Another Battery Degradation Thread

Under the same conditions? How do you do that? Even in a Lab, the same conditions are not always attained. So most of our assumptions, thoughts are really just guesses about what we think is so.

 

But, glad to hear you're getting 14 miles again.

 

Here are my observations. It is not at all scientific, only what I've seen. I bought my PIP last summer and the EV miles gauge always showed over 14 miles after a full charge. As the cold weather moved in the gauge slowly fell until Jan/Feb/Mar 2014 when it was about 11 EV miles after a charge. As the temperatures have started to go up here in New England my gauge has risen to between 13.8 and 14.1 after a full charge. When we actually get to summer, I speculate that I will be always above 14 EV miles. As a point of reference, I have an enclosed garage with level 2 charging. The outside temperature on the Prius LED display never went below 25F even during the days we were at 0F overnight. If this thread is still alive in July, I will post my observations again but I expect to see 14+ EV miles for Jun/Jul/Aug.

 

Finally - warming up nicely here and looking at 12 mo old Chargepoint reports plus my actual EV miles on my standard everyday drives I'm seeing no difference at all.
To answer that earlier post - if the degradation is this small each year I don't care at all. I get 15-16 actual in good weather so if that drops even 10% total over 7-10 yrs I'm good. I don't use gas now and I wouldn't then given my routine.

but If I was trying to make back that premium over say the Prius3 - and my commute was more like a 50-50...
Sounds like no one is seeing a measurable drop though so lets worry about something else

 

the red sox dropped a tough one last nite...

 

battery degradation...

 

The attached text files are CSV format.

They contain the raw data I captured for detail about battery-temperature.

34.7 miles round trip (24 EV, 10 HV). 2 full charges. 186 MPG overall.

 

I'll have a chance at some point to generate some graphs from the data. It should go a long way toward ending the FUD being spread due to lack of real-world data and such a wide variety of chemistry types available. In the meantime, I'll keep gathering.

The other day on the drive home, it was 76°F out. I did hill climbing and a bit of 55 mph along the way, staying in EV for the entire capacity. The battery-pack temperature stayed just below the 100°F mark. I believe that is the normal operating expectation for continuous discharge of the type in Prius.

We'll see what happens when it gets hotter out. But since most people simply use their A/C and the engine is there to protect the battery-pack, it's hardly a concern the rhetoric would lead us to believe.

 

the best i did on my commute when i first got the car was about 2 miles left when i got home. yesterday, at 70 degrees, i had 1.6 miles. this is far from controlled testing, but it's all we have. i will keep monitoring.

 

It's quickly becoming obvious that the claims of liquid-cooling is necessary for battery longevity were acts of desperation to undermine.

Today it was 79°F on the drive home. The 12 consecutive miles of EV driving I did never pushed battery temperature above 100°F, without anything but open windows to provide cooling.

The electric A/C is available and will be used when it gets hotter out while driving. That will make the air available for cooling even cooler. So, there's nothing they can argue. The A/C could even run as part of the recharging process. Toyota didn't find that necessary though. The chemistry chosen is proving worthy without the need for liquid.

By the way, I can turn it on remotely from my phone now using Entune. It does a very nice job of cooling the interior. 10 minutes of running consumes roughly 0.2 kWh of electricity.

 

Dates, prunes and figs will help with that... and they're all natural

 

According to Nissan, who regularly communicates with owners of the Leaf, they consider it "normal" for the battery to lose 30% of its capacity in 2-3 years, and then hold steady for the rest of its life. Perhaps the same is true of the Lithium battery in the Prius plugin

 

What would the variables be?

My observation was from turning the A/C remotely with the vehicle not being driven or even the hybrid system on.

 

Nope. Prius is not an EV. It is not depending exclusively on the battery-pack for power.

So far, 2 years and 3 months later, I have seen 0% capacity loss. I'm still reaching the same conditions under the same circumstances as I did when the car was branch new.

 

Getting back on the liquid cooling rhetoric... another reality hit me. The electric-drive in Prius is more efficient than Volt. As a result, less waste heat will be generated... hence less of a need for cooling.

 

My comment was only about consumption-rate, generic operation, not a specific goal.

Today's drive home provided a nice subject-matter example. It was hot & humid. So, I used the A/C the whole time. The air-temperature measured for battery-intake was lower than it would have been with the windows open. The temperature of the battery itself was too.

If we know that the battery is just fine under normal conditions and running the A/C for extra cooling in the hot, where's the supposed problem?