My first EV conversion: '69 Honda CA160 "Baby Dream"

Fun video. I look forward to your next one.

Sorry for the lack of update!

I just got the batteries and I'm in the process of re-configuring the ten 4p modules into a 20s2p pack. Thankfully the 4p modules are easier to divide in half than I thought. The pouches' tabs are lazer welded to copper and aluminum strips, and the strips are about 18ga and very easy to cut with sheet metal snips. The cells are easy to remove from the plastic cases too. I'll be able to reuse the cases to help compress the pouches but I'm going to cut off the holes on the sides that the bolts would go through, this will reduce the width by over an inch and allow me to make my "battery tank" a bit smaller. I'll use zip ties instead of bolts. Still working it all out in my head how I will keep the battery pack from rattling around in the "battery tank"

I also fixed up the front wheel, here's a little stop motion video of that job: https://www.instagram.com/p/CKufbhgpBWX/

JimVonBaden said:

Fun video. I look forward to your next one.

Click to expand...

Thanks! Here's the link to that video if anybody missed it.

This thread needs MORE PICTURES!! :thumb:

So this post will be all about the LG Chem pouch cells from batteryhookup.com. They're taken out of rack mount units and I believe they were used as battery backup units in server rooms. The should have around 2/3rds capacity left. When new each cell had around 15ah with a 3c discharge rating giving a discharge of 45amps. But at 2/3rds capacity remaining, each cell is now capable of 10ah and 30amps continuous discharge.

Therefore I will wire them into a 20s2p configuration to get 72v, 20ah, and 60 amps discharge.

I ordered 10 plus one extra in case one pack was lower voltage than the other. This turned out to be a good choice because one measured 3.73v while all others measured 3.76v to 3.78v. I won't bother to wire them all in parallel to balance them all out because I'll be using a BMS and I think that will balance them out for me.



But they come packaged into 4p modules. All four cells are wired in parallel, but two are on one side of the case and two are on the other, and their tabs meet in the middle are are laser welded to two busbars. I'll need to seperate them into two 2p modules, and then wire 20 of them in series to get 20s2p.



Thankfully, dividing them into halves was quite simple. I just used sheet metal snips to slice the busbars down the middle. Actually it wasn't perfectly in the middle, I intentionally cut one side a little more than the other so that the all the cells where left laser welded to a busbar with hole(s) for easy wiring later on.





Then I started to cut up the plastic cases too so that I could use them. They'll make packing the cells into a pack much easier than without them. Just like with the cells, I divided them into halves, except I left a little more meat on the side without the captive nut for the busbar bolts. This will let me screw the tabs into the plastic with little screws, I think that will be helpful when it comes time to make the connections.



So I have two types of 2p modules: the ones on the left and the ones on the right. The ones on the left were flipped over in their cases so that the positive and negative tabs were reversed. This will make it a lot easier to daisy chain them in series when stacked on top of each other.



The tabs are laser welded to busbars that are about 20 gauge sheet metal - but it is difficult to tell without the proper tool. The negative side is bare copper and the positive side is copper with a nickle coating.







I purchased this copper sheet to make busbar connectors but it might be too thin. It is only 0.025 inches, or 26ga. I also bought some 16ga aluminum which is a lot thicker. I'll also want the connections to be a little flexible because the cells need to be compressed and they could be a little shifty.

Can anyone advise on how to make the busbar connectors?

Should I use this this copper sheet, or should I use the thicker aluminum, or should I use neither? Could I use copper wire instead? Do they need to be flexible?

I found a few different formulas for calculating busbar CSA (cross section area).

Here's my crude notes:

TL;DR: different formulas and methods indicate that the CSA should be as a little as 0.016 square inches CSA and as much as 0.05 square inch CSA. For 100amps which is the size of the BMS I ordered even though I don't think the battery pack could do more than 60amps continuously, and the motor couldn't continuously pull more than 55amps.

The copper sheet is 0.025" (that was the thickest they had) so the busbars would need to be like an inch wide...? Could I double them up and make it half an inch? If using the aluminum sheet, it could be half an inch wide but not as good as copper.

I'm thinking about cutting off more of the plastic case so that I can just bolt the tabs directly to each other in series. I'm in no hurry to make that decision though.

Meanwhile...

The hub motor kit I ordered from QS over a month ago arrived yesterday.

First off, the brake parts are missing. I did not receive the calipers, brake lever, and brake line. Only the rotor was found, actually they gave me two rotors... I'm not supposed to use both, am I?



And the aluminum wheel was damaged in shipping.





But thankfully the axle looks good even though the box showed evidence of it taking some abuse. Overall the packaging was not good enough. And there's just no excuse for missing parts. Oh, and the torque plates fit very loosely around the axle, just as Jim described in his thread. They did include a bluetooth connector for the Kelly controller which I wasn't expected. I already purchased a bluetooth connector directly from Kelly a few days ago, I guess I could have saved myself $20 had I have know.

I already contacted the QS saleman and he said they will mail me the replacement parts - as soon as the Chinese New Year is over... which is in like three weeks from now!

So to be honest, I would think twice about ordering another wheel hub and kit from QS again. Thankfully though I have all the parts I need to bench test the electrical drivetrain. I ordered a contactor and some accessories from Kelly two days ago and... ugh, crap, those are coming from China too. I wonder if they're also waiting for the Chinese New Year to end before shipping them.

Another thing: QS laced the rear wheel with a radial pattern. This is not acceptable for a rear wheel! It doesn't have any strength to resist twisting forces.

So now I'll also need to be finding some new spokes in the right length for a criss-cross pattern. Anybody know of a good spoke length calculator?

Below is an image of the rear wheel on the new Sondors ev motorcycle. This looks like an even larger hub motor than what I have and they were able to correctly lace it. I don't know why QS couldn't lace my wheel like that.



Let's just hope that QS is better at building electric motors and not at building motorcycle wheels. Or at packaging and shipping.

To say something positive, at least I have more time now to work on my battery tank!

Thanks for this review.
Looking at what you received, I am glad that I dropped the idea to use a QS Hub Motor for my Bultaco conversion.

FedEx tracing tells me I will receive my mid drive motor and stuff from QS next week.
I will report if the package is as lousy as what you got...

Bummer about your issues. Mine came well packed and complete. Though, like you said, the torque plates were useless. Fortunately I didn't need them.

I'm moving at a snails pace now but still making some progress, here and there. The cold weather is not helping.

I figured out how to connect the cells in series without even having to worry about busbars. I had to step back and reorganize the problem in my mind, and when I did I realized that I was needlessly constraining myself by stacking them in the original order. If I separated them into two groups as shown below, and I flipped every other 2p cell module over in its case, then I could very easily wire them in series by fastening them directly to each other. Positive to negative, positive to negative, positive to negative.



Then I slightly reorganized them again so they would fit the desired shape, and made two connections with 4 awg copper wire. And I have 72+ volts!



However, to connect them this way I had to cut off more material from the plastic cases. I needed to remove the protective plastic around the tabs. This means that there is now nothing in between the cell tabs, nothing to isolate them from each other and prevent a short circuit. I learned this the hard way when I was testing the voltage, and...



...I accidentally welded the tip of my voltmeter probe to one of the cells!

My plan is to first wrap them in extra thick electrical tape, then stuff foam strips between them, and then wrap the whole thing in electrical tape. I can't find shrink wrap tube large enough!

I also have the BMS now (100amp from DALY), so I can begine wiring the balance wires before I wrap everything in tape and foam. The BMS is the shared charge-and-discharge-wire variety, and that just makes it even more confusing (can I have the charger in parrallel with the discharge wires or do they need to be seperated?). And my charger should arrive today too, I wonder if I can fit it in "battery tank".

would it be a bad idea to put the charger inside the battery box?

Not if it doesn't get too hot when charging. But why do you want to permanently take the charger with you? I only take my charger with me when I really need to for range. But mostly my round trips are shorter then the range so I have the charger at home ready to charge when I get back. Saves weight and room when not needed.

As a compromise, try fabricating a custom padded & ventilated charger carrying box on the bike, so you can take the charger along OR leave it home, as needed. Second choice would be a cargo box of some sort.

New youtube video coming very soon.

Here's the finished battery pack:



Next I will need to build the battery tank, the metal enclosure that the battery pack will go into. And I'll also need to figure out how to keep the battery pack from rattling around in there. I will probably strap it to the bottom plate which will be fastened to the tank with screws.

I'm going to fabricate it from 18ga mild steel sheet metal (16ga for the bottom plate), and then then have it powder coated. I'm also going to design large metal brackets that will allow me to fasten it to the motorcycle frame as well as provide strength in the absence of the old ICE engine, and the brackets will be laser cut from 1/2" steel.

I just uploaded a new video to youtube!

https://youtu.be/y8Lub23ZYis

[youtube]y8Lub23ZYis[/youtube]

Great video again :thumb:

Very skillfully made video. :thumb:
Especially the stop motion sequences in the beginning are great fun.

I was also watching the battery construction part with big interest
(because this is waiting for me, too, sometime in the future),
and to this part I've got a question:

If those battery elements are supposed to be compressed
(what I think I have read also in other battery build threads)-
why do you hold them together only by some cable straps,
and not by some more rigid construction,
like two boards connected by threaded rods,
or something like that?
Would this be TOO MUCH of compression?

If those battery elements are supposed to be compressed
(what I think I have read also in other battery build threads)-
why do you hold them together only by some cable straps,
and not by some more rigid construction,
like two boards connected by threaded rods,
or something like that?
Would this be TOO MUCH of compression?

Click to expand...

Good catch! They should at least be steel cable, as plastic straps have a habit of degrading and letting go after a year or three. The Leaf cells in my VX-1 are held tightly together by threaded rods.

I added a few more cable ties before wrapping it all up in tape, not sure that got captured in the video. If I remember correctly, there's five cable ties.

But when it comes time to strap it inside the battery tank, I was going to use something a little more heady duty. Not sure what yet though, so I appretiate the suggestions

So it's not too late to add a little more strength, thanks for the input!!

BTW I'm taking a little break from the bike build right now because I'm building a new garage, and we just learned that my wife is pregnant

I started construction on my garage so I have been busy with that lately, however it has been very rainy this week so I got a break from the construction and that gave me some time to work on the EV CA160 project. Oh, and my wife started demolishing the downstairs bathroom and laundry room and she wants me to work on that too. Oh, and my wife is pregnant and we just found out a few weeks ago, so now she won't be helping at all. So have less than 8 months to finish this yet no time to work on it!

There's two problems between the swingarm and the new rear wheel that I knew I would have to deal with even before the wheel even arrived:

• the swing arm is not wide enough to fit around the hub and onto the axle. It's 190mm wide and it needs to be 210mm wide to fit the wheel.
• the slots in the dropouts to hold the wheel will not work: they're too wide. The hub wheel's axle has to flat spots so that it won't spin relative to the rest of the wheel. There's a lot of torque (150 Nm max) that the hub motor puts on the axle, so this is very important. It needs to be a tight fit with no slop.

So before I could mount the motor/wheel inside the swringarm so I could securely test it, I needed to modify the swingarm. First thing I did was grind off all the old paint.



(btw, these images are all optimized for web shrunk down to an appropriate size and dimension, but if you click on them you will get the full size images)

Below you can see how Honda constructed this part of the swingarm. They sandwiched 6mm steel between to sheets of stamped steel about 18 gauge. The 6mm plate in the middle was welded to the bushing for the shock, as well. Then they spot welded it all together.

At first I thought that this would be a problem for welding onto, but my friend who did the TIG welding later on assured me that it was not an issue.



Of the other EV conversions I've seen where they use a Honda Cub or similar with a hub motor like this, they first widened the whole swingarm by cutting the center tube, widening it with new material, and then welding it back up. Then they added material to the dropouts to make them the correct size for the axle.

However I thought of a better way (IMO). The outside dimension between the stock dropouts was exactly the inside dimension needed to fit over the hub. So I decided I would knock out two birds with one stone by cutting out the old dropouts and welding new ones such that the inside surface of the new dropouts would be butted up to the outside surface of the old dropouts.

So I began "milling" the dropouts out of 3/8" steel and using a cheap HF drill press and a cutting wheel on an angle grinder. I could have designed them in a vector file and send them out to be lazer cut, but I thought it would be fun to do it myself.







I cut the slots in the dropouts to 11.9mm (with a 15/32" drill bit) when they needed to be 12.0mm. Then I used a file to carefully and slowly enlargen them until they perfectly fit onto the axle with zero slop. I wanted a very tight tolerance so that when I hit the gas or hit the brakes hard, it wouldn't shift and slam and eventially work it's way loose. If for some reason that axle where to spin with the wheel, it would coil up the wires between the wheel and the motor controller, ripping the wires out and destroying the controller.

Then I cut away the old dropouts. I needed to remove about 30mm diameter around the axle location, so that there wouldn't be any interferance with the disc brake hardware and with the motor's wires.



I tack welded one of the new dropouts on...



...then I used the bolts to tighten the other one on before tac welding it in place. This ensured that the two dropouts where perfectly aligned for the axle to slide in. I also made sure that the wheel was straight up and down, I did this by sight (used my eye-calipers).



Then I took it over to my friend's place and he used is 240v TIG welder.





Here's why he wasn't concerned about welding it to the sandwhich of sheet metal and plate metal: because on the inside, there was easy access to weld the two plats directly to each other.



However the TIG machine was having a hard time with this spot - apparently there was a lot of contamination. My fault as I did not know that TIG welding needed the metal to be perfectly clean and free of all paint. That's also why there was a few blow outs and holes in the above photos.



So I will have to weld that area myself, and I'll use my stick welder for this because my MIG welder cannot do metal this thick. Stick welding tolerates a lot of crap in the metal.

But what's important is that the wheel now fits on the swingarm!



And there is absolutely ZERO slop between the dropouts and the axle! There's no need for any torque plates, and the ones that came with the wheel had a ton of slop in them.

I'm very happy with how its turning out! I have a little welding to do and a little cleaning up to do with the grinder but the hard part is already done.

What a great way to do it, and it will look clean too!

It's been almost an entire year since I last worked on this project.

I've been just a little busy building two things: a baby and a new workshop. Well, my wife did most of the baby making work, but the workshop build easily took up all of my time. But now the time has come to get back to work on converting my 1969(?) Honda CA-160 "Baby Dream" to electric, a.k.a. Project Dream-E.

Her she is in her new home:







It's a motorcycle-building paradise. Yesterday I found myself sitting on the couch to work on the swingarm. Go figure lol.

Exterior:



Before and After:



...

The last thing I did on the CA160 EV was fabricate new dropouts for the swingarm, but there was one last thing to do: weld on a tab for the disc brake mount. I also welded on a few washers that will be nice attachment points for some zip-ties.



Next, I wanted to get the motor controller mounted to the motorcycle's frame/body (it's one stamped piece of stamped 16-ga steel), and get that sorted out before paint.

I knew I wanted it in this location, but it just wasn't going to fit perfectly, and I needed to reshape the body a little.



The above image shows the cooling fins on the backside of the controller, but on the other side is the controller itself.



The photo below shows the line that represents what I will have to cut:



As you can see, it doesn't perfectly fit in this indention in the frame where the old lead-acid battery was. I'll have to correct that.



Several hours later I had this:





I haven't yet but I'm going to reinforce that lower-right corner of the frame. Actually, I'll probably box it in with the other side. Originally there was a carb and air-box in that space, but that is no longer needed.

Great work on the baby, shed and Dream-E. You've been busy :lol:

QUESTION:

Does the battery box need to be air and water tight? The battery cells are encased in plastic and wrapped in foam and electrical tape. I'm going to build a metal box for it and im thinking about adding louvers for good looks and for air cooling of the batters.

what do you think?

I think they should be watertight, especially if you have foam around the cells.

thanks bjork