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

That's good advice. It was just a thought, especially since it was proposed in the instructions if the sensor wires happened to be a little too short. Just got me thinking whether the modules on the ends might run cooler anyway. The space between the NPB cells is substantial, so there probably won't be a big difference. Besides, there is a reason that Toyota put the sensors on the first and last modules and not one module in.

Speaking of which, I have all the NPB modules in and seeing how to maneuver the power cables (especially the safety plug cables). The pictures that you posted are a huge help. Thanks.

 

I was successful in getting the battery back together and into the car. Before putting the panels back I decided to jump ahead in the instructions to reconnect the 12v battery and the HV disconnect plug. I didn't want to put it completely back together and have it not work. I was pleasantly surprise that it started right up and the HV battery wasn't swinging up and down on the charge gauge anymore. The red triangle of despair was gone, and the HV cooling fan wasn't going at high speed anymore. I took it out for a test drive and it ran noticeably better. I think that the car had become more dependent on the ICE and didn't have quite the acceleration that it used to have. I was also pleased that it was charging at a civilized rate and not climbing quickly to full and then dropping again. I don't have many miles yet, but will report back from time to time to let everyone know how it is performing. So far I am quite happy with it.

When I have some free time, I plan on posting some pictures that might be of interest to others who are getting ready to try this great alternative to buying a new HV battery from Toyota. The pictures that others have shared were invaluable to me during this project. I'm fairly mechanically inclined, but wasn't too sure about working with high voltage. Looking back, I should have done it sooner, it wasn't nearly as bad as I thought it would be.

I also have a better appreciation for astronauts working in space with tools.

 

Any update on how the battery, and car, are doing since the new battery pack?

 

That's good to know.
I was wondering how it was working in "8AA"s car. He/she has not given any updates...

 

Been flawless so far for me.

 

Sorry, I haven't been driving it as much as I used to since I'm working from home, but I do try to take it out once a day. I've only put about 600 miles on it since I replaced the original modules with the new ones from NewPriusBatteries. So far nothing to report out of the ordinary, other than the fact that the car is acting more like it did when it was new. I haven't been too concerned about the mileage yet, since the cold weather is causing the engine to run more frequently, and I'd rather be comfortable than trying to save 2-3 mpg. I have noticed that the mileage is slightly higher than it has been for the past year before the battery pack bit the dust. Most notable has been that the high and low swings in the SOC have stopped and it's a lot more stable now. With some downhill regen, it does get up into the green, but most of the time it stays around the upper side of the middle where is used to stay when it was new. The other thing that I'm noticing is that the ICE is shutting off more frequently. I think because of the swings in SOC, it was running longer when stopped at a light, and would start up sooner.

I'll try to be better about updating until someone tells me to stop. I do feel quite confident taking a longer trip again. I had been using the car for local travel while I tried to figure out what I was going to do about the weak modules. Overall I'm very pleased. I wish that the clear-coat hadn't started peeling off, but that's not the fault of the battery, and I have had the car for 16 years.

 

Thanks for the update!

 

Well, My wife's 2007 Prius traction battery is needing replacing. I have been playing around with many different types of batteries for 20 years. I am now learning about lithium batteries. Has anyone converted their Prius to lithium batteries?

I did buy a retro battery from New Prius Battery LLC. It looks like the best option out there. I can not wait to get it. I just took out the old battery and have it all disassembled. What should I do with the old cells? They are all reading at 8.1 volts. I haven't done any load test on the individual cells. Just did the Dr. Prius and it said the pack was down to 28%.

 

Welcome to the forum. The developer of the Dr. Prius app, who goes by the name @jacktheripper on this forum is working on lithium batteries for Prius.

Here are a couple of threads about his project:

Rainbow Prius Hybrid Powered by Lithium! | PriusChat

Dr. Prius Packs Less Than A Year Away? | PriusChat

There is another forum member who lives near you who works on Prius batteries. He might be able to use your cells or help you sell them.
He goes by @PriusCamper

 

I would wait until the Prius is back running but then you are free to sell the modules that have not failed. I know Hybrid Automotive sells used modules. Perhaps they could purchase yours.

 

One thing: if you ever go for a Toyota pack requiring a returned core, you could put the old cells back and have a complete/original battery. Might never happen, just something to consider.

 

Thank you for the great links.

 

I thought about keeping them for fun projects. But, I have too many battery projects. I am currently working with BMW I3 batteries. I am building a battery wall for my solar home. I hope to get rid of my old lead-acid batteries.

 

Nothing exciting to report (but maybe that's a good thing). I have a little over 1100 miles on the NPB upgrade, and the car is still running strong. Very nice to have the Prius running as well as it did when it was new.

 

I finished the install of the New Prius Battery. It was a very fun and easy project. I am glad that I stopped before covering up the battery. I decided to jump ahead to hook up the 12-volt battery and tried starting the car. The big red triangle came on right away. I tried and clear the code. It kept coming back on. I turned the car off and disconnected the 12-volt battery. I then opened up the ECU cover of the traction battery. After looking over everything, I decided to give up for the night. The next day I checked all the connections. One of them was not quite pushed in all the way. Once I reconnected it. I was able to start the car with no problem. Today I drove it for 100 miles. No problems so far. We are planning on a 200 trip tomorrow. I have one question. The battery seems to never charge above 78%. This is using the Dr. Prius app to monitor the battery. I have never have seen what the stock battery would do. What should I expect with this new battery pack?

 

Yes the system starts cutting current around 78% hybrid synergy drive is designed to let the battery run from 40-80% and trying its best to keep it closer to 60%.

 

That is my understanding as well and maybe the Dr. Prius app is reporting the actual SOC, while the bar graph in the Prius is showing the SOC within the range it's trying to maintain (80% being all green bars). I did notice that after I had first installed the New Prius Batteries, the SOC (in the car) was more stable than it had been before the HV failed, however it was not going up into the green as often. After a few weeks of driving, it was starting to hang out more in the top of the blue range or the lower part of the green range. This seemed more like where it used to be when the car was new. I was wondering if the ECU needed time to get used to the new batteries to better estimate the SOC.

 

yes full green bars represent 80% and the last purple bar is 40%.

The slower it changes the better!

It was probably a combination of the battery ECU and the actual chemistry in the battery adjusting.

How is your fuel economy with your new battery?

 

I've been recording my miles and gallons, but haven't calculated it yet. The mileage shown on the dashboard has been in the upper 40s, which is about what it has been before in the winter here. There is definitely a hit in the mileage when the car runs the ICE just to keep the coolant hot. I only put a couple of extra psi in my tires from what is recommended, and I'm nowhere close to being any sort of hypermiler. I'd say that so far the mileage is close to what it was before, the big improvement has been that the SOC is more steady now, and the car has noticeably more acceleration.