# Mercedes SL class roadster conversion.



## lapwing (May 8, 2009)

So I spied the EV conversion list, and not one Mercedes.

I wondered why? Weight, yep luxus => heavier than some. But not as heavy as I thought. http://en.wikipedia.org/wiki/Mercedes-Benz_SL-Class

The sexy Princess Di model R129. 









Pros:


Not uncommon in sub $8 000 range is good condition. 
Curb weight 1900kg (4200 lbs), but potential for lots of weight saving (if AMG can do it maybe I can too)  
Rear wheel drive, for direct motor hookup perhaps with a larger differential reduction ratio. Possibly a 70 mph top speed/max RPM for better off the mark rear wheel torque. Maybe lower mph/ higher differential ratio => less Hp required.
Huge under hood volume once the crap is culled.
A very heavy engine/tranny/muffler combo. 
Every comfort known to man and then some.
Downsides:


Needs about 150KW for reasonable acceleration, at least that's with the original diff and box ratio. 
Very expensive parts.
Completely unknown - EV to gizmo interface.
Weight
Battery storage possibilities may be limited in the rear.

DC 9" Siamese, 2000A Gdzilla controller. 320V (100 cell - 60-100Ah = 20-30KWh pack) 30 mile range?
What ya think?


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## madderscience (Jun 28, 2008)

You've got the right sort of ideas as to what you would need to give the car the performance you want, and 30 miles will be plenty feasible with 20 to 30KwH (100 cells at 60-100AH) of battery on board, even given the heavy chassis. 

The prismatic LiFePO4 batteries have a C rating of about 3 I believe (at least for the thunder skys) so you should not plan on pulling more than 3x the AH rating out of them for any length of time. So that means with a 100AH pack at 300V, you could only get a continuous HP of about 90KW, (300V at 300A) or 120HP or so out of it. That would be ample for a driveable car but maybe not what you want. I believe the thunder skys do have a higher impulse rating (up to 10C, at least the newer ones) so it might be OK putting out more than 90KW for aggressive acceleration, but you should do your homework to avoid a costly design error.

This will be a high budget conversion, but it sounds like you expect that.

If its your first conversion and you don't have decent technical/fabrication/mechanical skills or ready access to those skills, you might try a lower budget conversion first (a lithium powered motorbike, or a simple lead acid conversion of a small car) just to get some ideas of what its going to take, before committing to a much more expensive build.

Good Luck.


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## kwikkiwi (Jul 22, 2009)

lapwing said:


> So I spied the EV conversion list, and not one Mercedes.
> 
> I wondered why? Weight, yep luxus => heavier than some. But not as heavy as I thought. http://en.wikipedia.org/wiki/Mercedes-Benz_SL-Class
> 
> ...


hey lapwing, how did you go with this SL500 conversion idea or yours. I already own one of these, its a 1992 SL500. I have owned it about 7 years so rather than trade it in and get bugger all I think its time to do the conversion. 
Did you do any more research about motor size and batteries etc?
It would be useful before I go commit to the equipment to hear from anyone who has any experience with this model or something similar in weight.


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## lapwing (May 8, 2009)

kwikkiwi said:


> hey lapwing, how did you go with this SL500 conversion idea or yours. I already own one of these, its a 1992 SL500. I have owned it about 7 years so rather than trade it in and get bugger all I think its time to do the conversion.
> Did you do any more research about motor size and batteries etc?
> It would be useful before I go commit to the equipment to hear from anyone who has any experience with this model or something similar in weight.


Nothing attempted so far. To many other projects need attention right now.

Other possibility is Soliton controller and http://www.ev-propulsion.com/controllers-throttles.html with automatic idle for hooking up to the transmission.

Netgain motor http://www.go-ev.com/motors-warp.html#WarP_11

Either way batteries will matter a great deal. Perhaps Headway. http://www.evcomponents.com/ProductDetails.asp?ProductCode=38120P

or Saft VL41m would be good choice if you could find someone to supply them. http://www.houseofbatteries.com/pdf/VL41M


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## DIGGER11 (Mar 16, 2010)

lapwing said:


> Other possibility is Soliton controller and http://www.ev-propulsion.com/controllers-throttles.html with automatic idle for hooking up to the transmission.
> ......


Haven't heard much about the Soliton - is it better than a 1,000A Zilla ?


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## aeroscott (Jan 5, 2008)

Just ran down to LA from Sacramento (411 miles each way ) to pick up a 2002 sl 500 silver arrow (last year of body style ) . This car is my friends , he has a ML , S , CL AMG and now a great SL . So my impressions after a 100 miles or so very solid . 25 - 26 mpg @ 65-75 mph . fast (300 hp ) . I noted a little tail wiggle under heavy power or quick lane changes , this is common in independent rear ends as they age . easy to fix with new rubber bushing . I was also told that replacing the front end rubber bushing makes car feel like new . 10 year or older rubber bushing harden, sag, etc . Got stopped going south on I5 for one hour bad car wreck , life flight , coming back threw LA this AM almost involved in 3 wrecks . blown engine just ahead of SL never saw so much smoke , crazy in a new cube cut me off and then everyone else (supper fast ) , travel trailer merges (almost) into the SL . all in less then 5 minutes . Back in the 70's LA had some of the best drivers , now it's unreal . Back to the SL . I think it would be great and sexy conversion car .


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## aeroscott (Jan 5, 2008)

Went for a ride last night , hard to believe it's 4,000 + lbs. it's so nimble . I'm not a sports car fan or haven't been till now . This is going to be one of the super cars for conversion .


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## kwikkiwi (Jul 22, 2009)

OK, time to start work on this SL500, I have decided to go ahead. I will do the right thing and start a web site posting all the images etc.

I know all the guys in New Zealand that build EV's and also part of Enatel/ Enasolar team, so if I can talk them in to assisting with design etc; it should be a very cool conversion.

Just have to decide now on the motor and batteries but as these tend evolve quite fast I shall try to design so that I can easily upgrade and change with as the new products become available. I suggest this will mean some sort of modular approach to the installation. Less welding and more bolts and brackets.

I look forward to any suggestions and of course you comments as I proceed.

 Alan


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## Bowser330 (Jun 15, 2008)

What do you think about this setup?

Motor = Warp 11 HV ~3500$
Controller = Evnetics Soliton-1 or Netgain Warpcore ~2500
Batteries = Lithium...100 Calb Sky Energy 100AH cells...

320V 100AH = 32kwh (100 mile range @ 320wh/mile)
1200A peak burst (@ 270V sagged and 1000A = 270kw = 362hp)
683lbs
$13,750


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## aeroscott (Jan 5, 2008)

My buddy has a 2002 silver edition about 300 hp. goes like hell , super fun to drive , smooth . just that much better as a EV .


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## Duncan (Dec 8, 2008)

Hi KwikKiwi,

I like the SL conversion - my wife has an old (98) 230SLK - its a nice car - if the motor blows up I may do something like that myself

_I know all the guys in New Zealand that build EV's_

A bit of a bold statement there! 
There are a lot of us hiding in odd places throughout the country

It could be useful to produce a list - I think I'm the only one in Gore, 
I heard about somebody in Invercargill - but I don't have any contact details, then there are all of you northern types


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## Merc450SL (Feb 22, 2021)

I would love to know how your car turned out. I have a 1980 450SL that I am entertaining converting to an EV. I am not set up to properly do it and don't really have the cash right now. But I am getting more serious each day.



kwikkiwi said:


> OK, time to start work on this SL500, I have decided to go ahead. I will do the right thing and start a web site posting all the images etc.
> 
> I know all the guys in New Zealand that build EV's and also part of Enatel/ Enasolar team, so if I can talk them in to assisting with design etc; it should be a very cool conversion.
> 
> ...


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## Cwby Trzn (11 mo ago)

Hey they say great minds think alike, so I had to join this thread I'd like to know whats been going down. Has anybody seen the Ford Electric Crate Engine? I want to convert an SL myself but don't even know where to begin, so im glad I came across this, hopefully somebody checks this once in a blue.


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## brian_ (Feb 7, 2017)

Cwby Trzn said:


> Has anybody seen the Ford Electric Crate Engine?


The product from Ford Performance is the *Eluminator* - search this forum for that name and you'll find a few discussions of it.


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## remy_martian (Feb 4, 2019)

You'll need to go through many threads here to gain the knowledge and approaches needed to do a conversion.

IMO, the Eluminator is all hype right now from a company still reeling from transitioning to overhead valve V-8's. No inverter, no controller, buy an entire Mach-E GT Performance and slide it all over, including undocumented pinouts and harnesses.

The problems appear to be so systemic, rumors are that CEO Farley is considering creating a separate EV company.


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## Cwby Trzn (11 mo ago)

The problems appear to be so systemic, rumors are that CEO Farley is considering creating a separate EV company.
[/QUOTE]

Thank you for all the info! What car do you have? I've been pivoting more towards an E500, is that something you've heard about, or any interest in Mercedes conversions?


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## Cwby Trzn (11 mo ago)

This is the most lit thread on this whole website, Y'all need to come back with some updates friends


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## remy_martian (Feb 4, 2019)

You need to make it interesting enough to be "lit". Cheerleading does nothing.

Most of the content and approaches talked about here in this thread 10 years ago aren't "mainstream" anymore, though a few people still use such motors and controls.

Which is why it's a dead thread. 

I suggest you read through a lot of build threads here on this forum to get an idea how people are doing things. Learn, learn some more, and then, as you continue learning and have accumulated a pile of cash and the passion to get it done, start a conversion. $5/gallon or $12/gallon (coming, imo) is not a reason to do a conversion...you can buy an EV these days for the same or less money and zero time spent. But you can't buy an electric 450SL or 500SL.


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## Cwby Trzn (11 mo ago)

Hahaha, I love that you put lit in quotations. 

This is actually going to be my first car, I sell real estate in NYC. been blowing my bank account on ubers too my showings. I was going to get a normal sports car but showing houses and offices in a Toyota covered in sponsor stickers wouldn't be as professional as id like to seem lol. 

So I was looking at getting something that's the same price as my down payment 15k. When I saw sl500/600 for under 4k I started doing some math and it seemed a restomod might be worth doing.

Like I said before this is my first car; nobody in my family drives at all, so you guys are the closest thing to family I have right now.

I've been looking at places like EVwest, Icon and Electrified garage. do you have any other places you know that specialize in conversions, cus it seems nobody has done the 500SL yet, or possibly my research skills are under par. 

And answer the question lol what car do you drive is it ev? did you convert it yourself?


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## Cwby Trzn (11 mo ago)

Also thank you for reaching back out to me it would've been very easy to just ignore me so thank you agin 




remy_martian said:


> You need to make it interesting enough to be "lit". Cheerleading does nothing.
> 
> Most of the content and approaches talked about here in this thread 10 years ago aren't "mainstream" anymore, though a few people still use such motors and controls.
> 
> ...


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## floydr (Jun 21, 2021)

Cwby Trzn said:


> This is actually going to be my first car, I sell real estate in NYC


For a first car you need something reliable IMO. Not a project. Buy a new or late model used car. Then start on the project Mercedes SL.
Later floyd


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## Cwby Trzn (11 mo ago)

I heard EVs are very reliable


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## remy_martian (Feb 4, 2019)

I suspect will spend as much or more at Icon on your SL conversion as you would buying a Model S Plaid...

But, few if any have an electric SL.


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## Cwby Trzn (11 mo ago)

NO WAY!? Ive been trying to do the math in mead but I always been bad at math, if my calculations were correct I thought no more than 20k


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## Cwby Trzn (11 mo ago)

My head* -__-


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## remy_martian (Feb 4, 2019)

Sell a lot of houses.


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## Cwby Trzn (11 mo ago)

For my Village! lol
What car do you have, is it an ev, did you convert it?


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## Cwby Trzn (11 mo ago)

Once I stack some more money, I'll be back and update everybody ya'll be the first to know


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## remy_martian (Feb 4, 2019)

You need lotsa fat stacks to do an SL right.


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## Cwby Trzn (11 mo ago)

Yeah? Put me one, what should I buy?


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