Variable Voltage System Stuff

[NotBudule2]

When upping the charge from 75% , why not go to 100% ? Is that considered overcharging ?

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[TJC]

15v? Man I wonder what the current is to the battery, maybe a sign that the battery is weak? Or yeah the BMS is not working right? I think the most I see while driving is 14.6v but then it will also go down to 13.9-14.1v when driving which is when I presume the BMS thinks the battery is fully charged.

I think it is normal behavior.

 

[TJC]

When upping the charge from 75% , why not go to 100% ? Is that considered overcharging ?

I went to 95% and disabled ASS in Forscan

 

[awd.nv]

I went to 95% and disabled ASS in Forscan

I disabled ASS too even though I always drive in T/H or Sport which disables it anyway. Figure if my wife or anyone at the dealer drives it, it won't be shutting off. I just hate the idea of an engine being started and stopped so many times a day (oil pressure wise and starter), especially with a turbo.

I will probably up charge level from 80% to 90% next to see what happens. I don't want to go fully off and cook the battery when it is 115F outside in the summer, the engine heat is more than enough for that though lol

 

[Cabose-1]

Okay i am going to ask it!! Cant help myself!!


If my wife uses the hair straightener plugged into the truck, will it still power my ebrake?? What if i use my c to c charger plugged into the cigarette lighter, how does that affect m dome lights?

2022 xlt fx2 with tailgate assist mod

 

[TJC]

When I haven't driven much, I will get 14.8-14.9 inside the truck and once the battery is charged it drops back to the twelves.

Add 0.2v to that and you are getting 15v - 15.1v at the battery

 

[TJC]

I went to 95% and disabled ASS in Forscan

OK, I'm game to give it a try. I'm gonna plug the BMS sensor back in and bump the SOC to 100.

Before I do I'll drive it for a while in the colder weather to obtain a baseline, then make the switch up and run the same routes at the same time of day, and as close to the same temperature as I can. Both daylight and night driving to cover all the bases.

I'm quite satisfied with the present setup, but the info is good to know.

 

[Gizmokid2005]

Also the Battery is a crucial part of the circuit. Without it in place, things will not operate correctly if at all.

This is a...loaded comment, and really not accurate.

Once started, you can pull the battery out of the equation and your truck will still run as if nothing is wrong. That hasn't changed in recent vehicles (and is still the best way to test if an alternator is bad or not).

 

[Frenchy]

This is a...loaded comment, and really not accurate.

Once started, you can pull the battery out of the equation and your truck will still run as if nothing is wrong. That hasn't changed in recent vehicles (and is still the best way to test if an alternator is bad or not).

Maybe if you're lucky. That's actually a bad practice on the EFI type vehicles. Doing that can and will fry an ECM/PCM without even thinking about it. I've seen it happen

 

[Gizmokid2005]

Maybe if you're lucky. That's actually a bad practice on the EFI type vehicles. Doing that can and will fry an ECM/PCM without even thinking about it. I've seen it happen

It's not a maybe if you're lucky.

If there's other electrical problems it has damage potential, but in an otherwise healthy electrical system, it's no more dangerous than a failing battery or alternator, which is to say not much.

My point being, the BMS has absolutely no bearing on what the charging system is doing within the vehicle.

 

[Frenchy]

It's not a maybe if you're lucky.

If there's other electrical problems it has damage potential, but in an otherwise healthy electrical system, it's no more dangerous than a failing battery or alternator, which is to say not much.

My point being, the BMS has absolutely no bearing on what the charging system is doing within the vehicle.

A battery randomly failing versus taking the battery out of the equation wall the vehicle is running is two different situations. Multiple times in my career with automotive I have heard people talk about removing the negative cable or positive cable off the battery well the vehicle is running. Their claim is to test the alternator. Funny thing is nine times out of 10 the vehicle shuts off because it's a modern vehicle. Of those times it happens you have about 50% of them having to replace an ECM/PCM because they fried it.

 

[RangerBill]

My point being, the BMS has absolutely no bearing on what the charging system is doing within the vehicle.

This is untrue. The BMS sensor monitors current into and out of the battery (calculating the battery state of charge), battery voltage, and battery temperature. The PCM then sends a voltage setpoint to the alternator based on battery state of charge and other parameters.

 

[Gizmokid2005]

This is untrue. The BMS sensor monitors current into and out of the battery (calculating a battery state of charge). The PCM then sends a voltage setpoint to the alternator based on battery state of charge as and other parameters.

It's not the sole control, otherwise a failure in the system would take out the electrical in the truck. Hence all of the vehicles that run without a BMS (or with the sensor unplugged) that don't have issues. They lose out on ASS and on a lower duty cycle in the alternator, but they're not otherwise harmed.

 

[TechEditor]

" They lose out on ASS"
Oh dear! Can't miss out on something I never had!

 

[RangerBill]

It's not the sole control, otherwise a failure in the system would take out the electrical in the truck. Hence all of the vehicles that run without a BMS (or with the sensor unplugged) that don't have issues. They lose out on ASS and on a lower duty cycle in the alternator, but they're not otherwise harmed.

If the BMS system is disconnected, the PCM has other strategy to send a setpoint to the alternator. If communications between the alternator control is disconnected, the alternator has a built-in failsafe mode to put out a fixed voltage. If the BMS sensor is connected, it is used in calculations for a voltage setpoint.

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