[bdcs]

>Oh, an EREV is fancy way to say "hybrid" ok

Kind of. EREVs are what locomotives have been doing for a century (and to a lesser extent barges), which is called diesel-electric in that field. I agree the terminology is lacking, but EREVs are quite compelling (and their high market share in China supports consumer demand).

Hybrid: * ICE must run during regular operation (except for ~very short distances at ~very slow speeds) -- this increases operational costs (oil changes, economy, engine designed for torque and wide RPM range). * Complex drivetrain with wheels moved by electric motors and ICE, axles, etc. * Generally 10-40 miles of EV range

EREV: * Basically an EV with a short range, and whenever you want to charge the battery on the go (or use the waste heat from the ICE) it can use an efficient (Atkinson cycle) engine to do so. (Though american EREVs have used poorly suited engines for parts availability and enormous towing numbers) * Generally 50-200 miles of EV range * Think "EV for daily commute; ICE for road trips (and heating)"

IMO EREVs would've been a better development path than hybrids or pure EVs.[0] Immediately lower TCO in various interest rate environments via highly-flexible battery sizes, no cold or range anxiety issues, technically simple drive train and BTMS.

[0] I mean the Prius made a lot of technical strides given the battery technology/costs and familiarity the industry had with ICE at time. Tesla went full EV which is a very optimistic approach, and works well enough if you stick around the charging network, but the batteries are still expensive and heavy compared to a small ICE + tank.

[nixonpjoshua]

I agree EREVs make a lot of sense, electric first but not requiring a full commitment, especially for a truck that sometimes has to do things like towing.

https://insideevs.com/news/777407/scout-motors-erev-reservas...

I'm sure this wasn't lost on Ford, 80% of Scout reservations come with the EREV and only 20% BEV.

Maybe one day they will have enough volume in the segment to justify making the pure BEV version again but with parts sharing with the EREV. An advantage to EREV design is that if done smartly you can offer the same vehicle stripped down and BOOM you have a BEV too.

[cogman10]

The problem with EREVs is they are more complex than a BEV. More parts to go wrong, to purchase, and ultimately a (potentially) higher price.

The reason to do EREVs for a manufacture is, IMO, primarily because they can't get a hold of batteries for a cheap enough price. And I think that's the weakness of the way Ford has attacked EVs. They haven't (AFAIK) really built out battery plants. As a result, they are at the whims of their supplier for their battery packs.

For a truck like the F150, that's a large pack requirement that probably ultimately likely killed their margins.

Edit OK, they've been working on a plant for the last 5 years, but it looks like they've done almost nothing. Like, literally just have some support structs up.

[NetMageSCW]

Studies have shown that hybrids are more reliable than ICE vehicles - it turns out that using EV mode of the time and ICE less often increases reliability. No reason an EREV shouldn’t be even better.

[jerlam]

One factory was done, and already producing EV batteries. They're converting it to fixed energy storage:

https://www.wdrb.com/news/business/all-1-600-kentucky-batter...

[Marsymars]

Even if batteries were very cheap, you run into scaling issues where your battery pack ends up very heavy, so then you're using increasingly more energy to lug your heavier battery back around for everything that isn't long-range towing.

[pensatoio]

Are they really much more complicated than a hybrid? Think RAV4 Hybrid. I’d much prefer a fully electric drivetrain with an electric generator to the joyless CVT.

[porphyra]

EREV is different from diesel-electric in that the EREV has a large battery whereas the diesel-electric locomotive does not. But the "ICE engine drives a generator which drives a motor" philosophy is similar in spirit.

[bdcs]

Yes true; good point. I think this is changing (e.g. regen braking for aux. power on passenger trains maybe eventually capacitors for traction drives in the future), but currently and ~almost all the time, this is correct and a good point.

[ehnto]

I think the term of art in the automotive space so far has been "series hybrid". But like you said, the differentiation here may just be the size of the battery. Series hybrids are still predominantly driven by fossil fuels, even if the drive is an EV drivetrain, due to the battery mainly acting as an energy buffer.

The absolute sweet spot, as someone from a country with long long distances, is a plugin series hybrid that has ~150-300km EV range and a ~60 litre fuel tank. That's getting me to work entirely electric, and then once a month when I need to see family I can chew down the fossil fuels.

[hcurtiss]

Yeah, the difference is the Powerboost hybrid electric motor is only like 50 hp. I want 350 hp of electric motor that can be powered by either the battery or an onboard ICE.

[m463]

I wonder about the specs though.

I recall the bmw serial hybrid was called a range extender, because the gas motor couldn't actually put out enough energy to drive the vehicle on the freeway.

So basically it was an EV with a small +xx mile extra range from the gas engine.

so no "ice for road trips", more like "ice for an additional +xx miles" then you need to recharge.

In comparison the chevy volt had a better hybrid design (not a serial hybrid) and you could drive it on gasoline only.

[NetMageSCW]

The i3 was bad, but Ford is planning long range towing with the EREV so it should be fine.

[yalok]

is there any good comparison of Hybrid vs EREV efficiency (when main battery is depleted), even with Atkinson cycle ICE for EREV? my understanding was that the main reason for all this complexity in Hybrids was due direct-to-wheel power transfer efficiency, while in EREV there's efficiency loss when converting ICE output to electric current...

[bdcs]

Looking to the Chinese market is insightful, IMO. There's one platform for a luxury sedan, and it gets ~200mi on EV mode (~100MPGe) and then ~400mi on gas. It works out to about 70mpg purely on gas. I'm not sure how it's so high, but I'm guessing a combination of low drag (Cd), efficient small turbocharged engine (you really only need enough power maintain high speed, not accelerate up to it), and lots of regen braking.

BYD and Geely have similar systems. Their ICE are around 47% thermal efficiency so like ~double what you'd expect in a pure ICE car + regen and other bonuses.

https://carnewschina.com/2025/08/02/im-motors-launches-stell...

[ninkendo]

I guess you’d call my Chrysler Pacifica an “EREV” then.

It’s honestly perfect for us. 32 miles on a charge, we barely touch the gas except for the winter when it’s so cold out we need the engine to warm us up. Any other time and the battery is all we need, and it charges overnight on a simple 110V wall outlet. Long trips are still possible, you just drive. We go through maybe 8 tanks of gas per year with our occasional long trips (compared to having to stop at a charging station for an hour, I’ll take it.)

[rootusrootus]

There have been no EREVs produced and sold yet AFAIK (though maybe BMW had a version of the i3 that did? I'm not sure). Dodge has one in the works. Ford has now announced one. The old Chevy Volt was philosophically wanting to be an EREV but was as a practical matter still a parallel hybrid.

[WorldMaker]

The Volt was only "parallel" when running from gas. It was still serial in that when running from battery it only ran from battery, then switched to gas generating electricity, with some mechanical assisted torque in edge cases (usually only past highway speeds or "mountain climbing").

That was mostly because the electrical conversion from a gas generator is still so relatively inefficient and slow compared to a modern battery. The mechanical efficiency of gas engines is relatively better (which is why ICE has survived as a category for so long). Batteries are far more efficient at delivering high power on demand as needed for torque than a gas generator.

Any EREV is going to have that problem and experience those trade offs. It's a unfortunately defining part of the category. It's also why Chevy has said there's no real future in EREV power trains because they are a worst of both worlds situation with too many unfortunate trade offs to consider, such as needing to be parallel in gas-only operation edge cases to make torque requirements.

[Dylan16807]

That version of the i3 definitely is one. Though the way it limits the gas tank and won't let you control it manually in the US for tax purposes sucks.

[panopticon]

No. The ICE isn't connected to the drivetrain in an EREV; it's only used to provide power to the EV drive system.

The Pacifica is what you'd call a plug-in hybrid (PHEV) because the ICE is still connected to the drivetrain.