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

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.

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

Postby oatnet » Sun Mar 01, 2009 10:54 pm

Malcom and Markcycle, you are correct - I reset it to .0500 and I now see triple-digit amps - Thank You! I don't know any better, and I was thrown by ebikes.ca's comment on the high-power external-shunt version:
By default, this unit is supplied in the High Range mode (resolution of 0.1 A instead of 0.01A, and display readings in kW instead of watts) and the shunt is set to 0.500 mOhm.
http://ebikes.ca/drainbrain.shtml

But my next questions: Will the polyfuses and long wire runs affect the CA readings at all?

Doc, you are also correct, I was thinking 100 watt-hours but typed ah. At 45mph, I have been expecting right in the the range TD specified, 350-500whpm over non-flat ground, but I am secretly hoping that lighter weight will get me to 250whpm. Other than downhill sections of my test route, the bus at 48v was not able to achieve speeds where drag was a serious factor. I am sure that given enough flat road I could run it through the gears and get to higher speeds, but it isn't very flat around here and too many stoplights will keep that from happening.

Assuming my CA readings are accurate, today I demonstrated that without serious drag, it only takes @100 watt hours to move the bus a mile, or 100whpm. When I add enough cells to achieve higher speeds, we can see how many more watts drag will consume - so if it is 350whpm@45mph, then I postulate that 250 whpm will be what it takes to overcome drag.

Jd, could you test that... "For the science!"


Doc, that is exactly what this build is about - testing it for the science, to see how LiFePO4 weight savings impact a large vehicle conversion (sorta the worst-case scenario vehicle). Sadly, what you see in the video today (speedometer on the left side) is all I can get out of it. Time to place my next order for Cells from Victoria at Headway and see what I can get from it. Trying to make up my mind on whether to go 90v as originally planned, or skip right 120v.

-JD

PS - yeah, I realized you can see parts of me in the clock. :oops: I strive to not post self-images on the internet, but figured it would be hard enough to see me that this one didn't matter. :D Besides, I had to get the data out!
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Thu Mar 05, 2009 1:07 am

Today I ordered (120) more cells from Victoria at Headway. :D Excellent Customer Service again!

I marked up an aluminum plate to mount (10) of the 48v-3.7v DC-DC converters. I used my drill press to make 6 test holes to mount one converter, and used my reversible drill with a matching bit to cut threads for screws... The tiny thread bit snapped off on the second hole :cry: . Any advice on cutting threads? I didn't use oil, should I?

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

Postby thomas » Thu Mar 05, 2009 5:33 am

I just do the threads with a hand tool if im afraid they will crack. I always use some oil but not sure how much its needed in alloy.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby markcycle » Thu Mar 05, 2009 7:38 am

For thin (less than .125") I use a combo bit its a drill bit and tap Greenlee makes it and its designed to work in a electric drill.

Ace hardware sells it
They save a lot of time

http://www.acehardwaresuperstore.com/gr ... tml?ref=42

Yes use aluminum cutting oil else the aluminum gauls the tap binds and breaks

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

Postby oatnet » Thu Mar 05, 2009 9:48 am

markcycle wrote:For thin (less than .125") I use a combo bit its a drill bit and tap Greenlee makes it and its designed to work in a electric drill.

Ace hardware sells it
They save a lot of time

http://www.acehardwaresuperstore.com/gr ... tml?ref=42

Yes use aluminum cutting oil else the aluminum gauls the tap binds and breaks

Mark


Shoot, I got the irwin bit and tap at Ace - 4-40 is might small. Thanks Mark!
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby lawsonuw » Thu Mar 05, 2009 7:33 pm

For tapping I've found "Tap Magic" to be nearly magical. (McMaster # 1413K42) No galling and cutting forces are half of dry. Just need a drop per hole. I also like "spiral point" taps. A few cents more but shoots the chips ahead of the tap so you can cut right to the bottom of a hole in one shot. A thread forming tap is something to consider too. No chips, but needs a ductile material and a slightly larger hole. (McM #2531A14 for example)

Instead of tapping 60 holes how about just ordering some thread cutting screws? (like McM #98273A115) When I've used 'em in plastic it helped to do some testing to find out what hole size worked best. (with the right size hole, sheet metal screws should also work)

Could also just drill through and install PEM nuts on the back side. I've used PEMs similar to McM #96439A160 on my own work. Just drill the right size hole and use a punch and hammer to seat the nut.

Otherwise, I do all my tapping by hand (as I rarely do 60 at once!) and most often I use a milling machine with a dead center in the butt of the tap handle to ensure perfect alignment with no bending of the tap.

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

Postby Kurt » Thu Mar 05, 2009 8:32 pm

+1 on the use of TAP MAGIC .
Drill bits,taps ,cold cutting blades and most tooling last for ever when you splash a little of that transparent liquid on them.

if I am not going into a blind hole. I always like to use gun taps if I am using a power drill to drive them. I must say it dose take the feel out of it that you get by doing it by hand .Its easy to underestimate the torque being applied of most power drills and when using small taps its very easy to snap one.

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

Postby oatnet » Fri Mar 06, 2009 1:01 am

Thanks Thomas (missed your post earlier today), lawsonuw, and Kurt! I'll have to give tap magic a try and see if I can actually do this. Vicor recommends 4-40 screws, so the bits are mighty small and fragile. My drill press makes nice, straight holes, but I am worried about keeping a hand tool straight enough to keep from snapping it.

I went back to Ace, found the tap I trashed was the last 4-40 they had, and I couldn't find the one Markcycle recommended. I'll venture out in search of another tap and some tap magic this weekend, failing that maybe I'll just drill holes and use nuts and bolts, instead of wasting time trying to be all sophisticated :lol: .

Or maybe my batteries will get here and I'll be more focused on bumping the floor pack up to 30 SuperCells. :mrgreen:

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

Postby dnmun » Fri Mar 06, 2009 1:23 am

JD, you can use self tapping screws. if it is thick plate, predrill to applicable size and drive them in with a driver. most aggressive would be the joist hanger screws because they are super strong and have a serrated edge to cut into wood since they are self tapping but 1 1/4" long, depending on the load, you could likely use 1/2" zip screws with hex head, 5/16" driver. lotta luminum in there now. you should be able to use non vacuum booster brakes, i think the older vans did not have vacuum assist, or maybe you could find another master cylinder without assist and hack it in.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Fri Mar 06, 2009 2:51 am

dnmun wrote:JD, you can use self tapping screws. if it is thick plate, predrill to applicable size and drive them in with a driver. most aggressive would be the joist hanger screws because they are super strong and have a serrated edge to cut into wood since they are self tapping but 1 1/4" long, depending on the load, you could likely use 1/2" zip screws with hex head, 5/16" driver. lotta luminum in there now. you should be able to use non vacuum booster brakes, i think the older vans did not have vacuum assist, or maybe you could find another master cylinder without assist and hack it in.


Hi dnmun!

The screws need to be tiny (4-40) to fit the slots on the Vicor DC-DC converters, do they make self-tapping that small, where can I find them?

Right now I am using the brakes without a booster and they are servicable, but when they had vacuum they were downright impressive. Besides, I have the vacuum system bought and built (see around page 4), I just need find a 3/8'-1/2" adaptor and they are working. The older Bus's didn't have front disk brakes, so their master cylinder wouldn't work.

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

Postby dnmun » Fri Mar 06, 2009 9:39 am

4-40 is for jewelers, can you drill out the slot to take the zip screw? you can buy them at the home depot in 100 packs, just easy to use and tapping aluminum is the pits, especially so tiny. if you need some 4-40 1/2 then you can use these and drill it out.
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old nickel plated brass screws from someones trash in the past
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby lawsonuw » Fri Mar 06, 2009 11:15 am

lawsonuw wrote:Instead of tapping 60 holes how about just ordering some thread cutting screws? (like McM #98273A115) When I've used 'em in plastic it helped to do some testing to find out what hole size worked best. (with the right size hole, sheet metal screws should also work)


The above McMaster part number is for a box of 4-40 self tapping screws. (I hate that you can't link directly into McMaster's web catalog) Alternatively look up your local Fastenal in the yellow pages. Fastenal's whole business is supplying odd screws and fasteners, they're likely to have what you want in stock or ready for pickup the next day. (there hours usually suck though)

I'd love it if could find the thread forming screws that PC cases use. The threads are three lobbed and they have a tapered point just like a thread-forming tap.

Lawson

P.S. a little poking around Fastenal's web site brought me to THIS search page. Looks like Fastenal has the nifty PC case thread forming screws in catalog.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Sat Mar 07, 2009 10:34 pm

Thanks for the advice, everyone - and thanks to dnmun who offered to send me the screws in the above picture. :D

Using that advice, I stopped by Lowes today and picked up some 1/2" #4 machine screws with a pointy tip. I drilled out all the holes I had marked, and with a little 3-in-1 oil I was able screw them in. It took some trial and error, and the right bit, but once I mastered getting them in with a power screw driver it went pretty quickly. I was really pleased to see the holes I drilled were precise, I had no problem mounting the converters, I was concerned that I would only be able to fit a few screws on each one.

My initial plan was to put three rows of these converters in, 30x48vx2a = 2400 watts, too much for a single Vicor PSU until I get a 220 line installed. This is just for balancing anyhow, so 10 of these will balance a whole 10-supercell row, I'll just need to move it to cover all three rows. Maybe I'll mount a Vicor PSU right on the aluminum plate!

I elected not to use any thermal paste - merely resting on the aluminum plate was cooled the onetested very well, and thermal paste can run and make a mess.

-JD

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

test fit_6065.JPG
Test fitting a few converters
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mounted_6066.JPG
Mounted permanently.
mounted_6066.JPG (70.4 KiB) Viewed 1111 times
Last edited by oatnet on Fri Dec 14, 2012 2:45 pm, edited 1 time in total. View post history.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Wed Mar 11, 2009 12:46 am

I got a call from Fed-Ex yesterday, reporting that my batteries should have been delivered yesterday, but that customs (in Anchorage AL) held them up 'looking for a better description of the product.' I guess these looked like little explosives on the x-ray :D , but at 8:30am today they cleared, and I hope they will be here tomorrow.

Since the weekend I have been making the copper strips that I use for charging, as well as holding the pack together. This is the second time I have made these strips, I thought I would document their construction...

-JD

0_pilot holes_6067.JPG
I cut (20) 0.5" x 12.5" copper strips, and on one of them measured holes that are 39.5mm apart. This leaves a mere .8mm between each cell - just enough to pass air, and provide some room for expansion, while fitting into the 12.5" space available in my battery tray. Then using a nail I tapped a pilot mark to line up the drill bit.

I stacked the strips and taped them together with electrical tape. Then I remembered that the last time I did this, the tape didn't hold very well, so I wrapped some fiberglass tape around that. Finally, I used a small metal bit to drill out the pilot holes.
0_pilot holes_6067.JPG (26.66 KiB) Viewed 1991 times


1_fuse wire hole_6071.JPG
In addition to the pilot holes, I drilled a small hole to slip a few strands for the charging wire through. When the copper strap flexes, I have seen some of the charging wires and solder come off the strap. By getting strands of copper on both sides of the strap, and solder through the hole, I form a mechanical bond that seems pretty strong.

Also note (more on this below) that the entire body of the cell is connected to the positive side. The Negative side of the battery can easliy be shorted to the case, so I put the bulk of the charging wire on the side of the copper strip where the batteries go, and feed just the few strands on the side where the negative end of the cell is at risk, so there is more clearance.
1_fuse wire hole_6071.JPG (26.87 KiB) Viewed 1991 times


2_m6_drilled_6073.JPG
Here I have drilled 1/4" holes through all 20 strips, which is slightly larger than the M6 set-screws the Headway uses, just right for my needs. Unfortunately my 1/4" cobalt bit was dull, I think drilling the Phenolic plastic did that, so some of the strips on the bottom did not turn out well. Fortunatly, I made spares just in case.
2_m6_drilled_6073.JPG (29.83 KiB) Viewed 3560 times


3_fuses_attached_6087.JPG
Strips stacked on top of the vicor chargers. The fuses have been soldered on the ends for the charging wires. It is VITAL that charging wires have fuses immediately where they leave the battery, because if you short charging wires, your pack will go up in flames - I learned this, first hand, on an ebike pack.

I connect the charging wire to opposite sides of the supercell to make all the individual cells the same electrical distance from each other. I eventually will stack rows of batteries in box full of trays, so I want all of the fuses to be accessable from one end. Hence, some of the straps have a long wire. This wire runs along the length of the copper strap, and if it shorts out to the same strap it is soldered to, no fire. Still, I double-heat-shrink the connection between 10ga extension wire and 10ga fuse wire.

The unused straps at the top will be cut up to make the 4s4p 12v40ah battery that will power the bus's lights/turn signals/radio etc.
3_fuses_attached_6087.JPG (73.83 KiB) Viewed 1115 times


4_circles_drawn_6091.JPG
I cut a piece of cardboard to the same dimensions as the contact patch of negative end of the cell, which is slightly larger than the positive side. I used an M6 screw to line it up, and drew the contact patch on the side of the copper strap where the negative ends of the batteries will go. This helps me line up the heat shrink.
4_circles_drawn_6091.JPG (85.99 KiB) Viewed 1115 times


5_heatshrink_laid_out_6099.JPG
I found this GREAT adhesive-lined heatshrink at a local electronics swap meet for $1 per 4' tube. I didn't even realized it was adhesive until I used it on the last battery strips, I just bought it for diameter, but it is perfect for this job, this heatshrink won't slip, and it is extra thick.


I measured the length I needed, cut up two tubes, and had the exact number of pieces I needed to do this job. Spooky. Here you see pieces laid out ready for the heat gun.
5_heatshrink_laid_out_6099.JPG (22.97 KiB) Viewed 1986 times


6_heatshrink_applied_6100.JPG
Heatshrink shrunk into place. It is vital to have this heatshrink here. If one of the cells twisted 90 degrees, exposed copper could cut through the battery's plastic wrap and short the negative terminal to the case. Between the heatshrink and the adhesive, that's not gonna happen now.
6_heatshrink_applied_6100.JPG (14.66 KiB) Viewed 1986 times


7_trim_end_6101.JPG
The copper past the terminal carries no current, but it too could short against the negative terminal and casing. It was simple to trim off with metal shears. I left some excess strap on both ends, in case I made a mistake drilling the fuse wire hole, or the other end came out too short; its all about the fallback positions!
7_trim_end_6101.JPG (22.15 KiB) Viewed 1115 times


8_end_of_batt_6102.JPG
Here is the copper strip against the negative end of the battery. The silver ring is the end of the case, carrying the positive charge. It is covered in some protective plastic, but you see how easy it would be for the strap to short between the silver ring and the negative terminal. The heatshrink covers the entire area where contact could occur, and you can see the adhesive oozing out which holds it firmly in place and makes a hard, thick coating. I like adhesive shrinkwrap!

Note that the set screw is put into the negative side of the battery. Once can put the set screw, hard against the bare metal of this side. The positive side is not a solid chunk of metal, and it seems like you could cut into the cell if you bolted the screw down on that end. With it bolted into the negative end, there is plenty of room to tighten against the positive end.
8_end_of_batt_6102.JPG (36.7 KiB) Viewed 1115 times


9_fuse_heatshrink_6104.JPG
The Fuse end of the charger strip needs to be protected from shorting against the case. Because of the charging wire and the short length of the space, this is difficult and never comes out neatly. I found that cutting the heatshrink on an angle helped.
9_fuse_heatshrink_6104.JPG (24.32 KiB) Viewed 1115 times



EDIT 12/14/12: replaced pictures lost when the forum crashed a few years ago.
Last edited by oatnet on Fri Dec 14, 2012 2:53 pm, edited 4 times in total. View post history.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Wed Mar 11, 2009 12:48 am

a_fuse_heatshink_6105.JPG
Heatshrink shrunk, and pushed into place as best I can. It also helps secure the charging wire.
a_fuse_heatshink_6105.JPG (17.55 KiB) Viewed 1982 times

b_finished_6106.JPG
Finally, complete battery connector strips, waiting for cells.
b_finished_6106.JPG (67.31 KiB) Viewed 3561 times


Hope that wasn't too boring!

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

Postby pwbset » Wed Mar 11, 2009 11:51 am

Very cool! I may have missed it, but where do you get that copper strapping? All I've been able to find locally is plumbers "copper plated" strapping, which I'll use, but wonder about conductivity losses or whatever.

I also saw last weekend a "new" auto shop in the neighboring town that carries old Type II Westys! They are beautiful! Now all I need is a lot of money. :lol:
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Wed Mar 11, 2009 10:23 pm

pwbset wrote:Very cool! I may have missed it, but where do you get that copper strapping? All I've been able to find locally is plumbers "copper plated" strapping, which I'll use, but wonder about conductivity losses or whatever.

I also saw last weekend a "new" auto shop in the neighboring town that carries old Type II Westys! They are beautiful! Now all I need is a lot of money. :lol:


Thanks pwbset! I went through the same painful search, but I finally found the ebay seller "metallectric" who sells 1/2", 1", and 2" thick rolls. I just went to look him up, but his ebay store says he is 'away' so ebay won't let you even look at his completed auctions. :roll: Hopefully he will be back soon, I have wiped out my stock of 1/2" and 1" (see below). I hope you find the Westy of your dreams! I think a splitty would be a very cool conversion, but I think the 72 up versions are the most practical and servicable.

First off though, LiFePO4 Porn 8) - Headway Heaven - (120) new cells arrived today via FedEx. The last batch of cells got here 3 business days after I wired payment, these cells took 5 days, but only because Customs interrupted the shipment in Alaska and SAT on them for two days, I guess maybe they looked like little bombs or something on the x-ray :lol: - the last batch sailed right through.

They are lined up like this, out of their white 2-cell shipping boxes, because I tested every cell; most arrived at 3.37v, 3-4 were at 3.38v.

THANKS Victoria, for a great product at a great price point and EXCELLENT customer service. It is always a pleasure to deal with you! :D :D :D :D

-JD

Headway Heaven 6112.JPG
2 boxes of cells, ignore the reflection.
Headway Heaven 6112.JPG (77.09 KiB) Viewed 4091 times


end_row_cutting_6108.JPG
Here is the last of my 50' roll of 1" copper strap, getting cut into strips that I will laminate together to form the ends of the third row of cells. Note the one strip that has already been marked up, top center, and drill points punched.
end_row_cutting_6108.JPG (51.49 KiB) Viewed 1195 times


end_row_taped_6111.JPG
The individual straps are hammered flat between two pieces of iron, one piece marked, and all of the strips are taped together for drilling. That will have to wait for tomorrow, I am beat from checking all the cells!
end_row_taped_6111.JPG (27.67 KiB) Viewed 2495 times


EDIT 12/14/12: replaced pictures lost when the forum crashed a few years ago, plus deleted (1) smilie since apparently an 8-smilie limit was implemented after I added this post.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby markcycle » Wed Mar 11, 2009 10:35 pm

Wow that sure is alot of cells those pictures are almost NSFW because its not good to endlessly stare into the monitor smiling with envy at some point your going to have to explain what your looking at.

I can see that bus burning rubber any day now

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

Postby oatnet » Fri Mar 13, 2009 11:28 pm

markcycle wrote:I can see that bus burning rubber any day now


Now THERE's a thought. I wonder if I can get to that point? That would make a heck of a video... Even if I end up not needing the full 180v the controller can handle, I oughta do it to see if I can do a burnout. Wow.

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

Postby Doctorbass » Sat Mar 14, 2009 12:14 am

Oatnet.. I really like your project!!..

wow all these cells at your home!! I would love having that!!!..

I just think... 100+ hours of intense test!! lol :lol:

Be carefull with 180VDC !!.. we want to keep you alive :wink: just 100VDC on my arm kick me strong!!!

Alot of Wh!... eee.. may i should replace with kWh !!!

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

Postby Lapwing » Sat Mar 14, 2009 4:28 pm

Be carefull with 180VDC !!.. we want to keep you alive just 100VDC on my arm kick me strong!!!

Alot of Wh!... eee.. may i should replace with kWh !!!

Doc


Yep, anything over 48V needs careful attention. Rubber linemans gloves are not overkill.

If you haven't already, this is a "must read"

http://www.evdl.org/pages/plasmaboy.html
http://www.evdl.org/docs/plasmaboy.pdf long version

Perspective is everything, and it helps to learn from others experiences.

I run a 72V system of 220Ah lead acid GC in my boat, and decided to isolate the batteries in 24V blocks. When the 3 contactors are off I have 3 x 24V banks. (easy and safe to work with and charge). Only when the contactors energise is it a 72V system.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby dogman dan » Sun Mar 15, 2009 5:37 am

Those isolated blocks of 24v are a damn good idea! While 48v might be pretty safe, you still get that tendency to vaporise a fitting when you screw up. I love good common sense ideas like that.

Now if I can just find a clean shirt to wear after looking at the pile of headways, dooling copiously. I can't stop thinking about that same pile of lithium in a geo metro or bug. As they say in Waynes World, someday,,,, it will be mine!
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.

See the frankenbike longtail at the thread below.
viewtopic.php?f=6&t=28389&hilit=bouncing+betty
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby Fishmasterdan » Sun Mar 15, 2009 9:54 am

Great project, somehow I missed this thread.

Keep up the good work. This looks like a really fun project.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby oatnet » Sun Mar 15, 2009 12:57 pm

Lapwing wrote:Yep, anything over 48V needs careful attention. Rubber linemans gloves are not overkill.


I hear you Lapwing!

In the picture below, note the linesmans gloves on the right. Each of the rows of batteries is 10 cells, 30.00v/33.75v/36.50v (nominal/resting/fresh charged). Note the red 2/0 cable connecting rows 1 and 2, with 400a Silicon fuses on BOTH sides. Rows 2 and 3 are connected by a solid bus bar for 60.00v/67.50v/73.00v, which I am thinking about cutting so I can fuse between them. The wire for each single-cell charger is fused right at the battery terminus, and although the unterrminated ends are just floating around right now, there are no fuses in them.

I also have contactors on both the negative side and positive side, energized by discrete circuits.

I spent a LOT of time thinking about every exposed surface, and have taken great pains to cover every potential contact point possible. I don't have exposed terminals like an SLA battery, and I am pretty sure i could drop a wrench anywhere and not conduct current - but I don't want to test it out either. :lol: When I put a sheet of plywood on top, this pack should be pretty well enclosed and maintenance free.

For the final mounting of the 180v pack, I am thinking of putting it between the front seats, 5 supercells per row, stacked 9 rows high (13.5"). Each row will rest in a tray that slides into a big steel box, each tray will be lined on all 6 sides with phenolic plastic, and each row will be connected by a silicon fuse. Cooling will become an issue at that point, and I have a lot of other vehicle-mechanical things to sort out first, so it will be a while before I go there.

ANYHOW, I busted my hump last night, and got all of the new batteries installed. :D :D :D I finished about 8:30pm and thought I would take it for a quick test. Clicked on the main contactor, clicked on the control contactor, pressed the pedal... and nothing happened.

So I tried to sort it out in the dark. I thought maybe I had popped a silicon fuse, but everything tested fine. Frustrated, I gave up for the night. I tested it again this morning, found continuity between the contactors, just no power! I ran a wire to test continuity of the negative 4/0 cable, which I had just been moving all over the place, and yep it was OK. Moved the wire to the positive 4/0 cable, which hasn't moved much - no continuity! I wiggled the battery side of the negative cable, and to my horror it came off in my hands, pulled right out of the lug.

So, power off, jammed the cable back into the lug, and viola! 108v. I could not resist taking it around the block to see how it rides. At 108v the bus now has at LEAST as much power as it did with the old ICE - plus with electric torque it is a little faster off the line. :D :mrgreen: :D :mrgreen: :D :mrgreen: :D

This means I have met one of my design goals; I have successfully converted this bus to match ICE speed/accelleration, and because I used LIFEPO4, it is LIGHTER than when it started. There was no need to use 10c cells because the 80ah supercells will only be running around 2c continious, 40% of Headway's continous rating.

The Cycleanalyst, which is only rated to 100v, was flickering under load, and I could smell something burning, so I unhooked it. Until I can figure out how to get it working over 100v, or buy a new Custom version from Justin, I am not gonna have performance data :cry: The cells were ice-cold immediately after the "ride."

Next, I need to fix/replace the 4/0 cable, wire the Vicor DC-DC single-cell charger system, and start dealing with mechanicals like the motor mount, brakes, fluids etc.

Then I am gonna try to soup it up - it will be a real screamer when I bump to 180v, even with the extra 80 or so lbs over stock that will take me to (I have hauled 1500lbs of slate in this bus, 80lbs is cake 8) ).

-JD <----- Sporting the EV Permasmile!

108v finished_6119.JPG
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the culprit_6122.JPG
Cable on the right, lug on the left.
the culprit_6122.JPG (50.17 KiB) Viewed 2290 times
Last edited by oatnet on Sun Mar 15, 2009 2:24 pm, edited 1 time in total.
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Re: JD's VW Bus Conversion EV project (2 of 2)

Postby Lapwing » Sun Mar 15, 2009 1:27 pm

Awesome project. Glad you are taking the safety thing seriously.

Quick recommendation on crimpers. For a couple of years I used a cheap set of chinese made, box-crimpers up to 4/0 for my marine battery installs (what my employer provided). I was never happy with consitancy of crimps, even when I got really good at judging just how much "extra" to adjust the size nut. Had a several slip out in what seemed a good crimp.

When I quit the boatyard to go out on my own, I e-Bayed a set of THOMAS & BETTS - TBM5. What a difference. Heavy buggers but for $50 - perfection. I use only Ancor and T&B lugs, because these two brands fit the tool and have good dipped plating that holds up.

I did a bit of dangle-load testing on 2/0 cable and ran out of weights at 330#. :)

There is a set on e-Bay now item - 170311308703 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=170311308703
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