The Great Hybrid Battery Debate

falconone

If memory serves me right, I believe it is ~100 lbs.

midnightcowboy

JOHN said "And of course, the fact that Prius generates electricty and immediately consumes it has been totally ignored here."

This is true for low speed 0 ~ 43 mph, iff (if and only if) the battery is fully charged. If the battery is not fully charged at low speed then the battery is charged. If the battery is fully charged, i.e. "contant state of charge" then YES the electricity goes directly to the eletric motor for propulsion. At speeds above 43 miles per hour then the electric motor is not longer used for proplusion. Instead it acts a a generator and contiunually charges the battery at highway speed, even if the battery is fully charged.

This is one of the main complaints against the HSD , the wasted energy at highway speed. That is why the highway mileage is less than the city mileage 51 highway versus 60 city.

The light hybrid Honda IMA is more designed for highway driving. The manual insight gets 60 city and 66 highway.

Just trying to clear up your confusion.

Have a good day,

MidCow

falconone

Post people get better mileage on the highway in their Prius. The EPA tests in the city are way off. I've driven the Prius in city stop and go and the mileage really suffers if you don't drive carefully. Out on the highway at a steady 65-70 I easily get low 50's. No way can I get that in 10 or so miles of city driving.

rx400hfan

MidCow said "Instead it acts a a generator and continually charges the battery at highway speed, even if the battery is fully charged."

Sorry this is absolutely not the case. If it were the case you could count on battery failure within miles! At all times the ICE is producing power and the battery is not being recharged a significant percentage of the power output of the ICE is in the form of electricity generated by MG1 being used to drive MG2.

midnightcowboy

rx400hfan said : "If it were the case you could count on battery failure within miles!" That may be your opinion but that is not the truth! Charging a fully charged battery would not cause this; this is not cycling, just wasting energy. This would be closer to the truth if a battery were fully discharged, then charged, then discharged. But still the failure wouldn't be within miles. This just isn't true with prismatic nickel-metal hydride batteries.

Now does it make sense to use one generator MG1 to drive another motor MG2 And at full output the MG! is significantly smaller than the MG2 and could only supply partial input. No because no conversion is 100% efficient Energy conversion and friction losses. Do you understand how the MG1, MG2, and drive gears work in the planetary CVT ? Go back to the techniocal details agin and look at what happens on flat highway cruising.

Okay, please explain why the highway mileage is less on the HSD and not on the IMA or any other ICE only. It is because of loss during full battery charge when MG1 contines to supply a charge.

And actually the implementation on the 400h is significantly different than that on the Prius, but I assume you understand that.

Good luck with understanding your Lexus hybrid.

Cheers,

MidCow Charging on

rx400hfan

MidCow said "That may be your opinion but that is not the truth! Charging a fully charged battery would not cause this; this is not cycling, just wasting energy."

Actually it is much more than my opinion and it is the truth. Any battery can handle a low rate of charge when it is fully charged without damaging it. This is what is known as a trickle charge. I would like to know where you get your information that indicates the battery in the Prius can absorb several KW of energy when in a fully charged state & not suffer a meltdown! I am aware of one person that almost lost their garage & house by overcharging one of these batteries from the grid while using a much lower charging rate then this!

If you are familiar with the design of the PSD in the Prius you will see that a very significant percentage of the power output of the ICE has to be absorbed by MG1 and the way that MG1 absorbs that power is by generating electricity. This electrical energy is sent to MG2 and added to the power that went from the ICE through the PSD to MG2 and the drivetrain.

And no these are not just my opinions. If you have a strong understanding of the laws of physics and of mathematics and you read and understand the analysis of the Prius on this site http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/Contents.htm all of the workings of the HSD will make perfect sense.

This site is not mine but I have been involved in mechanical & electrical engeneering for enough of decades to be able to fully understand this analysis.

As to why the highway milage is lower is another law of physics. It takes 4 time the power to offset the increase in drag when you double the speed of any object through the air. Any vehicle that didn't produce a lot of waste energy at lower speeds would have much better range per energy unit at lower speeds. This explains one of the main reasons the Insight has better highway milage then the larger Prius, It has less drag at those speeds.

rx400hfan

I said "It takes 4 time the power to offset the increase in drag when you double the speed of any object through the air"

Actually I used the wrong word here. It takes 4 times the force to double the speed, which is 8 times the power. So if it takes 4 HP to overcome the air resistance at 30 MPH it will take 32 HP to overcome that air resistance at 60 MPH

midnightcowboy

So that is true of all cars and I don't disagree.

But is doesn't explain why the Prius is rated at 60/51 and the 400h is rated at 31/27 while almost every other vehicle in the world had a higher highway mileage rating inspite of the air resistance.

Also in your previous post I said the battery is still charged when full and you said that isn't true. You said that would ruin the battery in miles. Then you contradicted yourself and said yes that the battery received a trickle charge when it was fully charged. The "trickle charge" is wasted energy. It is debateable what contitutes a trickle charge, whether it is 10 milliamperes, 100 miliamperes, 1 ampere, or something else. Anyway whatever it is it is LOST/WASTED ENERGY.

rx400hfan

"But is doesn't explain why the Prius is rated at 60/51 and the 400h is rated at 31/27 while almost every other vehicle in the world had a higher highway mileage rating inspite of the air resistance"

Actually that is exactly what I explained. Any vehicle that did not waste a significant amount of energy in a low speed environment such as the EPA city test would have a better city rating than their highway rating, just like the Prius & other HSD based vehicles.The fact that the ICE is running on most vehicles when they are sitting at a traffic light & their brakes are radiating all of the kinetic energy required to bring them to a stop as waste heat, is many many times more wasted energy the slight amount a topped up battery trickle charge would be.

By the way it was your insistence that there was such a trickle charge. It is my experience that there is no such trickle charge. The computer does not allow the ICE to charge the battery to the 100% state of charge so there is no such wasted trickle charge. So we are back to where this all started in that while the ICE is running and the computer determines that the battery SOC is adequate, for all of the significant % of power created by MG1 (as dictated by the laws of physics applying to the PSD) there is only one place that power can go and that is into MG2.

john1701a

> This is true for low speed 0 ~ 43 mph, if (if and only if) the battery is fully charged. If the battery is not fully charged at low speed then the battery is charged. If the battery is fully charged, i.e. "contant state of charge" then YES the electricity goes directly to the eletric motor for propulsion. At speeds above 43 miles per hour then the electric motor is not longer used for proplusion. Instead it acts a a generator and contiunually charges the battery at highway speed, even if the battery is fully charged.

Wow! That statement is filled with so many misconceptions, I don't where to begin.

Whether or not the battery-pack is fully charged has absolutely, positively nothing to do with when the "create & consume immediately" takes place. Which is a darn good thing, because in the 42,000 miles I've own my HSD, I've seen 80% just 3 times... all of which were the result of driving down a very lengthy valley. I've never seen 100%. Yet, I see that "create & consume immediately" mode around 100 times every single commute to & from work.

As for the electric motor not being used above 43 MPH, that is complete nonsense. It gets used on a very, very regular basis. There's no such thing as an absolutely flat highway. Any change in pitch (up or down) takes full advantage by letting the motor join in. And of course, if you aren't maintaining an absolutely constant speed, the motor will join in then too. Also when the battery-pack reaches the comfortable level (in the 65 to 70 percent range), the engine RPM will be reduced and the motor contribute rather heavily.

Remember, each mode can be as short as 1 second before it switches again. So seeing 10 to 20 changes in electricity flow during just a single minute is quite common.

THIS LINK provides proof. It is a video of the multi-display & speedometer from a drive over 14 minutes long, including everything from a dead stop to cruising on the highway.

JOHN

midnightcowboy

LOL -- Video screens tell it all instead of actual objective measurements. The LED bar charge gauge is an approximation. The video display is an approximation. It's purpose is to animate and keep kids happy and to try and explain the HSD system to mere mortal humans who drive cars. It is kind of like a cartoon of real life; the Dick and Jane version for elementary age. It is kind of like Micorsoft training, set a person down on the street and make it so simple anyone can understand.

I suppose the reason you don't think the Planetary CVT has gears is because it doesn't show it on the display screen. Agin the display screen is an approximation or representation that some programmer, like you, created of what is actually happening in the car. Hey maybe you could program it better

YMMV,

MidCow

When I "charge and consume immediately" it is usually at the "TO GO" counter at a restaurant

john1701a

> At speeds above 43 miles per hour then the electric motor is no longer used for proplusion. Instead it acts a a generator and contiunually charges the battery at highway speed, even if the battery is fully charged. This is one of the main complaints against the HSD , the wasted energy at highway speed.

How can such wild claims like that be made?

They are grossly incorrect, and there are piles of documents to prove it.

The "full" hybrid has 2 motors. One that generates electricity while on the highway and the other that consumes it on the highway.

I can't believe misconceptions are being spread.

JOHN

falconone

John... you have to understand that Midcow is now an expert on the Prius after his purchase of the Accord. His information is usually spot on. I really enjoy his posts, but I know you're quite accurate as well. I hope we get to the bottom of this.

Midcow.. I wouldn't call the MFD a cartoon, it's actually very informative.

john1701a

We are already at the bottom.

Those wild & unsupported claims contradict the "full" hybrid design entirely.

We know for a fact that electricity is created by MG1 (the small motor/generator) being spun by the engine. That electricity feeds MG2 (the large motor/generator) immediately, without ever having touched the battery-pack. Both the Multi-Display and the technical papers confirm this.

We also know that MG2 is fed by the battery-pack while on the highway. Again, that is confirmed. There is no charging "even if the battery is full".

His information may apply to some other hybrid, but definitely not one using HSD.

JOHN

stevedebi

Sorry, midcow, I'm with John on this one. Toyota designed the HSD to route power directly to the electric motor, to the batteries, or split. There is no way they would waste electric power (i.e. engine RPMs) on generating electricity to charge already full batteries.

falconone

Too bad the excess electric can't be sold back to California. I hear they can use it. :P :P

stevewa

FWIW a data point from Ford, a report from the Dearborn event indicates the engineers there have been trying to "kill" one of the Escape Hybrid battery packs for some time now without success.

While it is true that all batteries deteriorate over time, the batteries being used in these hybrids enjoy some advantages the AA cells you use in your digital camera don't.

1. Carefully monitored for State Of Charge at all times, only allowed to charge or discharge within a carefully controlled range.
2. Temperature controlled for optimal operating conditions
3. Individual cell banks monitored to assure all cell banks delivering the same voltage (this is a biggie because reverse-charging a cell will kill a battery faster than anything else).

At this point it looks like 150K miles should be considered the floor for hybrid battery lifespan, not the ceiling.

midnightcowboy

John, the owner of two Prius, and fairly knowledgeable about them has said:

His display says he never gets beyond a charge of 80% and then only rarely gets that. So does the battery get gfully charge or not ?

He has told me that the Prius has no transmission and is a planetary CVT
Then he has told me it is not a planetary CVT and does not have gears.

I thought the power was transmisted to the wheels through a planetary CVT with tow motor genrators MG1, and MG2 and a the drive to the wheels PSD. Now call it a transmission of not but the interation of the MG1, MG2, and PSD with the MGs acting alternately through either being motors or genrators crates an effective CVT type transmission. Is that not correct?

I guess the Prius software decides when the battery is charged "fully" or 80% or whatever and then diverts the MG1 generator output into the MG2 acting as a motor. But if I literally read John's response it is confusing.

He says: We know for a fact that electricity is created by MG1 (the small motor/generator) being spun by the engine. That electricity feeds MG2 (the large motor/generator) immediately, without ever having touched the battery-pack. Both the Multi-Display and the technical papers confirm this.

We also know that MG2 is fed by the battery-pack while on the highway. Again, that is confirmed. There is no charging "even if the battery is full".

First again it is mentioned the battery is "full" , but he earlier said the display never gets to more than 80% . So is full defined as 80% charge?

Second, If the MG1 is going directly to the MG2 and the MG2 is also getting power from the battery, then what is going to happen to the battery? It sure seems to me that would cuase it to discharge?

Cruis'n

MidCow

P.S.- Toying with the idea of getting a 5-speed manual shift hybrid commuter car, can you guess what it would be?

falconone

I thought you had one already. The 6sp Accord. What's wrong with that?

midnightcowboy

Nothing wrong with 6-speed Accord, will keep it. But driving like a hypermileage driver I can only get 27.1 mpg on daily commute and it gets the best mileage of the cars I have.

However gasoline bill last month was $373 Gas prices will continue to rise! I think we as a family put on about 3,000 miles a month.

A hybrid commuter could reduce that significantly. I am manually transmission challenged and the Toyota dealers are such Prius jerks or I would probably get a Prius.

Cruis'n in 6th,

MidCow

P.S.- What is the best manual shift hybrid for commuting ?

falconone

Maybe you can pick up a deal on a used HCH. I am not sure if the Insight has a manual, but that would be great for your type of driving. A used Insight would also be something to consider. Good luck!!

stevedebi

" First again it is mentioned the battery is "full" , but he earlier said the display never gets to more than 80% . So is full defined as 80% charge?"

Midcow:

I think that the Prius owner has to trust Toyota to manage the batteries. The software module keeps them below 100% and above 30% (as I recall). But in any case, the output of the screen display should not necessarily be construed as the actual charge state of the batteries. I suspect it is relative to what Toyota wants to maintain as "100%", not the actual battery state.

Maybe someone else has time to research more accurate numbers, I don't. But from the Toyota documentation on the Internet, it would appear that the generators can both drive the electric motors and charge the battery at the same time - whatever is needed at that moment - more electric motor, more battery charging, etc.

fndlyfmrflyr

Rare to see fully charged on dash indicator. Long down hill stretches, coasting, does get the battery fully charged.

railroadjames

As I understand it....The batts NEVER fully charges. The charging sys. is designed not to by (excuse the redundancy) design. Thats why they last so darn long. If someone has already pointed this out .....sorry for the repetition.
Railroadjames(love those prii)

aaron_t

In my words, disable = turn off the internal combustion engine to save fuel.

A lot of my time is accelerating to about 45mph between roads every 1-2 miles. Even on roads with traffic lights timed for the speed limit (plus 3-5mph), there are always others who go faster and catch every light. Wouldn't it be great if everyone did that? Yep, but it only takes as many drivers are there are lanes on the road to screw up the system. I can and have lagged behind to minimized my own accelerating, but I risk (and catch) getting passed by enough cars to miss a whole light cycle. Every light cycle I miss = 2-3 minutes.

Battery life may be under warranty for 150k miles, but that does not mean that it could not cost the OEM $5k to do that. Hypothetically (since no one yet knows), What would happen to resale value of hybrids with 130k+ miles whose batteries have not been replaced? That is unknown because very few hybrids have 150k miles.

I'll end the media reports since we must be reading different sources. We are but two samples.

misterme

You're right, nobody should impede traffic and it is not neccesary.

There have been some Insights for sale with that mileage and had no problem with resale, or resale value. I can't post links here to other sites for the rules but is not hard to find.

At that same Insight specific URL there have been a couple of new pack replacements for under half of your $5K figure. The other one was replaced by a used pack for even less.
Why did you stop at $5K, why not say $7 or more as some media reports?

falconone

Have you seen any engines that fail at 36,001 miles after their warranty expires? It is pretty safe to say that the battery pack will last the life of the vehicle. This has been rehashed thousands of times. What do you tell the guy selling his SUV with 130,000 miles? What about the tranny? Four by Four components etc..etc. Same deal. I am quite confident by battery will last beyond the life of the car.

aaron_t

I chose a random number because 7 years from now IF I bought any hybrid, the cost of replacement parts is unknown.

Falconone,

36k miles for an engine in 2005 is no problem. 110years of ICE refinement. 150k miles on a 10yr technology that's changing every 4 years is unknown. While I would have no problem buying any current hybrid, that does not mean I have more doubts about what it would be like in 150k miles vs. a comparable Civic, Accord, Corolla or Camry.

Have you studied the 4wd SUV/pickup market? I see pretty strong prices for 100-150k mile late model vehicles, even with the $3 gas. Survey Auto trader in your area.

falconone

I see even better pricing for small cars. In my neck of the woods SUVs over 100k miles are as good as paperweights.

kdhspyder

falconone..

funny.. when I deliver a Prius to new owners I often call this screen the 'cartoon' in order to direct them to the consumption screen which is more like biofeedback.

One tells a story while the other helps them to perfect their driving. Other than to the very well informed the constant flow of energy is confusing at best and even threatening to some.

kdhspyder

snakeweasel

Gas prices going down make the hybrids a little less desirable until prices start up again, plus when a hybrid starts getting to the point when they will need new batteries the resale value will drop like a rock. How long that would be is now just a guess.

But like you resale value to me is nothing as I drive a car till the wheels fall off, then I put them back on and drive some more.

falconone

Batteries are a NON issue. I'd be more concerned about YOUR tranny than my TRACTION BATTERY. I get a 150,000 mile warranty. Gotta love it!!!!! GO HYBRID!! Anxiously awaiting my delivery!!!!!

midnightcowboy

With the price of gas going up mayny new SUVs are becoming paperweights on the dealer lots. LOL

Cheers,

MidCow

Should I go for 60/66 or not that is the question ??

civicex05

Should I go for 60/66 or not that is the question ??

Whether 'tis nobler in the mind to suffer
the slings and arrows of outrageous gas prices,
or to take up arms against a sea of greedy oil companies.

snakeweasel

Actually batteries are a real issue. So far in a long term real life experience hybrids are a pretty well untested rather new technology. With more and more people keeping cars past 150k miles it becomes a big issue.

And why is it whenever someone mentions the battery issue hybrid nuts yell "transmission"? You are aware that your hybrid has a transmission too. Just with my less complicated car I do have less to worry about.

Enjoy your hybrid, but I will cautiously wait to see what happens.

falconone

Don't hold your breath. Batteries will outlive the life of the car. No batteries have worn out on the first gen Prius. The Prius does NOT have a conventional tranny. But I guess you didn't know that. Now you do.

snakeweasel

Don't hold your breath. Batteries will outlive the life of the car.

I seriously doubt that, batteries don't last forever they all die out.

No batteries have worn out on the first gen Prius.

I seem to remember someone on one of these forums stating that their batteries needed replacement, not sure if it was a prius or not. Either way there are few, if any, prius' (is it priuie?) out there with enough miles to tell. Lets discuss this in say 5 or ten years when enough get that 150+ mile mark.

The Prius does NOT have a conventional tranny. But I guess you didn't know that.

You guess wrong, I know that the Prius has a CVT, but it still has a transmission.

falconone

I has a MUCH simpler setup than a coventional vehicle. Advantage: PRIUS. The battery by all counts will last the life of the vehicle. Perhaps you should do a little reading up on how the battery is optimized by the computer to NOT go below a certain SOC. I can assure you that the Prius will outlive your Hyundai. Sorry to burst your bubble.

gagrice

I can assure you that the Prius will outlive your Hyundai

You seem awfully sure of the Prius II that is barely two years on the road in the US. I see nothing wrong with those that are sitting back and watching. Even the first generation is barely 5 years old and very few with high mileage show up on the green hybrid site. I think only 38 were sold and one has reached 100k miles in the US. Of the 350 Prius II owners reporting their mileage none have reached 50k miles yet. Hardly a good test of the traction battery. When a few thousand are out of warranty with only minor repairs, the statistics will be more telling. Then the bragging about how great the HSD system is, will be warranted. The skeptics including myself will have to take back some of our negative comments. I have watched the hybrid evolution since the first Prius rolled into San Diego, I can wait a few more years.

falconone

I am very sure of the traction battery as I have a 150,000 mile warranty. What does the GMC have??? 36k... LOL.... I ain't worried... You should be... good luck...

rx400hfan

"You guess wrong, I know that the Prius has a CVT, but it still has a transmission."

Actually no the Prius does not have a true CVT transmission it has a planetary gear with 2 motor/generators which when controlled by a computer cause the Prius to drive like it would if it had a CVT. There is no variable or changing gear ratios involved nor any slippage or disconnect mechanism involved. The planetary gear PSD in a Prius works more like a differential but in a simpler more compact Ring/planetary/sun gear design.

snakeweasel

I has a MUCH simpler setup than a coventional vehicle. Advantage: PRIUS.

Are you saying that a Prius is simpler than a conventional vehicle? if so you are sadly mistaken, a hybrid by its very nature is a more complicated beast.

Perhaps you should do a little reading up on how the battery is optimized by the computer to NOT go below a certain SOC.

I have read up on that but it is still unclear if the battery packs will last the life of the vehicle. The real world experiences have not gotten that far yet so it is an open issue.

I can assure you that the Prius will outlive your Hyundai.

How much you want to bet? 130k miles and no issues yet.

falconone

Hyundais have improved but they're really disposable cars. I can assure you that the hyundai can't hold a candle to any Toyota product, much less a Prius. Recent models have proven to be dangerous to occupants in side impacts. The lower models are also difficult to find ABS with. Traction control N/A. Cheap basic transportation. BORING.... not for me. Good luck with your hyundai. I look forward to years of satisfaction with my Prius.

Kirstie_H

Batteries, folks.

All batteries, all the time.

kirstie_h
Roving Host
Host, Future Vehicles & Smart Shopper discussions

kdhspyder

very few with high mileage show up on the green hybrid site.

Actually I have a couple of customers that put 60-100K per year on their Prius'. It's their office on wheels. No problems at the 100-150K mark as yet but as you stated they are just getting there and most Gen1's are just getting to the last year of the warranty.

But as falcon stated the batteries are designed to outlast the warranties by controlling the SOC. There are long discussions on this point that are frankly beyond me so I'll defer. Nevertheless how many people really keep their vehicles 200K or more. I do because thats only 4 yrs driving. For most it's 15-20 yrs of driving and they've had 4 vehicles in that time.

The other point which is always ignored is that the entire battery is very unlikely to fail at the same time. Even if one or two segments does decline.. it's only $100-150 per segment to replace them. I wouldnt be concerned until the 200K+ mark. ... and then how much is any vehicle worth? $1000-2000 at most. And who buys a 200K mi vehicle anyway? They are generally more valuable sold for the parts than they are on the road.

Until we start to get mass reports of 105K mi vehicles with failing batteries this is 'The earth is flat worry. Drive too far and you'll fall off.'

kdhspyder

falconone

May I add a correction to your post. I want people to get accurate information here. NOT falsehoods posted by people that aren't supportive and skeptical of the hybrid technology. I believe that EVEN if a segment of the pack fails, it can't be replaced. The entire pack has to be replaced. Something to do with each cell having the exact same characteristics. This makes sense, but if someone has add'l info. please post it.

GO HYBRID
GO GREEN

Prius... the one to catch!!!

Yeah baby!!!

stevewa

I can tell you the Ford battery pack monitors each cell bank and compares them for voltage, if one bank (5 cells if memory serves) gets out of whack it will throw an error.

So, if something does go wrong SOP would be to replace the pack, return the old pack to the factory for reconditioning. You get two packs about the same age, I'm sure you could make up one "used" pack with cells from the two. You could probably make 10 out of 12 that way.

The only instance I know of where techs have been sent into the inside of the battery at the dealer level is for the service campaign on the THS Prius where they re-sealed the connectors on each bank.

stevedebi

I think it would depend upon the age and status of the remaining packs. If the other packs are old and/or not holding charge as well as they should, the entire battery package would be replaced.

looking4prius

Although the lasting power of batteries is certainly one of the main concerns, there are other considerations. The first that comes to mind is safety...what happens to the battery should a hybrid be struck so that the battery is impacted? Is this/would this be a hazardous waste situation for firemen who would presumably be trying to help the occupants out of the car? If so, how hazardous? Can hybrid batteries be reconditioned? (Have any?) Can individual battery cells be replaced in any hybrid battery as the cells go bad? Are there any upcoming battery technologies that would produce more power/safety/longer life/weigh less?, and if so, will it be possible for any hybrid to 'upgrade' to such a battery?
It is easy to see what you guys think...what are the automobile manufacturers doing in the area of batteries? What kind of R&D (if any) is going on for hybrid batteries?

larsb

Some of your answers are here at Edmunds. Others are unknowns.