Is there a legitimate use for charge mode in the Prime?

I selectively use charge mode during my weekly commute into downtown Portland. I don't have charging capability in the parking garage I use and when it really cold out, the available EV miles noticeably goes down. So I use it during certain portions of the drive where there is a slight downhill grade (not enough to coast). It adds maybe a mile or two of EV range but it's enough for driving in the downtown area and my total MPG doesn't take a big hit. I don't imagine using it as much when the weather warms up.

 

This week I was doing some HV segments and forgot to hit the button on one segment eating up some battery. When I noticed it, I switched to HV mode, reset the total MPG meter. I was cruising along at 55MPH for a while and was seeing about 60MPG indicated.

I decided to return the battery level with HV charge mode. I changed into HV charge mode, and reset the total MPG meter again. Still cruising at 55 MPH, I was seeing 35 MPG for the approximately 7 to 8 miles in HV charge mode.

The total HV and HVcharge mode travel was 46 miles, and the "Gas Range Estimate" went down 50 miles.

 

In those 7-8 miles with an extra cost of 25 MPG, have you noticed how much % of battery you've gained?

 

It's a fairly invisible feature unless you know how to activate it. On my Gen 3, Prius Plug in, how I wished for a way to give a full EV charge without plugging in. Not that it was really necessary, but it was nice to run it on EV when you didn't want to create exhaust and noise.

 

I use it because my remote start feature in the app is buggy. When I drive in hybrid mode, my car app registers the charge at about 34% when the car is parked. But when I try to start the car remotely, it says, "Remote start failed. Charge level must be more than 30%." So I use the charge feature to maintain a partial charge, and remote starting no longer gives that error.

 

Is that still an argument given the artifical noise the P5 creates when driving in low speed EV mode?

This is generally a great use case, use carge mode to recharge your battery over 30%. Park and before getting back into the car use remote HVAC to preheat or cool depending on weather.

 

You could just switch to HV mode yourself, as I'm pretty sure using charge mode is pretty inefficient use of fuel. If you're gonna use the gas anyway you might as well use less of it in HEV mode instead of charge mode.

And B mode is meant for when you're going downhill to avoid fading your brakes, last I checked. It's like using the other gears in an automatic or in a manual, downshifting.n

 

Here are two further uses when Charge Mode might be useful:

1) Jump-starting an ICE vehicle
Mum's ICE engine (Mazda Demio) wouldn't start due to a flat battery, so I wanted to use my Prius PHV (aka Prime) to jump start her ICE. Because I'd heard that using EVs for jump-starting can result in damaging voltage drops in the Prius leading to possible loss of software/firmware/settings/.. (can't remember which) then I started Charge Mode while idling and charged her battery for 5 minutes before engaging her starter motor. Doing this started her Demio without problem and caused no sign of any distress in the Prius. I've had to repeat this procedure several times and there has been no sign of any trouble for the Prius. (Being flat is'nt good for her 12V lead-acid battery, of course.)

2) Before major up-hill climbs (especially with heavy loads in vehicle and/or towing)
A year or two ago I read of someone recommending charging the battery to 80% using Charge Mode shortly before a strenuous climb with heavy loads. His/her recommended procedure before the climb is:

- warm up the ICE e.g. using HV if not already warm
- engage Charge Mode to charge the battery to 80%
- start the climb (and turn off Charge Mode, presumably)
- engage Power Mode (this is my addition)​

As I remember it, the arguments were:

- Protecting the Engine i.e. it is already warm before the hard work starts
- There is more power available for the climb
(because both the ICE engine and the EV engines can contribute)
- The car is more responsive to the accelerator
(because the EV engine has better low speed torque for hairpin corners, etc)​

Does anyone have any thoughts about these two uses for Charge Mode?

Note: The issues around towing with different models of Prius are dealt with elsewhere, so we needn't discuss them here. If interested, amongst other discussions on the topic of towing with a Prius refer to:
2015 Prius Towing capacity and Hitch question | Page 2 | PriusChat
Hitch Install problem | PriusChat
Towing a caravan for ANY Prius? | PriusChat
​

 

The test drive at a dealership. They'll never charge the car enough for EV, and you can use it to charge the battery so you can see what the EV mode is like.

 

Personally, Charge mode is my once a week "get the damn engine fully up to temps" mode. HV aka Hybrid mode is really great from a fuel economy point of view but it runs the engine in small bursts and it will not get up to temps properly. By putting it in charge mode with a relatively low battery SOC, it keeps the engine alive long enough to get the engine oil fully up to temps and chase any humidity/gas that get's there.

 

Personally, I think that a person is over reacting if they run the car in "Charge" mode to force the car to run the ICE without stopping. DOHCtor's car is a Prime model with the ability to drive 40 miles on a charge, so....

If the car is only driving a couple miles, do it in EV mode and forget about moisture buildup as sludge in the crank.

If the car is driving more than a few miles, put it in HV mode and it will cycle on and off with plenty of time to heat up the oil. It has a heat reservoir that stores heat from the last time it was run.

The only time I need to run the ICE is when I make my monthly 1000 mile trip.

 

I do enjoy driving around without engine noise. I'll leave it in EV mode going around parking lots. There's no backup beeper anymore, but I guess it's not really needed. If someone gets in the way when you're backing up, the anti-collision sensors take care of it.

 

Show me the heat thermos on a Gen5 Prime.

Your profile shows Silicon Valley as the place where you live. Lucky you! You don't have to live with frigid -30°c temperature during winter.. in my case, 40 miles of EV range is more like 20 miles of EV range during winter and the car will force the engine on and off in order to have heat in the heater anyway, creating that mess..



Summer is not the problem in my case. Winter is!

 

Wasn't that abolished by Model Year 2010?

I don't remember any Prius model ever having a backup beeper outside, for pedestrians to hear. Both my Gen3s had it inside, as an alert to the driver only.

I haven't yet tested the anti-collision sensors on my RAV4 plug-in, but must say that such sensors on some Teslas are inadequate for certain parking lot scenarios. I've nearly been hit twice by Teslas suddenly stopping, reversing, and turning-backing into parking spaces without watching for pedestrians they may hit with the sides (not rear) of their cars. In both cases, I froze the instant their backup lights unexpectedly turned on, watched as the drivers didn't pay attention to where their front ends were swinging, and was braced to punch their doors if they didn't see me in time. Both were quite startled when they finally looked around and saw how close they were to me.

I'm not expecting my car's sensors to be any better, but don't normally perform back-in parking, except for reaching charge station cords.

The only item I do with my RAV4 Prime is #2, "warm up the ICE" before hill climbs. And the HV button does that well enough, no need for Charge Mode.

On some of the hills I climb, I don't want the battery as high as 80% at the top, because that won't leave enough room for full regeneration on the way down. And HV mode (on the RAV4, at least), when it uses some battery, will quickly refill it to the same SOC that was in the battery when HV was selected. So I usually use EV to try to drain the battery to ~50% before the start of the climb. Though note that even when the EV range is falls below "0" to "---", this vehicle has all the ICE power I want for mountain climbing. Even in my 2010-2012 non-plug-in Prii, I didn't feel a need for PWR mode in any mountains.

As for #1: In 15 years of Prius driving, I refused to jump start anyone. While it is certainly possible, there were also too many stories here of major electrical damage from botched jump starts, so it seemed the best prevention was to not do it at all. Get a jump box, battery charger, battery tender, etc. I'd even have preferred to pay for a stranger's service call out of my own pocket than to risk the Prius' electronics. In hindsight, it even seemed probable that (less costly) electrical failure in a previous car was related to jump starting strangers.

 

I can't say I ever knew where the beeping was coming from. I just assumed there was a speaker somewhere inside the body. Of course I was never outside to hear it when I was backing up.

 

That's what the "B" is for on your shifter tree. If you are coasting down a long hill with a full battery, there is nothing to stop your car from accelerating to dangerous speeds. Without any engine braking, your car has nothing holding it back from accelerating. Regenerative braking is a no-go when your battery is full, and friction braking will destroy the brake pads eventually, so all you have left is engine braking; "B" which is like the engine brake on an 18 wheeler. It controls the valves so that the engine works as an air compressor, creating drag. Remember, the brake pads on a Prius are not extra heavy duty, and they will wear out if you use them descending long hills.

 

One thing I've noticed, when someone walks behind you while you're backing up, the brakes lock instantly and it feels like you hit something.