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

[Dee Jay]

One man wave ~~~~~~ whoo ! ~~~~~

NICE!

I was suprised to hear how loud it was in the video,

Digital video cameras can pick up high freqs sounds really well

J

 

[oatnet]

CONGRADUTATION!

Dear Mr.JD,

very pleased to see the video of your electric car with our Headway LiFePO4 lithium-ion battery.

Best Regards
Victoria

Thank YOU Victoria, for making the excellent, affordable Headway cell; this brings the technology out of the clouds to something everyone can afford to use. Because it can perform at 5c, my 80ah supercells can supply the 400 amps of power needed to drive a 500 amp controller. Because I can discharge them to 80%, I can pull the same amount of watt-hours I'd get from a 130ah Lead Acid battery. Because they are so light, I don't need to lug around an extra 1500lbs of lead-acid batteries, steel mounting racks, or the extra capacity it takes to move that weight. Because they are rated for 1500 cycles, they will last three times as long as lead-acid cells.

The screw-hole end is a great innovation that makes them easy to assemble into a range of shapes - my simple battery tray doesn't even scratch the surface of the possibilities.

If these cells can effectively, affordably, convert a giant vehicle like a VW camper bus, imagine what they would do on a small, lightweight, aerodynamic vehicle...

NICE!

Thanks DJ!

-JD

 

[GGoodrum]

Very cool, JD. Congrats!

-- Gary

 

[dogman dan]

Awesome dude! 8) 8) 8) I can't wait to see how it does for you in the real world. If I understand right, you have somewhere around $3000 in battereies there. It will be very interesting to see how far you go on them, since they are so much lighter than lead. I'm thinking a bug conversion could be affordable if a lifepo4 pack under $5000 could be practical.

 

[pwbset]

Un-f*&^ing real... as a former westfalia owner that it hands down the coolest damn thing I've ever seen. I will be looking for old scrapped westys now in the hope of someday doing what you are doing! Outstanding work man!!!!

 

[jorhyne1]

Excellent! I know I don't really post here much, but I have been following this thread from the beginning and I almost get that EV grin just sitting at my computer screen. Can't imagine what its like to be piloting that thing!

 

[oatnet]

Thanks Gary!

Dogman, with LiFePO4 prices where they are now 5k is way more than you need to build a pack for a bug. What does a standard bug weigh? I think you could also go with a smaller motor - maybe even a 6.7" - so the conversion would end up much lighter than stock. I'd almost like to tackle one, but my wife would kill me.

pwbset, thanks! A westy with a bad engine can be had cheap... I hope you find one!

jorhyne1, thanks for honoring my thread with one of your rare posts, I am glad you have been enjoying it!

I tried charging the bus with my onboard charger; it worked well but the cells are clearly out of balance. So today's project involved setting up the 48v-3.7v20a DC-DC converters. I plan on mounting 30 of these little things - one for each supercell - on the aluminum plate I got earlier this week.

However, they each draw 94 watts, and the Vicor PSU I am using to drive them is rated at 1200 watts at 120v (although I have seen it supply 1400), so until I get a 220v line or two in my garage I can't power all 30, so I am just going to mount 10 for now - enough to balance a full row of 10 supercells.

First order of business was to trim them to 3.65v. I was planning on using a resistor to trim them, until I stopped being stubborn and started listening to Bill (powermed) and used a trim pot instead. It helped that I was able to buy (10) 100kohm trim pots for $2 at the Swap Meet today 8) . Now I can vary my setpoint to whatever I like.

I bought the wrong size drill bit/threadcutter so I decided to just wire up one so that I could balance the cells one at a time.

I was nervous about soldering the DC-DC converters -vicor has warnings about it - but I found that if I coiled a few turns of bare wire around a nail, it was just the right size to slide on the posts and stay put for soldering. It was then easy to build up a ball of solder on my 100w iron, touch it to the turns of wire for 5 seconds, then cool it with a wrench. before soldering, I slid the posts of the trim pot into the turns of wire to mount it.

I trimmed it to 3.65v, connected it to a vicor PSU, and put it in the bus. I burned my finger a few minutes later - that sucker gets HOT - so I rested it on the aluminum plate and it ran cooler. It may take a while to balance all 16 cells this way though <grin>.

-JD

 

[dogman dan]

The EV limitation I run into is that I live a bit out of town, and on a hill. So I need about 50 mile range, to drive 15 miles away and get home. And have some reserve for battery life. Nearest store for hardware, or groceries is at the bottom of the big hill. So loading on more lead just makes the hill harder to climb as I found out with bikes. For me, a project like that is at least 5 years from now anyway, since a photovotaic roof is a higher priority if I get my finances squared away. But I trust that from you, I can get real information. Some of the EV bloggers do like to exaggerate the results of thier build.

 

[oatnet]

since a photovotaic roof is a higher priority

Solar is good preparation for the future, as is any personal power generation. Did you see my post in 'general' on these motorwave microturbines I am trying out? Very cool concept, supposedly effective in light winds, but the company was difficult to work with:

Some of the EV bloggers do like to exaggerate the results of thier build.

I really hope to not do that, but I have to admit that I want the weight savings of Headway's LiFePO4 to translate into reduced battery requirements, so I am biased. I am trying to be vigilent and stick to facts; I also want to generate very specific WPM info so anyone following in my footsteps will have LiFe chemistry-specific results to base their builds on, it has been a real challange to engineer this without similar builds to compare it to. Accordingly, here are today's test results I went for an early-morning (pre traffic!) cruise to evaluate my watts per mile. I live in a moderately hilly area, so the results are real-world, not flat-surface. The video is below.
[youtube]tYd7jSsM5ZQ[/youtube]

When Justin first introduced the CycleAnalast I bought a beta version of the Jumbo Cycleanalyst (6-wire), specifically for the day I would do this bus conversion. I connected the V+ wire to the battery + contactor. I connected the signal to the controller side of the shunt, and both grounds to the battery - side of the shunt. The shunt is a .50ma/500a, so I configured the shunt resistance in advanced settings as 0.5000 .

Because any of these long 15' 20ga wires could short a huge amount of current and catch fire, I put a polyfuse on all three leads right where they connect. question: Could the polyfuse, and the resistance of the long thin wire, change the resistance and affect the cycleanalyst's readings?

The CA is configured in high-current mode. I am assuming that when I see 50.1 it is really drawing 501 amps, does that sound right? There were a few times it spiked up to 60.x, but my 400a Silicon fuses didn't pop, and Steven at Kelly assured me that the 500a controller would never draw more than 400a, so I think I didn't do something right.

Under peak load the 16-cell array was around 47v, or 2.937v/cell. This corresponds with about 3c on the discharge testing curves for the cells, or 240a on this 80ah pack.

I realized afterwards that I didn't check how many watt-hours the cruise consumed. When I powered the CA back on, I discovered that this version isn't saving data - not sure if it is a beta-bug or my wiring. I went and redid the cruise, this time the bus seemed a bit faster, but the tranny/transaxle fluids I pupt in 6+ years ago were way too viscous, and with the ICE I noticed it was faster after they heated up. I need to replace both of these with a lightweight synthetic.

I adding an extra block for the second cruise to exceed a full mile - and took the start/finish pictures below. If I have the the CA configured correctly, then it turned 100wh right around the 1 mile point. Since it was so slow, I figure this is what it takes to actually move the bus over that distance, and that additional current consumed will be to overcome drag.

On uphills the bus didn't want to go more than 15mph, which was disappointing but I should have expected that from 48v. Now I am wondering if I should go straight to 120v instead of 90v, even though that means building a second battery tray.

-JD

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

View attachment 2

 

[Malcolm]

Great to see the bus moving JD!

The shunt is a .50ma/500a, so I configured the shunt resistance in advanced settings as 0.5000 .

I'm not sure about this, but shouldn't that be a 50mV/500A shunt, which would make the resistance 0.0001 ohm?

If you enter 0.05 (mV) for the shunt value in the Cycleanalyst that should fix the factor of ten error in current readings, I think...

Very interested to see watt watt/hour mile figure you get.

Malcolm

 

[markcycle]

I am using the same CA and I calibrated it to the shunt I'm using. When I pull 150 amps it reads 150 not 15. In the setup you can calibrate the unit for the ohms of the shunt your using.

Great to see the van moving.

Mark

 

[Doctorbass]

Wow.. Great vid JD !! :wink:

I love to see the A and V reading while runing this EV!...

I would doubt that for one mile you would have draw 100Ah.. at 48V that's 4800Wh per mile!!! I would say.. Impossible!

I think that was the right A reading you had and no need to multiply by 10 the current.. So iwould agree with Markcycle on this. At the speed you ran it the power between 750 and 3500W i seen seems acurate...

A bus like this should draw around 350Wh per km at 100km/h.. so at 30km/h I would guess like 150Wh per km.

Will you wire the speed reading of the C-A ? I would love to see the watt reasing and speed!

The idea of replacing the oil lubricant of the transaxel is excellent.. stock oil would draw alot of power!

JD, your video are one of my favorite advertisment of the lasts week!.. please post some more We love it!

PS: Jd, You have a nice look with your black sunglasses!!! 8) ... (we can see you in the analog clock of the dash! :lol: )

Doc

 

[TylerDurden]

A bus like this should draw around 350Wh per km at 100km/h.. so at 30km/h I would guess like 150Wh per km.

My guess will be more like 300-350Wh/km @ 50kph.

 

[Doctorbass]

A bus like this should draw around 350Wh per km at 100km/h.. so at 30km/h I would guess like 150Wh per km.

My guess will be more like 300-350Wh/km @ 50kph.

Yeah... well maybe i should revise my numbers.. I thou about a normal sedan car stat... :?

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

Doc

 

[oatnet]

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. 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. Besides, I had to get the data out!

 

[oatnet]

Today I ordered (120) more cells from Victoria at Headway. 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 . Any advice on cutting threads? I didn't use oil, should I?

-JD

 

[thomas]

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.

 

[markcycle]

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/greenlee-drilltap-bit-drill-tap-and-deburr-in-p-12476.html?ref=42

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

Mark

 

[oatnet]

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!

 

[lawsonuw]

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.

Lawson

 

[Kurt]

+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.

kurt.

 

[oatnet]

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.

-JD

 

[dnmun]

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.

 

[oatnet]

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

 

[dnmun]

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.