How to extend LIMITED SERVICE LIFE of Prius PHV traction battery.

Not correct. Industry std is 85% efficiency. I did a lot of hunting to confirm this.

Also, the efficiency gets better with larger chargers. A 6.6kW has better efficiency than 3.3kW which is better than the L1. In my Leaf I see efficiency that range between 80% & 90%.

 

That's what I said. Mozdzen seemed to be asking Toyota to provide the upgrade, but I think it will be up to the after-market suppliers.

But do they make such mods available to the public? Or just something kept in house?

Not necessarily. Acceleration is limited by at least three factors: Power available from the battery (volts times amps); size of the motor; and choices made in the programming. I suspect that they'd need a bigger motor, a differently-configured pack, and different program to get more acceleration, because I imagine the whole package is designed and balanced for the most efficient operation within the chosen limits of range and performance.

They could make it accelerate faster, but they could also choose to give it more range without boosting acceleration. It just depends on the goals of the design team. They could even give the car more acceleration without giving it more range.

 

I wonder if they provide a gage to alert driver they are accelerating at acceptable / too fast pace? Something like HSI gage.

 

I think the gauge would be to hear to ICE turn on to help support the electric motor.

I'm sure Toyota software protects the battery and motor from excessive demands from the driver (pretty much 'idiot proof' as they did with the standard plug-less Prius).

 

I don't see your point about "false reasoning". Your example was in series and I was talking about a mixed series/parallel design. I will note, however, if the cells are the same the 96 cells provide much more power if they provided the same current. If they were asked to provide the same power, then the cells in the 96pack would each need to provide less current to have the same power. (P=IV).

However, my statement was about more cells using them in parallel. In series you add voltage in parallel you add current. So for a fixed current overall demand, the current per cell (hence stress on the cell) is lower in a parallel configuration. Designs often use a mixed series (to get desired voltage) and parallel (to get current) to achieve a particular power level.

 

Like I said before, you cannot compare across different cells (with different Ah capacities, different voltages) and different pack designs, without far more information then we have here.

In general smaller cells have higher power ratings in proportion to capacity. In general extremely long strings put you at risk for balancing issues and failure. These are just generalities though.

 

This article is relevant to the current thread and close to the current discussion.

Tesla Motors' Devastating Design Problem

It is worth reading even though it is a little long.

I didn't realize that the full price of of a Tesla traction pack was the same as a PiP (Advanced).

 

In order to go slower, you'd have to brake more and regen efficiency drops the harder you brake even before the physical brakes are engaged due to maximum regen. Furthermore, this is probably less of an issue on the Prius Plug-in than the Liftback, since the battery can discharge/charge at a faster rate.

Yes, it is available to the public. No, it is not kept in house.
Toyota Racing Development

MG2 is 60kW/80HP and MG2 is 42kW/56HP. Normally, MG1 is used as a generator to power MG2 in addition to the 38kW/51HP from the battery. MG1 as a generator means that is is drawing power from the ICE which is 73kW/98HP. Someone can correct me if I'm wrong, but I see 60kW + 42kW - 38 kW = 64kW of additional power that could come from a larger battery.

 

Yes they muffed it.
However I believe only like 6 have been affected and they fixed it in the model S thank goodness.

 

Interesting! Since the first production Model S has yet to be built, how do you know that?

 

Google News

 

If you read those articles, what you learn is that Tesla is in major denial of the problem which is quite carefully documented. The problem with ANY traction battery is that it MUST not be allowed to totally discharge.

It does not take major effort to prevent that but it CAN happen and if it does the consequences are HUGE.

The lesson is KEEP THE CAR PLUGGED IN!

It may be better under some conditions to keep the SOC below the full mark. But letting it get all the way empty by accident in the process is FAR, FAR more dangerous.

The people who just get into the habit of driving their car and plugging it in when they get home are not going to have problems. It is those who are trying to get the last possible electron out of their battery and who loose their concentration who get into trouble.

 

Luckily for us PiP customers, we probably won't have to worry about totally discharging the battery since the car will switch from EV mode to HV mode without us having a choice.

I would like Toyota to be upfront and estimate exactly how much more quickly we reduce the total charge capacity by leaving it charged but not used. I can't always predict when I will want to take an after supper trip in my car. Maybe I should charge it only part-way up, just in case??

I know when I first get my car, of course, I will drive it a full charge's worth after supper each night (just for fun). I'm not sure how soon that novelty will wear off.

 

what to do when going away for a month or 3?

 

Use the timer function built into the PiP and have it only charge for 15 or 30 minutes a day. Might even be able to get away with 5 or 10 minutes.

 

You definitely don't need to do this.

Charging once a week or even once a month would probably be fine.

 

Yeah that would require a separate external timer because the built-in one doesn't distinguish days, weeks, or months just time of the day. The internal one is actually usable to the minute so you could charge it for a minute. But after a month being unused they should be more concerned with making sure the remote key is turned off to keep the 12V battery from draining.

 

thanks guys. is it better to keep it full or at some lower level of charge?

 

From the Tesla manual as posted in the above link:
Keep in mind that when the vehicle is left unplugged with a full Battery, the initial rate of decline can be significant. When fully charged, the Battery’s charge level can drop as much as 7% a day and 50% within the first week. When the Battery’s charge level falls below 50%, the rate of decline slows down to approximately 5% per week. Over discharge

ouch - this is like your gasoline fuel evaporating out of your gas tank. Costing money and pollution. i wonder how much the auto-discharge rate can be halted, like the Li batteries in the AAA and AA sizes now available? Probably technically doable, but will cost more space and money.

This sounds like a problem for early adapters that will go away in 3-5 yrs or so, I hope.

Do NiMH batteries not turn into bricks so easily? I'm sure there have been Priuses parked for long periods where their batteries completely discharged, but I haven't heard of any nightmare stories about this, has anyone else?

 

The way to destroy an NiMH battery in a Prius is to run out of gas and continue to drive until the car stops. The NiMH battery has a lower power density than the Li Ion battery and has proven to be tough. On top of that, Toyota has supplied a very competent battery management system. The LiIon battery together with the ability to charge from the grid presents a slightly different challenge. We will learn more with time.

If you are going to store the car, unused for several months or more, consult your dealer. I would arrange for someone to use my car rather than store it for such long times which really applies to any car. Another alternative if you are not going to use a car for such a very long time is selling it. Problems happen when a planned short absence turns out to be a long absence. Be aware. There are traps out there which can bite.