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Is the W123 a good candidate for electric vehicle (EV) conversion?

24K views 35 replies 20 participants last post by  squibby 
#1 ·
Hi All,

I love the design and build quality of the W123 (and W124), and was thinking a MB wagon would be a nice vehicle to pursue as petrol to electric vehicle (EV) conversion. A classic style with modern power plant.

I am exploring cars that would be a good EV conversion for use as an around-town vehicle for errands and as a general utility vehicle. Something more safe and classic than a pick up truck.

Is the W123 one of the most trouble free wagon minus the engine? Thanks.

Richard
 
#5 ·
Hi All,

Thanks for all your feedback so far. I am just considering some chassis options. Perhaps a W123 is not a good choice for many reasons especially the cost of some cars and weight. It sure would be fun to have sleeper EV W123 that could out accelerate most modern cars if desired. ;)

The project I am exploring has a few goals:
1] Learn about how to convert a petrol vehicle to EV vehicle
2] Use the vehicle for around-town errands and local trips -- short range use (<100 miles)
3] Convert a "classic car" to EV for fun and educational purposes (I personally have no interest in owning a modern EV: Tesla, Leaf, i3, etc.)

Some examples of petrol conversions:
2002 SL500 Mercedes Benz “EV Benz
EV VW conversions
EV West conversion kits and components
 
#6 ·
I'd suggest building a hobby EV from scrap yard parts and get that working, then decide what car you want and how to convert it.

I have pondered the idea of making my 300D a hybrid, using the electric motors to drive the front wheels at low speeds, or to aid acceleration or reduce slipping in the mud. Full electric is a bad idea IMHO.

But this is the guy who wants to convert his W123 to a 4Matic...
 
#7 ·
In the US the power grid is about 30% efficient. If you're burning 1 kW the power company is generating 3kW just to get it to you.

That makes electric cars an illusion of efficiency. Hybrids - where a small engine runs a generator, charges a battery and braking energy is recovered - is the most efficient systems. But these cars are complex systems with all elements from drivetrain to aerodynamics designed for efficiency.

Probably be more to efficient to turn cut out the floorboards and push with your feet.
 
#8 ·
The real power of the hybrid is that it uses no energy when standing still, and that it can recuperate energy during downhills and braking. Even a very efficient diesel has an efficiency of exactly 0% when idling.

I am fascinated by the high price of hybrid vehicles, since the electric machines and their control circuits aren't that expensive.

A series hybrid, where the internal combustion engine serves solely as a generator, is the least efficient hybrid, since the inefficiencies of the subsystems are compounded. A parallel hybrid, where the internal combustion engine can provide mechanical drive, while using the remainder of its excess power to charge the batteries, or be shut off to let the electrics do their thing, is the most efficient. Electric motors run efficiently at light loads and low currents, where the internal combustion engine is the least efficient; electric motors run very inefficiently at high loads, when the current is big and heat generation is at its most - exactly the kind of conditions where the internal combustion engine is at its most efficient.

But there is still the issue of the mass.
 
#9 ·
Even a very efficient diesel has an efficiency of exactly 0% when idling.
Completely wrong.

At idle its still generating heat/ac to control cabin climate, electricity to power lights, hydraulic pressure to move the steering wheel if suddenly needed, hydraulic pressure to keep the transmission in gear and vacuum to boost the brakes that hold the vehicle still.
 
#10 · (Edited)
The W123 is a perfect vehicle for EV conversion. Just make sure to remove the seats, carpets, panelling, engine, doors, glass, hood etc. make sure you don't weigh more than 90lbs wet, and you are good to go. :D

Actually I suppose it depends on the range and space you have. We used electric motors on milk floats, and they were good at hauling large amounts of weight around town, but they had a very low top speed, and about a 30 mile range. You would need a big motor to haul a benz around, they are heavy sons of guns, heavier than some small pickups, but the right motor could make them a nice torquey, urban ride with a low top speed, and probably limited range, even given the increase in power from modern cells, unless you fill the back up with power cells.
 
#11 ·
The W123 is a perfect vehicle for EV conversion. Just make sure to remove the seats, carpets, panelling, engine, doors, glass, hood etc. make sure you don't weigh more than 90lbs wet, and you are good to go. :D
Yeah, the W123 is a tank. :) I love the design and ride of the W123. I miss my old 1980 300D.

With that said, I picked up a 1989 BMW 325i this past summer that has been a lot of fun to drive. It's so much fun as a petrol powered car that I wouldn't want to change it to an EV, but it does make me think about picking up another one for $1k-$2k for an EV conversion. The E30 is tough and durable little car!
 
#15 ·
Here go buy this! portland.craigslist.org/wsc/cto/5878494735.html
No financial interests in above link.
The 300 TD (E4 82 Mercedes 300D Turbo 123 Station Wagon-NO Rust, Straight,Sunroof - $950) looks like a good deal, especially with the extra turbo diesel engine. I am not ready to purchase anything yet, but it's nice to see there are some serviceable 300 TDs around. :) Thanks for sharing.
 
#16 ·
Ultimately if you were going to build an electric vehicle you wouldn't start with any petrol/diesel vehicle. That said, if your needs fit what's possible then any vehicle can be made to work so why not have the vehicle you want and make it electric?

Pluses of the W123 - without the fuel tank the boot is massive. The engine bay is massive too. So plenty of space for batteries. Electric motors are tiny compared to combustion engines, its the battery weight, cost and volume that is the big challenge. Then it's

I think, if your arms are up to it, you can get a non-power steering rack. Do you need heating and/or air con? Much easier if you don't need them. I know electric power steering exists, don't know much about air con/heating but suspect the latter be a big drain on the battery.

Then, is it about being purely electric or being efficient? Ie you could put in something like a 220CDi engine and have good economy and power.

If your vehicle isn't going over 50mph you could strip out the sound deadening. If you have the ability and money, you could start making replacement doors/boot/boonet out of carbon fibre and on and on.

Or hybrid, best of both worlds but I'm not sure what would fit/where you would source the drivetrain.

I'm 'electricing' a Vespa (LML/Stella). Makes no sense at all, a new scooter either petrol or electric would be cheaper, would handle better and wouldn't take probably hundreds of hours of my time but sometimes illogical stubbornness is the way to go.
 
#18 · (Edited)
As I mentioned in my earlier post...

The project I am exploring has a few goals:
1] Learn about how to convert a petrol vehicle to EV vehicle
2] Use the vehicle for around-town errands and local trips -- short range use (<100 miles)
3] Convert a "classic car" to EV for fun and educational purposes (I personally have no interest in owning a modern EV: Tesla, Leaf, i3, etc.)
This is an exercise to explore how to take a classic car (arguably one loved by many enthusiasts) and transform it into an electric vehicle for fun and educational purposes. It's not about what makes the most sense measured by any number of criteria, including the ones you listed above. :) I have a variety of other non-electric vehicles that fulfill other purposes from speed to fuel economy. :D Thanks for your thoughts!
 
#19 ·
I have been thinking about this a lot lately. I have a lot of time and money into restoration of my turbo coupe. Will I be able to drive it with a 617 20 years from now? Will taxes, fuel scarcity or some other regulation like inner city diesel restrictions in the UK and EU make it difficult? What will a nearly perfect W123 body and interior be worth if it's still carrying around an ICE?

I wish I had finished this project 10 years ago.

I have a feeling the day will come that I will be buying an off the shelf kit for W123 conversion to electric. That day is not today, or even in the near future. But it will come. These cars are just too cool and there are just too many on the road, and too many enthusiasts supporting them to let them die. EV modification parts will become easier to source, cheaper and easier for a DIY guy to install. In the next few decades battery density will improve to the point where even heavier cars like ours can be retrofitted for practical use at a practical price.

I'm not really looking forward to driving a W123 that sounds and feels like a golf car. Plus the 5 speed would likely come out for reasons of weight, simplicity and higher available torque. The tactile and audible features of these Mercs and a need to actively engage in driving them are major reasons I like the experience. I have other cars for just sitting in and pointing in a direction.

Anyway, these issues have been on my mind as I work on my project.

FB
 
#21 ·
I've thought the same things before. It's hard to predict. I'm just going to guess internal combustion never fully dies in our lifetime. Perhaps only a tiny percentage of cars on the road will be internal combustion but I find it hard to imagine it'll be completely phased out. The prices of fuel should, in theory, not be that expensive based on supply and demand but the tax issue arises. Worst case we make our own fuel I guess, even though I'm not really about that personally.

Overall though, I bet in the USA at least we will be fine, similar to how old model T's are still legal to drive. Who knows though. I've definitely thought about it a lot though just as you have.
 
#20 ·
I will add that I suspect W123s, 107s, first gen 126, early 124, and probably 201s will probably be the newest models for relatively easy conversion before body electronics make things tricky.

FBi
 
#22 ·
I will add that I suspect W123s, 107s, first gen 126, early 124, and probably 201s will probably be the newest models for relatively easy conversion before body electronics make things tricky.
In computers, we've gotten enough capability and enough people who wanted older systems that we just emulate them. Really, really well.

I suspect, given time and enough people who care, the EV replacements will come with a new ECU that makes the rest of the car think the ICE is still in there and working properly. The emulation will cheerfully pretend to be the engine and send correct, fake data to the other systems to keep the car working.

The hot rod guys are already reprogramming ECUs to make some of the body equipment not needed so that engines can be put in other cars; this is just that, but the other way around.

But it'll be harder, and a bigger hurdle than the simpler cars that weren't computerized and just relatively simple electronics or purely mechanical.
 
#23 ·
Sooner or later we’ll be seeing Goldie Wilson car conversions to electric. He was a little ahead of his time back in 2015, but we’re catching up.

FB
 
#24 ·
Hi Guys,

Interesting topic. This is perhaps one of the most divisive topics, some hate it, some love it, and others ignore it.

Just this morning Jaguar announced it will not make any ICE cars. So perhaps the writing is on the wall.

I am interested. But I want to sell my Dad’s W123 280CE first to fund the project.

If anyone does move ahead, please keep the bloke from the Aussie Bush in the loop.

Dan
Orange AU
 
#25 ·
And now this. I haven’t watched the series yet but the gentleman seems to have installed a Tesla motor, Bolt batteries and other equipment in a C123.

FB
 
#26 ·
Hi FratBoy…way to go – perhaps.

Yes, it does seem a cool conversion. Not that I know, but in watching a lot of car videos, it appears that very few 280CE W123 went to Continental America. My W123 (from my Dad) with the 2.8 litre engine is sluggish, I can only image the smaller engines would be like. Especially as these cars are about 1,625Kg.

In your wold Tesla parts are cheap and easy to find – the Model 3 poverty pack starts about AUD67,000….and the model S is way over 100K.

My thinking is bolt say a Hyper 9 AC motor with the appropriate gear reduction to the diff of the car. Keeping the Benz suspension. This arrangement has been done in the UK with a Fiat… OK no FIAT jokes – I like them.

Dan
Orange Au.
 
#27 ·
I’m only three videos into the series so far, but yeah, that’s a lot of work to put that Tesla motor where the rear diff used to be. Dang.

Seems a form factor with the motor in the trans tunnel would be more ideal, but I’m talking out of turn here. I really don’t know why he didn’t go that route in the first place, but I bet there’s a reason. His narration is very informative and be obviously didn’t hack this together quickly. A lot of thought went into it.

FB
 
#28 ·
Just finished the series. Holy moly is that car fast. He doesn’t get into range or charge time. The camera work is hand held, but it sure looks and sounds like a factory EV.

FB
 
#29 ·
I agree a nice series of videos. Just enough information and no overload. It was engaging and certainly a good idea for a diesel.

Unfortunately, Tesla’s are expensive down under and the Chevy Bolt/Volt almost non-existant. I have read that people use Nissan Leaf parts.

Dan
Orange Au.
 
#30 ·
I've heard people talk about doing this for a while, but I haven't heard of anyone actually doing it. As someone strongly opposed to the use of fossil fuels, I have had dreams of cramming an EV transaxle into the rear end of one of my cars - in fact, I even did up a few CAD drawings detailing the mounting of an industrial three-phase motor into the transmission tunnel of my "spare" W126, something I still may do. This seems to be a relatively controversial topic for many, but I think it's a great idea for those who are able (and willing) to put in the time and money.
 
#32 ·
Hi All,

I love the design and build quality of the W123 (and W124), and was thinking a MB wagon would be a nice vehicle to pursue as petrol to electric vehicle (EV) conversion. A classic style with modern power plant.

I am exploring cars that would be a good EV conversion for use as an around-town vehicle for errands and as a general utility vehicle. Something more safe and classic than a pick up truck.

Is the W123 one of the most trouble free wagon minus the engine? Thanks.

Richard
Hi, Richard!
I’m also interested in w123 EV conversion. We’re you successful in your project? Would be very interesting to know.
Regards,
Emin
 
#33 ·
Hi All,

I love the design and build quality of the W123 (and W124), and was thinking a MB wagon would be a nice vehicle to pursue as petrol to electric vehicle (EV) conversion. A classic style with modern power plant.

I am exploring cars that would be a good EV conversion for use as an around-town vehicle for errands and as a general utility vehicle. Something more safe and classic than a pick up truck.

Is the W123 one of the most trouble free wagon minus the engine? Thanks.

Richard
Nice thought of converting ev though but i have another idea ,in w123 or w126 diesel or petrol install electronic power steering , electric vaccum pump for diesels , electric compressor , electric radiator fan , electric water body , wheel hubs with fixed bearing could save alot power and gives good fuel average too...what you say guys comment ...lets reborn the legends w123 and w126 ...
 
#34 ·
Considering EV motors have a shed load of torque and all gas cars days are numbered both for parts availability and fuel. An EV conversion may be the only option long term.

I'd say with such a large hood and trunk area it wouldn't be too hard to find room for the motor and batteries.

There may be loads of W123s in the US, South Africa etc but here in the UK they are very rare and hard to keep running with expensive, hard to get parts and few technicians who work on kjet.
 
#35 ·
A hyper9 HV at 219Nm has more torque than the venerable OM617 and with 88kw of power has more getty up and go.

14 Tesla S cells @ 25Kg each can be distributed up front and in the rear to give you the juice to get you around and not disturb the suspension dynamics. Yes, the car is heavy, that's why I suggest 14 instead of 7, but you will get good range.

Look at Luis post about the rattling and other maintenance of his engine to see how we are having to molly coddle them through their senior years. Next engine replacement I do it electric as there is next to nix in ongoing under the hood maintenance. Still up to my elbows converting my Triumph Stag.
 
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