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
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