Got the equipment, need help deciding what to convert

9749 Views 61 Replies 8 Participants Last post by massawe, May 16, 2019

massawe

Discussion Starter · Oct 2, 2018

5

Hey EV gurus, my friend recently emailed me saying he was selling his partially finished EV truck conversion for $5k, and I couldn't pass up the deal, so I bought it without really knowing what I would end up doing with it. I have wanted to build an EV for a decade now so I figured this was as good a time as any.

The partial conversion is built on a 1994 Chevy S10 2-seater, which is a vehicle that doesn't serve a lot of purpose for me. I need something that can carry my wife and child safely, and I also find the Chevy to be a very boring car. So I need to decide what to build, but I am limited by the fact that I already have the equipment so whatever I choose needs to work with what I have. Here's what I now own:

60kWh Lithium-Ion batteries in 95 x 3.2V, 200Ah cells
125kW UQM PowerPhase motor w/ controller
6.6kW charger
BMS for 95 cells
1000W DC-DC step down converter
Pressure pump for brakes, etc.
Chevy S10 with hydraulic bed lift (partially installed)
A bunch of other small things I haven't looked at yet

I posted earlier on a thread about converting a Sprinter van, which is still an option, but I am starting to lean towards a city vehicle since I think that is still a better fit for me. I'm thinking I will need a fairly large vehicle since the battery pack is big, so probably either a sedan or an SUV. Also, since I am going to be spending a lot of time on this project I want to choose a nice vehicle. So this is about as far as I've come. Every day my ideas change and I figured some guidance from the community would help. Some of the options I've thought of are a BMW E series, and a Volvo XC60, but I'm pretty open still.

I guess at this point I'm looking for advice that would help me make the decision between luxury sedan and SUV, as well as things to watch out for that can narrow down my list (i.e. does it have to have a manual transmission? will these batteries even fit in a BMW E-series, etc)

Overall I'm very excited though, thanks in advance for any advice.

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toper

· #2 · Oct 3, 2018

I would definitely recommend finding a vehicle with a manual, especially for a first time conversion. While it's possible to do an automatic, it's a lot more hassle. You need to feed it oil, autos like to be at lower RPM's which is contradictory to electric motors, since they perform better at higher RPM's, and it's extra weight.

You may be able to fit them in a Bimmer, the one I am working on is a 2002 E46, and the trunk is actually massive. Along with the fact that the area under the hood is massive. The straight 6 engine means that the bonnet space is much larger than a V6, because the inline engine requires a longer hood. So you could theoretically have half the batteries in the back, and then also in the front engine bay, which helps with weight distribution while using all of those cells.

Porsches are also a fun conversion, though you may have to reduce pack size for that. There is a neat Audi Tesla swap on youtube on the Rich Rebuilds channel, you could do something along those lines as well. You've got a lot of potential with those components, that's truly a steal.

I don't think a SUV would be the best, there's a lot more weight to move, which will reduce the overall performance and range of the car. A luxury sedan is likely your best bet to get the most out of these parts.

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massawe

Discussion Starter · #3 · Oct 3, 2018

Thanks Toper, I had actually checked your post out not long ago, it looks like a nice ride.

It would be important to me to maintain some sort of trunk space, like enough to fit a stroller in the back. Right now I have a chevy volt, and my hope is that I could convert a car large enough that it would have at least as much space as the volt (which isn't much). At least most cars would have the third seat in back though, my 2013 Volt has used that for batteries.

I see your point though, on your thread people were indicating that even the BMW would be too heavy, and while my motor is slightly larger, it still comes in lower than pretty much any SUV I can find.

I'll see what options there are in the straight 6 or maybe V8 luxury sedan world.

Have you made any measurements of the engine and trunk cavities on your BMW? How's your build coming along?

Duncan

· #4 · Oct 3, 2018

Hi
I hate to be wet blanket but if you want "transport" buying a second hand factory made EV will give you a superior product for less money

I would only advise converting if you really WANT the resultant vehicle

So - sports cars?

Or - as you have a family - what about a "Classic Car" - not something dead rare but something unusual enough and fun enough - just about anything from the 70's

Something that you can take pride in as being "yours"

toper

· #5 · Oct 3, 2018

I had thought about doing that myself originally, a nice classic 70's era car. But that doesn't solve the weight issue. They are made of real steel and little to no plastic, so they drive like boats due to their immense mass. It would be really cool nonetheless, though the practicality may suffer.

And massawe, in terms of preserving trunk space, I am sure you could do this if you placed more batteries up front. That will still keep a normal weight balance, since the engine being removed is definitely heavier than just the motor and a few batteries. So you can maybe line the floor in one layer of batteries and just have a raised trunk liner. If you are using an older bimmer, that's likely better, as they were made less complex, so they are lighter overall, especially if it's a coupe or just a standard 'I' model. Mine is heavy because it has AWD, which adds an extra ~300lbs. You could go even older if you wanted to, the late 80's models are even lighter.

The

And my project is going well, it is on pause for a bit right now though. I am in college so I am away from the project, 350 miles away specifically, but I am trying to use this time to build up finances to get all the parts. I think near thanksgiving or Christmas time is when I plan to have all the parts in hand, and then I'll complete the conversion then.

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massawe

Discussion Starter · #6 · Oct 4, 2018

You are hitting the nail on the head a bit. The thing is I have always wanted to convert an EV, so part of this is fulfilling a dream. I do want something unique, which is why I am ripping everything out of the truck it is currently in. But I also don't want to own more than two cars, so I need to find the right balance. My other car will be a road trip vehicle, so it will be very spacious and gas-powered. This car will mostly just be for commuting around town, but I do want to be able to fit my family and a stroller (or something of similar size). But you are exactly right, choosing the right vehicle is key and so far I keep changing my mind each day, which is why I need help narrowing down the list. The battery pack generates just over 300V, the minimum for the motor, so downsizing the batteries to fit in a smaller car is not really an option.

I'm not totally convinced that I could get a comparable factory EV for less money though. I'm thinking if I spend ~3k on a chassis, then throw in another $5k for random parts and adapters, plus the $5k i've sunk already, I'm at $13k. I don't think I could find a comparable vehicle (60kWh, 125kW) for that price, but maybe I'm wrong? Anyway given the amount of work involved I could probably make up the difference by working at McDonalds the same amount of time I will be working on this car, so your point is still valid. I also currently have a Volt, which I love and I hate. I love not using gas driving to work, but I hate all the constant beeping, reminders, buttons for door locks, short electric range, etc. As soon as my new vehicle is up I will sell my Volt, hopefully for about $11k to make up most of the cost of my conversion.

My vehicle does need to be something I can take pride in, and something unique, like you mentioned. I'm open to classic cars but I have the same reservations that Toper mentioned. Also one of my biggest problems is that I'm not usually a 'car person,' so I don't have lots of cars I've dreamed of owning over the years, I'm basically just scanning the streets.

This is way too long of a response with very little substance. Sorry about that. One of the cars that looks like it could work well is the Range Rover Evoque, at 3,500 lbs, but I don't think this is realistic to find with a blown engine for under $5k. Perhaps BMW, Jaguar, Lexus sedans are the right places to look? Do you know of any good classic cars that would have a decent amount of space and still come in fairly light? If you have any suggestions of models that you think are good candidates that could help me create a better short list.

Thanks!

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brian_

· #7 · Oct 4, 2018

massawe said:
One of the cars that looks like it could work well is the Range Rover Evoque, at 3,500 lbs, but I don't think this is realistic to find with a blown engine for under $5k. Perhaps BMW, Jaguar, Lexus sedans are the right places to look?

If luxury interior touches and fancy toys are important to you, then these vehicles are great. Or you can spend half as much and get a more reliable vehicle which drives as well and is functionally comparable. The only good feature of the luxury/performance sedans is that they're rear-wheel-drive (if that matters to you), but in SUVs if you take the logo badges off you can't see any mechanical difference between a Toyota/Honda/Ford/Chevy/Mazda/whatever and the brands which cost far more.

The luxury brands do depreciate heavily, making them cheaper when used than a reasonable brand would be if they sold for the same price new, but one reason that they depreciate is that parts and service are so unreasonably expensive. If you buy one which is cheap because it has some major mechanical problem, it could have thousands of dollars worth of problems with parts that you are not going to replace with the EV components.

I know a guy who bought an Evoque, and he said at the time that he would have been just as happy with the Mazda CX-5 which he test drove around the same time, and only chose the Evoque because he really wanted a 2-door. I had a look at the Evoque - it didn't look worth twice as much as a CX-5 to me.

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massawe

Discussion Starter · #8 · Oct 4, 2018

I get what you are saying. Finding that middle ground is not easy. The thought of spending $13k and a year of work to have a Honda Accord that looks like the car my mom drove 10 years ago just isn't that exciting to me, and since the difference between a busted Honda and a busted Jaguar is only a couple grand it seems like it would be more rewarding to have a car that at least looked nice and felt more unique at the end.

That said, I don't want to end up spending more fixing up the mechanics of the car than I spend doing the conversion (in time or in money). So there's clearly a line. And I think I agree with you, the Evoque is over that line. I just like the size, weight, and look of it, but it is too expensive and parts would be hard to come by.

So what's in the middle? I think many BMW's fit in the middle: nice looking, big enough to fit the parts, and still plenty of replacement parts. Is there something slightly more exotic that would work though?

Its a big decision

brian_

· #9 · Oct 4, 2018

massawe said:
So what's in the middle? I think many BMW's fit in the middle: nice looking, big enough to fit the parts, and still plenty of replacement parts. Is there something slightly more exotic that would work though?

I think the choice of the term "exotic" is interesting. A current BMW is a good car (although not particularly reliable or easy to work on), but far from exotic. While some auto enthusiasts still drive them, most BMW (and Mercedes, and Porsche) owners just want a transportation appliance which will impress the neighbors who don't know enough to not be impressed. GM figured this out decades ago, and maintained multiple brands of basically the same vehicles in multiple trim levels, because many buyers cared so much about the brand badge - more than they cared about the actual car - so they would pay far more for a Cadillac than they would for the same car with a Chevrolet badge. Ford did the same thing with Lincoln, and the Japanese manufacturers eventually followed suit with Lexus, Acura, and Infiniti.

If style is the big factor, I like some of the Lincoln sedans. Under the skin they're Fords, which isn't a problem. But in style, only your own opinion matters.

massawe

Discussion Starter · #10 · Oct 4, 2018

While I've never owned a BMW, when I have driven in them I have found that they usually feel much nicer inside than a Honda or Toyota. I also think they are a nicer looking car, with more attention put into aesthetics than the Honda/Toyota. As you said, this is just personal opinion, but since with a conversion the motor and fuel source aren't tied to any particular car, I think the aesthetics factors in more than if I were buying a gas car, where I would care more about the engine, fuel economy, and price.

By no means am I tied to a BMW. I just just want my car to look nice, and I don't find anything particularly appealing about a Corolla or an Accord. I won't deny that branding influences my opinion, but isn't all of aesthetics pretty arbitrary really?

The reason I don't mention more exotic cars is because I've just never been a car person. I don't really know what kind of cars to look for, which is why I'm reaching out on this site for suggestions. I'm looking for help finding the right balance of exotic, reliable, and conversion-able. I'm very good with electronics but I've always just driven whatever car my parents got bored of and sold to me, I've never liked gas engines which I think has always turned me off to cars in general.

I agree about the Lincoln sedans. These are nice looking rides, and are usually fairly spacious. It looks like the MKZ is the only one that would be reasonable size. Personally I think the Town Car is a great looking car but probably way too heavy. Are there any other models that you like?

I'm mostly building the car to learn and to reduce my fuel consumption, but if I can make something that looks and feels impressive without drastically changing the price tag it seems like a good investment.

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Duncan

· #11 · Oct 4, 2018

Hi
It's all down to what YOU like - and it does need to be a "bit special" to justify the money

When I was in the USA (late 90's) I liked the Ford Thunderbird - a bit exotic but not expensive

Spend a few months thinking and looking - something will come up

massawe

Discussion Starter · #12 · Oct 4, 2018

The Ford Thunderbird is pretty cool actually. I like the new models, but they only come in a two seater. The 1988 model is pretty 80's looking, but definitely has some funkiness that I like. Also at 3258lbs it's pretty light, and replacing the original 104.5kW motor with my 125kW motor means it may actually drive like it's supposed to. The 60's and 70's models are great, but heavy and probably would require more maintenance than I'm ready to put in.

Maybe not the most spacious vehicle being a 2-door coupe, but it looks like the engine compartment and trunk are pretty large. Prob not super fun getting a baby in and out of the back seat, but maybe it will take me 9 years to do the conversion anyway and then the kid won't need the car seat...

Thanks for the suggestion, I'll add it to my list!

massawe

Discussion Starter · #13 · Oct 9, 2018

Well I've continued to compare vehicles like crazy. I created a big image of all the cars I liked, with the brand names and symbols removed, to help see which ones really stood out to me without the branding. I then showed this list to my wife. When it is all said and done though, my practical side is winning the battle, and I realize that if I can't pack enough gear for a camping trip or a short road trip into the car, then I probably won't even end up using it that often. I'd rather have a more 'normal' looking car that I use a lot than a hotrod that sits in my driveway.

So I've been looking a lot at the mid 2000's Volvo V50 T5. It has one of the larger cargo spaces at 27.4 ft3, it only weighs ~3,400lbs, and it comes with plenty of luxury options to make me feel special. It's not the coolest ride on the road, but I can add some stuff to make it look more unique and it certainly isn't ugly in my opinion. It is also basically the reincarnation of the 240DL, which was my first car ever in high school. I don't know if that's a good thing or a bad thing.

So besides that fact that it seems tricky to find one of these with a manual transmission (they do exist), does anyone see any reason that this car wouldn't work well, or any particular challenges I should prepare for? Also, do you have any other suggestions for similar rides? I looked at the Mercedes E350 Wagon (no manual transmission) and the Audi A4 Wagon (only 17 ft3 cargo space).

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brian_

· #14 · Oct 9, 2018

massawe said:
So I've been looking a lot at the mid 2000's Volvo V50 T5.
...
So besides that fact that it seems tricky to find one of these with a manual transmission (they do exist), does anyone see any reason that this car wouldn't work well, or any particular challenges I should prepare for.

The V50 is one of the Volvos built on Ford's C1 platform... it's Volvo's version of a 2005-2010 Euro-market Ford Focus, and a predecessor to the platform of my Mazda 3 (which I really like).

If you can't find one with a manual transmission, you could probably swap in a transmission from a wide choice of other vehicles on the same platform, but it's always a hassle to convert the shifter assembly and add the clutch pedal.

massawe

Discussion Starter · #15 · Oct 10, 2018

That's good info. I didn't realize so many cars had a common core like that. Hopefully I won't have to swap a transmission, but it's good to know I wouldn't need to find a second busted Volvo V50 to do it.

It looks like I was wrong about the cargo space of the Audi A4 wagon as well, a 2007 A4 Avanti is said to have 27.8 ft3, which puts it right up there with the Volvo. These are also much easier to find based on some quick searches.

piotrsko

· #16 · Oct 11, 2018 (Edited)

2 comments: typically the clutch pedal is a long through pivot rod brake pedal held in with circlips. So getting one from a junkyard and possibly doing some slight machining is a possibility. Get the brake pedal also because they are smaller than what is currently installed and will interfere.

If it's a factory option, the holes and mounting points are already there.

It's not that hard to either use the slush trans or convert to a handshaker.
You just need idle for one, and the modified floor plate for the other.

Ive done several swaps and lived to tell about it. Weekend worth of under car crawling.

DrGee

· #17 · Oct 13, 2018

massawe said:
Hey EV gurus, my friend recently emailed me saying he was selling his partially finished EV truck conversion for $5k, and I couldn't pass up the deal, so I bought it without really knowing what I would end up doing with it. I have wanted to build an EV for a decade now so I figured this was as good a time as any.

The partial conversion is built on a 1994 Chevy S10 2-seater, which is a vehicle that doesn't serve a lot of purpose for me. I need something that can carry my wife and child safely, and I also find the Chevy to be a very boring car. So I need to decide what to build, but I am limited by the fact that I already have the equipment so whatever I choose needs to work with what I have. Here's what I now own:

60kWh Lithium-Ion batteries in 95 x 3.2V, 200Ah cells
125kW UQM PowerPhase motor w/ controller
6.6kW charger
BMS for 95 cells
1000W DC-DC step down converter
Pressure pump for brakes, etc.
Chevy S10 with hydraulic bed lift (partially installed)
A bunch of other small things I haven't looked at yet

I posted earlier on a thread about converting a Sprinter van, which is still an option, but I am starting to lean towards a city vehicle since I think that is still a better fit for me. I'm thinking I will need a fairly large vehicle since the battery pack is big, so probably either a sedan or an SUV. Also, since I am going to be spending a lot of time on this project I want to choose a nice vehicle. So this is about as far as I've come. Every day my ideas change and I figured some guidance from the community would help. Some of the options I've thought of are a BMW E series, and a Volvo XC60, but I'm pretty open still.

I guess at this point I'm looking for advice that would help me make the decision between luxury sedan and SUV, as well as things to watch out for that can narrow down my list (i.e. does it have to have a manual transmission? will these batteries even fit in a BMW E-series, etc)

Overall I'm very excited though, thanks in advance for any advice.

Just amazing what you got for 5 grand.. 60kwh of batteries and all that extra kit! I'm trying to find a way to get 40Kwh under 3500 USD..
Wish all the best in your project. I also initially thought about getting a Range Rover to convert. I was put off by the cost & the serious reliability issues. I've opted to convert my Jeep Grand Cherokee instead.

massawe

Discussion Starter · #18 · Oct 17, 2018

A jeep would be a pretty sweet conversion. Would love to see your progress.

I'm setting up a test right now to make sure all these batteries are still in good shape. I know that they have been kept fully charged, and that they are basically unused, but I also know that they are at least 5 years old, so I'm hoping this hasn't caused much damage. I also read that they should be stored at 50% charge, which they weren't.

So I'm setting up a constant current load to test it out. Since I don't have a good way of pulling tons of power, I'm planning to just pull about 7A for 20 hours or so until I see the voltage start to dip. I do have a datasheet for the cells so that should help my estimate. I'm a little nervous though, because if I find that the batteries only have 70% capacity or something, then is it still worth installing them knowing that they are already on their way down?

The deal was too good to refuse though. Even if the batteries aren't as good as I'm hoping, I think I still have over 5k of equipment. It would be a bummer though.

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DrGee

· #19 · Oct 17, 2018

massawe said:
A jeep would be a pretty sweet conversion. Would love to see your progress.

I'm setting up a test right now to make sure all these batteries are still in good shape. I know that they have been kept fully charged, and that they are basically unused, but I also know that they are at least 5 years old, so I'm hoping this hasn't caused much damage. I also read that they should be stored at 50% charge, which they weren't.

So I'm setting up a constant current load to test it out. Since I don't have a good way of pulling tons of power, I'm planning to just pull about 7A for 20 hours or so until I see the voltage start to dip. I do have a datasheet for the cells so that should help my estimate. I'm a little nervous though, because if I find that the batteries only have 70% capacity or something, then is it still worth installing them knowing that they are already on their way down?

The deal was too good to refuse though. Even if the batteries aren't as good as I'm hoping, I think I still have over 5k of equipment. It would be a bummer though.

It was certainly a good deal. I would've jumped for it too! Well I suppose even if the batteries have lost so much capacity, you could still use them with a plan to replace them gradually as funds become available..
How are you settling up your constant load test?
You could hook them up to an iron if you can series and parallel them to give you 120 or 144V (a 1200W iron draws about 10A @120V)...

massawe

Discussion Starter · #20 · Oct 25, 2018

I built a PCB with a constant load test based off a couple NFETs with feedback from a 0.33 Ohm resistor between the emitter and ground. I tested it and it worked well, but then I realized I had designed it to pull 5A, and it was really just overcomplicating everything and was going to take forever to drain the battery.

I ended up just sticking together a network of 10W resistors to create a load of about 0.22 Ohms, and then just monitoring the voltage over time. I tried to characterize the resistors a bit before hooking them up to the battery to see how much the resistance changed with temperature. I saw about a 5% increase in resistance with 3A flowing through them, and no air movement. In my final setup I put a fan on it and spread it out over 6 resistors so it never got all that hot.

With this setup I was pulling about 45W from a single 3.2V 200Ah cell, and I ended up pulling 658Wh from the battery! This is 18Wh over the rated capacity, and I stopped pulling at 2.5V. Of course I was pulling current at a low rate of .075C, and the rating is at a 0.5C discharge (lots more internal resistance losses) but I was still pleasantly surprised by the result and feel that the battery is showing basically full capacity. The articles I had been reading were making me think I may have lost a third of the capacity from them just sitting there sop this was very reassuring.

So, with the batteries proven I'm feeling a bit more confident about moving forward. Anything I might be missing that could be skewing my results?

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