BMW sold over 250,000 i3s between 2013 and 2022, and with those cars having carbon fiber bodies and aluminum frames that don’t rust; plastic and carbon fiber panels that don’t dent; and interiors that hold up to abuse, there are naturally many i3s still on the road, looking good. The issue is that many of these cars (especially pre-2017s) have battery packs that have degraded to the point where they offer only 50 or fewer miles of EV range; on top of that, even i3s with perfect battery packs don’t really go that far on a charge. For years, i3 owners have dreamed of a replacement battery pack that could give their otherwise-in-excellent-shape i3s a new lease on life, and rumors seem to be swirling now of a potential new option out of China. I just spoke with a man who’s swapping new batteries into i3s in Los Angeles, and he tells me: This is a gamechanger.
The BMW i3 began life for the 2014 model-year with a 22kWh battery pack, then it received an upgrade to 33.2 kWh in 2017, and then things jumped to 42.2 kWh in 2019. Per CNET, BMW’s CEO said the company was planning another battery upgrade before the company ultimately decided to pull the plug on the science experiment-car in 2021 (or 2022 in non-U.S. markets). So if you want the highest-range i3, 42.2 kWh and about 150 miles of range has been your only choice.
Recently, though, there has been some whispering that the aftermarket might offer a battery upgrade for the i3. That whispering comes out of China, with numerous sales representatives posting photos and videos of BMW i3s ostensibly receiving battery upgrades. Here’s a video from “CVC” showing a full pack swap:
Here are some photos from that same sales rep showing the alleged 49 kWh pack:
Clicking on “Jinchua New Energy” shows that this Alibaba listing is from the same company, CVC, which has sold Leaf battery packs for a while.
I’ve also seen replacement i3 battery packs advertised by a different company. Much of the information online comes from someone by the name of “Echi”:
MTG’s website shows 54 kWh battery packs made up of prismatic CATL cells:
Some folks on Reddit say they were quoted $6500 for the pack, which is about the same as the CVC price. But are these companies legit? Has anyone in the U.S. done a swap? Well, the answer appears to be: Yes.
I recently stumbled upon the thread above on Reddit; the OP states that they bought a pack from China (presumably from CVC since they’re Samsung cells), and they say the work was done by a company called Maxxpower, out of LA. Here’s Maxxpower’s rather basic website: 
I called up Michael Boomer, who runs Maxxpower, and he told me that he actually got started with i3s after reading my articles about my beloved i3! He also says he actually saw me a few months ago in LA driving my Galvanic Gold 2021. Small world!
“The day I opened this shop you were next door at earl’s place getting hoses made,” he told me, hilariously. “The reason why this is partially your fault is I wasn’t even considering an i3 until you [wrote your story]….it snowballed. Several months later I’m at a shop where I’m installing batteries. Mainly focusing on that and taking the old batteries to be used in different capacities.”
So that’s how this is going to work. Boomer will take folks’ old batteries, replace them with new Samsung batteries from China, and charge folks $7,200. That’s an absolute steal given the alleged performance improvements.
After telling me that the weight increase of the upgraded batteries seems largely insignificant and that his own personal 2015 i3 rides fine after the swap, Boomer said: “It’s so cool to just be able to turn on the AC and not even look and worry and plan…it’s a totally different car now. You approach it completely different with that kind of range.”
“I can tell you what I’ve seen — real world Los Angeles driving — AC just kinda running in the background on Eco Pro, I’m getting, depending on how I drive, that can be anywhere from high 160s to 200 miles.”
For reference, my 42.2 kWh battery pack in my 2019 i3S yields about 140-160 miles of EV range.
“It’s pretty drop in,” Boom told me of the installation process, “although I wouldn’t recommend the average Joe try to do this in their driveway. The AC is tricky,” he said, referring to the oil in the refrigerant and the recovery/fill process. Installing a 650 pound battery isn’t something you can do with floor jacks, though Boomer tells me he just uses a QuickJack.
To get an idea of what’s actually being replaced, you can look at the video above to see the original BMW i3’s battery pack. It’s basically a bunch of VHS-sized prismatic cells. These boxes go into eight modules that make up the battery pack.
Here you can see the 12 cells that make up each module:
And here’s what the module looks like once it’s been fully assembled with a plastic cover:
The cells are precisely glued together and configured in such a way that allows for both optimal cooling as well as room to expand and contract. Needless to say, Boomer isn’t swapping each and every one and gluing them all into place. No, instead, he’s getting entire modules from his supplier in China. “They drop right in over the same bolts,” he told me over the phone.
The “VHS”-looking cells are the same size, but they’re more dense that the original ones from BMW, hence the 49 kWh. As I mentioned before, BMW itself went from 22 kwH to 33.2 in 2017 to 42.2 in 2019, all in the same battery pack, with another upgrade in the plans before the car was killed off. It’s great to see the aftermarket deliver the power density upgrade that BMW promised.
Of course, the swap isn’t going 100% perfectly. Boomer told me that “the one thing that has been the hangup for us is the programming of the SME,” referring to the battery management controller. “We have to manipulate it a little bit to make it think that [the battery] can hold more,” he said. The result, right now, is that the guess-o-meter range-estimator is struggling to deal with the new, bigger pack. “That’s one of the things that i think people will absolutely screw up if they try to do this in their driveway,” Boomer told me, though he noted that at least one of the Chinese battery suppliers offers an SME (he doesn’t know how well it works).
Michael Boomer said he has friends in China who are able to look at products to give him an idea of their quality. “I’ve been doing business in China for years; I used to own a synthesizer shop; I used to build custom parts for vintage synthesizers,” he told me, saying he’s owned over 40 cars, though this is his first foray into automobile modification (though apparently his electronics known-how in music translates quite well). One of his goals, he told me, is to “make EVs more accessible to people,” going on to say “and what everyone needs from it is range.” Boomer says he’s starting by offering Samsung cells instead of CATL or Panasonic, since Samsung’s brand in the U.S. is strongest.
There have been some concerns on forums about the replacement modules missing a cross-brace. “There’s a teeny cross-brace between the two rows of batteries… I think that’s way overblown,” Boomer told me. “I’ve actually measured the deflection from one side to the other; there’s nothing,” he said, though he is 3-D printing some parts to give people peace of mind: “It’s easy enough to fix,” he told me over the phone. As for other concerns about the quality of the packs, Boomer says he’s offering a one year parts-and-labor warranty.
[Update (03/13/2025 10:15 PM ET): I was recently emailed the link to discussions about that cross-brace. The German forum goingelectric.de includes lots of concern about the safety of these Chinese batteries, not just because of lack of bracing but because of alleged lack of thermal sensors. See the full thread here. -DT]
[Update (03/14/2025 11:30 PM ET): I received an email from a gentleman from Hungary who says he works on BMW i3s regularly and does battery swaps on them. He says he knows somebody who bought one of the Chinese batteries mentioned in this story, and that it did not function properly. So, again, it’s worth reiterating that there are lots of questions that remain unanswered, and that car batteries can be dangerous, so it’s worth approaching such products with caution. -DT]
Obviously, there are still many questions that need to be asked, and given how expensive and dangerous batteries can be, it’s going to be a while before people are comfortable forking over thousands of dollars for more range. But I’m excited to see where this goes. Because the BMW i3, with its carbon fiber body, aluminum frame, plastic body panels, and durable interior, makes for a fantastic, modular “forever car” that you could just keep until the end of time, upgrading it along the way. At least, that’s what I hope to do with my Goldie you see above.
> Boomer said: “It’s so cool to just be able to turn on the AC and not even look and worry and plan…it’s a totally different car now. You approach it completely different with that kind of range.”
> I’m getting, depending on how I drive, that can be anywhere from high 160s to 200 miles.”
> For reference, my 42.2 kWh battery pack in my 2019 i3S yields about 140-160 miles of EV range.
So a 20% increase? That’s… Not amazing. With the “game changer” hyperbole, I was expecting something approaching Tesla levels of range.
I wonder if ‘game changer’ would realistically apply to the older i3 models that featured the smallest capacity batteries, less so to the more modern ones.
Indeed. It’s a game-changer for Boomer, who owns a 2015 that gets only about 50 miles per charge. (this is not abnormal for a 10 YO i3).
For the few US buyers who managed to purchase a 2019-21 i3, yeah, it’s just a 20% bump.
Aaah, OK, thanks for the clarification.
OK.
Boomer. /s
Hahaha
Really great stuff to see people working on how to extend the life of these cars and make them even more useful too. I’m learning a lot just reading this about how this technology really works, and how so many factors unseen or just plain hidden from the average driver have far-reaching effects as well.
Well worth the monthly subscription. Thanks!
So I admittedly don’t know a damn thing about EV batteries, but it seems like only about 5 minutes ago that even the major automakers were still figuring out how to make large battery packs safe and prevent thermal runaway, etc.
Using a pack with denser batteries than the existing battery management system was designed for (bought off of Alibaba!) installed by a random guy who works on synthesizers for a living….? I mean, I respect the ingenuity and all but I feel like if my buddy did this to his car I might make him park out on the street.
I don’t completely disagree with you.
If it’s good enough for Echi…
A similar thing has been going on for years in the Prius community. I believe there was an article here a while back that people are starting to realize their aftermarket lithium batteries don’t have proper safety precautions and there had been at least one fire as a result.
I don’t buy the i3 as a forever car because old carbon fiber is sketchy and hard to repair correctly. In the bike world, no one wants to touch 20yo carbon frames, but 40yo steel frames have yet to become obsolete.
If it’s in a crash, I can buy that. But if not, I see no reason why an i3’s carbon fiber body won’t hold up forever, especially since the suspension is bolted to the aluminum frame below.
Aluminium can corrode, especially if bolted together with steel bolts. It turns to white fluffy aluminium oxide that you can stick your finger through.
My ‘97 Elise (it’s real name) suffered enough chassis corrosion to a suspension mount that it failed it’s MOT 20 years later. I had a corrosion failure of an aluminium coilover top mount on my MX5, and that was way less than 20 years old.
It’s relatively common to find old aluminium wheels that have corroded enough to leak at the tyre bead. It can’t rust, because rust is made from iron, but it does corrode.
As for carbon, some resins are less UV stable than others, and while I trust BMW to use a good one, the 30 year old carbon bike frame I’ve got is enough of a worry that I might never ride the thing again. It’s doesn’t help that the failure mode is sudden catastrophic failure, rather than bending a bit like metals tend to.
In summary: just because it can’t rust doesn’t mean it lasts forever, it just means it’s not made of iron.
Right; I’ve seen old Defenders basically turn to powder, so corrosion won’t be ZERO. But I bet it’ll be fine over 50 years or so. Time will tell, of course.
But the carbon body I do think will last forever. UV stability is an issue on the roof of the i3 (and indeed, they do bubble and fail, which is why it’s best to protect them), but the rest of the carbon is covered by panels, unlike a bike.
JLR is a special case, they leave the factory turning to oxide.
Urban legend is that the components to Scout IH entered the factory turning to oxide.
I’ve been riding and racing bicycles for almost 40 years. Broken frames over that time: 1 steel, 2 aluminum, 0 carbon, and one aluminum crank arm, and a couple of aluminum rear hub axles. Now, all I ride is carbon. I’d trust a painted (or clear coated) carbon part to be safe from UV and last longer than aluminum or steel. Best guess due to sweat dripping on the frame and other parts I’ve seen a lot of corrosion of both steel and aluminum bike parts.
My carbon frame is a Giant CADEX. Cast aluminium nodes with carbon and Kevlar tubes bonded on with, let’s hope, epoxy. It was cutting edge when it was new, but pretty old once I got hold of it. It’s got Pace carbon forks on it, again straight tubes but with magnesium cast nodes. The pace forks are known to have catastrophic failures of the carbon.
A new carbon bike will outlast me, I’m sure, but this is a bunch of failures waiting to happen. Pretty though, so it hangs on my wall.
All those metal/carbon joints definately make for more potential failure points. It’s amazing how things have changed with carbon frames. I’d never want to have a catastrophic fork failure!
Polishing aluminum puts it at risk.
The skinning process protects the metal.
Type matters.
I have a airstream made before they downgraded the grade used in the skin.
That was in the 70s.
No sign of corrosion on the skin.
[unacceptable comment deleted]
I haven’t read this yet (but will greedily absorb every word over tomorrow morning’s coffee) but it brings to mind this guy on Youtube who adds a second, larger gas tank to a REX i3 bumping the combined range to about 300 miles.
EDIT: but now I see this has already been discussed here at Autopian (of course): https://www.theautopian.com/why-bmw-i3-owners-have-been-building-potentially-dangerous-gas-tanks-into-their-front-trunks/
I’m confused because there don’t seem to be any chainsaws involved at all.
LA Synthco. Thought that Michael Boomers name sounded familiar. He used to (hopefully still does) sell hard to find parts for vintage synths. Just looked at his shop and looks like it’s shutting down- no more service and their stock list is shrinking. Ah well hopefully he does well with this new venture.
Cheaper than an LS swap
The range-extended i3s have a motorcycle engine. Hayabusa swap would be more appropriate.
Watched this today, mebbe the same Samsung pack?https://youtu.be/YV4AQSuyF_k?si=YJ86kCEnPOhyATaW
One year warranty. Caveat Emptor.
I’m about due to start looking at battery options for my 241000 mile Camry Hyrbid.
I hope the manufacturer doesn’t have a section of their website devoted to Jewish space lasers that control the weather.
Hopefully instead, this one is an artifact that adds colorless mana to your pool when tapped.
Huh?
I saw 100%jake install a newer i3 battery. He had some good info and points. Sounds like there is a good community around the i3. I’m not sure I would go though that effort but I guess if you had one a long time or got one dirt cheap and feel like trying to program all those modules why not. The battery swap it’s self doesn’t look bad if you have the right setup to put it on a lift and a lift table to get it out.
Or, just buy a used Chevy Bolt and save the grief.
I get that the i3 is all quirky and cool, but for fuxsake, a Chinese battery swap is a big ask to still have less range than virtually any newish EV, (aside from a 500e).
The Bolt doesn’t have a range extender.
At 2.4 gallons capacity, it’s arguable the i3 doesn’t have much of one either.
I think the difference between no range extender and a 2.4 gallon fuel tank is pretty massive. In 99% of use cases, that much gas will get you to the next gas station, and in a pinch you could daisy-chain those short hops together and get to wherever you need to go. Obviously that’s not something you want to do, but the peace of mind knowing you can do it is huge.
And you can hack the tank bigger. Not that big an ask if you’re OK having the batteries swapped.
Bolt doesn’t need one. 259 miles EPA range.
If we’re being honest, the extra mechanical complexity of a gas motor range extender just seems kinda silly. BMW should have engineered it properly to begin with.
I actually test drove an i3 when I was getting more interested in moving to a BEV. It’s a phenomenal car on many levels, with one fatal flaw, not enough range for the North American market, (or most other markets).
BMW missed the mark on the i3. It could have been great.
An old co-worker picked up a used Bolt recently and absolutely loves it. It’s his first EV. There are some amazing deals out there on Bolts right now.
I’ve done 38k miles in two years in my (full BEV 94Ah) i3 that I bought soon after David bought his first i3.
I still utterly adore it but don’t think battery is the biggest issue to it being a forever car. It’s now done 79k miles and I still get 110-130 miles per charge, 145 in perfect weather, which is no worse than the day I bought it.
However it is current at the garage (the superb Munich Legends) getting a new transmission at a cost of £1200. A less expert EV garage initially diagnosed the whine as motor bearings, which isn’t uncommon for high mileage earlier i3s, though upgraded by 2016 when mine was built. Replacing that would’ve been a £6k bill.
Remember that battery packs were even more expensive a few years ago than now. BMW was trying to make cars for a profit.
I always thought the i3 looked like the show-car concept that the Bolt ended up being the production model of, once the interior and things like the taillights under the rear glass were cost-cut and they gave it four normal doors.
One’s a luxury car and one’s an economy car, but if you truly just want an inexpensive EV with good range, the Bolt is a good option.
Agreed. Although the Bolt, at least in 2LT form, isn’t really isn’t missing anything aside from level 2 autonomous driving. Plus, it looks like a friendly little tree frog which is kinda fun when you dust someone at a stop light.
An i3 with a Bolt power train would have been the chef’s kiss. I’m still not sure what BMW was trying to accomplish with the i3. It’s like they designed this cool urban car but lost their damn minds when it came to the propulsion side.
This is related to the article Mercedes published about her Kei car. That one was only made “worthless” through taxation, but otherwise is a perfectly legit vehicle. An i3 might be 100% useful aside from dead batteries, so it makes sense the aftermarket should come up with something to help keep an otherwise perfectly fine vehicle on the road. I would have swapped the battery in my 09 Camry Hybrid when it died, if it didn’t turn out the engine was also drinking oil.
This is going to be the interesting part about BEVs. As battery technology advances, it won’t be too hard to drop way better batteries into an existing EV platform. I’m here for it.
Like dropping an LS into an 80’s square body truck. Similar packaging space to the original small block but massive gains in power and efficiency.
Can you snuggle with Maxxpower?
Swap in a new battery, then strap yourself in and feel the Gs!
At 49kWh capacity, the biggest downside relative to newer EVs is gonna be the 50kW fast charging.
I just got my $4k check from PGE so my 2016 i3 was officially $2k net. I’m barely getting 50 miles of range on highway 101, hoping the battery will completely fail before June of next year and I can get a replacement from BMW.
If not, now I have another option and the car would still cost less than $10k.
You are now in my prayer groups list of people who need divine intervention re: the i3….
If I recall correctly, it doesn’t have to completely fail, it just has to fall below a certain percentage of its original range. There’s a way to use the car’s onboard computer to get a readout, but it’s a little complicated—lots of forums that can tell you how to do it.
Lately the consensus has been that the battery needs to have some kind of failure code to be replaced under warranty, there are reports of people struggling to get a replacement just for being under 70% capacity.
I would wait for the solid-state battery switch.
However, I’m not an automobile writer, and the switch is worth several articles that will write themselves.
What year is this comment from? People have been saying “wait for solid state” since I was in university nearly 20 years ago.
They’re about to be introduced in a Toyota, I believe.
No idea what the real world cost of the SS batteries will be.
Or a Hyundai according to a different article I read. Or an ebike. Or a Honda.
Just wait until mini fusion reactor 🙂
It does seem like solid state is coming soon based on Toyota and some other automakers statements.
Still waiting for my flying car deposit to be refunded.
Isn’t the very real possibility of Bridgestone discontinuing production the i3’s unique tire size the bigger risk to forever car status? Do you really want to keep a car forever if you have to rely on sketchy, low quality knockoffs of highly specialized tires?
I think with wheel spacers and perhaps new wheels, we’ll figure SOMETHING out. But I do want the stock wheels, which is why I’m happy with the 195 55R20s I can easily fit on my i3S.
I thought David already crossed that bridge and bought years of cheap tires.
https://www.theautopian.com/how-my-new-bmw-i3s-fixes-the-i3s-horrible-achilles-heel-saving-me-thousands-on-tires/
Yeah, he’s good on tires till 2058.
Date codes? We don’t need no stinking date codes…(DT)
There are all lot of good quality i3 tires that are not Bridgestone. I use Continental winter tires and Michelin summer tires on my 2017 i3
This almost a no-brainer in my mind. The biggest problem being distrust in the Chinese source. However, I honestly think that should be a thing of the past. Chinese companies are seeing the value in brand equity and realizing such can be more profitable than churning out garbage.
Especially considering how many battery packs are probably coming from there anyway.
Agreed. I’m eventually going to do a rotary swap and I’m considering giving a $500 (no accessories) 13B off Alibaba a try. The company has been making engines for decades, and to me the worst case is it lets me get everything set up for a used 13B and I make a coffee table with the rotor housings, have some garage decorations, and still come out ahead.
Shit. Now I want one too. Alas, I have zero need but if could manufacturer even the flimsiest of excuses, I’d already be tracking shipping.
If you do such a swap, please, please, please let us know how it went. Like let Matt or Mercedes or David know, because if there’s not a story there, I can’t imagine where one would be.
This is going to be several years off, but when I finally do get to it I’ve had several people request I do a video series. I’m definitely no YouTuber, but I’ll probably record it all and post it. I’ve wanted a rear mid-engine rotary for a while I and I want to figure out how to make it work in an Alto, my favorite kei car.
I have a wedding to pay for first. And a future wife to teach how to weld so she can help me with it, because she wants to.
Love it! I like the i3’s and the innovations they have. Had an i8 I was able to pick up “super-cheap” (1/3 of a new lease at that time; original leasee put many security deposits down (he got from me which I got back at turn-in) plus a large down payment he ate) on swap-a-lease back in ’17 and owned for the remaining two years of a 3-year lease. Loved that thing… eco and stealthy for the daily commute, till you put in sport-mode (“Angry mode according to the kids when the dash and piping would go Orange!) and the kids were small enough to fit in back at the time! That was a fun daily driver. Exotic yet “practical” (though the doors were not so in the parking garage at work!)
If you come across a shop wanting to swap in eV powertrains or skateboard-platforms (a Model-S is within an inch wheel-base of my ’49 Mercury Frankenstein!), let me know. It’s already riding on a modified frame from an Olds with parts from Caddy, Ford, Pontiac, Desoto, Chevy, etc. so I’m not concerned about originality, and I saw that Icon one (waaaaay out of my price league these days)… Haven’t found anyone nearby (yet) willing to take on the task. Plenty of “totaled-out” Model S’s out there… 😉
For an idea, check out Boostedboi on YouTube. He’s done a couple Model S skateboard swaps with old Honda Odysseys of all things. Definitely hilarious to see a minivan dust pony cars and running 10’s in the quarter mile.
Looks like freight adds 15% plus you got another 20% with tariffs so closer to $9k delivered. Still cool. I look forward to the day that battery/motor swaps are more commonplace.
Also since AC seems a big concern on these cars a heat pump swap would be cool too.
Has anyone tried Z chips as an AC alternative?
This is another good article.
The only major Achilles heel is post-accident repair. David, please do this upgrade(or an even better one if it becomes available) when the time comes to replace your battery.
My battery will probably last me 20+ years, as I have the 120Ah which many have found to degrade 5% at most after 100K miles and 4 years.
But in 20 years, who knows what’ll be available!
Also, this upgrade is going to TANK my 2021 BMW i3S’s resale value! But if it saves i3s from the crusher, I’ll take it for the team!
In twenty (or thirty) years, you’ll just need a half empty can of beer and a banana peel or two.
Gotta’ get up to 88mph!
Indeed!
This is why I’m not keen to spend money on an EV, the technology is advancing so quickly, I see no reason to replace my current cars until the gains start to plateau.
Out of curiosity, what method are you using to track the various variables (e.g. price, range, etc.) and what criteria are you using to decide when a plateau has been reached?
I’m not that analytical about it, I’ll just wait for a vehicle I like that happens to be an EV and survey the landscape. The fact that completely different battery chemistries are pretty close to production tells me that there is a strong possibility of near-term improvements.
My wife and I both work remotely, so there is no rush to buy a vehicle, certainly not an EV. In fact my wife has only owned one car – a 99 Durango she bought new – and it has over 260,000 miles on the original engine and transmission. We lived in CA so it’s still in great shape. But I expect a catastrophic failure at any time now, and have a short list of vehicles she’s interested in, with price points ranging from $45k-$85k. None of them are EVs, expect the Scout Traveller which we’d get with the range extender, if her Durango somehow makes it to 2027.
If VAG is as bad off financially as they seem to be, I’m wondering if they’ll even be around in 2027, let alone Scout. If we in the US had access to the vast array of EVs manufactured in China, I’d be more confident in new battery chemistries being available in the near term. Obviously, if you have the luxury of time, they’ll show up here eventually.
I will not buy a Chinese EV, regardless of price. That’s one of the few areas I’m pro-tariff. Need to give our industry time to catch up – Germany is learning that lesson hard, as you allude with VW. We’re not counting on the Scout making it to market but have a deposit in, in case it does.
I think we could well end up in a situation like we have for many other goods, where the only country making them is China, because no other country can compete on price. Tariffs may well need to be permanent if we want to keep the auto industry alive here. Though I like low prices as much as anyone, I kind of wish we would have put tariffs in place years ago, when we still manufactured everyday items here.
Giving China the Most Favored Nation trading status was the dumbest thing we’ve ever done. The good news is that China’s population is shrinking, so sooner or later they’re going to have to actually pay people to work.
The aftermarket is what will make EVs. We are still on the bleeding edge here. Lithium Ion is going to go away for good reasons. Hopefully we can be patient and live with reasonably priced used EVs until that day.
I suspect most damage to the frame bad enough to damage the battery pack would essentially total the car. I do understand just pack can get damaged from underneath, but that is not too common an occurrence I’d venture.
So this means a possible 250-270 miles with a REX? That’s pretty great.