Electric battery degradation

The voltages you mention are appropriate to the 12V auxiliary battery, not the hybrid traction battery. There's virtually no chance that the aux battery is significantly affecting your mileage or your EV range. Plugging in doesn't charge your aux battery either; it starts being charged as soon as your car goes into ready-mode.

But it sounds like your aux battery is starting to bite the dust. It really doesn't have much work to do, other than turning on the computer in ready-mode, where-after the DC-DC converter takes over providing all the 12V power. My PiP arrived from the dealer with a bad aux battery. It wasn't holding a charge, and leaving the car in acc-mode for 10-15 minutes resulted in a dead aux battery, leaving the car dead-in-the-water. I had it tested and replaced.

 

Do you mean range? The car will adjust the estimated range based on your driving style and conditions, so its not necessarily your battery getting worse.

 

Pay attention, please.
Those numbers are his EV mileage range, not voltages.

My question is: Is that the estimated range that is displayed right after a charge.......or is it the number of miles actually achieved with EV ??
Seems like I remember that the estimate takes into consideration your past EV history.

 

Good catch. I thought I had read it enough times, but apparently not.

 

Battery degradation is not uncommon in any of the current completely electric vehicles, early Leaf owners are seeing about a 20% loss in batt capacity over the first 100k. I was under the impression that this was simply the nature of the beast.

 

these batteries are expensive, but you are in luck, you have at least a 100,000 mile warranty.

 

Best way to check for traction battery problems:

1. Find someone local with the same car (might be the hardest step!)
2. Invite them for an extended coffee break while the uncharged car charges.
3. Shut off A/C, seat haters, headlamps, etc.
4. Zero a trip odometer.
5. Drive as a convoy of two on the same route at the same speeds and accelerations.
6. Drive until you get near the end of the shorter displayed range.
7. Observe and note the odometer readings when EV mode ends.

Regardless of the initial estimated range, cars with good batteries should agree on the actual battery rundown distance within a few %.

I did this with a work colleague on his route to compare gas mileage on my previous (non-PIP) Prius, and we both hit 55 +/- 1 MPG, even though my usual route driven my usual way had been giving me only about 42.

 

The LEAF battery pack was poorly designed. It has no thermal management at all, not even a fan, other than some mild heating plates that are used to warm the battery under very cold conditions.

Battery degradation is a function of calendar time, cycling and heat. Aside from limiting the cycling or the low vs high charging extremes, the main thing you can do is to avoid cell high temperatures and preferably keep all cells at about the same temperature to promote even and consistent aging.

The Tesla's, Ford Focus EV and Chevy Volt use liquid active management to keep everything happy. Other cars like the Ford Energi, Prius Plugin, and others use active air cooling which takes advantage of the fact that optimal temperature ranges for people and Lithium batteries are about the same.

The LEAF just used a sealed and uninsulated battery compartment that radiates away the heat out the bottom of the car (or absorbes heat that way from the ambiant outside air or baking hot pavement. And the battery chemistry used in the LEAF tends to be somewhat more sensitive to temperature-based degradation.

Even worse, around 2014 they changed the LEAF to remove the 80% charging option -- now you can only do a "100%" charge. Nissan did this to "game the system". Previously, EPA rules resulted in the EV range estimate being an average of the range with an 80% charge and the 100% charge. By removing the 80% charge option (which used to be the default) Nissan was able to just report the 100% EV range which made the LEAF appear more competitive without actually improving the battery. The 100% charging will almost certainly result in somewhat faster battery aging.

I think the real problem is that Nissan was caught off-guard by the Volt and didn't have time to do a better job or better early testing to discover the problem. The Volt was shown off in January 2007 and committed for production by the 3rd quarter of 2007. The LEAF wasn't announced until the 3rd quarter of 2009 but was delivered to customers at the same time as the Volt.

We'll see what they do with gen 2 of the LEAF.

 

If what you say is true, then theoretically the batteries should last longer here in Canada.

 

Yes, probably.

 

Stats should therefore exist.

 

My EV range varies from 10 to 14 miles. It's about a 4 mile variance on a morning commute that I've been doing at 5:30 am every day for 7 years, over 2 years in my 2012 PiP. At 5:30 am, there is very little traffic so my driving style is as constant as it gets for real life situations.

Why the variance? Mostly it's down in the winter and up in the summer. My wife uses the seat heater in winter. I use the defroster which turns on AC in winter. I rarely use AC in summer. Precipitation is a drag in winter. Nights are longer so more headlight use. Batteries don't work as well in colder winter temperatures. Minor things but they all add up.

You're showing less than 3 miles variance and it is winter. I'd say all is normal.

 

my ryobi lithium batteries poop out on a regular basis. there's nothing for it but to buy new ones. i wonder if a grid charger would help?

 

The lithium batteries made in China seem to have a unique quality of going dead without being used. I bought 2 lithium batteries for my Sony SLR camera for $12. The OEM battery was $99. I figured there was nothing to lose, so I ordered them online from AliExpress. They seem to work well enough, but they go dead after a few weeks in the camera bag, whereas the Sony battery seems to hold a charge for almost a year.

 

ya, it's tough to find many things not m.i.c. these days.

 

I don't think the problem is "m.i.c."

If you want quality, they can make it in China. If you don't want to pay anything for it, they have that level of quality also.

 

They do...

Run these words through g00gl3 and poke around.

"lithium battery degradation map temperature"

Battery Capacity Loss - Electric Vehicle Wiki

 

This article has some good info about lithium battery degradation in general:
How to Prolong Lithium-based Batteries - Battery University

Based on the article, it seems to be a really bad idea to leave your car out in the sun especially if the weather is warm and charged to full capacity.

 

doc? doc?