2008 Prius Hybrid Battery

[Nathan jones]

4-5 mile trips are what cause lower mpg especially in winter. If a cell goes bad the dash will illuminate and tell you. Either put up with lower mpg (but better than equivalent vehicles) or regularly take 40 minute trips to improve the soc. Changing out a battery will not improve performance (but keep the spare if you do).

On board computers (thanks to the G21 team) keep the battery charge level not for efficiency or speed but for vehicle and calendar life typically well over 2-300k. A grid charger may help (likely will) but design it thoroughly.

Gen II battery is cooled (from the top)

N.B a smaller electric vehicle may be more suitable for such small journeys

**Ford won't use Denso...or Boron steel for that matter

[Nathan jones]

https://priuschat.com/threads/re-hyd...odules.152885/

Although this should be an ecofix not ecomodder thread

[S Keith]

Originally Posted by Nathan jones

https://priuschat.com/threads/re-hyd...odules.152885/

Although this should be an ecofix not ecomodder thread

This is not viable. The PP/PPE modules are so chemically resistant, there is nothing one can use to reliably seal the hole. Screws don't work either. While initial results can be impressive, the modules will slowly lose electrolyte and fail.

[Isaac Zachary]

Last I looked Toyota no longer sells Gen 2 Prius batteries. But you could get a new Gen 3 battery, swap out the modules, and take the Gen 3 battery back with the old modules in it as the core.

I agree that looking for a newer EV or Plug-in Hybrid wouldn't be worth it in the used market right now. I can't find a Prius Prime for under $25,000 within a 500 mile radius of my home unless it has a ton of miles on it. A new one is $28,000 and up.

I've heard good things about Nexcell lithium batteries in Prius as far as the Project Lithium is concerned. But I don't expect them to do extremely well in very high heat or very low cold. These aren't the cylinderical cells but are pouch cells. I do think it would have been better to have put them in metal module cases than plastic ones, though, for better cooling. Still, I'm tempted to get these for my Prius.

[S Keith]

Originally Posted by Isaac Zachary

Last I looked Toyota no longer sells Gen 2 Prius batteries. But you could get a new Gen 3 battery, swap out the modules, and take the Gen 3 battery back with the old modules in it as the core.

I could have sworn we've already had this conversation. Toyota is still selling the Gen2 batteries. They are their highest volume battery. There are just supply issues at this time. I've bought 4 in the last month.

Your plan would work, but you would pay about $600 more for the battery and do a lot of excess work.

I've heard good things about Nexcell lithium batteries in Prius as far as the Project Lithium is concerned. But I don't expect them to do extremely well in very high heat or very low cold. These aren't the cylinderical cells but are pouch cells. I do think it would have been better to have put them in metal module cases than plastic ones, though, for better cooling. Still, I'm tempted to get these for my Prius.

I'm extremely confident these will prove to be of lower value than the Toyota NiMH packs. These are simple drop-in substitutions of 5S LFP modules in place of the 2X 6S NiMH modules. Zero provisions have been made for managing the LFP cells as they should be. The car will treat them like Nickel.

They will likely be better than the horrifying cylindrical cells.

[Isaac Zachary]

Originally Posted by S Keith

I could have sworn we've already had this conversation. Toyota is still selling the Gen2 batteries. They are their highest volume battery. There are just supply issues at this time. I've bought 4 in the last month.

Your plan would work, but you would pay about $600 more for the battery and do a lot of excess work.

That's the rumor, yes, and I hope it's true. If I had my Prius fixed up more to the point the dying HV battery were the next step in fixing I'd try to get a Toyota battery. But I personally haven't heard of anyone who's been able to get one. But I don't know a lot of people looking for a Prius battery either.

Originally Posted by S Keith

I'm extremely confident these will prove to be of lower value than the Toyota NiMH packs. These are simple drop-in substitutions of 5S LFP modules in place of the 2X 6S NiMH modules. Zero provisions have been made for managing the LFP cells as they should be. The car will treat them like Nickel.

They will likely be better than the horrifying cylindrical cells.

Project Lithium does add a balancing circuit in each module. As long as the cells are balanced, the max and min voltages and currents of the Prius BMS do not go out of the range of the LiFePO4 cells. That's the beauty of LiFePO4 is that they charge up to full at 3.6V but can tolerate up to 4 just fine. 4V x 5 = 20 volts per block, which the Prius BMS will never let the battery reach. They can also tolerate faster charging currents, which is why the LiFePO4 Teslas charge faster than the traditional Li-ion Teslas. But if there is no balance circuit then yes, the LiFePO4s will eventualy fry themselves in a Prius. I haven't heard of anyone having problems with the Project Lithium drop-in modules even with many now running them in their Toyota hybrids. But as you will surely agree, they haven't proven themselves yet like Toyota's own NiMH batteries have either, and won't be able to until some 15 years later, if they make it that long.

[S Keith]

Originally Posted by Isaac Zachary

That's the rumor, yes, and I hope it's true. If I had my Prius fixed up more to the point the dying HV battery were the next step in fixing I'd try to get a Toyota battery. But I personally haven't heard of anyone who's been able to get one. But I don't know a lot of people looking for a Prius battery either.

It's not a rumor. I'm in weekly contact with my dealership. I collaborate with other builder in other regions, and they report the same.

Project Lithium does add a balancing circuit in each module. As long as the cells are balanced, the max and min voltages and currents of the Prius BMS do not go out of the range of the LiFePO4 cells. That's the beauty of LiFePO4 is that they charge up to full at 3.6V but can tolerate up to 4 just fine. 4V x 5 = 20 volts per block, which the Prius BMS will never let the battery reach.

Sounds like you're buying the hype. They are actually intolerant of > 3.65V. This increases the stress on cells. The reduction in charge voltage from 4.20V to 3.65V is a primary reason LFP has longer cycle life. Initial LFP specs identified the operating range from 2.0V to 4.2V. After a few years in the field, it was discovered that this was preventing them from reaching quoted cycle life and was reduced to 2.5V to 3.65V losing only about 5% of the total capacity.

There's no balancing between the modules, so while the 5S in a single module may stay reasonably well balanced, there's nothing preventing drift between modules.

I'm guessing you haven't spent dozens of hours working with Techstream. I've seen > 20V/block in techstream, particularly in cooler weather and regularly over 18.25V in all conditions.

NiMh SoC is both voltage, current and temperature dependent, i.e., it changes with temperature. LFP does not. When colder, the car will push the LFP to higher voltages than it will when hot.

They can also tolerate faster charging currents, which is why the LiFePO4 Teslas charge faster than the traditional Li-ion Teslas. But if there is no balance circuit then yes, the LiFePO4s will eventualy fry themselves in a Prius. I haven't heard of anyone having problems with the Project Lithium drop-in modules even with many now running them in their Toyota hybrids. But as you will surely agree, they haven't proven themselves yet like Toyota's own NiMH batteries have either, and won't be able to until some 15 years later, if they make it that long.

More hype. Gen4 NiMH modules (which are in all Gen2 packs) are rated for > 20C or 130A. Typical large cell EV rated LFP is 0.5C charge and 1C discharge. Yes, they can be designed for higher C rates, but the compromise is cycle life.

This was a sloppy and cheap implementation. The successful Lithium conversions go the extra steps to create a spoofing system to feed the battery computer the data it needs to have the car treat the LFP like it should needs to be.

I have extensive personal experience with NiMH and Lithium. I personally have >10kWh of LFP and 55kWh of Li-NMC and have done a lot of cell level testing. I've built an off-grid power system using the aforementioned Li-NMC for our eventual retirement home. I don't know everything, but I know what sound design approaches look like as well as bad ones.

[Isaac Zachary]

Originally Posted by S Keith

It's not a rumor. I'm in weekly contact with my dealership. I collaborate with other builder in other regions, and they report the same.



Sounds like you're buying the hype. They are actually intolerant of > 3.65V. This increases the stress on cells. The reduction in charge voltage from 4.20V to 3.65V is a primary reason LFP has longer cycle life. Initial LFP specs identified the operating range from 2.0V to 4.2V. After a few years in the field, it was discovered that this was preventing them from reaching quoted cycle life and was reduced to 2.5V to 3.65V losing only about 5% of the total capacity.

There's no balancing between the modules, so while the 5S in a single module may stay reasonably well balanced, there's nothing preventing drift between modules.

I'm guessing you haven't spent dozens of hours working with Techstream. I've seen > 20V/block in techstream, particularly in cooler weather and regularly over 18.25V in all conditions.

NiMh SoC is both voltage, current and temperature dependent, i.e., it changes with temperature. LFP does not. When colder, the car will push the LFP to higher voltages than it will when hot.



More hype. Gen4 NiMH modules (which are in all Gen2 packs) are rated for > 20C or 130A. Typical large cell EV rated LFP is 0.5C charge and 1C discharge. Yes, they can be designed for higher C rates, but the compromise is cycle life.

This was a sloppy and cheap implementation. The successful Lithium conversions go the extra steps to create a spoofing system to feed the battery computer the data it needs to have the car treat the LFP like it should needs to be.

I have extensive personal experience with NiMH and Lithium. I personally have >10kWh of LFP and 55kWh of Li-NMC and have done a lot of cell level testing. I've built an off-grid power system using the aforementioned Li-NMC for our eventual retirement home. I don't know everything, but I know what sound design approaches look like as well as bad ones.

Good to know! Thanks!

I stand corrected!

P.S. I tried to cheat at getting Tech Stream, but never got it to work. I also didn't see the point in renting it for so much money every year. I miss the days when all you needed was a voltmeter and vacuum gauge.

[S Keith]

Originally Posted by Isaac Zachary

Good to know! Thanks!

I stand corrected!

P.S. I tried to cheat at getting Tech Stream, but never got it to work. I also didn't see the point in renting it for so much money every year. I miss the days when all you needed was a voltmeter and vacuum gauge.

LOL... I watched my dad do that. I've had a blast from the past trying to get my 97 GMC Sierra 2500 HD with the 7.4L running. Cranked like mad, but no start. Getting fuel at the rail per the pressure gage, and getting spark at the coil and 2 of the 8 plugs I tested. Wouldn't even try to hit. Snap-On Ethos Pro showed no issues anywhere.

I was at a loss and consulted Google. Rotor and cap situated at the firewall and incredibly difficult to replace. No obvious damage or other visual concerns when removed, but that was the fix. A whopping $70 in new AC Delco parts, but at least triple that in the swear jar.

Part I removed was noticeably different than the AC Delco part. Likely an aftermarket, and those have a bad rep.

I'm getting too old for this...

A good compromise with Techstream is to pick up a Tactrix cable - very high quality and about 1/3 the price of the Mongoose. Then it's pretty easy to find a good quality copy of TS that's not riddled with a virus. I might know a guy.

[redpoint5]

I bought a cable and Techstream CD off Ebay. The only catch was something like I had to run Windows 7 or something. Newer OS wouldn't work.

I don't consider it stealing to disable an annoying reverse beep, especially when I had to pay for the stupid cable. The right to repair should encompass the right to make routine software changes. The fact that it takes anything special is silly. Should be able to make those changes with an iPhone or Android app for free. Or, better yet, just a menu option in the touchscreen display that already exists in 95% of vehicles.

The fact that OBDII codes aren't accessible on screen in the futuristic year of 2000 is criminal.

More predictions about how awesome things will be in the future; in the year 2000.

https://www.youtube.com/watch?v=4W52CFVoivk

https://www.youtube.com/watch?v=kmzpdd4pWvM

https://www.youtube.com/watch?v=AukA-kDNSNc

https://www.youtube.com/watch?v=aScP6QB3Nx8