Higher capacity battery mod?

I like the enthusiasm and ingenuity shown, only question I have, since I'm interested in refueling my old hybrid motor what are you looking at for return on investment ROI or your budget constraints.

 

For me.. my goal of 100mile range on EV mode while being able to drive up to 80mph in EV mode like the Gen 4 Prime was my baseline. This in theory should allow me 24 hours easy of not needing to have ICE come on while out boondocking in the middle of where ever I am, while being fully powered up using everything from air fryer to keeping my server and gaming pc running and its various networking devices along with fridge running.
The thought that id have two 150ah 12V lithium batteries along side a roughly 50kWh HV battery should get me there. Finally, the extra capacity HV battery would provide enough juice when fully charged to propel the rear Electric engine that made the car AWD faster than a non dual motor baby tesla... so the Prius wins in a stop light street race up to 79mph.

 

I would like to upgrade my cells. There are a lot of NMC-cells for sale directly at the manufacturer, or their Chinese resellers with capacities as high as 52AH, which would at least double the original capacitiy (21,5AH). There are even 62AH available, but they are 28mm instead of 27mm.



The manual states the cells are 105x148x27 (mm) but at which position are the terminals exaclty?
This particular listing says the dimensions are 95x148x27, so they are a little bit lower, which would be no problem as long as the terminals are in the right position.
Can someone point me in the right direction, considering cell dimensions? And experiences with those kind of cells?

Thanks in advance.

 

Do you seriously trust a Chinese seller?
Marketplaces sell things that do not pass the test for a serious buyer.
This is a lottery with inflated capacity and reliability indicators. And of course, the super prize is a fire.

 

Incredible, daring & well executed! is what comes to my mind when I see your project.
Did you do anything to the programming of car itself?
How does BMS of the car take the enormous amount of extra capacity?
Do you have to reset faillure codes every time?

So many questions...

 

At least thousands of people, worldwide, make their own powerbanks, electric scooters, cars, "powerwalls", etc. with those cells and 90% of the aftermarket Prius battery-replacement-shops use those Chinese cells.
Of course you need to pay attention to what they advertise with, but +/- 50AH for those cells is nothing special today.
The LiFePo4 which I orderd, 7 years ago, were 105% of their advertised capacity and still have +/- 95% of their original capacity.

Long story short: Yes I would like to try them in my PiP.

 

You have the approach of an amateur who does not understand how it works, but dreams well.

There are enough videos on the Internet of these homemade devices exploding and burning.

 

when used in a Prius? really?

either way... I applaud Kess... we need more owners like that person and myself, because If there were and there were not members like MAX2 discouraging folks but rather providing breadcrumbs, man... where we would be as a community and owners would be light years ahead of where we are now... why the negativity MAX2?

 

I am not discouraging crazy ideas, but simply warning about possible consequences.
A competent engineer will figure out all electrical issues on his own, take into account the effect of additional mass and volume on the car's centering, and solve many other issues himself.
An amateur will ask - is it possible to replace? Another amateur will answer him that it is possible. Voila! The effect of a Chinese firecracker that explodes at the wrong time.
Yes, if you are so knowledgeable and skilled, then why don't you work at Toyota? Your ideas and innovations could be realized with a huge profit.

 

Haha, your analogy about the Chinese firecracker is spot-on—timing definitely matters! You're right; this kind of modification requires careful thought and skill.

For me, though, it was never about the money or even working directly for Toyota. It all started around a campfire with about 10 to 15 Prius owners. At that time, I was just one of two plug-in Prius owners who had a lift kit. As we discussed our next adventure, we quickly realized that unless your Prius was lifted, getting in and out of certain areas was going to be tough. I figured, "Hey, I'll just get a small batch of lift kits made for us and call it a day." Little did I know, a few of those folks shared it online, and suddenly, I had people reaching out from everywhere looking for the same thing. And here I am, making parts for the Prius that nobody else had thought of.

Toyota and I actually go way, way back. Funny story: Back when Toyota's Ontario Parts Centre was getting ready to launch, even those IBM guys in blue suits couldn’t figure out the technical snag. The whole operation was dead in the water until I—a kid about to start high school at the time—solved the issue and got them up and running.

So, honestly, it’s never been about the money or even a position at Toyota. If I ever worked directly with Toyota, they'd have to hand me the reins with no red tape. I'd want to create something revolutionary for the people, something that could outshine even the Supra. Unless they offer me that level of freedom, I'll happily continue innovating right here alongside our passionate Prius community.

 

Maybe straight to Tesla?
You'll become the second person in the company.
And when Musk gets completely stuck in politics, you'll become the first?

 

Heh… I’m definitely more of a Czinger guy. If I ever get the chance, I’m gunning straight for them—or their software company, Divergent. The moment I finish assembling my supercomputer (we’re talking six Minisforum AI X1 Pros clustered together), I’m dropping $15,000 on their AI CAD platform without hesitation. After that? It’s mine… muahahahaha — cue the evil villain laugh.

With their software and my collection of 3D engine and part scans, I could do some wild stuff. Like, imagine feeding it a 3D scan of a Gen 2 Prius engine bay—first with the suspension and CVT, then again without them. Then toss in a 3D scan of a 2.5L RAV4 engine and let the AI do its thing—designing the exact parts needed to make it all fit together seamlessly.

Honestly, even without that software, I’m confident I could get most engines to drop in as long as I’m not cutting or modifying the suspension. And based on my research, the Prius ECU might actually recalibrate itself automatically. The only thing is… this hasn’t really been tested with anything over ~1,990cc in a Gen 3. It might handle bigger displacement just fine—but hey, only time will tell.

 

In many ways this is tempting, and the price is what gives it the biggest appeal. In the US it looks like it would cost around $1,300. Of course, there are a few concerns I would have before doing something like this:

1. Are the electronics in the car up to the task of managing the extra capacity of this battery?
2. Will the car be able to detect any heat issue and shut the system down to avert a thermal event (fire/explosion)?
3. Are the terminals in the correct location and size?
4. Is the stated capacity accurate?

If all of the above check out, then a direct replacement seems great. I have to imagine that the above items are not all OK, because there is probably a good reason that NexCell is selling their replacement for more than triple the cost when on sale.

 

I think you nailed it

 

Of my above questions, #2 seems the most important one. Can anyone point me to any resources about the battery protection features this car has to prevent a thermal event? Are there spaced out temp sensors and the car will stop charging when the temp is higher than it should be?

 

To all your questions there is one answer, "no", in one form or another.

 

this is the thing... If I'm not mistaken, I might be the only one with a PHEV thats actually modifying it, let alone has modified the hv cells once and about to upgrade again to a higher capacity than even the Gen 5 Prime has! That said, all the other commenters have the non PHEV... personally, id take with a grain of salt anything they say as its all hypothetically speaking.

Now... this is the thing... ill go into more detail in email but, you are focusing on the wrong cells! When I say stay away from the blue cells, please head my advice. That said, Yes to #1 and #2 if you use another battery cell that's not the blue ones. Have you seen this video?

I started it right where you need to see "key" information.

 

I am willing to believe this, but I have not found much info one way or the other. Very few here seem to have dug into this particular battery, and real world testing is much more credible than a blanket "Toyota engineers are very smart, so doing anything different is dangerous."

Looking at the NexCell install video, it seems that Jack is basically just swapping out the cells and some spacers, no modification to the electronics. If we accept that the NexCell upgrade is safe and reliable (hard to debate without more data points) then it would be possible to have a safe sway as long is they are the "right" cells. Here is the install video I am referring to for the install.

@black_jmyntrn, your thoughts are intriguing, but I would need a lot more documentation and proof before I would take your word to "stay away from the blue cells, please head my advice." You claim to have a lot of groundbreaking ideas, but I think many remain skeptical without clear and detailed explanations. The video that you posted shows Toyota cells from a different model, but are you saying to source those instead?

 

Lithium cells should not be used without a BMS. Voltage and temperature control are mandatory.

The more powerful the cell, the more it will bang if something goes wrong.

The costs of designing voltage control, BMS board control will reduce the expected advantages of using these cells to minus. The financial issue will kill this idea completely.

If you want to drive only on electricity, buy a Tesla or BZ4X.

And remember that Chinese batteries sold on marketplaces are usually rejected elements at the factory.
They are cheap, but the price corresponds to the quality.
After a certain number of cells of average quality, you may get a surprise in the form of a "firecracker"

 

The PIP batteries are lithium based (not sure the exact chemistry) and would have to have a BMS for Voltage control and cell balancing. Now, one could say that the onboard systems are not up to the task of the bigger cells, but it seems that NexCell has disproved that.

As for cheap Chinese cells I agree that it would be a roll of the dice. I would think to hook them up and do some controlled charge/discharge cycling to monitor temperature before assuming they are all winners. I am open to other cell ideas if anyone has leads.