# Planning Mercedes Sprinter y.2000+ conversion



## skooler (Mar 26, 2011)

Hi Sprinter,

Why 2 different models/designs?

Do you need 2 separate vans for different purposes?

That weight looks on the heavy side. Maybe 3500kg gross laiden weight. Probably closer to 1500kg empty.

Have you got a set budget or a bottomless pit of cash ready to throw at this!?

It's definitely possible. I think you are looking at about 25000 euros for the longer range.

With the power range stated, the size and weight of the vehicle and your preferred locations to source components. I'd consider the following components.

Kostov 11 alpha motor

Soliton 1 controller

I'm going to take a stab in the dark and say 400-450wh/ mile.

Meaning for 100 km range (62 miles) will need roughly a 35 kwh battery pack ( 10000euro plus)

Hope this helps!

Cheers,

Mike


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## Sprinter (Apr 23, 2012)

> Why 2 different models/designs?
> 
> Do you need 2 separate vans for different purposes?


-Yes, 2 different vans.




> That weight looks on the heavy side. Maybe 3500kg gross laiden weight. Probably closer to 1500kg empty.


- GLW of 3500kg in the Interurban model will always be reached. It is a passenger van, so I want to build the vans with "reserve". It should be 100% reliable, service disruptions won't be tolerated, as I will be the first who inserts EV in the public transportation. I can do calculations, so if you could help me with the formula's (last time I did physics was in high school).




> Have you got a set budget or a bottomless pit of cash ready to throw at this!?


-Well, I thought of hiring some polytechnic professors, to design the controller, dc-dc converter, charger... in such a case I'll do some cost cutting to the non-battery related components, motor not Included. Overall 20k euro's budget per van.




> I'm going to take a stab in the dark and say 400-450wh/ mile.


-Same idea here, does regen help a lot (AC system)? The roads are 50/50% hills.



One last question, seen the budget, what are the most reliable battery distributors or manufacturers?


P.S. Thanks for help Mike!


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## drgrieve (Apr 14, 2011)

My advice would be to tackle one project at a time.

The urban conversion should be easy to do and the lessons learnt from that project would help on the harder conversion of the InterUrban build.

Usually to determine wh/mile or wh/km we base it on a similar vehicle - but not many bus conversion projects on this site!

So you may have to do the calculations your self. Have a look at determining energy usage doing a roll down test (or also called a coast down test).

Basically get the bus up to speed on a flat road (110 kmph) and time how long to takes to get to 0 kmph in 10 kmph intervals. Then repeat in the other direction. From these timings you can work how much energy is lost to aerodynamics and rolling resistance.

In regards to AC unfortunately there isn't an off the shelf product available at resonable price point to DIYer's. For the interurban it wouldn't help much but would be good for brake assist (down hills, regular stops). So the money better spent on more batteries.


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## Sprinter (Apr 23, 2012)

Then I'll start with the Urban Model.

So if I got it right the Test looks like this in coast down and viceversa.
110-100 - *seconds
100-90 - *seconds
90-80 - *seconds
80-70 - *seconds
70-60 - *seconds
60-50 - *seconds
50-40 - *seconds
40-30 - *seconds
30-20 - *seconds
20-10 - *seconds
10-0 - *seconds

What about shifting when going 0 - 100km/h? Is it taken in consideration?


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## skooler (Mar 26, 2011)

Sprinter said:


> -Yes, 2 different vans.
> 
> 
> 
> ...


There's not really any set formulas you need to know the wh/mile. That can be calculated using the drag coefficient, crossectional area, weight and rolling resistance. The best way of calculating it is to see it in the real world!

Once you have the wh/mile you supply simply multiply by the number of miles and then divide by the % dod written as a decimal ( e.g. /0.8)

I'd buy everything off the shelf... That way you get a known reliable product, no safety concerns and you won't need to worry about stuff like EMC testing.

My opinion on ac is that it's an overpriced, underpowered technology and you are better off going for a more powerful dc motor and spend the extra on batteries. You can expect a 10% range increase at best with an AC system

As for batteries. The most suitable cells for this application are normally CALB or Sinopoly. Which country are you based in?

Cheers,

Mike


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## Sprinter (Apr 23, 2012)

Republic of Moldova.

So i come with more numbers. 140km at most during a day. 7 trips by 20km, with 40 minutes break between them. I saw there are chargers capable of 8kwh output. so the battery pack should provide a 100km range.

The question is how much w/km usage... Is it correct to state that if the mass doubles it will use roughly twice as much watts? (guess not).

Any ideas how I can calculate?

Thanks again, Mike.


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## drgrieve (Apr 14, 2011)

http://ecomodder.com/forum/showthread.php/coastdown-test-06-gmc-canyon-20405.html
http://www.diyelectriccar.com/forums/showthread.php/evdl-coast-down-test-determining-watt-12542.html
http://www.instructables.com/id/Measure-the-drag-coefficient-of-your-car/
http://physics.technion.ac.il/~rutman/car/Roll-down test.pdf

Happy reading


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## Sprinter (Apr 23, 2012)

I've read all those threads. The conclusion is you can't (I mean real usage), wright?


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