Anybody switch the hybrid battery charge mode?

If I were about to drive into London or Paris and the fast DC chargers were broke or in use and I have an appointment or I am upwind of Clarkson.

Bob Wilson

 

I believe that in number 4, hv does that anyway. Et least the energy monitor shows it that way.

 

It shouldn't. If it were doing that, every time someone drives at, say 35mph on flat ground, they'd be accumulating Ev range at a pace of about 1 mile per mile of driving. I don't think it does that. It just sustains charge by providing make-up power to the Hv battery to compensate for drains like AC and auxiliary loads.

 

It does that by alternating with engine off - electric on.

 

With the PiP it doesn't and I believe with the Prime too.
In HV mode, the Prime performs same as regular gen4. Although there is momentary charge in-charge out around the target point of the HV portion of the battery, the net result is zero same as in regular Prius.

 

What if you use a heavy duty extension cord and charge from inside the garage or something?

 

Based on the earlier discussion I eventually realized that as a general statement, even in HV mode using ICE to charge the battery is never efficient. With the few limited exceptions that Lee Jay mentioned.

The main reason HV uses ICE for charging is to keep enough charge available to assist ICE during acceleration or hill climbing. It is this assistance that allows the use of a small, lightweight and efficient Atkinson Cycle engine, which would not otherwise not be acceptable to consumers due to anemic acceleration (if you have ever driven with a nearly depleted traction battery you know what I mean).

The other big reason of course for having an electric motor is to be able to use it as a generator to reclaim energy during regen, which as you mentioned would otherwise be wasted. Those two benefits (small, efficient ICE and regen) are most of what makes a hybrid more efficient than a gasoline vehicle. Not wasting gas idling when stopped helps also. And the Prius also has other attributes (low Cd, lightweight materials) but those would benefit any car, not just a hybrid.

A plug-in adds yet another efficiency. Having a larger battery and motor allows storing grid energy, which is more efficient than gasoline.

However using Charge Mode to fill up that larger battery is pretty much out of the efficiency picture, with few exceptions. It exists presumably for those few who might know how to use it correctly, and even then the gain sounds like it will be minimal. The average user would probably be better off leaving it alone.

 

If you use the right one, and use it correctly.

 

how far is the run? a quality 12 gauge extension cord would be fine for 25 feet.

 

You will need to make sure there are no other loads on the 110volt circuit that you will plug your EVSE into. I would also lower the Prime's charger current from 12 amps to 8 amps. This will increase the amount of time to charge, but should not be an issue charging overnight when using the "departure" charge timer. Extension Cords are inherently unsafe..... Better safe than sorry!

 

I disagree slightly, but I believe (and I could be wrong. Did I drink that Toyota koolaid?) that running the engine at a very light load is not efficient, and burns much more fuel than the Toyota engineers consider ideal. They have calculated the if you run the engine at a little bit higher load, and store the excess power into battery, for use later, that the total power usage is better (more efficient) than running at light load. And at higher load, then engine efficiency again moves from high efficiency, and a battery assist moves it back. So the battery and the engine and motors are an integral part.

 

I used to think so also, but then the Prime presented a contradiction to this idea. Which is that in HV mode, even though the system now has greatly increased battery capacity, apparently it will not charge beyond the normal HV limit even if some or all of the EV range has been used up. Apparently the only time HV will replenish EV is during regen.

I suppose part of the problem is the losses that occur when gasoline energy is converted to stored energy and then to motive power. Thus negating some or all of the gains of using the engine at its most efficient load. Another problem is that if ICE is used to rebuild EV range, it could potentially be competing with grid power. I.e you don't want to use gasoline to charge the battery, no matter how efficiently, then arrive home with a full or nearly full traction battery and not be able to recharge from the grid.

However if competing with grid power was the only issue, then assuming that you know how many miles remain until you arrive home (my new acronym for that is MTH), then HV could in theory, when efficient to do so, replenish EV range, until EV range equals MTH. In fact that is how I first thought Charge Mode would work, that you were telling the HV system to go ahead and charge into the EV range when efficient to do so. Then when EV range equals MTH you would turn off Charge Mode and switch to EV. But it seems that when you turn on Charge Mode you are telling the system to charge EV continuously even during times when it is not efficient to do so.

 

I test drove a Prime the other day and the battery was depleted enough so it was in HV mode. Thanks to Prius Chat I knew what to do. When we returned to the dealer after the hybrid test drive, I put the car into charge mode and let it idle for about 15 minutes so I could do a proper EV test drive. The sales person had no clue what I was doing. The EV test drive went well. It's a nice driving car in EV mode-- not a Tesla, but a really nice driving car.

So here's a reason to put it into charge mode: When the dealer gave you a depleted battery and you'd like to try EV mode.

 

Also after you buy it and you are driving it over to the relatives to show it off you want to make sure you have a full charge!

 

I use charge mode sparingly.

I use charge mode when away from home city so that my remote city miles are electric (trying to avoid engine warm-up cycles for short urban trips)

If I have a 100 mile highway run I stay in HV, I do not charge, discharge, charge etc.

Returning home the last ten miles or so are city so I use charge mode to enable me to shut down combustion for the last part of my trip.

I charge only at home, always trying to arrive home with near zero range.

Even if charge mode does not save money I find city EV driving more enjoyable than HV. It's not that I enjoy polluting the countryside

 

Im sorry to be the guy that askes how do you use the charge mode n how do you turn it on?

Posted via the PriusChat mobile app.

 

Something wrong with reading the original post in this thread?

 

Or consulting with the owner's manual?

 

The attached chart shows the HV mpg at constant speed that is equivalent to the charge mode mpg you are getting at that speed plus using (at that same speed) the EV miles added.

Assumptions:
Charge mode time from zero EV to 80% charge: 0.6 hrs (36 min).
Full charge EV range (AER): 23 miles @ 60 mph, 24 miles @ 50 mph, 25 miles @ 40 mph.

Example calculation for 40 mpg in charge mode @ 60 mph:
((0.8*23+60*0.6)*40)/(60*0.6)=60.4 equiv. mpg.