I'm confused (no surprise there) about EV charging

[Mavster Mechanic]

Okay, another question. On my hybrid I've never used the "L" button on the shifter. If you're going down the mountain would it be like downshifting to first gear or is it smart enough to choose an appropriate ratio?

It is variable based on wheel speed.

More like dropping 1 gear from wherever you are at. As you slow down or speed up it will adjust by itself.

L on a hybrid is for slowing.
I find it does nothing for "pulling" power.

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[HeyBales]

I think someone posted max engine brake was at 4800 rpm. Probably limited by application of hydraulic brake pressure so watch that while engine braking happens.

Seems like that's what I've seen. Maybe 4500. At that point though - loud is the term!

There is no brake pressure applied during that.
Unless adaptive cruise does that.
Normal CC didn't.

Otherwise like any tranny engine air braking that happens - eventually it's not enough and the driver needs to press the brakes to maintain speed.

 

[HeyBales]

Okay, another question. On my hybrid I've never used the "L" button on the shifter. If you're going down the mountain would it be like downshifting to first gear or is it smart enough to choose an appropriate ratio?

In addition to above comments - downhill on hybrid gets Grade Assist, and to maintain your speed the system will apply max regen automatically, even more than Low would do at certain speeds normally.

Of course Grade Assist works with Low too.

The problem I have with being in Low in any kind of rolling terrain that is steep is the interaction between them.

As soon as the slope isn't considered a "downhill" the Grade Assist lets go.
Depending on your speed the Low you are in may mean a quick reduction in speed since likely not pressing the Go pedal, maybe even the brake was being feathered because the engine braking wasn't enough. Now you gotta get to the Go pedal with correct pressure to maintain speed.
Or the Low isn't enough resistance at it's normal setting for the speed and you increase and have to get on the brake pedal.

Maybe I just need to use it more beyond testing on a few steep hills I'll travel.

 

[HeyBales]

I really wish the Mav had a tach to see exactly how high the engine is revving going down a long steep hill, which I drive almost every day.

You could enter Engineering Test Mode some day.
It has a tach available to view - but you'll lose many other views for that drive.
But at least for that drive - you can see what the RPM does.

https://www.mavericktruckclub.com/forum/threads/2025-engineering-test-mode-access.61547/post-1087390

 

[A112358]

You could enter Engineering Test Mode some day.
It has a tach available to view - but you'll lose many other views for that drive.
But at least for that drive - you can see what the RPM does.

https://www.mavericktruckclub.com/forum/threads/2025-engineering-test-mode-access.61547/post-1087390

Interesting. Thanks. I didn't even know there was a Test mode.

 

[Tall Hobbit]

It was handy to have been catching up on older threads and reading this one today, which put a lot of the explanation to these questions in my head beforehand. Thanks, @Traegorn

Also helpful to see the response this thread is getting. I have in mind a related question ahead of a trip in two weeks involving a long steady downgrade, say 3,000 ft over 8 miles.

Will also say, this is the first cruise control I've had that so aggressively brakes for you to keep you down to the desired speed, probably also due to the unique nature and capabilities of eCVTs; in any case with Grade Assist its a feature, not a bug, right?

 

[MakinDoForNow]

Seems like that's what I've seen. Maybe 4500. At that point though - loud is the term!

There is no brake pressure applied during that.
Unless adaptive cruise does that.
Normal CC didn't.

Otherwise like any tranny engine air braking that happens - eventually it's not enough and the driver needs to press the brakes to maintain speed.

When in low and max engine brake the driver touches brake pedal hydraulic braking happens.

 

[Glen Baker LLC]

Interesting. Thanks. I didn't even know there was a Test mode.

You can also use test mode to correct and adjust any mileage discrepancies, between the optimistic computer mpg and actual mpg figured out at the pump.

Yes, you can manually tune your indicated MPG. Ford did this one right, but doesn't make it easy.
Enter Engineering Test Mode:
1. Depress & hold brake pedal.
2. Depress and hold the OK button on steering wheel.
3. Wait >5 sec, then insert key and switch ignition to "RUN" (OFF-ACCY-RUN-START).
4. Continue holding OK until green "ET" appears in dash display at top right. (~ 15 sec)
5. Use OK & MENU buttons to explore
6. AFE Bias is "Average Fuel Efficiency"; tune it to match your MPG. 1000=default, 970 reduces displayed MPG by 3%, etc. You would use 1000*367/390 = 941.
To start the engine, momentarily turn key to START and depress accelerator pedal (like usual). It took me a while to learn THIS little secret that's not in the user manual but should be.

 

[Darnon]

The "L" button is primarily designed for optimization of downhill driving with regen created by drive motor transferred to the dcdc converter, to charge HVB, 12v, furnish electricity for all operational needs then activate ice braking through gear set with any additional needed by hydraulic brakes. Speed going down hill will not let ice rpm exceed the max designed rpm.

The DC-DC converter doesn't work as an intermediary between the drive motor and HVB at all like you describe. It's simply an accessory to the HV system that steps down to "12v" (13.6-15.2v).

 

[KenE]

You could always get a scangauge lll

Scangauge III is an excellent product. Or get a Car Scanner Dongle and use their App. There are MANY more parameters to observe besides RPM. Also, as other posters in other forums have stated, when going down a long hill, the high RPM's dissipates HVB charge that exceeds highest allowable value, as well as engine braking.

 

[HeyBales]

It was handy to have been catching up on older threads and reading this one today, which put a lot of the explanation to these questions in my head beforehand. Thanks, @Traegorn

Also helpful to see the response this thread is getting. I have in mind a related question ahead of a trip in two weeks involving a long steady downgrade, say 3,000 ft over 8 miles.

Will also say, this is the first cruise control I've had that so aggressively brakes for you to keep you down to the desired speed, probably also due to the unique nature and capabilities of eCVTs; in any case with Grade Assist its a feature, not a bug, right?

Grade Assist is a feature.

I've not decided if it is the normal Cruise Control maintaining downhill speed with slight brake application that happens to be still in the realm of regen, or Grade Assist that was going to happen anyway.

I think I recall which hill I can go down where Grade Assist decides it's not enough hill anymore near the bottom and releases it's extra resistance and I speed up under Normal regen, Slippery regen for sure.
I'll try to set the CC (I don't have ACC) and see if it applies some "braking" on that part to maintain speed.

That is one buggy aspect of Grade Assist - an undulating downhill with various levels of steepness.
You take your foot off the gas near the top at speed desired - it holds it. (regen or ICE braking)
Until the slope is too shallow and it releases regen, but you still increase speed due to some slope.
Now you are going faster and that is new set speed as it gets steep again and Grade Assist is on again. Repeat a few times - could be much faster than desired.
I've even caught that around here where there are no long downhills. 1st time I was at the bottom and wondered why I was 5 over where I started. Noticed that effect.

So maybe CC or ACC will apply the brakes to keep the speed down during the non-steep parts.

I've not been testing newer cars normal transmissions.
Do non-hybrid vehicles using CC or ACC go into a lower gear automatically on downhills to maintain speed?
Or just auto-apply brakes?

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