out the battery and the charging ?????

[larryh]

I have an annual inspection coming up with the dealer soon. They check the battery as part of the inspection. People might find my observations useful.

Edited May 28, 2014 by larryh

[murphy]

I wonder if they are treating the 12 volt battery the same as they do the HVB in the mistaken belief that it is good for the battery. They prolong the life of the HVB by never fully charging or discharging it That is valid for a Li-Ion battery. It is not valid for a lead acid "starter" battery. Wet cell lead acid batteries are supposed to be kept at 100% charge most of the time.

 

I also wonder how they are determining SOC for the 12 volt battery. Measuring the voltage under a known load would provide an estimate. Measuring the coulomb (look it up) flow into and out of the battery would be better.

[Easy Rider]

I wonder if they are treating the 12 volt battery the same as they do the HVB in the mistaken belief that it is good for the battery.

 

Measuring the coulomb (look it up) flow into and out of the battery would be better.

 

No not possible. Others are not having problems like that. And the Engineers at Ford aren't THAT stupid.

They have known how lead-acid batteries work for about 60 years now and nothing much has changed.

 

 

The two people in this thread who ARE having 12 V battery problems either have odd driving habits OR their battery is bad. Based on the experience of other hybrid owners, of all different kinds of models, it most likely is the battery itself but it could be the charging system or even just a bad connection somewhere.

 

As far as knowing the SOC, it's pretty easy. You apply a know voltage to the battery and see how much current it accepts. As the current flow goes down over time, you drop the voltage a "step" and have a new standard for the current flow.

 

The problem with that IS.......that as batteries die, they tend to develop a high internal resistance which makes it LOOK like they are fully charged when they are NOT.

 

You charge it up with an external charger.

You let it sit for at least an hour.

You apply a load tester to it.

If it fails, you replace it.

Pretty much the same procedure that has been used for 60 years or so.

 

There's a "gotcha" with the load test too. Sometimes there are intermittent connections or intermittent shorts inside the battery.......so that it is possible to have it test "good" only to fail a few minutes later.

[Easy Rider]

I have an annual inspection coming up with the dealer soon. They check the battery as part of the inspection. People might find my observations useful.

 

Indeed folks here might find your observations useful........and the ensuing discussion too.

 

I just hope that your dealer visit isn't TOO far off.

My wild guess is that you have less than 60 days before things get a LOT worse.

 

 

 

[corncobs]

As someone that has maybe seen the BS message twice in 1.25 years I just got one.

 

Mine has been sitting in the driveway since Friday and was moved once a few feet to get her cleaned easier. Today I drove 4 short trips around town and now at stop #4 I turned of the car and got the BS message almost immediately maybe after 20 sec.

 

It's all about the longer drives and charging the LVB like Larry said and short drives just take the life out the LVB.

[larryh]

I tried a simple experiment to verify what SOC is measuring. I plugged the car into the 240 V charger with the charger turned off and turned on the car. When I do this, the DC to DC converter is disabled and the entire 12 V power supply to run the car comes from the 12 V battery. The lights, radio, and other accessories in the car consumed 23 amps of power for about 25 minutes.

 

I previously did this unintentionally. The car stopped working after 45 minutes. So extrapolating, the car is completely dead when the SOC is about 25%. I don't intend to repeat this experiment again to determine the actual value.

Note the first time that I did this unintentionally, the voltage fell significantly more after 25 minutes than the other day. But that was when it was cold at the beginning of February. Both times, the voltage started out the same at 11.65 V. In February, the voltage dropped to 10.85 V after 25 minutes. This time, it fell to 11.3 V.

Edited May 28, 2014 by larryh

[larryh]

I also wonder how they are determining SOC for the 12 volt battery. Measuring the voltage under a known load would provide an estimate. Measuring the coulomb (look it up) flow into and out of the battery would be better.

 

It would be nice to know how they are determining the 12 V battery SOC and how accurate it is. I suspect they keep track of the amount of current flowing into and out of the battery. Obviously, the car tracks the 12 V battery current and voltage, or I wouldn't be reporting it. It also tracks the 12 V battery estimated temperature, age, and type. Finally, it has several counts that it maintains: Cumulative Battery Charge When Ignition Is On, Cumulative Discharge From Battery When Engine Is Off, Cumulative Discharge From Battery When Engine Is On, and Cumulative Discharge From Battery in Sleep Mode. I suspect this method requires a good model of how the battery works. Unfortunately, batteries don't always work as expected, and then the model would no longer accurately describe how the battery works and would yield incorrect results.

Edited May 28, 2014 by larryh

[Easy Rider]

Can't cut and paste here.......AND can't delete my own pathetic mistake of a post........so I will just leave this dummy and start over.

MOST FRUSTRATING.

Edited May 28, 2014 by Easy Rider

[Easy Rider]

As someone that has maybe seen the BS message twice in 1.25 years I just got one.

 

 

Sounds to me like you REALLY need a battery tender.

I saw one at Lowe's today for $20.

[rvlasek]

Thought I had it licked with new Battery change out on February 27, 2014 by Ford Service after contacting Ford customer Service, " Battery Saver" message returned again this week, pretty much every time turn off ignition............

[corncobs]

 

Sounds to me like you REALLY need a battery tender.

I saw one at Lowe's today for $20.

Well I already have one but I know why I saw one today but it's not enough reason to hook up a battery tender.

Maybe I try to connect my solar charger again which I removed for window tint other than that I turn off my car and leave right away 99% of the time.

[hybridbear]

Well that's more like what it should be.

 

A small battery tender can be had for about $30 and is useful in several situations.....like leaving something on and running the battery down by mistake.......or finding the battery that you suspected has finally gone flat on that morning that you MUST be at work on time for an important meeting and can't wait for the tow truck......or when you plan to leave the vehicle idle for more than 10 days.

 

It is also a quick rough way to check the battery and charging systems health. You connect the tender after it has sat overnight. If the "green" light comes on within a couple of minutes, it's a good bet that everything is healthy. OTOH, if the green light is still not lit after several hours, you might want to get it checked out. The system really IS designed to keep it almost fully charged all the time.

 

BUT it is your time and your money and YOU that will have to deal with the hassle if it finally fails at a bad time so don't get a charger; no skin off my nose.

 

I encourage you, however, to not wait too long before getting it checked out.

Concerned that you're unable to sleep at night due to worrying about my 12V battery I decided to hook it up to the charger at my parents' house this afternoon. The charger showed that it was putting in about 7 amps when I first turned it on. After about 4 hours it had dropped to 5 amps. At that point I unplugged it because we were leaving. The car now reports the 12V SOC as 99%. It will be interesting to see where the SOC goes over the next week. It seems to lose about 15% SOC when the car sits for a week without being used, as it does every week.

[GrySql]

Can't cut and paste here.......AND can't delete my own pathetic mistake of a post........so I will just leave this dummy and start over.

MOST FRUSTRATING.

I've got a better idea, don't post anything and give us a chance to catch up on all the great advice you've given us so far.

Believe me, it's MOST FRUSTRATING for us too.

 

(BTW, since you're new here I thought I'd mention that using CAPITAL LETTERS is the same as SHOUTING AT SOMEONE. It's rude, but you probably already knew that.)

[Easy Rider]

I've got a better idea, don't post anything and give us a chance to catch up on all the great advice you've given us so far.

Believe me, it's MOST FRUSTRATING for us too.

 

(BTW, since you're new here I thought I'd mention that using CAPITAL LETTERS is the same as SHOUTING AT SOMEONE. It's rude, but you probably already knew that.)

 

How about commenting on the CONTENT of my posts instead of taking pot shots about my posting STYLE ??

 

And occasional words in CAPS is a perfectly acceptable form of EMPHASIS in a typed communication.

Why does it bother you anyway ?? Or is that just another pointless criticism because you don't like or agree with some of my posts ??

 

If my posts are frustrating to you, it is ONLY because YOU make it that way.

[Easy Rider]

Concerned that you're unable to sleep at night due to worrying about my 12V battery

 

I guess I've said too much already.

Please let us know how long it is before your battery fails completely.

 

I sleep just fine at night.......,but thank you for caring.