jonescg's NEW electric racebike BUILD thread!

[Jay64]

I have been trying to get caught up with this thread, I missed a few pages worth of posts when I was gone on my trip. I also was going to suggest something like the EIG setup as I was reading along, but then saw that AW already suggested it by the time I got caught up to the last page. I will take one of my packs apart today and take some detailed pics. I was really impressed at how simple but efficient these pack designs are. I was a little concerned about trying to replicate it for different packs because of the cost of making an injected mold part. But if you are thinking of making something using that process anyways, doing it this way might be a lot cheaper, since the part is basically the size of each cell, and then the stack into each other. But this specific design only has them connect to each other in a straight up stack, they don't connect side to side stacks. But if you are custom making them for the a123 pouch size, then you might be able to do an addition to have them connect side by side as well. But let me go get a pack right now and take it apart for some pics. I know you have a pretty good idea of what you want to do right now, but thought I would just add this info just in case it helps you in some way. It will also be good to have the pics for other people's info.

[Jay64]

I have been trying to get caught up with this thread, I missed a few pages worth of posts when I was gone on my trip. I also was going to suggest something like the EIG setup as I was reading along, but then saw that AW already suggested it by the time I got caught up to the last page. I will take one of my packs apart today and take some detailed pics. I was really impressed at how simple but efficient these pack designs are. I was a little concerned about trying to replicate it for different packs because of the cost of making an injected mold part. But if you are thinking of making something using that process anyways, doing it this way might be a lot cheaper, since the part is basically the size of each cell, and then the stack into each other. But this specific design only has them connect to each other in a straight up stack, they don't connect side to side stacks. But if you are custom making them for the a123 pouch size, then you might be able to do an addition to have them connect side by side as well. But let me go get a pack right now and take it apart for some pics. I know you have a pretty good idea of what you want to do right now, but thought I would just add this info just in case it helps you in some way. It will also be good to have the pics for other people's info.

[Jay64]

Ok, here are some shots of the way EIG did their bat. stacks. I have more pics, which I can put up here if you want, but I don't want to clog your thread with them if you don't. I'll probably start another thread in the batt section.

Here is one 22s stack from the front. On the top in the center you can see the end of a long bolt that has a nut on the top to keep the front of the stack compressed.

Here is how they connect the the rear of the pack. There are 3 strips that all the plastic plates bolt through to keep it together in the back.

Ea. tab has a copper angle welded to them. One is bent up and the other is bent down. There is a copper bar that goes across the stack at each level and that makes the series connection with the pouch above and below ea one.

connections.jpg (226.08 KiB) Viewed 761 times

It looks like the brass angles were tack welded on, but it almost looks like a sort of press weld. Not sure what the technical term for that would be.

tack_weld.jpg (244.07 KiB) Viewed 761 times

Like I said, I have more pics if you want, and I will be trying to put together another thread with maybe some more details.

[Hillhater]

Chris,
i dont know if it helps any, but if you are not aware , Jack Rickard over on his EV TV blog is also working on an optimum construction for a "pouch cell pack" and has started a competition for designs. But in the meantime, his tests has shown some problems with screw clamped tabs developing resistance after a while.
It worth a read of the blog 7 comments section, if you have not been there already.
http://jackrickard.blogspot.com/2011/11 ... mment-form

[jonescg]

Cheers Guys,

Jay I like the look of those cells. The C rate concerns me though. If they were good for >300 A burst then maybe they would be good.

OK, one more point about cells - I think the corrosion / tightening issue won't go away, which makes me think soldering is a good idea in the long term. I found I could unsolder my 2 mm copper plates by holding a micro torch on the plate and lifting it off with a pair of pliers. Provided there is some means to hold them (say, via the balance lead) and torch them, it will come off without too much resistance. Abraham's idea of drilling holes in the copper where the tabs meet is a good one - as at least you will see for certain that the solder is going where it is supposed to. The idea is that I won't have to do this very often, though. That also means the material I use to make the front plate needs to be fairly heat tolerant.

NOW, something a little different.

Since I am in the mood for spending a lot of money on this bike, I might as well go all out and build a decent reduction for the jackshaft. I initially had the idea of a primary chain driving the jackshaft, which drove the rear wheel. I had several folks tell me that installing a fixed ratio chain drive is tough, and the slop will get annoying. I don't know if this is true or not, but it does sound plausible. So I thought about running a series of gears.

This is what Brammo et al. do in order to keep the bulk of the motor out of the way. I know this means getting expensive things made, but it sure would look sweet, and sound a bit quieter even though I'd no doubt lose some oomph through friction. Maybe even get a cast sump made for it?

What do you guys think? Too much trouble?

[Hillhater]

I think your gear train is gearing UP not down ! .. need the small gear on the motor shaft .
Remember your gear drive would need tensioners , casing, oil bath, seals, etc etc
.. BUT, i would go with a belt reduction..for quiet, smooth, simple, clean, reduction drive. ?

[jonescg]

Ah shit, yeah. Well I blame MS Paint for that. You know how hard it is to get a circle to line up with another circle?? Just pretend the circles are the same size.

Belt drive would need a very deep profile to not slip.

Gears wouldn't need tensioners would they? They'd be fixed in place with a set of double row bearings, and the final jackshaft would still have a pair of bearings as per the original idea. Yes, it would still require a sump, gaskets and lube, but this wouldn't be too hard would it?

[Jay64]

Chris, I wasn't suggesting you get the cells, I was showing another option for holding the a123 pouch cells. Seems like the eig cells are impossible to get. I'm thinking that having holding trays like these made for the a123 cells would have a market, since so many people are using a123 cells.

[nieles]

why not make the gears usefull and pick a motor with a higher rpm, or reduce the size of your rear sprocket.

Gears wouldn't need tensioners would they? They'd be fixed in place with a set of double row bearings, and the final jackshaft would still have a pair of bearings as per the original idea. Yes, it would still require a sump, gaskets and lube, but this wouldn't be too hard would it?

the gears need to be meshed properly, some sort of tensioner could come in handy.
an other option is to experiment with different meshings on a test plate and use that for your end design

[jonescg]

why not make the gears usefull and pick a motor with a higher rpm, or reduce the size of your rear sprocket.

Gears wouldn't need tensioners would they? They'd be fixed in place with a set of double row bearings, and the final jackshaft would still have a pair of bearings as per the original idea. Yes, it would still require a sump, gaskets and lube, but this wouldn't be too hard would it?

the gears need to be meshed properly, some sort of tensioner could come in handy.
an other option is to experiment with different meshings on a test plate and use that for your end design

The jackshaft is due to the fact that I need to sling the motor as low as I can. If I did direct drive from the motor to the rear wheel, the chain would be too long. Also, it would take up the entire body of the bike if I did this. So my strategy is to hang the motor low and run a drive up to just in front of the swingarm pivot.

I would have thought if the sums were done right, then the gears would be fixed in place and you don't need to tension anything

Jay - yeah no worries. But I do like their moulded trays. However I think I'll solder these tabs in the end. Done and done.

[AussieJester]

There you go AJ, I did come around to fibreglass eventually

DiDn'T Doubt it for a minute CHRiS, fiberglass is..........your destiny Only thing that blows me away is
you haven't made the molds and laid up the glass already so you can start stackin' packs maaan!!!

KiM

[Hillhater]

Belt drive would need a very deep profile to not slip.

you would have to select the right belt, but belts are the way most modern transmissions are built.
Look at the big bikes , Harleys use belts for primary and final drives.
I know 8mm belts , 30mm wide are used for 50 hp drives.

[adrian_sm]

Just stumbled across this.

Source: http://www.carsguide.com.au/news-and-re ... rigin=hpc4

"We can buy a standard energy cell and then we have to adapt them to make it into a battery for us. So the first thing we have to do is attach a set of terminals to it. As a high-volume production cell they actually weld all the cells together. That's not a good idea for a small-scale battery because if something goes wrong we have to throw the entire battery away. So essentially, this (the terminal construction) is our technology we've had to develop. You lay a sheet of copper on the ground, lay a sheet of aluminium on top of it and then you put 50 grams of ammonium nitrate on that and explode it."

[full-throttle]

Just saw this in the Renew magazine:

Renew118pg77.pdf

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[jonescg]

Hehe, yes it's a bit dated but reads well nonetheless. I doubt I will race this year, unless someone else wants to race it for me (and pay all related expenses). I'd rather dump the money into my next bike.

[wedge]

For a donor bike I think you are best off buying a complete running bike then selling the engine. The BEC (Bike Engined Car) guys are always looking for late model engines, especially 1000's. www.ozclubbies.com.au and www.racemagazine.com.au are probably the best way to get in touch with them. I think you could sell the engine and other bits (radiator, exhaust, ecu, loom, fuel pump etc.) for over half the cost of a good late model fireblade etc.. No problems with crash damage this way either.

[jonescg]

I have been thinking more and more about batteries. The greatest concern I have is the maximum and average currents passing through the terminations with a motor at full noise. I was wondering if taking advantage of the revised TTXGP rules was a good idea - bump my system voltage up to 700 V DC maximum (4.12 V per cell at charge)

Assuming the absolute worst-case scenario, my 150 kW peak motor would cause a current draw of about 240 amps (at 640 volts assuming ~3.8 V per cell under load). 240 amps isn't nearly as scary as 400 amps, and I was drawing 600 amps through my 50 mm2 cables on Voltron. So maybe a 170S 3P pack is a better way to go? Still gives me just over 9 kWh worth of juice.

Sure makes soldering tabs together a fair bit easier...

[jonescg]

OK so I decided to solder up 9 of my individual cells into a 3s3p arrangement and do a load test. Test rig was as before: a dead short


I found after being bent over a few times, they don't like being bent or soldered again. I figure a generous dose of flux would help things along. I decided to use some solderwick to parallel the cells first, then for the series connections. It looks absolutely hideous



But a dead short held for about 5 seconds (enough to make the PVC insulation on the jumperleads too hot to hold onto) made the cells warm up a lot. The current started at 270 amps and finished up at 220 amps. The terminations were still at ambient temperature. I wonder if the tabs just don't have enough copper to sink the heat out of the cells like I did last time with the 5 P setup Anyway, 250 amps on a 3P setup is 16C, which would render the cells dead flat after 3.5 minutes.

If I were to build a big pack this way, I'd try to use a slotted board of PCB underneath to prevent any solder from dripping onto the cells, as well as serving as a bit of thermal insulation. It would allow the tabs to be bent over more neatly too.

[c_a]

This looks so ugly

Should I build you a pack?

[jonescg]

As long as you use Turnigy's I should point out that I wouldn't use the thin solder wick for the actual pack, these are just my abused test cells.

My 80 W iron is too hot. It just burns the flux after leaving it on for more than 10 mins. After 30 mins it's glowing red hot Flux would help on the tabs for sure too.

[full-throttle]

That looks familiar

pack.jpg (190.94 KiB) Viewed 632 times

My 20 year old Weller died the day I was finishing my pack, so finished it off with a 200W chinese monster (courtesy of BenMoore) I invested over $500 in soldering equipment since..

Are you going to insulate each bank?

[jonescg]

So it was YOU who reduced hobbyking's stocks of 40C individual cells!

Dude, that pack looks frocking awesome! Well done! That's precicely what I'll be doing with my packs. I'll make them into magazines of about 66 volts and slide them into the pack. How did you find soldering the tabs? I think I need a better flux

I'll be pulling much higher currents so I need something a bit thicker than the ~8 mm2 wire you've used.

[full-throttle]

Nah, wasn't me - all those cells are from 4S packs.

I'm using a low-residue no-clean flux. It's really nice. A good soldering station with a quick recovery time makes the job easy. The Curie-point ones are the quickest (Pace, OKI, Metcal) Don't use the plumber flux

[E-racer]

Are those from the 4s hardcase packs? If so can you give me the actual cell dimensions.

[jonescg]

They are probably the same cells I'm using - Turnigy 5000 mAh, 40C. They are 50 mm wide, 140 mm long (including tabs) and 9 mm thick. The tabs are off to one side; about 3 mm in from the back of the cell. The tabs are 16 mm wide, barely 9 mm long, and 5 mm in from the edges, with a 4-6 mm gap between them.