EV battery recharge question

A sound plan.
If the goal is to reduce gasoline use, you don't want EV charge left when you get home though.

 

How can I tell when I went from regen to friction brakes while using the pedal?

 

look at the hsi

 

At the very least when the battery was full.

 

HSI = Hybrid System Indicator.
Do I look at the bar nearing the bottom of the arc and leave a little space so the friction brakes don't come on?

 

I have a hard time telling when the battery and its different parts are fully charged. I have taken my car with a fully charged EV section of the battery ( from a wall charge) down a long hill in EV mode and gained miles on the miles remaining gauge. Seems similar when I do it in HV mode. Maybe I should try using the percentage of charge reading instead of miles remaining reading. I will have to look that up on how to do it.

 

I drive the route 1-2x yearly in my Plug-in Prius. But as far as mountains go in the west, it's not much. Max elevation is only about 4000', and people like to fly through there, so it's either go with the flow or crawl with the big rigs.

Going south into Los Angeles over the Tejon pass ("Grapevine"), you can probably regenerate 6-8 miles if you follow the trucks in the right lane. With some careful driving heading the other direction back into the central valley, you can probably regen 8-10 miles on the steeper descents.

Now get up into Sequoia or a few other places, and you can probably fill your ~25 mile battery from empty on the mountain descent due to higher elevation and slower speeds (less air drag).

 

Not really, If it needs more breaking than the charging system can handle, it will use the ICE to do some of the breaking.
It's when you get down below 10 mph that the friction breaks may engage.

 

I thought the engine braking only came on with the shift selector was in the B mode.

 

Auto B mode? I don't think there is such a thing.

Regenerative braking occurs whenever you get off the accelerator pedal. Greater regenerative braking occurs in B mode.

I can't think of any time I'd want to use HV Charge mode. Maybe if I had the car loaded to the max and knew of a very steep high speed up grade ahead and knew the gas engine alone wasn't going to be adequate. I haven't been in that situation.

 

so when hitting the hills do you suggest getting out of EV mode into HV mode then hitting the eV mode on the descent ?

on my commute i kill the EV battery but i'd like to optimize my drive accordingly.

 

There is no need to switch to EV mode for downhill portions of the drive. If the engine is still cold when you hit the downgrade, it will keep running even after you put it into EV mode until it warms up. If you are in HV mode on the upgrade and the engine is warm, it will turn off on the downgrade simply by letting off the throttle. At this point you may wish to reapply the throttle ever so slightly so that the generator does not slow down the car but not so far as to actually use any battery power. Alternatively, once ICE turns off you can put the car in neutral and coast down the hill.

 

Not unusual for me to return from Reno to Sacramento with full charges, right to my garage. Roughly 70 miles all downhill on I 80. The Prime should be better.

 

I am still confused about the B mode on the transmission selector. What I thought was when in the B mode the engine was allowed to be turned by the car's wheels and to save gas and to increase load the spinning engine was not fed gas. Because the traction motor/generator makes the electricity, not the ICE, regeneration would not be increased but decreased because the car would not need the brake pedal to be applied as much or the car would slow down sooner and not get as much regeneration.

Of course if the max regeneration was already being made the B mode would save some amount of friction brakes and lessen the possibility of brake overheating.

Seems to me the friction brakes and B mode wastes some amount of potential regenerated energy.

 

Unless the battery is full, B mode should regenerate not engine brake.

 

If B operates in the Prime like it does in previous Prii, less energy is diverted to the battery as the engine is allowed to spin up.

 

That seems to be the case. A long gentle hill near my house gives me a 0.2 mi increase in EV miles when I coast down it. I tried it in B mode this morning and got a lot more braking from the engine and only 0.1 mi EV increase.

 

In Ev mode you got engine braking?

 

If B means spinning up the ICE with M/G1 to waste energy, then yes.