Variable Voltage System Stuff

[TJC]

Ok, so what do you guys all set your charging level to in Forscan?

My XLT Tremor was defaulted to 75% I presume because of the accessory switches they added. I wonder if the Lariat Tremor went up from 75 to 80%?

It bugs me that key on, engine off I register about 12.1v, always been that way but now that I have forescan I was thinking about bumping it up

If you are measuring from the cab 12v port, add 0.2v to that number.

That voltage is still way too low to avoid sulfating your battery and having it fail prematurely.

You need to be seeing 12.65v or better, and that is the absolute lowest safe voltage. I can also state with confidence that the voltage will drop rather dramatically overnight without you doing something about dark power drain. You can mitigate the draw, but only at the expense of turning off features that you may consider important.

I turned a lot of stuff off and my 2020 Ranger now has a very similar drain over night as my 2005 Ranger. I let them sit for a week and measure the voltage. The drop was the same. Prior to the changes made, it was behaving like your truck (11.9v - 12.1v in a single night)

The charging pattern is identical to the 2005 Ranger as well with one exception, it is 0.2v higher. Probably due to the fact that the 2005 came with a standard flooded battery while to 2020 came with an AGM battery, which can handle a slightly higher charge voltage.

I no longer see low battery warnings and I rarely use a charger on either truck. I have let both sit for over a week without issues. I do have onboard desulfators on both trucks.

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[notsolinear]

Not to beat a dead horse, but I'm in agreement with @ctechbob and @RangerBill on this one: The shunt/ammeter on the negative terminal of the battery is only able to measure the net current (amps) flowing into or out of the battery. You can't directly measure the capacity of the battery (which is measured in Amp-hours). The analogy would be if you have a 100 gal (amp-hour) water tank and you release at a rate of 10 gal/hour (10 amps) for 1 hour then you should be down to 90 gal (amp-hours), or 90% full. That's how the vehicle estimates the battery state of charge (SoC) in percent. The reason it's forbidden to bypass the ammeter on the battery is that, in certain situations (like ACC on, engine off) you can draw amps from the battery without it being observed by the shunt and now the true SoC is lower than what the computer thinks it is (or the opposite with a battery tender, the true SoC would be higher than expected).

I also agree that the ammeter on the battery is not related to nor aware of how many amps are being supplied by the alternator, nor is it part of a feedback mechanism to command the alternator to supply a given number of amps. Amps only pass between the battery's positive and negative terminals if it is charging or discharging. Take a look at any battery charging graph: As the battery approaches fully charged the current reduces down to zero. Once the battery is fully charged that ammeter will read effectively zero yet the alternator continues to supply many amps to power all the vehicle electronics.

One related exception I would believe is if the vehicle controllers commanded the alternator to a higher voltage when they knew a lot of large loads are active (e.g. big lights, inverters, seat heaters, defrosters, etc). That would put less stress on the wiring by lowering the number of amps and be more efficient by reducing resistive losses. For example, supplying 2,000 Watts at 12.7 Volts requires 157 Amps. Supplying the same 2,000 Watts at 14.7 Volts only requires 136 Amps. That's a 13.4% reduction in resistive loss and cable heating due to lower amperage. Unless the vehicle has a second ammeter on the alternator itself it's likely that state would just be based on pre-determined knowledge of what accessories use high current and when they're switched on.

 

[Frenchy]

Not to beat a dead horse, but I'm in agreement with @ctechbob and @RangerBill on this one: The shunt/ammeter on the negative terminal of the battery is only able to measure the net current (amps) flowing into or out of the battery. You can't directly measure the capacity of the battery (which is measured in Amp-hours). The analogy would be if you have a 100 gal (amp-hour) water tank and you release at a rate of 10 gal/hour (10 amps) for 1 hour then you should be down to 90 gal (amp-hours), or 90% full. That's how the vehicle estimates the battery state of charge (SoC) in percent. The reason it's forbidden to bypass the ammeter on the battery is that, in certain situations (like ACC on, engine off) you can draw amps from the battery without it being observed by the shunt and now the true SoC is lower than what the computer thinks it is (or the opposite with a battery tender, the true SoC would be higher than expected).

I also agree that the ammeter on the battery is not related to nor aware of how many amps are being supplied by the alternator, nor is it part of a feedback mechanism to command the alternator to supply a given number of amps. Amps only pass between the battery's positive and negative terminals if it is charging or discharging. Take a look at any battery charging graph: As the battery approaches fully charged the current reduces down to zero. Once the battery is fully charged that ammeter will read effectively zero yet the alternator continues to supply many amps to power all the vehicle electronics.

One related exception I would believe is if the vehicle controllers commanded the alternator to a higher voltage when they knew a lot of large loads are active (e.g. big lights, inverters, seat heaters, defrosters, etc). That would put less stress on the wiring by lowering the number of amps and be more efficient by reducing resistive losses. For example, supplying 2,000 Watts at 12.7 Volts requires 157 Amps. Supplying the same 2,000 Watts at 14.7 Volts only requires 136 Amps. That's a 13.4% reduction in resistive loss and cable heating due to lower amperage. Unless the vehicle has a second ammeter on the alternator itself it's likely that state would just be based on pre-determined knowledge of what accessories use high current and when they're switched on.

Whether you like it or not, the Amp Meter on the Ground Cable still Measures the Load that is being pulled when any Electrical Load from the Vehicle is on and pulling a Load. That is the whole point of it. The overall goal is to improve Overall Efficiency. Not to say that some Manufacturers haven't exactly done it in the best way as we already know some are questionable.

Since many here seem to not want to believe me, I will get my Amp Clamp out in the next day or so and show how it works.

 

[awd.nv]

If you are measuring from the cab 12v port, add 0.2v to that number.

That voltage is still way too low to avoid sulfating your battery and having it fail prematurely.

You need to be seeing 12.65v or better, and that is the absolute lowest safe voltage. I can also state with confidence that the voltage will drop rather dramatically overnight without you doing something about dark power drain. You can mitigate the draw, but only at the expense of turning off features that you may consider important.

I turned a lot of stuff off and my 2020 Ranger now has a very similar drain over night as my 2005 Ranger. I let them sit for a week and measure the voltage. The drop was the same. Prior to the changes made, it was behaving like your truck (11.9v - 12.1v in a single night)

The charging pattern is identical to the 2005 Ranger as well with one exception, it is 0.2v higher. Probably due to the fact that the 2005 came with a standard flooded battery while to 2020 came with an AGM battery, which can handle a slightly higher charge voltage.

I no longer see low battery warnings and I rarely use a charger on either truck. I have let both sit for over a week without issues. I do have onboard desulfators on both trucks.

My 2019 Lariat was set at 75% setpoint. I just recently changed it to 90%.

Thanks, I do daily drive it so the draw overnight is not too big of a concern. I will have to put my meter on it to see what key-off voltage is at the battery but I was just going off my Scan Gauge readings with key on accessory and no radio/blower motor running. It does hold 12.1-12.0 relatively well but that does not leave much power reserve in my book. I just bumped it up to 80% to see how she does. After a few days, maybe go up to 85%.

I think it was about a year ago the dealer put a new battery in for me, I was not having issues but the advisor said it was marginal and I was still under warranty. So I presume the current battery being about a year old is still in good condition (again no issues, trying to get more life out of the battery). We are soon heading to Utah where lows will be in the 28-30F range, really would prefer the battery to have the capacity it was designed for.

 

[TJC]

Whether you like it or not, the Amp Meter on the Ground Cable still Measures the Load that is being pulled when any Electrical Load from the Vehicle is on and pulling a Load. That is the whole point of it. The overall goal is to improve Overall Efficiency. Not to say that some Manufacturers haven't exactly done it in the best way as we already know some are questionable.

Since many here seem to not want to believe me, I will get my Amp Clamp out in the next day or so and show how it works.

Not completely true. I believe it measures net load. The battery is not in a serial circuit with the alternator. If the alternator produces enough energy, there will be no load on the battery.

 

[Frenchy]

Not completely true. I believe it measures net load. The battery is not in a serial circuit with the alternator. If the alternator produces enough energy, there will be no load on the battery.

Be patient. This week(don't know what day right off, probably the weekend) I will break out the good old Amp Clamp and provide the proof. Mind you the vehicle that will be used also has Variable Voltage and the Amp Clamp being used is a Fluke Meter.

 

[OFC Ranger]

 

[TechEditor]

Who cares what the BMS does. It has been proven to shorten the life of the batteries. Just disconnect it and control the charge the way it has been done for over 100 yrs. It just works! I disconnected mine 9 months ago, but the damage was already done after 1.5 yrs of chronic undercharging. Battery is not in the best shape for this winter.

 

[got3fords]

Who cares what the BMS does. It has been proven to shorten the life of the batteries.

I swear the BMS on my truck only works about 25% of the time lately. I have been seeing the charge voltage hovering around 15V lately. Maybe it's the colder weather? I can't remember what it did last winter. I should keep a log. Stock battery, onboard desulfator. Last health check showed around 4mΩ IR.

 

[TJC]

Be patient. This week(don't know what day right off, probably the weekend) I will break out the good old Amp Clamp and provide the proof. Mind you the vehicle that will be used also has Variable Voltage and the Amp Clamp being used is a Fluke Meter.

Simply look a the connections on the battery. Positive has mulitple lines feeding it, all BEFORE the battery. The entire body of the truck

I swear the BMS on my truck only works about 25% of the time lately. I have been seeing the charge voltage hovering around 15V lately. Maybe it's the colder weather? I can't remember what it did last winter. I should keep a log. Stock battery, onboard desulfator. Last health check showed around 4mΩ IR.

I have seen it go that high and slightly higher. 15.6v IIRC. Usually when coming to a stop. And I have seen to drop to the 12v range when it discharges a battery that has just be fully charged with an external charger.

It is going to do what it is programmed to do.

I do not like an under optimized (Charged) battery.

Ford does.

To me it is EPA (gov) foolishness. Getting that extra .1 mpg at the expense of battery half life? I wonder if the EPA geniuses did the analysis of battery production / and recycle recovery technology vs the gas savings from an environmental perspective. I'll bet not!

They certainly have not done an honest environmental analysis of CO2 on the planet.

 

[got3fords]

I have seen it go that high and slightly higher. 15.6v IIRC. Usually when coming to a stop. And I have seen to drop to the 12v range when it discharges a battery that has just be fully charged with an external charger.

When mine runs high like that, it's usually constant. Sitting still or moving.

 

[awd.nv]

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.

 

[got3fords]

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.

It's not every day, but it's been often lately. Sometimes will drop to upper 12's or anywhere in between.

 

[IdahoRanger]

It's not every day, but it's been often lately. Sometimes will drop to upper 12's or anywhere in between.

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.

 

[Cabose-1]

Edit

I have so many questions

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