I’d love a car with a tiny battery for 99% of the time when I’m just driving locally and the ability to have an extra, large battery that can be slotted in when I want to make a longer trip. With only the short range battery most of the time, my car’s weight is low and efficiency high.

Maybe I could keep that battery in my house and use it to store solar electricity most of the time. It seems like it should be possible to design a system for slotting it in that doesn’t require me to physically lift its weight.

I’d also be happy to drive into somewhere local that rents me that long range battery and slots it in with machinery designed for the purpose.

I don't know if any company is exploring what you are mentioning, but battery swapping for electrical scooters (Gogoro) is in common use in Taiwan. Instead of you charge your scooter, you drive to a battery swap station and exchange your empty battery for a full one. see [1].

But some companies are also investigating battery swap stations for cars. So, you might not be able to swap a short-range battery with a long-range battery yourself, but I imagine that would be possible with those battery swap stations. See [2]. Battery swap stations means that you have full range again for the same time it takes to fill a car with gas. But obviously, you need to have enough of those stations to make it usable. And if every car brand is gonna create its own mechanism for battery swapping, then that would probably only be interesting in city areas where it's worthwhile for the manufacturer to run those stations.

[1] https://www.electrive.com/2022/01/18/battery-swapping-statio... [2] https://www.bbc.com/news/business-61310513

Edit: typo.

We've been doing this in the Philippines since 2013!

https://www.youtube.com/watch?v=f9aEWxexrMI

Just started raising VC this year lol

I love the idea of using those extra cells for solar or perhaps renting them.

I can't see why no one is exploring this gap in the market. It might only appeal to nerds at first but that is true with most technologies in their infancy.

We need what is effectively a giant version of a double AA battery. Yes we also need battery management systems and heating/cooling to go with these things but these are solved problems, just not standardised yet.

Please someone take note and do this!

> With only the short range battery most of the time, my car’s weight is low and efficiency high.

That would however subject the smaller battery to more charge/discharge cycles for obtaining the same mileage. Wouldn't that shorten its life?

I’d be happy to have a shorter life on my small, cheap battery because it should be cheap to replace.

>I’d love a car with a tiny battery for 99% of the time when I’m just driving locally

That's basically what an electric cargo bike is, functionally.

>I’d also be happy to drive into somewhere local that rents me that long range battery and slots it in with machinery designed for the purpose.

Rent the whole car...

>my car’s weight is low and efficiency high.

...and you don't have the weight the rest of the time.

> Maybe I could keep that battery in my house and use it to store solar electricity most of the time.

That's utopian. These things weigh a ton, you'd need a forklift.

Sure, but there are jacks that can be purchased for home use that can easily lift a ton or two. If this was a thing, the battery would have to self-lift itself into place, or have home-installed battery swap station.

...say like a battery trailer with a CCS socket, and with extra storage as well, for long journeys?

Low tech FTW.

Smartrail is still a better soln but we have to be realistic here.

I have heard of proof of concept camping trailers that not only have batteries but also motors in the wheels so the can provide extra power when you drive (restoring the range you loose when towing) and also regen braking. Not low tech, but would be really useful https://www.greencarreports.com/news/1133124_towing-with-an-...

Will any electric car let you drive while it's plugged in?

I'm pretty sure Tesla's Rivians get locked into park when the charger is connected.

I think you're correct, my Fiat certainly doesn't. That is, however a firmware update away provided the type2 or CCS protocol can distinguish between a mobile or static charger, or be extended to do so. My OP was a slightly off the cuff post to highlight the use of a trailer for say cheap city cars, rather than a removable battery.

> Will any electric car let you drive while it's plugged in?

That’s what I was wondering too. Like you, I’m pretty sure the major EVs don’t let you drive while charge, but I haven’t actually tried it.

No, even my PHEV doesn't let you drive while plugged in.

Or you just rent the battery for the trip. Sort of like propane tank exchanges. Drive to the station add a 600 mile battery, drive somewhere, swap or charge it and drive back. Most people would only need 40/50 miles of range 90% of the time. And that range could charge very rapidly as well.

Look into the XBUS by Electric Brands. It is a light vehicle (because they are a less stringently regulated market in Europe).

Modern EV design has the batteries integrated into the structural frame of the car. This is because the batteries are the heaviest part of the car, so you want them to be close to the ground and secure from impact. This also makes it very inconvenient to replace.

Lots of companies (even Tesla) have attempted the replaceable battery concept but none have been able to make it work efficiently.

NIO is doing battery swapping at scale in China. Here's a random article about how it works: https://insideevs.com/news/591837/nio-battery-swapping-stati...

Tesla was never serious about replaceable batteries. They could get more tradeable credits for replaceable batteries, so they told everyone they’ll do that, got the credits for the cars that were supposed to have replaceable batteries, and never followed up with the actual tech.

That's FUD as far as I'm concerned. If they were just aiming for regulatory credits it weighs have been far cheaper to use human labor to do the swaps than to develop the robotic apparatus they developed.

Tesla did a decent market test on batteries, the test failed and they moved on.

The "market test" was a shack across the street from a 100% free Tesla Supercharger station. To use said shack, you had to be one of a select group invited, make an appointment days in advance, pay a fee, and risk that you're trading your $20K battery for a worse one out of someone else's car. They invited a couple owners and journalists to do a few swaps for the magazines, collected their extra ZEV credits, and then disconnected the phone and let the one person staffing the place go back to his normal job. If that looks like an honest market test to you, then I don't know what else to say.

I did recall Tesla wasn’t serious about battery swapping but can’t find any information about getting credits for doing that, let alone just announcing it. Can you back that up?

The statement is worded critical of Tesla, but IIRC there's some truth to it. They engineered the Model S to be battery-swappable, and there was some advantage wrt. the regulatory credits to doing so. Can't find a link, but I remember reading it.

They rolled out this service to a couple of spots in California, which was probably sufficient for the the credit regime, but ended up not expanding the program further and terminating it after a few quarters. The official explanation was that it was not widely used.

https://youtu.be/H5V0vL3nnHY?t=57

There may have been other business reasons. I have no idea what was discussed on the executive level but wouldn't be surprised if they considered some tradeoffs of complexity, costs and customer attractivenes to not be worth it. Honestly, it's very rare that you actually need or strongly prefer to have this kind of service rather than just recharging at 150kW for 15 minutes. So if it adds considerable cost or complexity, I could understand the decision to drop it.

A short time later, they started welding an extra metal shield onto the bottom of the Model S, to act as an extra layer of protection against collisions with highway debris that caused some high-profile battery fires. I had the impression that this precluded battery swap, so at that point the business decision must have been made to not expand the program further.

If the regulatory incentives was key in the decision to do this and then later drop it, that's a fundamental property of incentives to do something that might not be a good idea in isolation.

I am critical of Tesla, as it success was largely due to to public subsidy, and I believe we should hold such enterprises to the highest of standards, to guarantee the public made a sound investment. But I digress.

A short summary of the extra government subsidy Tesla got out of the non-existing battery swaps is here: https://seekingalpha.com/article/2724835-after-earning-tens-...

We'd only need a compromise here. The concept that failed, afaiu, was batteries you'd swap at the gas station on a trip, which you probably want to take no longer than refilling your good old ICE car took. That seems impractical for several reasons. But if you had a range extension pack that you could add/remove in 30 minutes before a longer trip, maybe that would be more realistic?

Would it not be significantly easier if we're using 4 or 5 independent modules instead of a giant monolith? Aren't cars routinely lifted into the air when being serviced?

I understand that the structure of the car's body may be suboptimal and require extra reinforcement but if we're really serious about EV adoption and reducing battery cost then perhaps a trade-off worth making?

For an EV the main design constraints are aerodynamics and weight. If you need to add additional reinforcement to make up for the battery packs that haven't been installed, you're carrying that weight around all the time and taking a range penalty.

So assume your vehicle has 3 packs. You normally run it with just one pack because that's all you need to commute and run errands during the week. When you go visit the relatives in Florida, you install the other two packs to get the additional range. The car needs additional structural elements to meet safety standards when the extra packs aren't installed and they add 5% additional weight. That's weight you're carrying around every day, and that has a range cost.

Could it be worth it to swap out the extra structure elements when you install the extra packs, so at least you aren't taking the range penalty while driving long distance? Yes, but the manufacturer isn't going to want the liability of a customer removing what is a passive safety device, and then forgetting to reinstall it when they go back to city travel using only one pack.

NHTSA will also have input to this. From what I can tell - the applicable FMVSS is this one that deals with EV side impact protection, electrolyte spills, and electric shock.

https://www.nhtsa.gov/document/final-rule-occupant-protectio...

If you want the batteries to be removable, I suspect the extra couplings in the water coolant loop would make that problematic.

Check out how tractor hydraulic attachments handle liquid couplings. And hydraulic systems work at much higher pressure than simple coolant loops.

All the more reason to ditch the 5000lb car and go for like a 50lb emoped instead.

> I'm not sure why we aren't making EVs with small but upgradeable batteries.

NIO is:

https://insideevs.com/news/591837/nio-battery-swapping-stati...

https://insideevs.com/news/392660/nio-battery-swap-loved-by-...

https://insideevs.com/news/583809/nio-baas-battery-swapping-...

https://insideevs.com/news/596640/nio-500kw-ultra-rapid-char...

> Like for example a $20k car with a 10kWh "good enough for now" starter battery

10 kWh wouldn't get you very far in a car. In a scooter or quadracycle 10 kWh can be useful.

Thanks.

> 10 kWh wouldn't get you very far in a car.

Tell that to Chevy Volt owners. It's amazing how much all electric driving can be achieved with just a little bit of careful driving. I barely use my range extender now, it's just for the odd long trip.

I think we should start thinking in battery cargo trailers. When do you want extra range and battery? When you're going on holiday. What do you want apart from extra range when you're going on holiday? Extra storage space!

So why not just start selling battery cargo trailers which can provide your main car with extended range when needed?

It's also much easier to swap and rent out physically, financially and emotionally than your main car.

Most drivers can't handle trailers. The roads would be so much more dangerous if trailers were commonplace.

Trailer hookups can be legitimately difficult. Even in the simplest case, they can be time-consuming.

Humans are notoriously bad at backing up with a trailer attached.

Heavy trailers (batteries) are extra dangerous -- tail-wagging can be scary!

Cars with trailers don't fit in parking spaces.

...

A replaceable battery has to be in the underpan of a car. Or split across several battery modules, but keeping the center of gravity low, and between the axles.

This makes a lot of sense, except that driving with a trailer isn't very enjoyable. I bet the aerodynamics would suffer too

I would prefer to see this because the current ability to replace batteries in EVs is crap.

I’ve owned enough second hand laptops to know what second hand EV ownership is going to feel like.

Laptop batteries and EV batteries have a completely different performance profile. The data we have suggests that the battery will retain 80% of its maximum capacity for about as long as the rest of the car is expected to survive.

You miss the point.

Most people don’t buy new cars. Most people buy second hand vehicles. They now risk degraded batteries and a huge incidental cost.

My car cost me £5000 second hand. The cheapest EV battery replacement here is £12,500. I could write that car off twice for the price of a battery and still have enough money to go on holiday.

When you buy the bottom end of the second hand EV market which is realistically what most people will have to spend on, you’re looking at the 160 mile range leaf. With an 80% battery that’s 128 miles of range. Which is near useless for the average user. I couldn’t even drive to see my mother in it without charging twice on the way.

I will not own an EV as the incidental risk trade off is too high and the up front cost of a new EV is too high.

My EV is 1/10th of the cost to run and maintain than my diesel car. I’m more than happy to spend an extra 20-30 min charging on a 4 hour drive when I choose to drive the EV.

My diesel has also done just over 340,000km and it’s pretty shot. Hard to start on cold mornings and I’ve had to sort out some leaky injectors and seized joints on the driveshaft. There’s another couple of hundred thousand kilometres left at best.

The EV is coming up to 100,000km and it stills drives just as spritely as the day I got it. The battery is showing 100% state of health and I’m convinced it’ll happily do a million kilometres or more.

Replacing major components of an internal combustion vehicle will frequently cost more than the car is worth.

That's usually the cause of scrapping a vehicle in places where structural rust didn't get it first.

What would it cost to replace the engine or gearbox of your car?

They do below a certain point yes. But at that point you just buy another one and drive it until the engine falls out. This is how most people operate.

On my vehicle an engine costs about £1275 to put a refurb in it. Gearbox about £550.

There is no rust anywhere on my 8 year old vehicle.

People run like this out of financial necessity. They don’t have enough income to run an EV.

So batteries on EVs generally don't fail dramatically, they slowly lose range over time.

So someone buying a used EV will presumably buy something with enough range for them to get around, and then over time if they notice the range starting to decline to the point that it might be an issue, they'll have some time to save up & trade in their car for a better one. Their current car won't be worthless on the used market and someone who doesn't have as large of range requirements (e.g. a 2nd car for commuting) will still buy it.

There are other issues that can prevent an EV from charging at all, but they have usually cheaper fixes than a whole battery pack replacement like you're talking about.

May be UK is especially cheap for car repair but costs you mention are unrealistic for major repairs on those components. I had gearbox problems on 10 year old car and independent mechanic suggested to sell car to scrap yard - in his opinion trying to fix it will end up costing more than car is worth. It was before Covid inflated used car prices though.

From quick check in google: If you are extremely lucky, you’ll get your transmission replacement completed for $2,500 all in. If yours is one of the more expensive types, it could easily range to $6,000 or even more.

EVs aren't for everyone, especially if you have long range requirements. My daily work commute is under 6 miles round trip.

That said, 20% degradation after 10 years isn't a huge deal for me. I'm sure in that time, battery replace/refurbishment will be much cheaper. There is a company in Oregan that will replace a 40kwh Leaf pack for $7000 .

Just out of curiosity: is a car really the best option for a 6 mile round trip? That's a distance where I'd consider walking.

> Just out of curiosity: is a car really the best option for a 6 mile round trip? That's a distance where I'd consider walking.

Walking!? So 1.5-2hrs each way to get to work? On really hot or cold days, that’s going to be torturous. Had you suggested riding a bike or maybe a scooter/moped I’d have not said anything, but suggesting folks walk that distance felt a bit off the mark.

> 128 miles of range. Which is near useless for the average user

Maybe if that is your only car. As a commuter or grocery car it would be fine.

Why would you want a car that can be used only for those tasks leaving you to seek other forms of transport for leisure and family?

The main positive factor of vehicle ownership is destination and route flexibility and if you trade that away then the advantage is gone.

We have two combustion cars, a Corolla and an Outback. The Corolla gets everyday use, the Outback goes on long trips or if I need to haul some furniture.

An EV to replace the Corolla would be ideal. Perfect spot for this scenario.

The main cost for cheap 2nd hand cars is the fuel in my experience. So you can have a cheap fuel commuter car and a "real" car for trips and towing your boat.

Requires parking for two cars though. But since we are talking about an EV it requires a house anyways since most apartments have no charging.

Yeah but you can manage the fuel within your cash flow. Difficult to get credit and manage the purchase of a large expensive car. And having two cars is too expensive as well.

> And having two cars is too expensive as well.

Maybe so, but the average American family has about 2 cars. Lots of sources for that, but here’s one from top of search results:

https://housegrail.com/how-many-cars-does-the-average-americ...

America is not the world and is not the entire market.

> America is not the world and is not the entire market.

Show me where I said or even implied that? Why must you argue and pick battles with everyone? Maybe time for a break?

True. The setup kinda requires that you need two cars in the first place.

Some families have to 2, 3 or even 4 cars. So it might not be such a bad idea.

> With an 80% battery that’s 128 miles of range

Sounds perfect for the average American as a daily commuter / errands car. Yes, no road trips without inconvenience, but that still doesn’t make it useless, it makes it a great secondary car instead.

> 80% battery that’s 128 miles of range

i know i am not an average user but that's like a month of driving for me.

Most journeys (80%+) are under 15 miles.

> The data we have suggests that the battery will retain 80% of its maximum capacity for about as long as the rest of the car is expected to survive.

How long is the rest of the car expected to survive?

I rarely do long range driving, and my commute was short for years (a couple miles each way) for about a decade before we switched to work from home a couple years before the pandemic, and I'm not interested in travel so my usage is not going to up much when I retire in a few years. I anticipate a need for at most 100k over the rest of my life, which almost certainly will be less than 25 years.

Would a current EV be likely be able to handle that with just reasonable maintenance?

I'm currently driving a 2006 Honda CR-V that I bought new and could probably reasonably keep driving another 10-15 years. That's what I want out of an EV.

Is it mainly because cars are idle/off most of the time, unlike laptops and smartphones, or is there something else at play here?

Big batteries have much more sophisticated battery management systems that are designed to be as kind as possible to the cells. Also they reserve a capacity of 10% on either side, leaving 80% usable capacity available to the user. Li-Ion batteries don't like being fully charged or fully discharged.

Also due to their capacity most EVs are charged at about 0.1C whereas phones (especially with rapid chargers) are charged anywhere between 1C and 3C.

You're commenting on an article about LFP batteries which have an expected lifespan of about 750,000 kilometers.

When they deliver them and have been on the market for 10 years we have data. Until then it’s vapourware.

Chinese manufacturers have been shipping LFP car batteries for several years now.

It's almost as if EV is just an excuse to get the consumer to spend waaay more than is needed, wasting all the energy in production in producing cars that cannot be upgraded, than about about minimising the environmental impact. And that's because it is.

Corporations do not care about the environment, but they do know a good story when they see it. If they can get you to buy the same car multiple times, this is great business for them. If they can lobby governments to encourage the scrapping of old but serviceable cars, eg by fining non-EVs for their emissions, that means you will be forced to buy sooner.

It's all business. Neither corporations nor the governments that service corporations care about either the people or the environment. I wish people would recognise this fact, but corporate-government schooling/science/culture has everyone believing that government is here to help!

Batteries are limited by charge/discharge C rates, which is relative to the size of the pack. Which means not only would your range go down, but so would performance and charge speed.

You can push batteries harder, but they’ll generate more heat and degrade faster (lower cycle life). This ends up counterintuitively in a higher long term cost of ownership.

Good news is C rates are getting better over time.

This idea reminds me of LiGo batteries (https://ebikes.ca/product-info/grin-products/ligo-batteries....).

I think when it comes to the car this idea could be viable but I think the risk is potential change with the weight distribution. You could probably have some weights that are replaced with batteries when you upgrade to keep the weight constant but then you are reducing your range.

10 kWh is less than 40 miles / 60 km. It's good enough for grocery shopping but it would be akin to always running with your fuel light on and with 1/20th of the fueling stations (ok you would charge at nighttime). I wouldn't be comfortable with that unless I am going to pay for it half of an equivalent ICE car.

I've used a PHEV with 40km of range on electric. It was 100% enough for doing daily driving. I would love to see a small town-oriented not shitboxy EV that's cheaper than fiat500/mini-e.

Sure, but it's plugin so there's a backup. The parent didn't mention plugin, and a pure electric with a 10 kWh battery might not even be enough to pick up someone at the airport or to visit a friend in the weekend.

That's like 80lbs of LFP batteries, I really don't see why there isn't some easy way to add this to existing ICE cars.

Retrofitting is a completely different story, I agree.

Have you seen the video of the bike battery swap.

https://youtu.be/yGwmPcClWrE

I wonder if a good solution is a smaller fixed battery for lower cost then "range extenders" like this for the bike you can swap in for longer journeys or a topup on a busy day type thing.

Like these mopeds with one or two swappable batteries https://electrek.co/2021/11/01/gogoro-electric-scooters-swap...

We already have upgradeable ICE engines. How legal is it to swap a more powerful engine from the same model car? Car companies hate that sort of thing because anything that extends the life of a used car directly translates into a lost new car sale

...except that this 'RAM' would weigh hundreds of kilos more and completely and utterly change driving dynamics but yea sure.

Not only that, but the weight of EVs is a huge toll on the infrastructure, esp. in more historic centers

Compare the weight of a Tesla Model 3 SR (most popular version) and a BMW 3 Series (its most comparable model to the Tesla Model 3). Weight difference is negligible.

BMW sold 50,000 3-series in 2021 whereas Tesla sold 900,000+ Model 3/Ys.

Compare the Model 3 to a Camry (300k units), Civic, (260k units), Corolla (250k units), or Accord (200k units), and you'll see the lightest model 3 available weighs more than the heaviest trims of all four, and the 3 is on the lighter side of 250+ mile EVs by a pretty decent margin.

Is the BMW causing just as much road damage as a Model 3? yes.

Does the weight of the average sedan go up substantially as we convert to EV? Absolutely

Profit motive. Planned obsolescence and the need to buy another within a certain time period.