Newsweek on Hybrid batteries

If you search and read the archives here, you can find out a lot about the NHW11 vs NHW20 battery.

First, there are a LOT more NHW20 batteries.

Second, While PriusChat is not a scientific site, the fact that many NHW11 owners have reported battery issues (most resolved nicely!) and extremely few NHW20 owners have reported any battery issues cannot be ignored. Not publishable in a science report, but good enough to spend $25k for a Prius. Note that NHW20 posters outnumber NHW11 posters by a huge margin so the difference in battery problem reports is stunning. The NHW20 battery is fantastic.

Lastly, most of the interest is in battery failures overall, not out of warranty rate numbers. It's hard to overlook that many of the NHW11 owners are still in the warranty period, even with a 2001 Prius (like me).

 

Hi All,

The NHW20 battery has improved resistance internal connections. This is written up in the THS II technical description somewhere. So, this battery is not going to get as hot as the NHW11 battery. That has to improve the NHW20 battery life. And since the NHW11 battery is at .1 % already, I for one am happy with that.

 

I agree with everything you are saying, but I'm just saying that these numbers don't prove what we believe to be true. It's a piece of data that tends to support the theory, but it's not proof. The only proof would be to determine the total percentage of battery failures in the NHW11 vs. NHW20, but that data will only be complete once all NHW11s and NHW20s are out of service.

 

This reminds me of a real life joke. A man with two sons had a very irregular yard that his sons had to share mowing every week. All of his attempts to create a dividing line ended with one son complaining bitterly. Finally his solution was to flip a coin and have the coin winner pick which side of the yard to mow. The loser got to make the dividing line. The Dad never knew if the line divided the yard equally, but he knew the dividing line was good enough.

You are right that exact numbers and "proof" are not available till all the data is collected. However, there looks to be enough "relative" feedback to show that the Prius NHW20 battery is something a new Prius buyer should not worry (excessively) about.

 

This is only due to the recent high costs of fuel. If gas prices ever get back down to a "normal" cost per gallon, you will see dealership lots full of Prius vehicles that they are discounting. When I bought my 2007 back in late 2006, I got $1,000 off MSRP plus got the Federal tax credit. I am sure many people are now paying over MSRP to get one, thanks to fuel costs.

 

Hi Bob,

Do you know of anyone doing this yet? I've yet to have an opportunity to see the two modules side by side, but ISTR reading on the Panasonic EV site that the NHW20 module is the same width and height but 10 mm longer. That would worry me about how close the terminals and busbars would get to the steel cover or whether the cover would even go back on. Am I right also that the NHW20 modules have two terminals on each end for lower resistance integration? I guess you would just put the NHW11 busbar modules on one row and ignore the other - as long as the other row is not in the way. Another question would be, for the 10 mm longer module, did they alter the spacing of the tapped holes on the bottom for the screws that hold the modules to the bottom plate?

These are the questions I would have upon reading the literature but not holding the modules in my hand. Judging from the work you've been doing, I expect you've probably answered some or all of them already, and I would be very curious what you've found out.

-Chap

 

Rest:

"If gas prices ever get back down to a "normal" cost per gallon..."

If, indeed. I suspect that they are not yet normal, and the new normal will be closer to $10 than $5.

Miracles could happen though, no doubt about that.

 

I don't get it.....

"Philip Card of Utica, N.Y., says a Toyota dealer wanted to charge him $3,900 to replace the battery on his 2001 Prius, which had 350,000 miles on it when he bought it used on eBay this year for $4,357."

So, here's a guy that bought a car for a bargain basement price and he's upset because he has to put $3900 worth of work into it after *350,000 miles* ?

If that's your biggest gripe, turn in your driver's license and buy a bicycle because you'll never be satisfied with anything that has an engine and four wheels.


And this is what's supposed to make me concerned about hybrids? Heck, any brand of car that can still start after 350,000 miles..... that's called a SELLING POINT.

 

What planet is this going to occur on?

 

Hi Chap,

Since Bob hasn't gotten around to seeing your msg I will reply to the above question. The NHW20 module contains six cells. As I understand this, there is a double connection from one cell to the next to lower the internal resistance. The module terminals are similar to NHW11 modules to the extent that there is only one positive and one negative terminal. However, the height of the terminal above the bottom of the module differs between NHW20 and NHW11.