Stereo Dual Battery - BMS Questions

[OEMPlus Raptor]

I'm running two Mosconi 5/30 amps and they don't even make the lights dim when the bass hits and I'm still on the oem battery.

 

[EricM]

This dude uses caps... You can see them lined up under the amps 25 sec into the video.

 

[Shane361]

This dude uses caps... You can see them lined up under the amps 25 sec into the video.

That's EXO..been following his build for a while. Are you SURE that isn't his Lithium bank? I'll watch it later.

 

[raydulce]

Your stock system can easily support a 1500rms amp. I do believe the magic number is somewhere around 2800 actually. I run a D3400 under the hood and 112ah of Headway Lithium in the bed with no ISO. I do believe I disconnected the smart charge part of the system. Also have Mechman370 alt. Done the "big three"? Where did you bring your zero into the cab? I need to get external voltage regulator for the Alt but apparently they don't make one that won't throw a dash code. Ford vehicles with the smart charge are not exactly ideal for larger stereo systems.

I'm going to look at the "big 3" soon, and possibly a larger alternator if there any issues. In my last truck I had upgraded the alternator, dual batteries, and the big-3, but I'm new to this BMS system...

 

[raydulce]

Here’s the information published on BMS.

The Electrical Energy Management system utilizes a load shed strategy to help control discharge of the battery and prevent, when possible, an excessively low battery state of charge. The BCM uses a battery monitoring sensor to monitor the battery state of charge.

• Generator current sensor
• Battery current sensor

These sensors serve as input to the Electrical Energy Management system software. If the sensors malfunction due to wiring issues or failure, a DTC will be set. In most cases the Electrical Energy Management system functions will be turned off until the sensor operation is restored.

To maintain correct operation of the load shed system, any electrical devices or equipment must be grounded to the chassis ground and not the negative battery terminal. A connection to the negative battery terminal causes an inaccurate measurement of the battery state of charge and incorrect load shed system operation due to the current being used bypassing the battery monitoring sensor. Refer to the Battery Monitoring Sensor component description in this section.

Battery State of Charge

The battery monitoring system charges the battery current flow and voltage to determine the battery state of charge. During the drive cycle the battery monitorning system software monitors the charge and discharge current and increases the state of charge during charging, and decreasing it during discharge. During rest periods (key off with no electrical loads) when the vehicle enters sleep mode, the battery voltage is sampled to calibrate the state of charge. The sensor automatically executes this calibration anytime the vehicle enters sleep mode and when the total vehicle current draw is below 400mA. It takes 4 to 6 hours in the sleep mode to calibrate the battery state of charge to high accuracy. If the system draw does not allow the battery state of charge calibration over the previous 7 to 10 days the state of charge quality factor changes to flag this and some battery monitoring system functions, which rely on the accuracy of the battery state of charge, may be temporarily turned off until a calibration takes place.

NOTE: Any devices left attached to the power socket that draw in excess of 200mA (or less depending on other battery loads), prevents a battery monitoring sensor from calibrating the battery state of charge

THanks for sharing this.

It's also my understanding that the truck has a target State Of Charge set to 80%. I believe if the battery reaches 80% charged, the alternator voltage will drop to stop charging and save fuel?

I suspect with an aftermarket amplifier turned up to any significant level, I'll pull enough current to keep the alternator "on" and the system voltage in the ~14 volt area. Is this likely correct? (I'm just trying to learn all I can.)

Also, I have a bit of strobe lighting for work/safety purposes. Beyond a minimal MPG, and perhaps overall battery longevity impact, is there any negative I'm missing to changing the SOC to 90% or 100% (so my lights run longer with the truck off)?

Thanks!

 

[FordTechOne]

THanks for sharing this.

It's also my understanding that the truck has a target State Of Charge set to 80%. I believe if the battery reaches 80% charged, the alternator voltage will drop to stop charging and save fuel?

There’s nothing published about a set percentage; it’s an algorithm calculated by the BCM and then send to the PCM where it’s further adjusted and then sent to the alternator.

I suspect with an aftermarket amplifier turned up to any significant level, I'll pull enough current to keep the alternator "on" and the system voltage in the ~14 volt area. Is this likely correct? (I'm just trying to learn all I can.)

As long as the battery current sensor is reading the amp draw then yes, charging voltage will adjust accordingly.

Also, I have a bit of strobe lighting for work/safety purposes. Beyond a minimal MPG, and perhaps overall battery longevity impact, is there any negative I'm missing to changing the SOC to 90% or 100% (so my lights run longer with the truck off)?

Thanks!

That can result in battery sulfation, I wouldn’t change that without knowing the consequences.