[vanman]

First wanted to say - wonderful community you all have here! I've caught the EV conversion bug and would appreciate help vetting my plans. I want to convert a VW Vanagon to an EV - thankfully this has been done before, so at least I know it's possible.

I have very limited space and will have to pay for storage while the car's immobile, so I'm planning on doing the build in a (maybe) strange order:
1. before buying the car - buy the electronics and a "minimum viable battery" and get working together on a benchtop so I don't have to pay for space during this time
2. do as much mechanical work as I can ahead of time
3. buy and convert the car as quickly as possible (and no doubt realize everything's been done wrong)

Think that's reasonable? Any reason I shouldn't try to get things working on a bench before buying the car? I expect some wiring might end up being the wrong length, but not sure why else this would be a bad idea.

Major parts:
- VW vanagon
- tesla model s drive unit (direct drive, starter kit from ev west)
- LG Chem batteries (6 in series to start (=> 365v, 15.6kWh) as the "minimal" battery, to be expanded later)
- charger: TSM2500? nominal voltage is 312v but seems to be able to go up to 420v...
- dilithium bms
- dc-dc converter: used chevy volt converter?
- thermal management: not sure - would be nice to find some pre-made liquid heating/cooling plates for the batteries

So - do my plans and parts list make sense? Any recommendations? Thanks for reading this far!

 

[brian_]

Do you know where you will be placing the battery modules? If they are in the same arrangement as they are on a Chrysler Pacifica Hybrid, you could use the whole Pacifica pack with its cooling system... used, of course.

 

[daltonguitar]

Hey, cool to see your doing an EV Vanagon version; I'm in the middle of doing one as well! Just wanted to throw in my two cents on what your doing.

In terms of a motor, if you use the Tesla Model S Drive Unit from EV west you will be absolutely mobbing in that van but that kit is quite expensive. If money is no issue and you looking for straight power go for it but if money and time is a factor for you I'd suggest getting a Netgain Hyper 9.It is not quite as powerful as a Tesla Drive Unit but you'll be able to go at least 85mph if not faster in a vanagon. An advantage going this way is you can just connect this motor to the transmission which saves a bit of time, ev west has the adapter plates too, and this system is a third the price of the tesla unit.

In terms of batteries, LG is the best way to go in my opinion, lots of power and good price per kWh. If you live in the LA area look up TechDirect, they sell their units for a few hundred cheaper than ev west. Also, talk to ev west about some LG Parallel boards. I just picked some up and been experimenting with them a bit. They will help you save allot on the BMS but just be aware that there is some risk in using them but talk to trent at ev west he'll explain all that to you and what precautions to take.

In terms of BMS/ Charger, if youre going to use a dilithium system, Id recommend you using the Thunderstruck EV 2500 high voltage Charger. I like this combo because the charger and bms can communicate to each other very easily since they made by the same manufacturer, theres not much in terms of coding you'd need to do to get them talking. Also check and see what their highest voltage charger is because I think its only 312v.

In terms of DC converter i got myself a SEVCON DC/DC Converter but its really up to you on that one, cant really go wrong there.

With my build, I was originally going with a DC motor because it was cheap but things have been picking up at my work so Im saving up for a hyper 9. I drew up a schematic for how I was gonna wire everything and the batteries Ill attach them to this post. Since there's so much space in the back where the engine was, I'm planning on building 2 battery boxes on each side of the motor that can hold 12 LG Chem Modules. I currently only have 8 but once things start moving Ill pick up some more. I'm personally not doing anything in terms of cooling for the batteries, I was thinking of just adding a few fans to the box to move the air around a bit but I'm still not sure. Maybe if you choose Lg chem too we can work together on something? Theres some space in that engine compartment I'd hate to see it go to waste.

 

[brian_]

I'm personally not doing anything in terms of cooling for the batteries, I was thinking of just adding a few fans to the box to move the air around a bit but I'm still not sure.

If you're going to do that with the LG modules, my suggestion would be to at least clamp the modules down to aluminum plates with fins on the other side, for more effective heat transfer. Blowing air around the other sides of the modules seems relatively pointless in comparison to what is done on the side of the modules which are designed for heat transfer (the bottom in the stock installation in a Pacifica).

 

[vanman]

Thanks for responding!

Brian - getting a whole Pacifica pack is a really interesting idea, it'd be nice to use something a pro designed and my goal layout is very similar to the Pacifica's. I couldn't find any sources for a whole pack after a brief search - think this is this the kind of thing where I'd need to find a Pacifica being parted out?

Dalton - awesome, glad to hear you're working on a Vanagon too! There's just something about 'em. Appreciate hearing your experience. Great schematic! I definitely have some questions for you:
- do you know how you're going to mount the motor to the vehicle frame?
- your traction pack is ~240V, right? are you worried about running the Hyper9 that high?

I think you have a good point r.e. hyper 9 vs tesla - speed isn't my goal, I'd probably be better off spending the money on battery capacity. I like the idea of getting rid of the transmission but maybe it doesn't make sense, and I definitely wouldn't mind having a lower voltage system.

You've probably seen these but I've been enjoying these vanagon conversions on youtube:
- EV World Tour (with the Azure motor and tesla batteries) from a few years back, has really thorough videos
- these guys ("DreamEV") just started a few weeks ago! using a tesla motor and LG Chem batteries apparently, looking forward to more progress from them https://www.youtube.com/channel/UCHhLr-rQs1cvEq-n-dpKbTg

 

[Tremelune]

I love an electric bus! What are your range goals? Seems like the cheapest way into batteries is to pull them from a used car like a Leaf, Volt, Bolt, Tesla, etc...

A Leaf motor/inverter can be had for about $1k, and it's not much bigger than the Tesla unit. Gearing is comparable, though you'll need custom axles. EV West sells a nice package, but $12k for a motor that a Vanagon chassis can't much handle seems...excessive, when a small Tesla motor can be found for a few grand...

I'm iffy on this, but from what I've read, batteries require more cooling during charging than full throttle, so your cooling needs may very well be determined by your charge speed and pack size. With the Thunderstruck charger, my 240v 16kW Leaf pack barely raises above ambient after an hour of charging at 5A from 120v mains.

 

[vanman]

Hey Tremelune! I'm planning to save up for a pack that will get me 70 miles or so at 65mph - which I know is a fairly tall order, so in the meantime I'm happy with a tiny pack for testing. I definitely need to spend time looking into pulling batteries from used cars - have any tips for finding good sources?

Happy to hear that battery cooling might be simpler than I expect - I guess I'll go into it hoping to do air-cooled and see how hot things get in practice. And glad for more advice r.e. the tesla motor - this thread has convinced me that it's overkill on all accounts.

 

[Tremelune]

I like the route of buying a whole car and selling the parts that aren't used. It's more work (and a car's worth of space taken up), but it seems like the cheapest way in. Best bet is to scour Craigslist, eBay and local wrecking yards...There are people who buy up EVs and part them out at profit, so there is some competition.

 

[daltonguitar]

Brain- Thanks for that suggestion, Ill probably end up going that route. I do remember hearing how those modules transfer heat it really didn't cross my mind to implement cooling in a similar fashion. Hopefully soon I start making some diagrams for a box and post them here for some feedback.

Vanman- Yah the Vanagons are just awesome. I bought mine about a little more than a year ago off someone on craigslists. It was in horrible condition and I spent allot of time prepping it for a conversion while I saved up money. I had to deliver allot of pizzas.
Regarding mounting the motor, my plan was to reuse the original motor mount (the one that looks like a big mustache) and connect that to my motor. Ill attach a photo I did of how I was planning on connecting them. Now that I'm planning on swapping it out with an AC Motor, I'm holding back on deciding what to do until I have the motor and can take all the measurements I need. I think I'm going to bolt the 2 battery boxes onto the frame and maybe attach the motor to both boxes. I'm still unsure but Ill let you know when I have a more concrete plan. Regarding the voltage, my DC schematic had a voltage of 128VDC. I had the modules wired in 2S4P or cells in 32S4P. Since each LG Module can't be considered as just one big 64V battery, you have to be a bit creative in how you wire them together. When I transition to the Hyper 9, Ill most likely use them in 3S3P with a total of 9 batteries. That will give me a voltage of around 190, which I think will be fine but Ill have to double check.

Yes the EV World Tours vanagon conversion was definitely an inspiration to me. Its funny I recently got my hands on an Siemens AC motor similar to the one he used, but its a bit smaller and came out of a Ford Ranger. Ill attach a picture of it to here. I was debating using that motor for my build vs a hyper9 since I already have it but looking into it, it seemed like getting a controller and inverter for it would cost more than just selling that motor and my DC one and buying a hyper 9.

If you haven't seen it already you should check out the guys at solarrolla. They did a conversion of a VW Bus for Redfoo (The LMFAO guy) that has a solar poptop! Since the top of these vans are so big and flat on the top its perfect for adding panels. One day when my vanagon is electrified I want to follow in their footsteps. https://solarrolla.com/

 

[brian_]

Regarding the voltage, my DC schematic had a voltage of 128VDC. I had the modules wired in 2S4P or cells in 32S4P. Since each LG Module can't be considered as just one big 64V battery, you have to be a bit creative in how you wire them together.

Why not? Why can't you consider the module as a "big 64V battery"? Each module is a 16S XP set, where 'X' (the number of cells in parallel within the module) doesn't matter. Maybe I've misunderstood what considering the module as a 64 V battery means.

 

[daltonguitar]

Why not? Why can't you consider the module as a "big 64V battery"? Each module is a 16S XP set, where 'X' (the number of cells in parallel within the module) doesn't matter. Maybe I've misunderstood what considering the module as a 64 V battery means.

When connecting the modules in series, you can think of them as one big battery, but the issue comes up when connecting them in parallel. I try to think about it in terms of connecting each cell together rather than each module. Each module is arranged in 16S0P, which is 16 cells connected in series with each other. When you connect that module in series with another module, that means you have 32 cells in series with each other. Now think about what happens if you connect a module in parallel. Each module still has 16 cells connected in series, so connecting them in parallel would mean that the only cells in parallel with each other would be just the one cell on each at end of the module. To effectively parallel cells you need to have each group of cells paralleled at the cell level and have each parallel group in series with each other. The only way to get the LG cells arranged this way would be to to open the modules up and change the wiring. Because of this, when paralleling LG Chem, you need to think of each LG module in parallel as a separate pack. If you look at my schematic for example, I had 8 modules and wanted a voltage of 128VDC. To do this I connected one module in series with another, which gave me my desired voltage. I did this to all the other modules as well, having a total of 4 groups with 128VDC each. Then all you have to do is parallel those groups together and thats it. I hope that kind of clears it up for you, hopefully I didn't make things even more confusing

 

[brian_]

What I didn't catch is that by "big 64 V battery" you really meant "big 64 V cell", in which there was no need to balance between cells within the module. The 16S module is simply a 64 V (roughly) battery... but lithium batteries are not really suitable for parallel combinations unless each has its own BMS.

... Now think about what happens if you connect a module in parallel. Each module still has 16 cells connected in series, so connecting them in parallel would mean that the only cells in parallel with each other would be just the one cell on each at end of the module. To effectively parallel cells you need to have each group of cells paralleled at the cell level and have each parallel group in series with each other.

Yes, that's the problem in paralleling any batteries or modules. You do need to either reconfigure modules (not worth the trouble in most module designs), parallel them together at the cell level (not likely safe through the small-gauge BMS wires, not practical to install large-gauge wires), or monitor and control separate modules with separate BMS inputs.

Everyone who configures a pack with two or more strings of cells or modules, then parallels those strings, faces this issue and takes the last approach (multiple BMS, if they use a BMS at all). A few people actually parallel at the cell level without physically reconfiguring with the module, typically only with Leaf modules that have a high-capacity terminal for the cell-level tap, but sometimes using the BMS wires.

 

[vanman]

Your comments and the document here: https://www.orionbms.com/manuals/pdf/parallel_strings.pdf
have made me worried about the safety of my battery plans.

My goal is to be able to expand capacity over time as I save money, but I'm not sure what a good way to go about it is. Previously I was planning on using three LG CHEM 60v Pacifica batteries in series for ~180v, and adding more strings in parallel as money allows. That seems to be a bad idea! Is there a better way to do this?

Currently seeing a few options:
- try parallel strings after all - will it be relatively safe with a BMS per string? that's a lot of BMSs...
- choose different components that can handler higher voltage, and expand capacity by adding more battery modules in series
- try to make my own battery pack from cells - seems expensive and complicated
- ???

 

[Knightgreider]

Following this thread now!