Prius Prime Plus in my hands

100% usable isn't 100% SOC - that's the point. I would guess that Nissan is using a float voltage of 4.10V to 4.15V, rather than the 4.2V I use on my model airplanes or the 4.35V that my phone uses.

 

And I've even seen 4.365 V float on my old Nexus 5. Phones push their batteries hard. (And my Pixel XL is charging at 4.403 V, at 90% SoC, 1230 mA. I'm checking what its float voltage is...)

Looks like the Leaf uses 4.125 V max, preferring to float around 4.100 V: Battery pack voltages - My Nissan Leaf Forum

 

It seems that with the very new BEVs, 100% usable is very close to 100% SOC.

Posted via the PriusChat mobile app.

 

Which makes total sense for both devices. Phones have a lifespan of something like 2-3 years, while cars are more like 10-15 years. The difference in float voltage is comparable to that difference in lifespan.

 

It is close. Too close for everyday charging when it is not needed. That is the point

 

No, it's not.

4.125V, as reported above, is around 85% of the charge you'd get at 4.2V, and around 75% of the charge you'd get at 4.3V.

 

No. Leaf reserves about 0.5 kWh at the top.

 

You are missing the point.

If the Leaf charges to a float voltage of 4.125V per cell as its "100% charged" voltage, then it's only charging to about 85% of where it would be charging to if it were charged to 4.2V per cell.

Battery specs - Electric Vehicle Wiki

"24 kWh [2] (16 kWh available, 67% DoD [3], 21 kWh declared [4])"

The difference I'm talking about is the difference between "24 kWh" and "21 kWh declared" (which is 87.5%). This is the difference at the top of the charge. The difference at the bottom is DoD (Depth of Discharge) showing it doesn't discharge all the way either.

 

I don't think so

The nominal capacity of a new, pre 2017 LEAF is 24 kwh
22 kWh is available from a "100%" charge
I think (but I am not positive) that there is more reserve at the bottom than the top, but certainly not less than half.
So AT MOST, 1 kWh of battery is unused at the top.

This is too little to protect the battery against accelerated aging if charged to 100% daily unless the climate is cool year-round -- and even then, I am skeptical about the practice. There is a lot of anecdotal evidence that the 2014+ LEAF batteries are degrading faster than the MY 2013 manufactured after april. These two groups have identical batteries but differ in the default charge SoC.

 

Still not getting it.

That 24kWh rating is already de-rated from what it would be if the batteries were charged to 4.2V, 4.3V, or 4.35V per cell, and further de-rated from what it would be if they were ever allowed to be fully discharged.

That's the point!

If they don't do that, then they're morons because the battery isn't going to last more than 2 years.

I don't think they're morons.

 

Moron is somewhat in the eye of the beholder, but most LEAF owners see 5-10% degradation a year, and in hot climates up to 20% a year.
LEAFs are not engineered for a 10-15 year battery life. Prime are, but then Prime sets usable to about 62% of nominal.

From 4.2V, yes. So is the Prime battery.
And from there, the LEAF uses 22/24 while the Prime uses 5.5/8.8

 

duplicate

 

Messed up the post above, here are my questions:
I believe the paper referenced by Bob Wilson got its information from an article in plugincars.com: Eight Tips to Extend Battery Life of Your Electric Car | PluginCars.com

My questions are related how to get the longest life out of my Prime's battery:
1) Should I use 8A instead of the standard 12A when charging using L1 at home? (I have plenty of time before departing for work.)
2) I realize Toyota has built in safe guards for the battery to not allow too much discharge or too high of a charge. But should I keep the battery SOC in an even narrower range than the Toyota safeguards would ensure, ie keep the SOC between 40 to 65%, to get the longest battery life especially when I am just making small trips within town?

 

1) use 12a if you're not tripping the breaker.

2) no, trust toyota has done the right thing.

3) don't overthink this.

4)

 

i disagree, but we're all guessing, and giving our own feelings i think. if i can charge at home and work/on the road, i will gladly carry my oem evse, even if i don't want to buy an L2 for home.
people are spending 20, 30, $40,000. for electric vehicles, and will be unhappy spending $3-500. on a second evse?

 

To what part of the post you disagree? I just gave facts.

 

Yikes. And yet the forum is full of discussion about charging costs.