Prius Battery Replacement (GenII) Like you've never seen - NEW Cylindrical Cells

Thanks for the info, 2k1 Toaster. I'm interested in trying your product. Hope to hear from you soon.

Posted via the PriusChat mobile app.

 

You cannot have pressure without restriction, so that comment is just silly.

The IMA system is also not as well controlled, charge or discharge, as that of the Toyota HSD. Working ANY battery thru more of it's capacity will reduce cycle life and increase temperatures.

The power of a cooling fan is not nearly as important as the care taken to design the SYSTEM, something Toyota clearly understood. If you look at the Honda airflow paths, specifically before 2011 (we are in the Gen2 forum), it is hideous and a miracle they get the life they do. This independently suggests that cylindrical cells may cool better.

Convective heat transfer????? Not. Heat transfer between the cells and air is by CONDUCTION - two objects (cells & air) in direct contact. Convection is a function of conduction, the mass of air flowing over the cell(s) and temperature differential between the two. Heat transfer is basically a function of mass and specific temperature (differences). The more mass of air that flows the greater the heat transfer for a given system and component temperatures. Reducing restriction increases flow and therefore the mass of air thru the system.

????

ROFLMAO!!! Obviously you have never experienced "wind chill"!!!!!

I never claimed the cooling WOULD be better, only that I could see how it could be. Greater airflow always improves cooling, but there is more area in the OEM cells to conduct the heat from. Given the very tight passages and infrequency of fan operation in our car, it seems that Toyota's BMS is mostly responsible for heat management in either case.

 

BK......the Prius is based on high velocity cooling?

I bought my car brand new 10 years ago. In that time I have only heard the battery fan come on once after leaving it in the sun with no tint and no shade all day.
For the remaining 10 years never once have I heard that fan so it's on very low all the time. So low it barely pushes the little rubber vent flap. I use the hybridauto charger that forces the fan on full blast. Even at full blast there's not a lot of velocity coming out of that flap hole. So daily use in 95 degree temps does not require
Hardly any velocity whatsoever. The battery does not seem to get very warm at during daily use.

Battery cooling is not critical at all.

 

I don't really have dealer pricing.
Take a look at other thread as to not bog down this one.

It has nothing to do with being a competitor.
If nothing else it actually provides a stronger argument. They do not trust average Joe's to do the job correctly.

 

I don't think I would make that statement, but certainly battery power MANAGEMENT is the more important factor.

 

Technically I am with 05PreeUS. BK to me is possibly hung up on some things...can't tell. That said, it would be a major technical accomplishment to successfully develop a non-Toyota new replacement batt as good and safe as the orig OEM. Even two-thirds as good as OEM is probably a winner.

It would be nice to get more input/advice from the battery experts in our PriusChat community.
In addition to EricBecky, there is JDenenburg, 3ProngPaul, and less active these days but Paul Taylor of ReInvolt used to be on here, not to mention Sielerts and I apologize to the many others I missed.

I certainly see a need for such a product, if it can be done.

 

Evasive non-answers.
Let's try it another way:
1) How much do you charge to instal a brand new Toyota battery? And how long is your warranty?
2) How much will you charge to instal this experimental battery? And how long will your warranty be?

 

An off brand, with no warranty, that is two-thirds as good, must also be AT LEAST one-third cheaper than the OEM. Otherwise, what is the point in taking an expensive risk?

 

Retail price for the Toyota batt easily runs $4000 at the dealer with Labor etc. So chances are this is cheaper. Also there can be delays getting the batteries installed at Toyota.

You can ask Toyota for discount, which works in some cases. But it will not work in many cases, eg; if the car is older or the battery has already been replaced with a Dorman or the owner messed with the cell replacements.

You are basically saying if you got goodwill coverage from Toyota for low cost replacement, or had access to @ericbecky in TX, why bother with this? But that is not the niche of this product.

I totally agree coming up with a successful product has hurdles: (1) first has to work technically, and then (2) people need to want to buy the product. These are hard hurdles to cross. But this is not Shark Tank, the business profit is 2k1's problem.

 

NOT CHEAPER! You are skewing the actual prices!
We can buy brand new packs from a Toyota dealer for $2070. We can choose to get it installed at the dealer, at an independent shop (Lucious charges $300) or DIY. This experiment's price is the same as a genuine Toyota pack. At $2000+++ there is no rational reason for most people to take a (expensive) risk on this engineer's unproven project.

As I am a, soon-to-be customer, I find the OP's belligerent answers to be, staggeringly unconvincing.

 

Oh how I only wish Luscious Garage or Texas Hybrid Batteries would set up shop in northern Virginia.

I do agree that Luscious Garage price, whatever it is, is a good benchmark.

 

That is some painfully dishonest accounting. The core refund is a guaranteed, immediate refund from Toyota+++. You can't add to the cost of the battery. Your best-case, $700ish scenario, involves loosing ALL of that very same $1350+++ core refund if/when your experiment fails!!! At best, your scheme requires owners to take apart their dangerous HV battery packs and try to sell them slowly, piece by piece, via ebay and Craig's list ... over the course of God-knows-how long! Add time for packing and money for mailing materials+++. Add multiple trips to wait in line at UPS/FedEx and USPS+++. Add the likelihood that people will not be able to sell all of their old cells+++.

Most consumers just want their car fixed in a day or two and to pay for it with a credit card+++! And they want a warrantee+++. Informed consumers, however, wouldn't feel confident on the highway testing your rare, $2000+++ battery packs.

Having said that, your knockoff version of this design still looks good! We all wish you the best of luck. Please report (good and bad) back when you have more than a few short months of "real testing" on your one Prius. Cudos for trying, but you need to lower the price and do MUCH more real-world testing.

 

Actually...... they DO!

When you purchase a "major component" from a retailer, be it a dealer or jobber for "cash-n-carry", you DO GET CHARGED the core price on your bill. Only AFTER you return the core do you get your money back. Now, if you have core in hand and leave it, you get an instant credit for it.

That does not change the MATH....

New OEM HV packs run, let's say $2k for argument sake (good luck getting a dealer to sell it for that, OTC), therefore:
$2k + $1350 core = $3350, once you return the core to the dealer and it is accepted (BIG if, especially if not an OE pack at some dealers), your net parts cost discounting tax would be $2k.

If you purchase an aftermarket HV kit from the OP (as an example, NOT an endorsement), the kit is $2k and you still have a core worth ~$1350, or individual cells go for at LEAST $40/ea x 28 = $1120 and there is $$$$ to be made in shipping. Therefore your net parts cost discounting tax, assuming shipping is a wash, would be $2k-$1120 = $880

Now, there is nowhere on EARTH where ~$900 is 2/3 the cost of a new OEM HV pack for a Gen2.

 

In all fairness, I wouldn't trust average joes not to screw it up either. Not to mention it's a pretty big electrical hazard that most people aren't trained to work around.

If Jerry Springer had a Priuschat episode, I imagine that it would look like this thread.

 

Technically correct, but irrelevant as MANY factors influence airflow. Please research ideal gas low and obtain a basic understanding of fluid dynamics.

Cycling through more of its capacity does not increase temperature. Current flow increases temperature. Again, while the Honda systems permit more total range, they don't routinely run SoC down to 20%.

You tout the importance of the design of the cooling system, yet you then completely dismiss it with your speculation. You have a cooling system designed for prismatic cells with a given spacing and a given section thickness... yet somehow putting in widely horizontally spaced cylinders with tightly packed vertical spacing and fatter cross section is better.

I'm very aware of the IMA cooling system configuration. There were three primary configurations, and all had their problems because of... the airflow characteristics of cylindrical cells. So Honda's cooling system DESIGNED for cylindrical cells suck, but somehow Toyota's system designed for prismatic cells will work better than ALL when prismatic cells are replaced with cylindrical cells.

Triple negatives of your own admission... yet you speculate it will be better.

You lack even a fundamental understanding of the terminology:

Conduction: "the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material."

Conduction occurs where cells are in contact with other cells.

I will also take the opportunity to correct myself. The correct terminology is "forced convection". By simply using "convection" I was technically inaccurate because the airflow is forced. Note that conduction does not play into it in any meaningful way when compared to the convective heat transfer (forced).

This is irrelevant. Do yourself a favor and check the NASA link. It will dispel any notion you might have that airflow around a cylinder is remotely better than airflow through a very well defined nearly straight channel.

With basic understanding of the principles, you can't see it. Greater airflow does not always improve cooling if other alterations are made or if the geometry itself causes disruptive changes. Again, check the NASA link for proof that more airflow around a cylinder doesn't improve cooling.

"Infrequency of fan cooling" - what do you base this on? There are 7 fan speeds, 0-7. The fan is only audible against normal ambient noise when the fan is on 5 or 6. On speed 5, you're battery is about 120°F, and you're not going to hear it unless you are paying more attention to it than the road. The speed that everyone hears it on is 6, when your battery is at about 130°F. Just because you can't hear it doesn't mean it's not on. I can tell you that any time the battery is above about 90-95°F, the fan is on based on much recorded data from Torque Pro and the extended PIDs.

 

toyota dealers are all over the map on price. those who can get for close to 2k may choose to go oem.
but those who are quoted much more may find this a good alternative, if they can find an installer.

and then, there's the toyota reman with all new, edit: old cells, in cali for $1,850.

 

Given the dramatic configuration change, an apples to apples comparison between the two sensor configurations isn't valid. You have 112 additional potential hot spots in the cylindrical pack. That is of course not practical, but to get a representative sample, you would need at least another 30 sensor locations to establish the thermal condition of the cells. You could probably get away with 20, and you could probably get away with only doing 4 at a time, but if you haven't done an actual thermal survey of the pack, you can't make any claims as to its temperature.

If all you have is comparative readings from the 3 sensors, your data is meaningless. Those sensor positions are at high flow locations in the pack and I would not be surprised will actually read lower due to higher flow past the sensors as you will get more airflow BETWEEN the cells but over less of their surface area. You have compromised airflow in 112 locations, and you know nothing about those locations.

You may be a genius with electronics; however, you do not appear to have competency in at least some mechanical principles, aerodynamics, fluids or heat transfer. By comparison, I know almost nothing beyond V = I * R and P = I * V.

Since I have a feeling no one is bothering with the NASA link:




Judge for yourself if STACKED cylinders will fair better..