How bad for the battery to be depleted into HV range without charging for an extended period

I can notice this very much on a full battery and getting up to speed on on ramps.. that car actually feels.. ZIPPY... my gf will press the PWR button for me before we get on the freeway and we smile.

 

who wouldn't smile when their girlfriend presses the power button?

 

The power light on the power brick will always be red. It means it's connected to the wall socket and has access to electricity. The little light on the car next to where you stick the car's charging plug will be orange when charging and dark/black when done charging (or waiting for the timer).


iPhone ?

 

Thanks for the European perspective on the light. Mine is green when plugged in. Interesting that they differ.

 

Lithium Ion batteries do NOT like sitting around in a highly charged state. Especially in hot weather. Doing so is the BEST way to ruin the cells. A chemical reaction takes place on the plates and slowly reduces the useable surface area (and thus capacity) of the battery.

The timer function on the onboard charger is not there just so you can use cheap night time electricity, it's chief function is to make sure you only charge the battery to full capacity JUST BEFORE you plan to use it.

Also the reason Toyota recommend you park in the shade whenever possible in hot weather, and DO NOT charge the car up and leave it parked fully charged when you go away on holiday.

The sweet spot for Lithium Ion cells is around 3.3 to 3.9 volts. This is the voltage range Toyota use for hybrid mode on the PHV. 3.9 to 4.2 volts is the extra boost they give the battery to use in EV mode. Sitting up at those higher voltages without being used is NOT GOOD.

Same goes for extending the life of you laptop and battery power tools - don't leave them in the sun - it's the #1 killer of battery capacity.

 

i've been saying this for years, just not as authoritatively.

 

My first PHV post, though I put "pen to paper" a few times in my Prius C days.

Post #25 got me wondering about how Toyota uses the PHV li-ion battery, so I dug out my Torque pid list to do a bit of testing, relying on there apparently being 8 blocks of 7 cells, yes?. At SoC 23%, average cell voltage was around 3.5, 3.90 volts came along at 78%, and 3.95 volts (max) at 86% - is this pack protected or what!

Now I am used to using LeafSpy to monitor my Leaf, and an average 3.90 volts in that case is at about 36% SoC, so Nissan pushes the Leaf battery way harder than Toyota does the PHV. Why do I bring this up? Because my day-to-day use of the Leaf is all very short trips (max 12-13 miles return), and I like to charge frequently (4-5 times/week). So knowing that li-ion storage is recommended to be at/under 40% SoC, that's what I do with the Leaf - never more than 39%, 40 min charging at 240v/15A EVSE. The unexpected outcome is that for the last 3 years I have had no Leaf degradation at all; still at 95% SoH, for a May 2012 build. Note, though, that charging to 40.x SoC results in a couple of thou' drop in the Leaf, AHr and Hx variables - it's a tight cutoff.

So if I assume the Toyota li-ion battery can be treated the same i.e. for no degradation at all below 3.90 volts, Toyota's VERY conservative approach still allows for both a decent amount of EV range and a long, long life, yes?

Am I too optimistic?

 

Apparently so. I don't get great range, but most of my driving is stop and go on roads with 50-55 mph speed limits in Florida heat. Just about as inefficient as you can get. The car came from New England and I got it 8 months ago, so it probably had it pretty easy up there compared to here. I usually get about 10-11 miles out of it this time of year. About 12 miles in "winter." But to charge from no EV range to "full" usually takes 3.3 kWH or more, so I think it's still pretty healthy.

It sounds like you're trying to treat your Leaf battery similar to the way Toyota treats the Prius battery. Great idea!

 

Your winter sounds like our summer - around 80F/26C. It was about that when I got the car, and tested Toyota's claimed 16 mile range successfully. Our first day of spring today, and have been getting about 12 miles across town lately, stop-start, 60-65F.

PHV's were never sold new here - too expensive, but Toyota has bought up low-mileage demonstrators in Japan, shipped them over, and refurbished them to Kiwi specs for about 70% of the price of a new Gen 4, plus a 5-year warranty. So I don't know mine's history, but it has been all good so far.

My real-life "experiment" with the Leaf has turned it into a "keeper", and so I am looking for the same outcome with this car - don't think it going to be too hard! I also get a free hour of off-peak power/day from the power company, my EV running costs are zero, so life is sweet !

 

Some of us have seen some degradation. Not crazy amounts, but definitely enough to be noticed.