Toyota Prius Owners Are Swapping Tired Old Batteries For Lithium-Ion Ones And Seeing Big Gains

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The Toyota Prius was the first hybrid to market when it went on sale in 1997 (though the Honda Insight beat it to market in the U.S.) and the main model line has spawned five generations of cleaner, more efficient vehicles. As you might imagine, that leaves thousands of older Prius models driving around with high miles on the clock and tired batteries. Salvation is at hand for the tinkerers out there, though. Some owners are now electing to pursue battery upgrades for their aging hybrids to unlock better fuel economy and slightly improved performance.

The key is that until the fifth-generation model, most examples of the Prius were built using older nickel-metal hydride (NiMH) technology. While these were historically cheaper than newer lithium-based batteries, they make a tradeoff in performance. NiMH battery packs are larger and heavier than lithium packs that store the same amount of energy, and generally can’t deliver anywhere near as much power.

Thus, with aging, old-technology batteries, early Prius models are ripe for a battery upgrade. Project Lithium, also known as NexPower, is the main player in this space, offering a range of lithium cell upgrade kits for a wide variety of older Prius models. Beyond that, the company also offers upgrade kits for other Toyota and Lexus hybrids like the Camry Hybrid, GS450h, and the Alphard and Vellfire vans.

It all comes down to drivability and efficiency. With a weak or dead hybrid battery, a Prius can be a lot less fun to drive every day. It forces the car to rely more on its ICE combustion engine, and there’s a loss of the beneficial low-down torque from the electric motor when the battery can’t deliver. For a tired old car, a lithium battery upgrade can fix all those problems. It can even go further because, with additional battery capacity, the motor can work for longer before the saved juice in the battery runs out. That’s really helpful when going up long hills, or when trying to drive the car longer distances in EV-only mode.

Jack, the man behind Project Lithium, openly shares information on the project on his YouTube channel.  In one video, he walks through the process of upgrading his 2006 Toyota Prius. After 150,000 miles, the original NiMH battery was dead. He ably demonstrates how to remove the stock battery and replace it with the new cells. The Prius’s battery is at the rear of the car, just behind the rear seats. It’s accessed by pulling out the back seats, along with a bunch of panels, trim and carpets out of the trunk. It’s important to know what you’re doing during the removal process to avoid any electrical safety issues, but Jack makes it look easy. He pulls out the pack, noting that the stock part weighs a hefty 80 pounds or so.

Out of the car, the construction of the battery is obvious. It’s made up of multiple separate blocks all connected together. In total, it adds up to an NiMH pack with a tiny capacity of just 1.31 kWh when new. Compare that to the hefty 100 kWh pack you’d find in a Tesla Model S Plaid.

2006 Prius Gen2 Nimh To Lithium Upgrade Installation Guide 7 45 Screenshot

 

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As Jack demonstrates, the interconnects between the cells are easily removed to break the pack into its individual modules. It’s very simple compared to modern EV packs, which are full of cooling channels to enable higher performance and power delivery. These modules are removed from the battery frame, and replaced with the new modules from Project Lithium, which are full of high performance lithium cells. The new battery modules can then be hooked up with the stock interconnects, the battery frame can be bolted back together, and the whole assembly is ready to go back in the car. As a bonus, the more energy-dense lithium cells mean the pack weighs roughly half as much as the stock unit. Once installed, the battery’s vital signs can be inspected via the Dr. Prius phone app.

It’s not a project that you should take on if you’re completely unaware of the dangers of electricity, but it’s not beyond the realms of the educated amateur mechanic. Alternatively, Project Lithium has a network of installers that it works with to provide customers an easier option. The packs from Project Lithium start as low as $2,455 for the Prius C, which only needs 10 drop-in replacement modules. A Toyota Highlander or GM Tahoe hybrid uses double the packs, and the upgrade kit costs closer to $5000 when it’s in stock. That’s not a bad price for a brand new battery pack, even despite the low capacity. After all, it took significant effort in research and development to engineer the packs as a near-drop-in replacement.

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Early development photos from Facebook indicate the replacement battery modules use rectangular “prismatic” lithium cells. This makes sense for packing efficiency, given the rectangular modules in the Toyota battery design. Credit: Dr. Prius/ Dr. Hybrid, Facebook

Performance benefits are slight, but noticeable, according to the company, and many forum anecdotes concur. This is because the Prius motor and supporting electronics were only designed to draw so much current, based on the capabilities of the NiMH battery. However, where the lithium battery upgrade comes in handy is that it can keep the motor running at full power for much longer than the stock pack. Thus, it won’t necessarily provide much more punch, but what punch is on offer from the stock drivetrain will be on tap for longer. It’s a boon in sustained high-load scenarios like going uphill.

The killer app is in fuel economy, however. TheChip, owner of a third-generation Prius raved about the upgrade on the Prius Chat forums. “I managed to get 54 mpg on my round trip, even with some leadfoot driving. Previously, I’d have been around 38-42,” he noted. Do the maths, and that’s 26% less fuel, a healthy win you can take to the bank. He also noted the ability to get a full 3 miles of all-electric driving, something non-PHEV Prius models never really excelled at. Previously, he couldn’t even achieve a full mile. Other owners have posted smaller but still noticeable gains. On Reddit, owners with the lithium packs noted mileage gains on the order of 10%, or roughly 4-5 mpg.

Hybrid Repair Shop Series Troubleshoot Check Hybrid System Error Nexcell Prius Lithium Battery 7 2 Screenshot
The Dr. Prius app, from the same developer as Project Lithium, is used by many owners to keep an eye on their battery’s state of charge and performance.

A small additional benefit is that the extra battery power can come in handy for accessories, too. Some owners have enjoyed the ability to sit in their cars for a quarter of an hour with the AC on, with the engine dutifully remaining switched off. It appears that longevity hasn’t proven to be an issue in the wild, either, as some have had the batteries in use for several years now, racking up thousands of miles.

Gains to fuel economy are great, but it bears considering the costs. The kits from Project Lithium cost a few thousand dollars. So, for example, let’s say you live in California, where the gas is $4.80 a gallon, and you do 15,000 miles a year. At around 45 mpg, you’re using about 333 gallons of gas a year. Bump that to 50 mpg, and you’re only using 300 gallons of gas a year. So, saving 33 gallons at $4.80 a gallon nets you $158. Even if you were only getting 40 mpg before, you’re only saving $360 a year.

So, ultimately, swapping out the battery for better fuel economy maybe isn’t the smartest investment. Really, the biggest gains to be had are for a Prius with a dead battery. Not only will fuel economy improve, but the car will be much more drivable when it can properly use its electric motor again. Hence the tagline: “Fall in love with your hybrid again!” In that situation, even a reconditioned NiMH pack will be a boon, but the lithium upgrade is a nicer way to go. Oftentimes, it’s desirable when repairing a car to put in something better if technology has moved on. Think of it as akin to fitting electronic ignition to a classic muscle car that still has points.

https://www.facebook.com/drpriusapp/photos/pb.100063625414121.-2207520000/1130140107506980/?type=3

Ultimately, it’s neat to see an aftermarket company spring up to provide better, more potent battery solutions for hybrid vehicles. Once upon a time, hybrids and EVs were these new, shiny things. Now, they’re becoming familiar to us, and a grassroots industry is springing up to support, maintain, and even improve them. As enthusiasts, that’s something worth supporting, especially when it’s keeping more of these cars on the road for longer!

Image credits: Project Lithium/NexPower/Dr.Prius

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137 thoughts on “Toyota Prius Owners Are Swapping Tired Old Batteries For Lithium-Ion Ones And Seeing Big Gains

  1. I didn’t see in the article anywhere (always possible I missed it) but what is the capacity of the upgraded poser pack? Curious so see how much of a gain the lithium gets over the factory 1.3kwh.

    1. The projectlithium website also doesn’t tell you unless you dig into the FAQ:

      Prius pack capacity (14 blades): 1.456 kWh

      So, each block is about 1/10th of a kWh.

    2. According to the FAQ section of their website, The V1.5 standard Prius pack has a capacity of 1.456 kWh, although I couldn’t find specs for the current V2, but assume likely a 1.5 kWh, so slightly larger, not huge but reasonably larger.

      The big benefit comes from chemistry change, where the lithium cells have about 80% usable compared to the OEM NiMH supposedly only having 40% or so available of its 1.3 kWh capacity, more than doubling your available power.

      1. Interesting. I would have suspected a larger gain in the chemistry switch over. Although I don’t doubt you are correct and real world use would be greater than the base numbers suggest.

  2. Since the start of the shift towards electric cars, I’ve been hearing people arguing that dead batteries will total electric cars because of how expensive it will be to replace them. I never bothered countering that argument but my suspicion was that when those batteries started dying, tech would’ve evolved over time and gotten cheaper; if you keep the form factor and power delivery/thermal management/other technical specs, you can probably retrofit any battery tech to any electric car. Over ther years this could mean more expensive options for the latest tech and cheaper options if you wish to just replace batteries with similar, relatively outdated ones. I believe this would gradually turn the exercise of replacing dead batteries into a normal, way cheaper procedure than it is now. Also, with the need of maintaining form factor, maybe this could mean old battery “shells” getting reused by swapping out old cells for whatever new type of cells are out there (or similar ones for a cheaper option).

    With the industry selling us the idea that everything in electric cars is more durable and reliable than in ICEs, the public has a right to demand that such things are taken into consideration by automakers – if they’re telling you the car you just bought will last longer than an ICE, they should make good on that selling point.

    Also goes without saying: reusing parts and keeping cars for longer on the road, and lowering the demand for new cars is an environmental imperative, so I’d argue automakers have a moral obligation of incentivising this. If moral obligation isn’t enough, I sure hope for regulatory obligation.

    1. I think the biggest problem with replacing batteries in a lot of EVs is that they’re structurally integrated to the chassis which makes them extremely laborious to access. Take into consideration the high mileage a car that needs batteries would likely have and the resulting depreciation and replacing batteries in such situations wouldn’t be very cost effective. I don’t, however, think the issue of battery replacement will remain relevant in even the very near future. With Tesla having a 150,000 mile pack warranty and some people claiming 300,000 miles on their Teslas with very little degradation, technological advancements will eventually render the point moot if they haven’t already.

      1. Lessons learned I guess. The more we dive into this transition, the more it looks like we’ll need standardization and better engineered solutions for the new problems that arise. Structural batteries are a mistake in my opinion, although I understand why that’s the way to go at this stage. And to be clear, that can still be the case for luxury offerings in the future; but for entry-level offerings I believe it would be smart to rethink batteries. Making them easily replaceable/refurbishable should be priotitised, I think.

          1. Industry standards are fundamental yeah. I understand that it wouldn’t be ideal to set them too early in the transition, you need real world testing to come up with industry standards that make sense. But I’d say it’s about time that this starts getting addressed more seriously.

  3. If a Prius has a dead battery it won’t drive at all since the HV battery is used to start the engine. Now an original Insight can operate just fine with the HV battery disconnected and if fact you are supposed to disconnect it and start the car at least once per year to exercise the 12v back up starter.

  4. I have a 2012 Prius v on its original HV battery still and I occasionally ponder what option I’ll go to if/when I need to replace it.

    I still get 37-40 mpg most of the time so I don’t think failure is imminent, but who knows.

    I’ve heard a Toyota NiMH replacement costs ~$3-5000 but comes with something like a 10-year/100,000 mile warranty (just for the batteries), whereas the Project Lithium is something like $2300, but only a 2-year/unlimited mile warranty.

    Still, since it’s so much less battery capacity than a PHEV or EV, I guess the thermal management stuff doesn’t become a huge problem. In that sense, this feels like one of very few things in the real world that sounds like a straight-up linear upgrade for the car, like something straight out of a video game. “That’s right, the pack weighs 40 pounds instead of 80 and you actually accelerate faster, and get better fuel economy.” What a rare opportunity.

    So from the sound of things, I’m leaning towards these rather than OEM.

    Glad this got its own article. I’m definitely looking to pursue this when The Time Comes.

    1. I have a 2012 v as well. 225,000 miles and original battery still going strong. I consistently get 40 mpg in warm weather with mixed driving. Low 30s in the winter.

  5. Cool article! If these packs were a Lil cheaper I’d be all over this as I’ve considered it. I’ve had good luck with my batteries and have taken about 10 toyota and ford vehicles to 250k to 420k and never had a battery issue until last summer when my 2015 avalon hybrid said 2 blocks were bad at 323k

    I replaced one single cell with a $30 used ebay cell (the other block static tested out ok. I didn’t load test it. I should have. )

    Forums all told me this was foolish and like playing whack a mole. They probably right.

    I have 11k on the POORLY done battery ‘refurb’ and I’m hitting 40 mpg regularly and car drives much better then it did with one bad cell outta 34. I didn’t use a torque wrench or wear rubber gloves.

    Still throws a hybrid code though sometimes, but no longer identifies any bad blocks. I just reset it.

    Waiting for driveabilty issues then I’ll run dr. Prius app and replace a few more cells if any are identified.

    The whole process takes about 6 hours but it’s pretty exciting if you’re into this nerdy stuff.

    I’m the guy that trys to get every last mile outta used parts, used tires, high mileage cars whatever I can. I don’t do all that well with the ladies anymore.

  6. The service and repair practices demonstrated in the Dr. Prius video violate various industry standard safety practices. NEVER disassemble an HV battery pack without wearing/using the proper protective gear! The person demonstrating these repairs should be wearing class 0 electricians gloves with leather protectors, as well as wearing safety glasses. Insulated tools should also be used, in order to prevent accidental arcing across terminals. The pack voltage exceeds 200 volts; even a severely depleted pack will still produce very high voltage such as this. If you contact the wrong terminals in the assembled pack, you could be exposed to 100 volts or higher even though the service disconnect has been removed. This voltage can cause personal injury or death. Another issue with the procedures shown in the video is the complete lack of correct fastener torque verification. Incorrect torque on high current electrical connections can and will cause added resistance through the connection, which will eventually cause the connection to overheat. Incorrect torque on those “blade” connections can cause a vehicle fire – or at a minimum a decrease in performance. How do I know all of this? I hold several related certifications, including ASE light duty hybrid/EV specialist certification.

    Don’t get me wrong – I like the idea of repairing and upgrading the battery pack on an older hybrid, but the safety practices shown in the video are appalling!

    1. I guess it is a trade secret for the torque numbers.

      I survived, no shocks, this fall on a gen1, 2003, 182k, resolving a p3030 – snapped wire error. Local mechanic autel report showed 5 modules reading zero. Said battery was toast. Suggested 2 aftermarket sources. $2k, but recommended junk the car, it is old, and get something newer.

      As a novice, compromised at middle ground on safety. Used basic insulated gloves, moved with care, used insulated tools (1000v rated) when working with anything more than 1 module, Used gloves and insulated nut driver even on 1 module. Followed the instructions on Toyota service guide to steps to remove battery.

      Modules tested at 7.6 to 7.9, with 2 at 7.2volts. those 2 at the far end of the pack.

      Saw the purple sugar and corroded bus bars and high voltage cables and sense wire harness. Replaced them and the computer. There was corrosion inside the computer.

      Vinegar to clean the module nuts, and wipe off any purple sugar.

      Parts set me back $350 and $200 for tools. Torqued modules at a ‘good tug’ at the end for each.

      On reinstall codes cleared, and now have put on a 1k miles

  7. My real issue isn’t w/ the battery pack but the whole idea of planned obsolescence.

    Whether it be pressure from the Federal Government or political action groups to get “old and unsafe vehicles” off the street which are perfectly fine, but only deemed unsafe due to the lower standard of driver’s training and licensing requirements or arbitrarily increased safety standards for new vehicles in DOT/NHTSA policy and Federal Legislation, but this whole idea that vehicles shouldn’t be used longer or kept up to date, or be supported for longer.

    This consumerist/capitalistic dynamic is causing true and intense environmental harm.

    1. I can count a few people who are close to me that are only alive today because of what you call “arbitrarily increased safety standards.”
      Growing up in the 80s and 90s, most cars around the 5 year mark were starting to get pretty rusty, the exhaust would be falling apart, the engine would be worn out and needing rebuild. Even to make it that far, these cars needed plugs, wires, cap and rotor, all replaced at least annually, plus a mechanic would have to manually tune the engine to keep it running ok. By ten years, cars would go home to the shredder.
      It seems like now they’ve gone too far with reliability, and it hurts their bottom line. This is why companies like Subaru and Nissan are designing obsolescence into their vehicles by using conventional CVTs.

  8. I’m only ok with this because the replacement cells are LFP. Still have some concerns about how these will be thermally managed compared to the nickel batteries, but LFP is much safer for this type of experiment vs. NMC/NCA which need a lot more thermal considerations.

    I think it’s a cool idea, and if it keeps priuses out of junk yards… I’m all for it.

    1. Keeping an otherwise viable Prius out the junkyard is a noble enough reason to do this swap. I like the idea of stretching the range between gasoline fills another ~50 miles/tank.

      The author’s economic argument is a little too back of the envelope. If swapping the batteries costs the equivalent of three or four payments on a new car, extending the life of an otherwise serviceable vehicle by, let’s say, five years is money well spent.

      1. Assuming the math above, I’m seeing refurbished gen 2 prius packs between 900and 1500. So if the new lithium pack runs 2500, assume the mpg gains/fuel savings range above, you’re at 5years/75k miles to 9.4/142k miles to repay the difference. If the reliability holds up then you could easily be looking at the last HV battery the car would need for its probable life span.

        I’d really be interested how the swap is going for folks in the middle of the country where you get much colder Temps. while hitting similar summer temps to California.

    1. Probably 95% of people would be better off just picking small Prius, medium Prius, or big Prius but no one was ready for that I guess.

      RIP small Prius and big Prius.

        1. Wait, seriously for a moment, what makes Prius C bad? Just that it’s small?

          Which, I mean, I’ll gladly sacrifice the difference in mpg between a regular Prius and the Prius v (which I own one) for the space, but if I was really just looking to move myself, maybe one passenger, and nothing else, why not a C?

        1. You’d be surprised, there’s a cavernous hidden compartment where the gas tank should be + the frunk. I loaded our Outlander PHEV (midsized SUV) to the roof, and to test the cargo space before buying the Model 3 I successfully transferred every single item in the M3 with room to spare. Best part was I could actually see out the back of the Model 3.

          1. Seats up, I’d believe that. But not only does it depend on the cargo in question (you might be talking luggage vs other cargo for OP), the Prius v has 67 cubic feet of max cargo space, seats down and more squared (i.e. not working around a rear bulkhead) and more accessible with a taller and wider opening area to it – seeing around 28″ for the v, vs. 18″ for the 3 in height, and 42″ vs 37″ respectively.

            1. Seats up in both cases with 4 passengers, I compared 4 large+medium luggage, several ski boot/helmet bags, random shaped bags, jackets stuffed, etc.. I can fit (5) 24″ roller luggage bags in the trunk alone.

              Sure, if you’re regularly moving large appliances, the open space of the V will be better, but for practical use like 99% of people use it (partitioned), the space is similar. I almost never put the seats down in any vehicle, and I have a truck for moving large items. Road tripping with 2 kids in the back is my primary need. Maybe this is a testament to how inefficient SUVs are. I think Tesla tanked their numbers on the M3 to make the MS look larger, personally because I could fit more in my M3 than the Outlander, easily.

              Pruis V ~34 ft³
              Model 3 ~23 ft³
              ’18 Outlander PHEV ~30ft³

              1. But that’s based on your use case, not HairyNug’s. You said it’s sure to have better cargo space, which is not the case by both max volume or by the size of the cargo area opening.

                And if you’re making an assumption on what most people do – most people can’t swing multiple vehicles like you having a truck, so they get something that can play multiple roles, which is where max cargo cargo volume and its usability is relevant here. Based on type of cargo sedans can often fit more than expected, I agree with this; another site regularly tests cargo space with luggage and fit as much or more in a Civic sedan vs. the hatchback despite the latter having more seats-up cargo volume. But the flexibility of the hatch opening + dropping the seats can be more useful than occasionally filling up the trunk with luggage.

                1. I was hoping when the M3 came out it would be a 5 door ie hatch back like the MS…
                  Tesla (smart from a business standpoint), created the MY as a completely separate vehicle just different enough from the M3, although realistically although it is called a cuv/suv… it really is a hatchback version of the M3
                  Comparing to the Prius V…

                  I think the MY is a better direct comparison from a loading stuff perspective and it really is all down to the more interior volume and hatchback vs. M3 trunk.
                  Challeng is… cuvs/suvs are the most popular car segment and therefore can command higher initial purchase price And given the MY is still only 3(ish) years old… not a ton of used examples available, although I have seen used MY getting close to and occasionally dipping below $30K with clean titles and below 60k miles

                  1. I agree the the Y would be a more apt comparison. With the pricing where it’s at for new, it’s no surprise it’s reached the level of popularity that it has. The sizing is right for volume of crossover sales out there, and once you get to the midsize crossovers and/or premium brands, it’s not like it’s necessarily more expensive either, sometimes even less.

      1. I’ll definitely say that a used AWD Model 3 is on the short list. I just find it hard to stomach not owning a hatch. I can’t even begin to explain how incredibly useful my Honda Fit has proven to be

        1. I cant think of a good reason the 3 wasn’t a hatch, and I’m with you there. That said, its still very practical and a useful amount of space with the false floor, which is a tad larger than a large piece of roller luggage. You can remove the floor and stand things upright. I’ve got a truck, so anything larger goes in there.. but not everyone has that luxury.

    2. Have you considered the RAV4 Hybrid? Basically the same fuel economy and dimensions with just a bit of a higher ride height. Its not exactly the same but I love mine.

        1. Prius v wasn’t rated that high – 43/39, still better but not quite as large a gap. At that point there’s also the extra pep of the RAV4’s larger motor. Though it will be interesting if the next gen RAV edges higher still and beats/exceeds the old v.

    3. Truly, the 5th gen Prius having similar fuel economy to the prior year but worse headroom and storage space disappointed me so much.

      Yeah, they look nice and they’re competently fast…and I guess that makes them the right move for Toyota to fight declining sales…but they’ve betrayed the spirit.

  9. “The Toyota Prius was the first hybrid to market when it went on sale in 1997…”

    This came up a couple of months ago but I don’t intend to let go of the fact that the Owen Magnetic and the Woods Dual Power both came to market in 1915.

    1. Let it go, let it go
      Can’t hold it back anymore
      Let it go, let it go
      Turn the key and slam the door
      I don’t care what they’re going to say
      Let the Prius rage on
      Toyota never bothered me anyway

    2. Put together in a sentence like that, “Owen Magnetic and the Woods Dual Power” sounds like an indie folk band name spoofed off ‘Edward Sharpe and the Magnetic Zeros.’

      1. The Lohner-Porsche vehicles use internal combustion engines to charge their electrical systems but only their electric motors directly provide propulsion, so it depends on what definition of “hybrid” one wishes to use. The Owen and the Woods use both their engines and their electric motors directly for propulsion.

        1. Isn’t the Owens technically not a hybrid? As far as I can tell the electric motors just act as a transmission and there’s no traction battery or physical connection from the engine to the wheels (just like the Porsches)

          I could be completely wrong.

          1. My mistake, as it’s not right to call the Owen’s system direct. The only significant difference between it and the Lohner-Porsche is that its generator and motor combination is contained within a single unit driven by the engine instead of being separated in different parts of the vehicle with only the generator at the engine. The electric motor/generator “transmission” in the Owen can also operate entirely on battery power, however, much like the Lohner-Porsche.

  10. I kinda wonder what the long term life of this mod is. The charging profile and SoC profile for NiMh and Lipo4 are different and the modules are still going to treat the new pack like the old one.

  11. Damn, that one guy was only getting 38-42mpg?! What’s that at an average speed of 120 mph or is that just how bad they are without a healthy battery? The new Corolla hybrid I had as a loaner averaged around 55 mpg without trying. I can’t imagine having to drive such a terrible thing to only get mileage that’s so mediocre.

    1. I’m guessing that was with a degraded battery. My Dad has a Prius of the same gen that gets 45-50mpg, depending on weather and how he drives.
      Also, that new Corolla hybrid probably already uses lithium-ion batteries.

      1. That was my experience as well driving a beat-up ’04 Prius from 2015-2019. 35 mpg in the winter, 45 mpg in the summer, and 55 mpg on country roads when you can cruise forever between 45-60 mph.

    2. My friend had a 2008 Prius with around 250k on the clock when the battery finally gave up. For the last year or so she had the car, she was only getting low 30s. Even though the car was undrivable when she got rid of it, she was able to get $800 from a local shop here that only works on Priuses. They probably had 50 of them in varying conditions in the field in front of the shop. And I know $800 doesn’t sound like a lot but that car was trashed. Filthy inside, smoked in, dents, completely failed clear coat. But it never gave her any major trouble at all until the battery started going out.

      1. I think this is the model behind the loaners for a local chain of service shops. They advertise that they are an independent hybrid repair center including battery replacement, and have a whole fleet of wrapped Prius’ that I imagine they picked up cheap and fixed up.

    3. Gen 4 toyota hybrid more efficient then Gen 2 amigo.

      Prius at 120 mph gonna get pretty crappy mpg. But my 2010 was amazingly smooth at 110 mph I was impressed. Didn’t record the mpgs though.

      I’d love to know what prius get for mpg at 80 mph and above.

      My avalon and lexus es300h goes down to 30ish at 80 mph at least recently at 40 ish degrees f.

      1. On a 4400 mile road trip out west (MN, ND, WY, MT, out & MT, WY, Co, NA, IA, MN back) I avg. 44-46 mpg US at an avg. speed of 78 mph) in a 2012 plug-in prius that was packed with 2 adults and 2 aged and sized kids plus luggage

        Around town tank mpg avg is 64-68 mpg US 8 months out of the year
        Around town tank average in MN winter is 54-56 mpg US

    4. What’s a prius average for mpgs at 80, 90, 100, 110

      Don’t think they go much faster then 110… but mine was smooth at 110.

      One of my drivers blew an engine on a 2005 that liked to drive 85 for extended periods on an engine that ate oil.

      I typically drive slower cause I love getting that good mpg and I’m a loser

      1. That’s pretty bad, then. My ’12 5MT Focus SE got that in a combined cycle and that was a much better car to drive than a Prius. Even my GR86 gets low 30s.

        1. By “normal highway speeds” I did mean the speeds I expected to be driving one across the country when I was looking into them a few years ago, which was 75-85. I think they do significantly better at 65 and below. On a flat highway they’re basically just a proportionally heavy car with a tiny engine.

          1. Yeah, early on in its life, the people who bought them tended to be those 55-65 drivers (in the left lane, of course), but when the fuel prices went way up, it seems all kinds of people started buying them and driving them at normal 70-85 mph speeds (Around here, the old Prius stereotype is long dead. I’m more likely to see them weaving between lanes doing 90 than a BMW, though they’re usually just driven the same as anything other car.).

  12. Cool idea. I didn’t realize the Prius batteries were NiMH.

    The closest I’ve come to such a swap was with a Roomba. When his cleaning runs got shorter and shorter, I realized that his battery was losing its ability to hold a charge. I replaced the original with an aftermarket Lithium-ion version in a simple plug-and-play operation, which not only provided more power but was also lighter.

  13. I was going to replace the battery in my ’09 Camry Hybrid with cylindrical batteries from Electron Hybrid Solutions, which I found out about through a ChrisFix video on Youtube. However, after the battery died, it turned out that the engine was also drinking oil. Our bought new and driven daily for 15 years Camry is going to basically go to scrap now.

    1. The oil drinking problem is super common on the 2000’s Toyota 4-Cylinders. Try a piston soak with some B12 Chemtool or run some seafoam in the oil for a while, usually resolves or at least greatly reduces it

  14. Interesting! Pre-pandemic I had done a few battery pack swaps in older Toyota hybrids — mostly Prius and Lexus RX — and even the first time it was only a single long day to do it solo. Also was a good way to turn a few grand profit on one of these cars, since the prices quoted by dealerships at the time were 3-5x actual cost once you factored in labor and parts markup.

    The quality aftermarket support around good hybrids continues to grow, and I’d expect it to continue and with BEVs being added more in time. We’re not yet at the point where independent mechanics are doing these commonly (but they do them, for reasonable prices), but that day is quickly approaching.

  15. Looks like an impressive package, but with the economics, probably not gonna sell many unless gasoline price skyrockets. Right now it’s going the other direction despite a Mideast war.

    1. They actually sell a pretty good amount, they go out of stock regularly. Their price is ~10% lower than what it would cost for an OEM battery at the dealer

  16. I wish this existed for the soon to fail batteries on my first gen Ford Fusion Hybrid, but it makes sense given the number of Prii vs. the number of Fusions.

    1. Fusions are programmed to use less and less of the battery after 8 years which really hurts the hybrid performance. You can reprogram it to think it’s brand new with a laptop and forscan pretty easily.

      It’s worked well on all mine. I’ve never had to replace any of my ford batteries. I have 2 at over 300k.

      Yours might not be as bad as you think

      1. I have done the BECM reset and MPG went from roughly 23 to 30, but the battery discharges quickly in EV mode and I’m assuming it won’t last too much longer.

    2. I looked hard at the Ford Fusion hybrid energi and the Ford C-max energi when I was looking for a new to me commuter 6.5 years ago. I ended up with a 2012 plug-in prius bc I couldn’t justify either of the ford’s as being any better than the Prius plug in. The sales number differences between both of the ford’s vs the Prius plus Prius reputation and reliability ratings won me over

  17. I’d have concerns about charging, since the Prius charges the battery strictly via regenerative braking. Lithium Ion batteries have different charging requirements than NiMH. I’m not seeing anything about modifying the charging circuit.

    1. I did see this in the site FAQ:

      Q: Do I need to make any modifications to my car to support the use of lithium?

      A: There is no requirement for any changes to the software or hardware as each blade of the battery contains a specialized balancing circuit that ensures the optimal performance of each lithium cell. The vehicle is designed to operate the new battery in a similar manner as the NiMH battery but at a higher voltage, which encourages the usage of electric power.

      There’s also some additional text acknowledging the difference in charging requirements from NiMH, so it sounds like they’ve built the required mod(s) into the batteries themselves?

      1. If each replacement module has its own BMS that’s a significant amount of cost. Necessary given the different chemistry batteries but costly. Someone has to weld all that stuff together and assemble it.

  18. So, explain to me again, why having a standardized battery pack design is so totally impossible, that it will never happen? Totally unworkable? Just can’t do it?

    Yeah, that’s what I thought.

    1. Oh, it’s doable, but automakers would prefer you go to them, and not Dorman, for a new battery, or even better, junk your old car and come to them for a whole new one

    2. Whoa whoa not so fast. Can we standardize a power tool battery form factor first !! Actually there’s some rumblings out of the EU they may mandate universal power tool batteries, kinda like forcing Apple to USB-C. So perhaps standardizing EV batteries isn’t a complete pipe dream.

      1. No to standardized tool batteries, terrible knock offs will flood the market with crap. All things (reasonably possible ) should be usb-c charging capable, but yet again terrible knock off cables are flooding the market and killing devices.

    3. I could give them a pass sice battery tech is in frank evolution, my big issue is with software blocks, since a newer denser battery tech would be easier to fit into the massive packs we have been using.

    4. There are aftermarket adapters available for power tool batteries, and it looks like Aventon and Worx collaborated on a bike earlier this year that used Worx batteries, and it’s sold by both Worx and Lowe’s, at about $600 more than Best Buy charges for the regular version, while Aventon doesn’t even carry this model on their own site anymore.

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