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

[pwbset]

The VW addiction grows! Gonna drag home these lovely twins for next to nothing and convert the one on the right to EV eventually.

[oatnet]

Nice score! I look forward to the details!

-JD

[oatnet]

The headway pack was getting way under-utilized, so I took it out and replaced it with this 26s PSI pack, which is enough to move it around:



The Headway pack ended up in my Vectrix instead, here is a VIDEO of the migration:





Link to build the Vectrix build thread:
viewtopic.php?f=12&t=17071&start=60

[oatnet]

The Bus has been through a lot of changes this year. It used to have 8kwh of Headway 38120S cells, which I rebuilt into a 45s5p (164v/50ah) pack and installed it in my Vectrix eMoto. That left me without a way to move it back and forth for street cleaning.

At that time, I had just purchased 26 new-old-stock 10ah PSI cells for pennies on the dollar here, when "Cycle Nine" went out of business. These 10ah PSI/BMI/Lifebutt cells are large and heavy (the size of the Headway 40138 16ah cells) but I have seen discharge ratings from 14c to 20c, depending on who is inventing data at the time. The Bus's Kelly controller is rated at 500a, but that is motor side, it actually pulls no more than 250a from the battery, a 25c load for a 10ah cell. Since it only spikes at 250a as the bus starts to roll, and the cells were dirt cheap, I built a 26s1p pack with them, and they have been doing great ever since.




A few weeks after I built the battery, I came across Robb Protheroe from pluginsupply.com selling 140 PSI cells on ebay. 48 were new, 92 allegedly used less than 10 cycles, but they were also dirt cheap and would work great in the Bus. I was stupid enough to buy them off ebay to get the bulk discount, and after a few days of promises he came back to me, saying FedEx was too difficult to ship with, and he needed more money to ship it LTL. I was peeved, but he already had my money, and it was still cheap, so I caved and sent him another $150.

It took me a while to go through the cells, and found the bottommost box in the carton of "new" cells was missing 4 cells, and (2) were used had a broken pole. A few more cells had low voltage and fast self-discharge. There was supposed to be a set of pair of "lego blocks", a Bus Bar, and set of nuts/washers for each cell. Unfortunately, a bunch of the lego blocks were smashed to pieces, and the shipment was short on Bus Bars and nuts. So I had to pay $150 more than we agreed, and I was short 6 cells and parts.

I started by charging all the cells. I paralleled them into strings of (8) cells, put each string on a single-cell charger, and after charging let it sit on the trickle charge for a few days. Then I let them sit for a while, and matched them based on the Voltage they had self-discharged to. I know that I am supposed to match cells based on IR, but it is my opinion that matching reduces the self-discharge rate of paralleled LiFe cells, presumable because the stronger cells aren't wasting current charging the weaker cells. I've built my last few paralleled packs this way and they seem to hold voltage much longer.

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I knew I wanted to max out the controller with 48s=175v, which meant I had enough cells to do 3p/30ah. The Bus's 250a load would be an 8.5c disharge for a 3p pack, so that was OK. I decided to build the sub-packs in 6 rows of 6 cells, 12s3p, which would give me 36v nominal/44v charged, and just be light enough to be portable and modular.

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I had enough cells to build (3) of these subpacks, and when they replace the 26s pack currently in the Bus, I'll use it's cells to finish the 4th subpack.

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I managed to salvage most of the lego blocks by putting the broken ones on the outside, and meticulously extracting their broken tabs from other blocks. I assembled 6 pack-ends from the blocks and sorted cells into 3 of them. In the end, I only needed to buy a dozen more blocks from AndyH who was kind enough to sell them to me at cost.

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I used (3) 100a fuses between cells 6 and 7, 50a more than the 250a load, although they would probably pass 500a before blowing. If these fuses go it will likely be messy and impactful, so this is not my system fuse, just a last-chance fuse to protect the pack.

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I meticulously cleaned the bolt connectors on each cell, and the bus bars, and loosely bolted them all together using washers and split washers I had harvested from headway cells.
I added bus bars to parallel each block of 3 cells; when I put them on the same parallel string they stacked up unevenly on the center cells, so I put one on each side, giving them the appearance of the number 5 or 2, and causing my wife to ask my why they said "5 5 1" and "2 2 2" on the side.

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On the right side of each pack, the "1's" in the "5 5 1" are where the positive and negative power leads will be mounted. Note that the leftmost column of (6) cells does not have bus bars on it yet. That is where the top row of 6s3p cells is connected to the bottom row of 6s3p. I originally planned to use (7) of the two-cell bus bars to connect all 6 cells, inelegant but easy. AndyH also sold me all of the Bus Bars he had at cost, which was a whole lot of them, but I still needed more.

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To solve the problem, I made 6-cell bus bars from copper strap, which replaced 7 of the PSI Bus-bars on each subpack, and gave me just enough Bus-Bars to finish the first three packs. It took a long saturday to make (8) of them, so I could stack (2) on each pack. The top 4 bars here are rough cut, so the holes don't line up precisely with the batteries, and the ends haven't been trimmed. The bottom 4 bars have been fitted and trimmed and are almost ready for use.

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I tinned around the holes to eliminate oxidation and reduce resistance.

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Here a pair of the 6-cell bus bars are in place. You can also see that I added balance wires, custom-making each one to length. I added andersons to the balance wires, and balance-charged the packs.

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There are (3) parallel strings, and each one gets its own discharge lead. I put 10ga on the two outside strings, but made the center string 8ga. The 10ga each get (1) 45a anderson connector, but I split the 8ga into (2) 45a anderson connector, for a total of (4) 45a connecters per terminal. This gives me 180a rated throughput which is a little short of the 250a peaks, but I have put 90a loads on these 45 connectors for years, so I remain confident I could pull 360a if I needed to.

Note the rightmost lead also has the wire for cell balancing.

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These are the 10ga leads for the sides, again note the balance wire coming out of one side. I put a lug on each side of a wire, bolted it onto the battery, and then cut it in the "middle" so that both sides of the wire were even.

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These are the 8ga leads, looks like I set aside the 4th pair before I took the picture.

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With everything in place on the cells, I removed every net, generously applied locktite, and torqued it down. Which highlights another drawback of these cells - the bolts on these cells are HOLLOW, presumably to save weight. Even being gentle, I managed to snap off one of the cell bolts, ruining the cell, so I tightened the rest by hand, using just the socket. I was able to fully compress the split washer like this, and I could feel when the nut hit bottom, so I think I have done the best possible given the fragility of the terminals.

This picture shows the (3) 12s3p sub-packs lined up end to end. The balance wires are in Green heatshrink. Notice that the sub-pack in the middle has andersons on both terminals, but each of the end batteries terminate in a lug. The lugs will connect to the fuse and 4/0 wire that I used in the bus, and the andersons will connect the sub-packs together, making it easy to insert the 4th sub-pack when it is built. I'll put heatshrink over the blocks of andersons to protect and hold them firmly together.

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Here you can see the I used hot-glue to keep the balance wires in place, and I put big wads of it were the balance wires/discharge leads come out of the lego blocks, to keep them from moving or chafing.

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One of the blocks tipping 33.6lbs on my super-accurate scale, just light enough for me to comfortably carry. By breaking the pack into sub-packs like this, and by using simple andersons to connect them, I add a fallback position for getting stranded. I can easily take the packs out of the bus, transport them to an electric outlet, and charge them there.

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The old Headway pack that matched ICE performance was configured as only 30s, but these three sub packs are 36s, so it will see more voltage than it ever did before. When the 4th pack is built, it will be a full 48s, a 60% power bump.

The controller is rated to 180v, and a 48s pack will come off the charger at 175v. However, after the fluff charge burns off, the pack should be around 164. I have enough cells to make a 4s3p (12v) booster pack that I might add to increase power and range, but that could well be more continous watts than the controller can handle.

The 4 sub-packs will tuck neatly into the space between the front seats, unlike the headways layout that consumed the whole floor of the bus. It will weigh 144lbs, making the bus even lighter too. Unforutunately, 4kw is not much for a car pack, and I still don't know the WH/M this giant vehicle consumes. If it is 333wh/m, it will have a 10 mile range, but I think it will consume much more - in the worst case 1,000wh/m will only give me a three mile range.

I'll be content if I can just drive this to the beach like I did in its ICE days, and park with the side door open to the water. The beach is less than a mile, but I have big hills on the way, so it is all up in the air. If not, at least I got to see how the bus runs at 144v, and the 4kw pack would be ample in a NEV like a GEM.

It is hard to believe that we used these cells on eBikes when their only competition was a123. I remember when they were state-of-the-art, but now they seem large and bulky, and the fragile hollow terminals are annoying. The size and volume of the cells make this the LiFePO4 LFP warns us about. However, volume/weight/durability are not design criteria for this application, but low cost, inert cathode, high c rating, high cycle life, and the great modular lego-block system still make it an excellent choice.

[pwbset]

That's beyond cool oatnet! Thanks for sharing! Would love to see some videos of running at the higher voltages when you get a chance. Doubt you remember, but I got 2 spare 1970s for parts a few years ago (photo somewhere in this thread) and was going to go electric with one of them. Realizing I couldn't afford that I "bartered" them last month for a year's free supply of beer. Seemed like a good idea at the time. Haha. Ironically I'm now negotiating 6 months worth of said free beer for some much needed wrench time on my '72 bay camp mobile, which is still my baby.

Someday I'll go electric still though...

http://blackstarbeer.com/blog/heating-up-whitefish-montana/#/read

[oatnet]

Thanks for the kind words, pwbset! The pics of your babies are at the top of this page, sorry to see them go but glad you got good barter from them. I'll be testing, posting videos and data after I finish the 4th battery and get the bus up to a full 144v (175v off the charger). I want to feel the full difference between the new 48s pack and the old 26s I was running at, so till then I'm just moving back and forth across the street.

I got the three built batteries into the bus last weekend. I also removed the old wood tray that I build for the headways, so this was the first time I have seen the (dirty) carpet underneath it in a couple of years. It is sooooo nice to have that space back! I didn't realize what an obstacle the battery placement was, until it wasn't.

Three subpacks in series, 36s, and the first time I have seen this cycleanalyst climb up to 122v.

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They looked so HUGE on my workbench, but they look so small in the bus. This location is temporary, I want to either move them between the seats, or squeeze them into where the gas tank used to be.

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-JD

[texaspyro]

80lbs is cake ).

Less than one third of a fat chick...

[oatnet]

If you have been keeping up on the a123 module thread (click here), you already know I bought (1) 28s3p and (3) 7s3p modules, to make a 49s3p pack for the VoltsBus. That is 178.85v hot off the balancer, 60ah, 9,702wh@3.3v nominal, 7,761wh usable at an 80% DOD.

I installed that pack in the bus today, and took it out for a spin, stopping at the beach for the first time since it was gas-powered, stopped at the video store on the way back. I covered 4.4 miles, and consumed 1,977wh (12.1ah), so incredibly the bus only used 450wh/mile! I was mostly doing 30-35mph along surface streets, but there are steep hills along the route, so I was expecting 1,000wh/m, 450whm is was quite pleasing.

I did have some trouble on the way back. I was cruising up the steep hill, put it in third gear, and heard a wierd grinding sound - picturing the clutch hub coming free of the shaft. I had plenty of momentum to carry me up the hill to the light, and when it went green, everything was fine, no noise, plenty of power. Shortly thereafter, I'm going up a gradual hill but accellerating hard, I put it in third again, weird sound again, and I lost driving force. Voltage fine, but no amps, which makes me think of an EV problem that belies the grinding sound I thought was clutch.

I run out of momentum 30' from the crest of a hill I could have coasted on home from. Hop out, check the controller, I can feel a spot of heat on the huge aluminum cooling plate so it might have just gotten hot and tripped the thermal... So I power off the controller - takes a long time to drop to 0v from 162v - but when I turned it back on, I had power!

Because of the power-off, I lost stats on vmin, but when I got to the beach, my aMax was 185a, and my vMin was 154.0, or 3.14v/cell. Resting voltage was a rock-steady 162.7v both at the beach and when I got home, or 3.32v/cell. This power is conducted through @25' of 4/0 cable to the controller. I think the 48s PSI pack dropped to 120v on a 250a load.

CLICK HERE to see a 360 panorama of Voltsbus at the beach. If you are on a smart phone or tablet, hit gyroscope to see the 360 even better!

I don't think I listed any pictures of the 48s PSI pack with all 4 modules installed, here it is in all of its 174.4v glory!

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Here is the complete wiring harness for the pack, 32oz, or 2lbs. The modules have a pair of mounting holes for each terminal, so I am using pair of 4ga wires for each connection. I like that this makes it reduntant - if one lead comes loose I don't have a plasma ball from the arc - and the 3-up rule means a pair of 4ga is equivilent to 1/0, great for short runs.

The 28s pack weighs 107lb, and the (3) 7s packs weigh 30lb, so 199lb installed.

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Last night, when I moved the a123 modules into the bus, next to the PSI pack.

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On the left at 134.4 lbs, the 4,752wh 48s 30ah PSI pack, and
on the right at 199 lbs the 9,702wh 49s 60ah a123 pack.

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ditto

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Here are the modules "installed." Don't see them? They are tucked under the seat, until I find a safer home for them.

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Peek-A-Boo - there they are - a really good fit, too.

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Weird how the black cable in the back makes the whole carpet look lumpy.

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a view of the cockpit up front, maybe I'll install that matching carpet in the back now...

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Checking the voltage before we go - 177.7v sounds lucky to me!

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She made it! Parked at the beach, on an oddly gray day - but I'll take it.

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Ahhh Beachside camping at its best.

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[pwbset]

oatnet you're my f-ing hero man. so cool!! you could easily fit 2-3 of those packs in the bus and probably get decent range. $$$ I'm sure, but still... sofa king cool man!

[njloof]

Great to see those modules working well without too much hassle. What's your long term balancing/BMS plan for them?

[Ypedal]

that thing is cool man !!!..

i'm amazed you bolted all those together and only snapped 1 lug !

it's pain too.. in order to remove a cell, you have to remove the blocks from an entire side !!!... ( is why i made my PSI packs in 24v chunks ) .. thse PSI cells are a real deal 5C cell, they will do 10 but sag badly at that level and get HOT.. imo.

[oatnet]

that thing is cool man !!!..

i'm amazed you bolted all those together and only snapped 1 lug !

it's pain too.. in order to remove a cell, you have to remove the blocks from an entire side !!!... ( is why i made my PSI packs in 24v chunks ) .. thse PSI cells are a real deal 5C cell, they will do 10 but sag badly at that level and get HOT.. imo.

Hand tightening with a socket was the key, and watching the spring washer compress helped. I really hope I don't have to replace cells anytime soon. The 250a demand from the Kelly controller, 8c+, got them hot enough for me to smell them, mighta been the hot glue I smelled instead. I agree they would be happiest at 5c/150a, but they would have done the job if I hadn't installed the a123's. Based on the 450wh/m from the beach ride, I could theoretically do 16 miles on a charge with the a123 pack...

The PSI pack is sitting in my garage now, 4.7 kw looking for me to find a new project to call home.

Pwbset and njloof, thanks for the kind words! With quality chemistry like a123 I do periodic balancing with single cell-chargers, and bulk charge the rest of the time. I carefully baseline the pack so I know what a discharge looks like, and watch the WH on the CA to know how much juice I have left in the tank.

-JD

Edit: I just got a question about the dimensions of the new a123 modules, thought I would add links to the tons of pictures I posted on the a123 module thread. so you can see them, and I can find them later:

The first link has measurements of the 28s showing roughly:
28.00" long
9.75" tall
6.30" Wide

viewtopic.php?f=14&t=38901&start=255#p575061
viewtopic.php?f=14&t=38901&start=255#p575214
viewtopic.php?f=14&t=38901&start=285#p575820
viewtopic.php?f=14&t=38901&start=285#p575827
viewtopic.php?f=14&t=38901&start=300#p576267
viewtopic.php?f=14&t=38901&start=375#p579756
viewtopic.php?f=14&t=38901&start=390#p579938

Here HomboldtRc indicates: "The modules dimensions are 6.5" wide x 9" long x 9.5" tall"
viewtopic.php?f=14&t=38901&start=225#p574427

[silverrich1]

where did you buy your psi cells from? and how much did they cost?

that thing is cool man !!!..

i'm amazed you bolted all those together and only snapped 1 lug !

it's pain too.. in order to remove a cell, you have to remove the blocks from an entire side !!!... ( is why i made my PSI packs in 24v chunks ) .. thse PSI cells are a real deal 5C cell, they will do 10 but sag badly at that level and get HOT.. imo.

[oatnet]

After the countless man-months invested in this bus project, planning designing building revising testing upgrading... I was stunned when it only took 3 hours for me to strip it from a running EV to a completely stock rolling chassis.

To be fair, I had already stripped the massive headway pack for my vectrix. But funny how our personal monuments can come down with so little effort. Trying to figure out whether to sell the motor/adaptor/controller, or use it on a new project.

Oddly, the guy came in a tow truck to pick it up, at 10:30 at night. The setting made me nervous, but he paid cash and all went well. He makes/sells biodiesel, and is going to put a diesel into it, so it will continue to be an alternative fuel bus...

I will miss this Bus, but remember our adventures together. Good luck, little bus!

-EOL

[dnmun]

your loss is in all our hearts, RIP.

[The fingers]

Reminds me of the day when my '56 oval rag top got towed away by the guy I sold it to. Maybe it will be run on bio diesel. Hope you get to see it in it's new role.

[Merlin]

was nice to read....any news?

[Dauntless]

News??

I for one am wondering why he stripped it down and sold it.

Did you eventually build something else with your parts? Perhaps another project thread?

[oatnet]

I did eventually get an email from Luis, the guy who bought it. Looks like he did a lot of work to clean it up, majorly buffed it out etc, his pics are below. He reports he put another VW motor in it, and his kids love going to the beach in it. I let it go cheap to move it fast, so it really warms my heart to see this good-kharma bus getting the use, attention, and care it deserved, instead of slowly deteriorating on my street, only moving from one side to another for street cleaning.

The EV parts are being used in another project, which I am not ready to post about yet, but will be its own dedicated thread with a pointer back to this page. I'm always happy to answer questions, but sadly now that I no longer own the bus, and don't really know the guy who bought it, I am not likely to have anything new to update on this thread. If you are desperate for input you could always peruse the thread linked in my signature to view a number of my favorite projects!

-JD

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