Is hypermiling killing the battery?

Who is this "a lot"?

Have you seen Honda Civic Hybrid Battery Reliability | Hybrid Batteries - Consumer Reports News that was posted at Honda Civic Hybrid — Shocking Battery Failure Rates | PriusChat ?

Also see Lifespan/Operating costs - Prius Wiki.

http://www.toyota.com/content/ebrochure/2013/priusc_ebrochure.pdf says on the last page "11. Hybrid vehicle battery expected life is 150,000 miles based on laboratory bench testing..."

There is also Worldwide Prius Sales Top 3-Million Mark | Toyota (from July 2013) and Worldwide Sales of Toyota Hybrids Top 6 Million Units | Corporate from January 2014.

If you want to see "a lot" for a small # of units sold of a non-Toyota, namely the Tesla Model S (about ~30K Tesla Model S sold worldwide so far, deliveries began June 22, 2012), there's a nowhere near complete list at Main Battery Replacement + a few that the OP didn't want to count for some bizarro reason at Main Battery Replacement. There are many more scattered thru other threads.

The Chris that's mentioned there had his swapped at 8K miles. Edmunds had theirs replaced before 20K miles.

 

I'm also running in EV as much as possible (66%), here is my picture in the Top 20 - MPG Record Holders.



FE (MFD) = 97.1 mpg
FE (Calculated) = 90.7 mpg

The top hypermiler, ufourya, has his EV at 78%.

IMHO, if running at low speed and low load conditions, EV is my preference. No doubt the battery has to be recharged, it is still more efficient than running all ICE in that type of conditions.

Vincent

 

The OP describes driving under 40 and trying to use EV mode as.much as possible. I try to do the same if possible and it doesn't interfere with traffic. I cant keep the Prius in EV mode if it doesn't want to stay there either by me putting just a little too much pressure on the accelerator or if the battery is low enough. In both cases the car turns on the ICE regardless of my desires. Since the car controls this kind of behavior and not me I don't see how it can be harmful to drive in EV mode. If I had a control to override the car that would be another matter but I have yet to find anything that does so.

 

How much of that is constant speed EV, and how much of it is gliding?

 

Our traffic does not permit me to do gliding, so most of that is constant speed EV or neutral. As you can see, my avg. speed is much higher than ufourya.

Vincent

 

Mine is usually about half and half gliding and just enough power to maintain speed-usually 25-30 mph. If I get too close to 30-35 mph then I am also very close to the EV line and the Prius C will start up the ICE on its own.

 

hey, if no one can convince you, we won't try. all the best!

 

If that is mostly constant speed, then it pretty well matches Bob Wilson's mpg-vs-speed graph for the liftback. So no surprise.

 

One way to switch on the ICE is going fast.
The other way is just going FAR enough that the battery is depleted.
In the C, that is only a couple of miles.......or less.

The battery is there to "help" the ICE, not replace it.

 

I also notice my best mpg comes with low speed EV if not using P&G.

 

I could have worded my original reply better because it certainly did make me sound close minded. However, I came to these forums almost a year ago to learn, I have learned much, and I will continue to learn. My comment "no one will convince me" was specifically aimed at the argument that says essentially you want to keep your ICE running and avoid EV mode. That argument defies logic and definitely does not match my real world experience.

 

My best short run so far is 3.2 miles at 99.6mpg - I didn't realize that I was electric almost that whole way until I arrived. I had been behind someone doing about 20-25 on the way to the Post Office on a mostly flat route.

 

now this, i agree with. you shouldn't 'try' to keep your ice running any more than you should 'try' to drive in ev mode.

 

I don't claim that one should try to keep the ICE on either, any more than one should try to keep the ICE off. Pulse & Glide -- ICE on in short bursts, then gliding with the HSI bar shrunk to zero (or almost so) can beat both.

 

Why not? If the experts are wrong, they, and we want to know it. An 'alternate' view is useless unless we know whether it is wrong or right!

Here is something you could do to convince me, figure out the energy movement in your way of driving. It could be as simple as a record of how long you are in each mode, and at what speeds. We know the efficiencies of various energy routes, and we should be able to calculate your overall efficiency, and compare it to other methods.

 

How about 118.9 MPG, on a GenII?
New World Record Challenge: over 50km/L(117mpg) tank

 

My best honest round-trip mpg has been 67 mpg.

I love my car too much to get mad at slow drivers

 

I don't know if I'd agree. When the ICE is being used, the EV motor is also constantly on and providing motive power. Cruising along without the ICE on would seem to yield better mileage without any detriment.

It's not as if the EV motor rests at all when the ICE kicks in. In fact, the EV motor is at full power usage any time the ICE is running.

 

Whether the EV motor is running is not terribly relevant (and it is almost never at full power, by the way). What matters is the path of the energy. When you are running ICE and EV, the energy is coming from gas through the engine, with some of it converted to electricity by one motor, and (mostly) converted immediately back by the other motor. All that has some efficiency losses. Using just EV has the energy coming from gas, converted by the engine through a motor to electricity, *stored in the battery*, *retrieved from the battery*, converted back by a motor. All with some efficiency losses. It is easy to see from this, that using EV has the same efficiency losses as running on ICE, PLUS the efficiency losses of storing and retrieving from the battery.

The reason that hybrids are more efficient at all, is two-fold, 1) they allow load balancing on the ICE engine (including turning it off completely when appropriate), allowing to run mostly in the peak efficiency range (and to be more efficient in that range by not requiring as much power at high-load times). 2) by storing and reusing energy that would otherwise by lost to heat in the brakes.

 

This is always happening, whether or not the car has the ICE running or not. The difference is that when the ICE is running, it's also using up gas to drive the car. If one could theoretically drive all the time only on the ev motor, with the ICE kicking in only for charging the battery, efficiency in terms of MPGs would be very high.