Charge or Not to Charge?

Yes, except full on the Prime is 85% state of charge. Toyota does not allow more than that. So this is something you do not have to worry about beyond what the manual states.

 

As far as I am aware Toyota basically forces you to keep the battery charged within healthy limits so you cannot really kill it. I think the usable portions for the car as an EV are somewhere between 10% and 85%. You can kinda see this if you look at the number of miles you get on a charge.

For example my car thinks I can go about 30 miles on a charge and my average miles/kWh is 4.6. That means the car really only thinks I can use about 6.5kwh or about 70% of the full battery capacity(8.8kwh).


iPhone ?

 

In general, keeping a charge in a lithium ion battery imposes more wear than keeping it nearly depleted. What's even worse is to keep it charged in high temperature.

Example: You drive your car one hour per day, 20 miles. Which is better for the battery?

A) Drive 20 miles and plug in charger immediately
B) Drive 20 miles and set charging timer to complete charge in 23 hours

Answer is B, because for 22 hours a day, the battery will be holding a low charge. The battery which holds a full charge for 22 hours a day will not, on average, last as long.

 

Yes. Due to the range anxiety, BEV manufacturers allow 100% charging of their batteries so they can report the maximum range of the vehicle. The Prime doesn't have this problem as it has the gasoline engine as back up. 15% on the top is reserved. On the bottom, the Prime turns into a Prius so state of charge of the Prime rarely goes into either extremes of low or high.

 

Yes answer B and the Owner's Manual agrees.
But the owner's manual does not give information for my situation:
Driving 1 mile to work each way, along with possibly doing errand driving wthin town of 10 miles daily, 5 days a week. Longer drives over the weekend using the gas engine.

Question:
For a daily commute round trip of 2 miles am I best to wait until the traction battery is nearing the end of its EV range to plug in to charge (using the delayed charge programming to be ready for the next planned departure time.)? In other words plugging in daily, to get a full charge daily, would not be as good for the traction battery. Is my thinking correct?

 

i am tinkling you are correct. if there's no chance of doing more than your commute, i would drive it a few days before recharging. hard to say how much difference it will make in longevity, but if you kept it topped for years on end, it probably wouldn't be a good thing.

 

I don't think it's necessary to over-think it or get crazy about it, but as a general habit, if you charge on a timer that makes it charge at 4am -ish, it's probably better over the car's lifetime. But I just plug mine in whenever and I don't think about it much. I avoid keeping it fully charged all day long while sitting in the hot parking lot all summer. It's a car and with the insane 10 year 150,000 CARB state warranty, it's not something I worry about.

 

For this situation, you may be correct but there is more to it than just straight up what is good for the battery. Consider this: If you had to drive an additional 10 miles on any given day and you don't have enough EV remaining, the ICE would have to cover the difference. The longevity of the ICE is likely shorter than electric motor. Overall, for the car, I would say it is better to top up every day unless you are absolutely sure you will not exceed EV range.

 

But longer than the battery. People have driven Prius hybrids over 250,000 miles on the ICE that came with it.

 

The Prime is a hybrid. So Toyota has included a buffer of unused capacity to extend the battery's useful life so it doesn't end up needing replacement under the federal and CARB emission warranties.

The Li-ion battery simply is never fully charged, even when 'full', on the Prime, Volt, likely most of the plug ins out there.

 

People have driven well over 250,000 with the battery that came with it. We'll just have to disagree.

 

I meant longer than the Ev traction battery. I doubt you'll get 10,000 full range discharges out of one of those (two a day for almost 14 years), and that's what it would take to drive 250,000 miles on that battery.

 

but the car will go 250,000 miles, before you put 250k on the battery. if not, might as well buy a bev.

 

Of course it will.

My point is, using the Ev system to preserve the lifetime of the engine is ridiculous, since the engine will usually outlast even a regular Prius hybrid. If you get half of your driving mileage on the battery, you're already doing twice as good as anyone with a regular liftback, and we know how those things last.

 

I agree. In my original post I was only concerned with how to make the battery last the longest possible. I do not expect the electric motors or ICE to fail first.

In fact I think starting the ICE, when I intend it to start, is a good thing. I would probably keep the fuel level in the gas tank on the lower side when I am the Monday thru Friday work commute mode to help prevent the fuel from aging and spoiling. Then any longer trip using the ICE would require additional gas added to the fuel tank helping to keep the fuel fresh.

 

The answer is keep it in the middle of its charge range, and keep it cool when fully charged. Of course, the car will essentially force you to keep it in the middle of its range and try to keep it cool.

If I knew I was only going to drive a little each day, I wouldn't top up every night. But the biggest thing I'd never do is charge outside during a summer day. I wouldn't want the battery to be fully charged while hot soaking in the greenhouse that is a car in the summer sun.