Ranger Mods

I'm still trying to understand exactly what is going on with the dual battery setting and its effect on the alternator behaviour and resulting state of charge. First some background. Everest Trend 2015 currently with 800CCA 80Ah AGM [Century DIN75LH] battery fitted. Initially the dual battery system was fitted by a local Auto Elec - simple isolating solenoid and a "trick" to tell the alternator that it has a load from some non existent heated seats. I have never understood this, nor had a satisfactory explanation, however I believe whatever it was may now be removed since Ford installed the above battery and reset the BCM module - as the alternator voltage suddenly was no longer constant 14.4 V - also see attached Forscan output from FCIM module.

So.... I've run some tests measuring Volts, Amps & SOC for Single Battery, 90% Dual Battery & 100% Dual Battery - See attached output
Single battery charges to around 85% SOC and then the alternator starts to cut in and out with charge fluctuating [+ -] 20 Amps in a very erratic manner. Is this normal? - have others experienced this erratic charging behaviour? I would have expected a smoother response from the alternator.

Dual Battery 90% has a similar behaviour - but charging to about 95%. It would appear that the BCM is monitoring the SOC and cutting the alternator voltage when the target SOC is reached.

Full Dual Battery 100% Shows much smoother charging with a constant 24/7 14.4 Volts & Amps slowly reducing as the battery slowly reaches maximum charge as you would expect. It did not reach 100% SOC this run - bit over 90%, but it did before & I expect with constant 14.4 V charging it will eventually reach 100% again.

So my questions to the more auto electrical astute are:

1. Ford appears to feel that charging the battery to only 80% SOC is good for the battery - Is this true? I would have thought repeatedly undercharging the battery may not have been such a good idea?

2. Is long term continual charging [14.4 V] of a sealed AGM battery not a good idea - with overcharging resulting in gassing and loss of [non replaceable] electrolyte in these valve regulated sealed batteries? As my dual battery is very part time - mainly not in the car, except for trips, would I be better to run mostly in single battery mode or part dual battery [what level?] for better battery care & fuel economy? Or just leave it dual battery full time.

3. I have now installed a DC-DC charger for the second battery - do I even need dual battery mode now?

4. Have others noticed the erratic charging behaviour in single battery mode? Is this normal?

Cheers

John

Excellent post John. I too will await the responses from any experts here as I too have been trying to decide. My setup is similar to yours and have set mine to 14.4v in Forscan.

I played with this stuff in Forscan and I have settled on two things.

I run mine on 14.4volts which is supposedly 90% but it still sits on 14.8v and reach 97% capacity.

I will switch mine to 16v, DBM when I tow the van so it charges the van battery.

I could never achieve 100% with the original battery, even running DBM, so I think the battery may not be the best.

I have a Bluetooth monitor on the van battery and the Ranger alternator keeps the vehicle and van batteries at 100%, now I have a better battery in the Ranger.

No DC2DC charger required at this stage.

I have a compressor fridge in the van so it will/does run directly off the battery.

Ross are you saying you measure 14.8v alternator output?

Where are you measuring from?
What are you measuring with?

Just a note on item 2 above. I have had my 120amp charging at between 14.3 and 14.6 for 6 years now without ill affect.

Measured at the battery with a multimeter Stewart, and also get 14.8 with OBDLink.

Get 14.8 all the way back to the caravan battery.

As we all know, not all multimeters will read the same either.

What ever I do I only see a max of about 14.28v so may look into this further.

I will try my other multimeters tomorrow.

The voltage in my graphs is control module voltage - but I'm sure this lines up with my direct multi meter readings - but I'll check this & amps as well.

Do either Stewart or Ross have any insight / comments on the somewhat erratic charging behavior[+-20A] once the target SOC is reached - I guess I'd expected a somewhat smoother response from the alternator.

Ross - In my 90% test the voltage sat on around 14.4 volts steady during the initial charging period and then in the latter period fluctuated between 14.9 volts when the alternator was charging and 12+ ish battery volts when the alternator was idling. I guess at the end of the day the 90% mode did bring the SOC up to around 95% and stabilize it there as requested.

Stewart - Can you throw some light on exactly how SOC is being computed in the BCM? I presume it is based on some form of cumulative Coulomb counting based off the shunt on the negative battery terminal. This gives accurate changes in the SOC - but how is the absolute "full battery" reference SOC determined?

Having done some more research - it would appear that FORD think single battery mode - part charging the battery to around 75% is a good idea - but can't find any battery manufacturer sources to support this & I would certainly like some spare capacity in my battery when needed.

The other issue is that a healthy float charge for an AGM battery is around 13.6 - 13.8 volts - so continuing to charge indefinitely at around 14.5 volts on dual battery mode may have some consequences for battery life.

On balance, I think I agree with Ross - maybe run dual battery on trip with a second battery on-board and 90% dual battery mode the remainder of the time.

John

I tested the charge volt readings from 3 sources today.

Forscan charge capacity set 14.4v @ 90%

Batery @ 98% capacity.

Multimeter #1 = 14.80v (usual one used)

Multimeter #2 = 14.82v

OBDMLink = 15.10v

This is info I have been given

State of Charge in Volts

Sealed or Flooded Lead Acid battery
100% = 12.70+
75%   = 12.40
50%   = 12.20
25%   = 12.00
0%     = 11.80

Gel Battery
100% = 12.85+
75%   = 12.65
50%   = 12.35
25%   = 12.00
0%      = 11.80

AGM Battery
100% = 12.80+
75%   = 12.60
50%   = 12.30
25%   = 12.00
0%      = 11.80

saeb wrote: ↑Sun Jul 01, 2018 10:23 pmJust a note on item 2 above. I have had my 120amp charging at between 14.3 and 14.6 for 6 years now without ill affect.

My car battery is 80A/H, or 1,030 CCA.

netless wrote: ↑Mon Jul 02, 2018 12:04 pmThe other issue is that a healthy float charge for an AGM battery is around 13.6 - 13.8 volts - so continuing to charge indefinitely at around 14.5 volts on dual battery mode may have some consequences for battery life.
John

It maybe no good but only time will tell, I would rather have a battery 100% full than only 70% full.

These modern cars use a lot of power with all the electronics.

I would rather replace the battery in a few years than to be having battery issues.

The Ranger has battery/charging issues and I don't know if the Raptor has Smart Charge.

It doesn't have Adaptive cruise along with a few other things.

Hi Ross

I've checked my OBDLink measurements against my multimeter

The car is currently running in 100% dual battery mode but with no second battery installed.

Everest with ignition / AC / Radio on - but not running

OBDLink MultiMeter [clamp for Amps @ negative earth ; Volts across the battery terminals]
12.3 V 12.3 V
-16 A -16 A

Everest with ignition / AC / Radio on - and engine running at idle - SOC increased from 94% to 95% during these readings

OBDLink MultiMeter
14.4 V 14.35 V
+34 A +34 A : Jumping about at bit

So I'm pretty happy that the OBDLink measurements in my graphs do reflect true measurements at the cranking battery.

Ross I agree with your battery charge level chart - this is my understanding as well.

I used a three stage charger to bring my 80 Ah AGM cranking battery to full charge and final "rested" voltage was 12.86 V and the BMS SOC read 100% which tallies nicely with your table.

I wonder if the non charging steady state full battery [~0 Amps in] voltage is how the BMS calibrates the "absolute" SOC level - as opposed to SOC changes measured on the earth shunt?

Saeb

I think old dumb alternators also put out around 14 + ish V 24/7 - so I guess car batteries are designed to survive this - perhaps 13.6 V float charging is just an optional luxury comfort for modern batteries.

John

I just did a test with the motor off.

One battery only @ 100%

Multimeter was 12.80v (AGM battery so a good reading)

OBDLink was 13.1v

Even in dual Battery mode the BMS is still active. It will load shed as designed, power steering, fans etc. Which may account for the erratic behaviour you are seeing.

At some point I will show all options to do with the BMS and you may be able to make further adjusts and give feed back on those changes. It may also help to understand a little more on how the system operates.

OK Let me know if you open up any further options in the BMS - I would be good to understand better what the BMS system is doing.

Here are the available and changeable BMS items, there are no more and everything else in is firmware so cannot be changed. Default values were from a 2017 XLT I think.

Most items are best left alone.


Function Default Value

Battery Type Cfg (NA): 48
BMS In Car Cfg: LIN
BMS Transport SIeep Cfg: DISABLE
Capacity CIip Cfg (Ah): 30
Climate Fan Speed Limit Cfg (Detents): 9
Climate Fan Speed Limit Rear Cfg (Detents): 9
Climate Fan Speed Power Limit Cfg (Detents): 12
Climate Fan Speed Power Limit Rear Cfg (Detents): 12
Coolant Fan Step Limit Cfg (NA): 19
Drain Load Shed off Cfg (percent): 100
Electric Power Assisted Steering Load Shed In Car Cfg: ENABLE
Feature Max Cfg (Counts): 8
Load Shed Vehicle Type Cfg (NA): 2
Refresh Function Active Cfg: TRUE
Shed Timer Enable Cfg: ENABLE
IVT Sensor Cfg: NONE
SOC Critical Cfg (percent): 30
SOC LSoff Cfg (percent): 40
SOC Max Cfg (percent): 95
SOC Off Cfg (percent): 0
SOC QF Check EnabIe Cfg: DISABLE 2
Start DeIay Time Cfg (milliseconds): 5000
Target SOC Cfg (%): 75
Time Load Shed off Cfg (seconds): 2700

Thanks Stewart - I'm away for a while now - without the Everest - so I'll think about this more when I get back.

Just as a matter of interest - what BMS parameter is being set when the various target SOC levels are being selected in Forscan? I thought it may have been a voltage related setting - but the only likely candidate that I can see in the above list is Target SOC itself?

John

Target SOC Cfg (%): 75, which equals 12v, 100% equals 16v. The data stored in the BCM is a voltage and not a percentage.

Yes I've observed the erratic amps coming out of the alternator once target SOC is achieved. I always put it down to the on demand electrics (fans, power steering etc). I doubt it was going into the battery.

I've always understood that over charging and maintaining a charge voltage past 100% SOC would result in gassing and definitely shorten the battery life. I got 7 years out of the AGM's in my trailer, which is excellent lifespan, and they were always charged properly with multi-stage chargers (CTEKM300 for AC and CTEKD250 for DC). On balance, I think under charging is the lesser of two evils, but obviously not good if you'd like your van / trailer batteries fully charged. I only enable dual battery when I take the trailer out on a tour and need to rely on alternator charging each day. I'm thinking of replacing the D250 with a D250SA so I don't need to do this.

tezza4x4 wrote: ↑Wed Oct 10, 2018 12:16 pm Yes I've observed the erratic amps coming out of the alternator once target SOC is achieved. I always put it down to the on demand electrics (fans, power steering etc). I doubt it was going into the battery.

Excellent description Tezza. You would be right and is called load shedding, power steering, fans etc. all take advantage of the feature.

saeb wrote: ↑Tue Jul 03, 2018 11:34 pm
SOC Critical Cfg (percent): 30
SOC LSoff Cfg (percent): 40

WHat do these two affect?

SOC LSoff would have to be when loadsheding is completely shut down.
SOC Critical would be SOC critical point, not sure whats happens in a critical point but I would assume modules will go to deep sleep.