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JD's VW Bus Conversion EV project (2 of 2)


1 MW
Apr 26, 2007
SoCal, USA

I've had a 1974 VW Camper Bus (Bay Window, transporter, whatever) for years. Recently I've mostly just driven it from one side of the street to the other for street cleaning. Last week it caught fire while I was doing that. Unlike most VW fuel-line fires, it was an electrical problem - appropriate.


I wanted to convert it to electric years ago, it is a big light sturdy platform powered by a mere 66hp ICE. Didik mentioned that the only most successful conversions he had seen were on VW Bus's for those very reasons ( http://www.didik.com/criticalev.htm ). After a thorough analysis I decided lead acid's weight required too many tradeoffs, especially if it meant killing a perfectly viable ICE road vehicle that had been coast-to-coast several times.

Last year I almost bought 90ah Thundersky cells to do it, they had enough w/h to do my target commute but they were unproven and too expensive to gamble on. plus they only do 3c and 270 amps would be lame on hills. Larger cells would make the project cost too much to interest me. I focused on doing a lightweight vehicle instead, which lead me to my Comuta-Car project.

Then the Fire. At first I thought I would have to scrap the Bus, the comuta-car project was in progress in the garage, I didn't want to sink time/money into a 2nd fullblown EV project, and if I don't move the bus every week for cleaning I get parking tickets. Then I realized - that is as far as it has to go right now, across the street and back.

If I put in a motor, adaptor plate, and control system into it, then a 500wh string of a123's should be up to the task of crossing the street. Then I can resume the ComutaCar project. I can use the 48v80ah ComutaCar pack in the bus to see how much current it draws and get a better idea of just how big a pack I need. Plus I can prove out the Headway cells in the Comuta before splurging on a huge pack. In the worst case I can move the motor/adaptor plate/controller to a Vw Bug chassis and build a lightweight vehicle or just sell them.

So today I bought a Kelly KDH14500B controller on ebay, 144v500a = 72kw boost and 29kw continuous. It's a month old, I paid $798 for it, about 30% off Kelly's price.

I bought a brand-new ADC FB1-4001a 9" motor on eBay for $1274, @25% off street price. This model has a tailshaft so I could stick a generator on the tail and use it to achieve regen on a series motor.

I am buying a CanEv adaptor plate. The ADC motor's base bolts to the plate and the plate bolts to any aircooled vw tranny. The Flywheel/Pressure plate is bolted to a hub that is keyed to the ADC's motor shaft.

The rest is just building the control/safety system, which I have laid out and I'll post tomorrow.

Most Lead-Acid bus conversions add 1000-1500lbs over stock. According to my list of what mass is coming out and what is going in, the LiFePO4 bus will be merely 35 lbs over stock when equipped with a 100v100ah pack. Since I don't have to push all that extra mass around, I have no idea how any wh/m it will actually consume. That is where the little 48v ComutaCar pack will come in handy - the RPMs will be low but I should still be able to get a rough baseline.

Fun detail - the vw transporter has a special enclosed, protected chamber for the gas tank. I think that space will be big enough to hold an entire 100v100ah LiFeP04 pack, making for a very clean, safe install.

That's a nice vehicle to convert – most of the mechanical parts are available off the shelf for VW conversions and it's the sort of vehicle that people don't mind too much if you take things slow. Mind you, if you really only need to drive it across the road and back you could just add a few more 12V lead acid batteries in parallel with the existing one and drive it on the starter motor :)

I'm not sure of the weight of the '74 bus but it does look a bit on the heavy side for a lithium conversion, though on the other hand it makes sense to convert something you like, and if you see it as a rolling test bed then why not. Have you decided on a BMS yet?
Actually a bus would be a good lead powered EV. It sure as heck can carry the weight. I used to cut and carry a cord of firewood everyday in one. It actually handled a lot better than a pickup with a half a cord. 8 golf cart batteries from sams club might be worth the investment.
Malcolm said:
I'm not sure of the weight of the '74 bus but it does look a bit on the heavy side for a lithium conversion, though on the other hand it makes sense to convert something you like, and if you see it as a rolling test bed then why not. Have you decided on a BMS yet?

Hi Malcom!

After experiencing way too many cell-killing BMS problems, I switched to Single-Cell chargers last year. For discharge, I typically verify correct total voltage at the start, use a CycleAnalyst to meter watts to a 70% DOD, and have yet to lose a cell since. I probably should install an LVC with an 'emergency override' for situations where pulling over is worse than losing a cell.

The Bus is big and sturdy, but not as heavy as it looks - the ICE is only 66hp. By using LiFePO4 it stays at stock weight, so I still only need 66hp for equivalent performance. It should actually end up lighter than most Econobox Lead-Acid Conversions with equivilent usable capacity! Drag is a concern, but I am hoping the lozenge shape helps, plus I have a few ideas to mitigate it, belly pan, shaving the protrusions, etc.

My ADC adaptor plate shipped today! ( http://www.canev.com/KitsComp/Components/Adapter%20page.htm ) Since the design allows me to keep the vw tranny/transaxle I don't need a reversing contactor to go backwards. The plate was $825 and the shipping $43.85 (i was quoted $37.50).

I went through the Kelly Controller wiring Diagram, and while it is clear (I like their documentation and support) it is difficult to continiously map that diagram onto the hardware in front of you. I made myself some visual aids to make it easier and thought I'd post them here for anyone else heading down the KHD14500B path. First is the diagram that fits my installation from Kelly's excellent manual. I broke that out into two diagrams, one for the drivetrain power system, and one for the control system, and I'll update it with wire colors etc as I go along. I'd appreciate hearing about any mistakes you notice!

Oh, a question for the EE gurus... One part of Kelly's website ( http://www.kellycontroller.com/mot/Products.html ) says the KDH model of their controllers are "Isolated!". Does that mean that the control and power systems are isolated from each other, perhaps optically? In that case, should I use a separate power source for the controller instead of a DC-DC power supply to keep the systems discrete?


PS - these are draft diagrams from a novice, and could be completely incorrect/outdated, so be warned.



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I found that link I mentioned earlier, Frank Didik commented that the "vast majority" of the gas-to-electric car conversions are "almost unacceptable" due to the net 1500 lb gain from the old lead-acid batteries, saying "In most cases, the end result is too heavy, underpowered, very short range and low top speed".

Then he goes on to say:

Perhaps surprisingly, the most successful conversions seem to be the VW bus. I think that the reason is that the frame is relatively strong to begin with, so that the batteries have a relatively good base and the VW bus is a rather light weight vehicle."

Smart Man. :D Hope it does as well with light batteries!

I'd suggest putting the key switch in series with the input to the dc-dc rather than the output. This way there will be no drain when it is turned off.
Thanks for the tip Fechter! That makes good sense, I'll move the switch.

On christmas eve I made arrangements with a VW shop to remove the engine and transmission. I chose the closest one to minimize towing charges.

My arrangement was a little awkward because the owner doesn't like to work on the aircooled stuff anymore. Luckily he was intrigued enough with the project to give it a try. He has a small lot so I needed to juggle getting the bus in and out on the same day, and he _might_ help me mount the DC motor. He would load the engine and bits into the middle of the bus, I'd hassle through selling the engine, which might recoup the cost of the removal but not the tow. Then I also had to figure out how to dispose of the gas tank. Lots of fiddly details to stress about when I want to be thinking about the ADC not the ICE.

Then I had a better idea! Last night I put an ad on craigslist advertising a free VW bus engine to the first technically qualified person to bring their tools, and remove the engine and gas tank. Today I had my pick of folks, chose a nice guy named Fernando who dropped the engine right on my street. Even better - it is going to replace the blown engine on his bus, so it has a new life, it has been recycled! It was an elegant solution, he got a great engine for free, but I feel a little like Tom Sawyer.

The gas tank and exhaust were much lighter than I thought, but a lot of bits were removed in the process that probably made up the difference.

Anyhow, if you wondered what the inside of a 1974 volkswagon bay window transporter looked like without an engine or a gas tank, here is your chance. The gas tank slot is smaller than I thought - usable space is 41"x10.5"x10.5". I am considering a support that extends the bottom of the gas tank slot to 15", exactly big enough to house up to a 147v100ah pack.
EDIT 12/12/12: replaced pictures lost when the forum crashed a few years ago.

starting work_5565.JPG

just jacked up_5550.JPG

engine dropped_5575.JPG

empty bay no gas 10.5 x 10.5 x 41 space.JPG
Brilliant! I was just about to suggest a better alternative to paying to have the engine yanked. It takes a bit longer to do it on vans, but on bugs i know guys that can have one on the ground in under 15 minuites. I'm a lot slower, I'ts taken me an hour.
Fernando Cordoval, who removed the engine, never returned the flywheel/clutch/pressure plate as promised. I'm a dumbass - when he said he didn't bring the tools he needed to remove the flywheel, I should have just pulled out my rachet and done it myself.

As it turns out, he also took the throwout bearing and other parts when I wasn't looking, so it looks like he was planning on stealing it all along. I guess that is why he looked sheepish when I gave him all the extra stuff, like (6) new Mann oil filters I was never going to use. He even got 11 free gallons of gas. I was pretty annoyed that an action so benevolent could be so abused, since he didn't return the parts he effectively stole my engine. I filed a police report, supplying pictures of him, his partner, their truck and its license plate, and video of him agreeing to return the parts on Tuesday 12/30/2009. I hope it aggravates him as much as it did me, I emailed him the police report and left him a voicemail about it so he can at least worry about being deported.




Above is the adaptor plate and hub (hidden in the plastic) I purchased from http://www.canev.com/KitsComp/Components/Adapter%20page.htm for $825. I was quoted $37.50 shipping, invoiced $43.85 shipping, and ultimately the total bill was $884.20, $15.35 more. The last $15 was probably CA-US conversion, I just wasn't expecting it. I paid on 12/23 and it the tracking system shows it actually shipped on 12/23, and arrived on 1/6 (New Years and Xmas holidays slowed it down.


This is the Kelly Controller KDH14500B (144v/500). I won it on ebay from a private seller for $798 plus $11 shipping, $809 total. It appears unused, came in a new box with all the original parts (diodes plugs etc).


Brand-New ADC FB1-4001A 9" motor with a tailshaft, weighing in at 143lbs vs the old 275lb ICE. The delivery guy was very suprised at how much it weighed for a little box. I won this NEW on ebay from the folks at cloudelectric.com for a stunning $1274 - much less than the typical $1700 I see on the street. They shipped it freight for $185, and I opted to spend an extra $100 for liftgate service, so my wife could "receive" it, instead of me rounding up a few folks at work and rushing home to do it. Because of the holidays I didn't actually connect with cloudEV to pay them until late on Friday 1/2, it went out on Tuesday 1/6, and arrived here on Friday 1/9. I still have to open the box! :D


I got the PotBox (Curtis PB-6 clone) on sale for $72.50 and a 500a shunt for $27.95 from http://www.electricvehiclesusa.com/product_p/th-pb-6.htm , shipping was $12.50. This was the cheapest price I could find on a PB-6, their prices are great. I spent an extra $6 for the version with a safety microswitch, PB-5 is the model# without t. I ordered on 12/29, they shipped promptly on 12/30, and it arrived on 1/8.

fuse holders_5608.JPG

I ordered (100) waterproof ATC fuse holders on a 10ga loop for the charging lines, for $1 each. One of these will go on each 8p "cell" so that if there is a fault in the charging cable the cells won't short through it, like they did on my xtracycle pack. Another one will gone on the positive end of the DC-DC charger for the cell to protect it in case of a short. I also ordered (100) 30a fuses for them for $12, my converters charge at 3.7v/20a so I have some extra capacity for future improvements. It cost $14 to ship Priority Mail from ebay powerseller seibs71 who shipped them within the hour of my order, and I got them in 2 days.


EDIT 12/12/12: replaced pictures lost when the forum crashed a few years ago.
Bummer about the clutch parts. The pressure plate is cheap, and you want new throw out and pilot bearings anyway, but dang, the flywheel will costya. Maybe you could scrounge up one from a junkyard but it will be a pain to have to do the looking. Damn I'm drooling over this build. 25 years and I still miss the ol van.
dogman said:
Bummer about the clutch parts. The pressure plate is cheap, and you want new throw out and pilot bearings anyway, but dang, the flywheel will costya. Maybe you could scrounge up one from a junkyard but it will be a pain to have to do the looking. Damn I'm drooling over this build. 25 years and I still miss the ol van.

Once you get Bus in your blood, you get if for life :evil: :shock: :evil: :D

I did a lot of research and finally found out that the 200mm/210mm/215mm were all the same casting/outer diameter, just surfaced for different clutch sizes. I bought a 200mm flywheel on ebay for $129 shipped (thanks, 'Best Offer'"), and a cheap crap clutch/pressureplate/tool also on ebay for $98, both nearby so I'll have them monday. I thought about getting the lightened 12lb version, but then I thought the normal 17lb flywheel would help cushion the driveline against the torque of the electric motor.

Can you actually replace the pilot bearing in the end of the crankshaft? I thought that was just for the flywheel with the glandnut, this is the 5-bolt version. If so I better sort one out quick, and I still have to buy the release bearing.

This bearing I was talking about is in the center of the flywheel, and supports the end ot the tranny shaft. Sometimes it is a bushing. It may be actually on the engine, so maybe you don't have it anymore anyway with the electric motor.
dogman said:
This bearing I was talking about is in the center of the flywheel, and supports the end ot the tranny shaft. Sometimes it is a bushing. It may be actually on the engine, so maybe you don't have it anymore anyway with the electric motor.

I looked it up, and it is in the end of the crankshaft on my year, and you are right, there are no provisions for it on the CanEV hub. I read about someone else having a similar problem (above 4000 RPM) and their solution was to bore a hole in the end of the motor driveshaft and press in a bearing. Looks like the motor will be easy to move in and out, so I'll get it running first so I can move it back-and-forth and sort out the problems later. While I was under it today I noticed the wheelside CV boot was split, so I have to do the half shafts too and wheel bearings while I'm at it - but if the bus is moving I can pay professionals to do it for me. <grin>


Fernanando reappeared out of the blue, reported a death in the family had him out of touch for the past few weeks, and dropped off the flywheel/pressure/clutch combo. I can hang onto the ones I ordered friday. :roll:

I also sorted out my drilling jig for making strips to join the cells. I put a narrow copper strip and drill a 6mm hole every 39mm. Then I put a 12mm M6 set-screw point first into the potted end of the cell as far as it will go. Then I put the set screw through the copper strip and screw in the main-case side of the cell.

Cells showing set screws_5652.JPG

Below you are looking at a 6.6v100a (2s10p) "pack" capable of 500a continous output. The copper strip serves to parallel the (10) 10a cells into a 100a supercell, and I will land the fuse for the charger lead on one end. By putting the next charger lead on the opposite side of the supercell, the path through all the individual 10a cells should be electrically equivalent, so they should all get the same charge. 48 supercells will get me the 144v pack I am looking for.

Steven of Kelly Controllers told me that although the KHD14500B Controller puts out 500a on the motor side, it never draws more than 400a on the battery side. I am going to build the actual pack at 8p for 80ah and 400a continious output. I intend to eventually mount this pack in the gas tank, but during testing I am going to build it on the floor in the middle of the bus, one cell high (1/5"). The space is 60 inches wide and 48 inches deep, so I can build a row of about 10 supercells from one side of the bus to the other. I'll builld a wood enclosure of plywood sheets and 2"x2" to hold and separate the rows. I can build fit 3 rows of 10 supercells (fuse between each row) into the space, good for about 30 supercells or 96v. I can see how far/fast that gets me and get a better sense of how big the pack needs to be. Once I know what I need, it should be very easy to reconfigure the pack into its final location.



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EDIT 12/12/12: replaced pictures lost when the forum crashed a few years ago.
Here is the brand-new motor!


hub and parts_5611.JPG

This is the hub and parts that came with the red adaptor place. The Flywheel and Flywheel locking plate bolt to the hub using the 5 bolts in it. The four short bolts mount the motor to the red adaptor plate shown earlier. The four long bolts attach the adaptor plate to the tranny bell housing, the big long one on the upper right by the starter. Oh, and the little rectangular block is the key that connects the motor shaft to the hub.


motor and hub_5637.JPG

This is how the adaptor will position over the motor - the end of the the tranny input shaft will be inside this hub, almost to the end of the motor shaft (I Hope)


EDIT 12/12/12: replaced pictures lost when the forum crashed a few years ago.
Funny how that works. A guy I know bought a new car and a new engine for it together twenty years ago. Now he's too old to drive anymore, in his nineties, and still has a brand new engine in a crate in the gargage. He says it's the only car he ever owned that never needed a new engine. :D
Last weekend, I lost all of my data for the last three months to a virus... :evil: So I had lots of pics to post, but now they are gone. :oops:

Today I finished a row of (10) 80a supercells, thought I would share a pic before another virus deletes it. It is 53.25" long, 12.5" wide, and 1/5" high. It is made up of (80) 0.75lb cells, and weighs 60 lbs. The floor of my bus has space to lay (3) rows of these, for a total of 90v80ah rated for 400a@5c.

For now, this will be good enough to get the bus from one side of the street and evaluate how big a pack the bus needs. My next goal will be to build that pack and relocate them to all to a special rack where the gas tank was.

10 supercells_5766.JPG
Wow, I don't know whether I do or don't want to see pics of that many headway cells. :shock: You might want to reconsider street parking for that bus once it has a few thou worth of cells in it! The crime of the future is gonna be stripping lifepo4 packs out of ev's.
I finally got a chance to work on the Bus today, and got the motor assembled and installed. I drilled a 1.5" hole in a piece of 4x4 to accomodate the tailshaft, and stood the motor on end on top of the 4x4 so that all the parts would lay flat when installed.

First I had to insert the key into the shaft. It was not easy to fit, and when laid directly against the key slot it would rotate rather than go in. I finally laid it against the corner of the slot at the end of the shaft, and was able to tap it in with a hammer. More careful hammer taps slid the rest of the key into the slot, and a few more slid it flush with the end of the shaft.

The hub is now slid over the shaft and the key. This also was a tight fit, and the key was roughly cut ad the ends, so I had to file the upper edges for it to clear. It took a few taps of a rubber mallet to sit the hub flush against the end of the motor. In the next photo you can see the two holes for the set screws; each hole has a pair of set screws, one to contact the shaft, and the other to lock in the first. Lacking guidance, I torqued them to pretty effing tight. NOTE: these do NOT use loctite. DO NOT USE THREADLOCKER HERE! I wish this hub came with a pilot bearing (or someplace to press one in) but it doesn't. I hope this isn't an issue, it is probably fine when the clutch is clamped, but it certainly makes me less inclined to change gears once in motion.

View attachment 2
Then the red adaptor plate is bolted to the face of the motor. Lacking guidance, I torqued them to pretty effing tight with blue loctite. The center hole is tight so the plate rocked a bit, and didn't lay flush until torqued down. Note that 1 of the 4 bell-housing bolts is thicker and longer than the others, it goes next to the starter on the upper right side of the bell-housing. Make sure your adaptor plate is bolted on to orient A1/A2/S1/S2 the way you would like or you will be yanking the flywheel back off to change it. I chose to have these bolts facing up, so when looking at the shaft end of the motor, the big bolt hole is on the upper left.

The flywheel is installed, with the bolts torqued to 80 foot/lbs in a "star" order (per vw manual). I used (4) slide clamps to keep the flywheel from spinning, and held it as tight as I could with both hands, as my petite wife put her all into pulling the torque wrench. We are both sore from this one, but got it done. I used blue locktite which I hope will be adequate, maybe after I verify it is all working I'll tear it down and use red.

Then I laid the clutch disk onto the pressure plate, and centered it by eye as best I could. It helped to have the motor standing on end so I could spin the flywheel and see where the clutch was off-center. Then I carefully laid the pressure plate on top, inserted all the bolts for a few threads to make sure it was lined up, then loctite-blued each bolt in turn and hand-tightened it. I finished by torquing each pair of opposing bolts in turn, to 18 ft-lbs (per vw manual).

EDIT 12/14/12: replaced pictures lost when the forum crashed a few years ago.