Electric Race Bike

[Jay64]

Since the discussion is now turning away from the original motor question, I figured I would start a thread in the motorcycle section. This is continuing from this thread:
http://endless-sphere.com/forums/viewtopic.php?f=30&t=38197

Basically I'm looking to build an electric race motorcycle. This build is going to be based on parts I already have with a few additions. I already have a couple of '06 GSXR 600s that were set up for Pro racing with top of the line Ohlins suspension and Marcheshini rims. I will be using one of these as the chassis for the build. I have 2 Agni 95R motors that I will be running in Series. I will need to get a controller for these, so I will probably go with the Kelly controller suggested by Luke:
http://kellycontroller.com/kdh14600d24-156v600a-seriespm-controller-p-530.html

I have a bunch of Headways that I originally bought for this build, but with the new Lipos, I think I will probably go that route. Looking at the TTXGP rules, I would probably enter the Formula TTX75 rules, which have a 7.5kwh limit on battery packs. The Turnigy nano-tech batteries I was looking at are the 8000mAh 5S 25~50C Lipo Pack, which are 18.5v. If I go with 8s of these packs (40s cells) than I will have 148 volts. That will leave me just over 50ah for capacity to stay within the 7.5kwh rule. So if these packs are 8ah, I will need to go 6p, for a total of 48packs, right? That would be over $4k.
These packs seem like a good balance of power and price. There are some packs that have higher C rates, but the price per wh seems to be quite a bit higher. I'm not sure how much more power the Agnis would be able to handle. 25C is pretty high for a 50ah pack. Does anyone have any other suggestions, reasons to use something else?
Oh, I just remembered that I have 44 of the AIG 20ah cells, set up in 2 packs of 22s each. But that would only get me 20ah of power, I don't know if that would be enough to finish a TTXGP race. Would it be possible to use those in combination with another type of battery, since it is near impossible to get more of these? That would cut my battery cost almost in half. If I got 30ah of the turnigy's to add to these that would be just over $2.6k. If I did it that way, I could probably finish the whole build for about $4k.

[frodus]

8 of those packs in series, 6 in parallel for a 48Ah 148V pack, 48 packs. 7104kwh

It'd be a pretty good pack, super light. Lots of connections, so be prepared. I'd avoid using the connectors that it has on there (although keep the balance leads on there). Use some high current connectors to a bussbar. Parallel the balance wires between parallel batteries.

Are you using a BMS? or just going balls out?

[Jay64]

I would be willing to go balls out for a race bike. I could always individual balance between races. But the TTXGP requires a BMS now. So I would also have to find a BMS that could handle this much power. All the BMS units I have seen are for smaller, bicycle sized packs.

I just found out that the TTX75 isn't a separate class, it is just an award, I guess for the end of the year. So what do y'all think would be the maximum power that the Dual Agni setup could handle for race distance? I think the races at Infineon and at Laguna Seca will need more driveability out of corners than all out speed, while the rest of the races at PIR, Miller, and Daytona would benefit more from all out speed. There are other bikes running about 200 mph, so I will have to try to get something as fast as possible, but also be able to make up time in the corners. Since the TTX75 is just an award, I guess I should just try to go with as much power as the motors can handle.

[Jay64]

Oh yeah, do you have any recommendations for the high current connectors? I'm assuming that those wires are good enough to at least get each individual pack power to the bussbar, and then larger wires after that.

[frodus]

well, there's several flavors of BMS, what is there definition of BMS? If it's monitoring only, you could potentially just do some cell-log's with alarms so you have a warning when they're low, and another gauge for measuring pack temp at a few places.

For high current connectors, that's a toughie, maybe LifeForPhysics can comment. Those barrel connectors aren't good for continuous amps. Ideally you don't want connectors, you want to bolt on the power connectors to a bussbar, but there's the possibility of shorting things. The wires are fine for the power, but I don't know that the connectors are.

[Jay64]

well, there's several flavors of BMS, what is there definition of BMS?

A Battery Management System is defined as an electronic device connected at the series
connections of a group of battery cells with the purpose of providing automatic control
during charging and discharging to ensure that the cells charge voltage is kept within the
limits specified by the cell manufacturer.
A Battery Management System is compulsory for all entries where the battery pack cells
could present a risk of overheating leading to degradation of insulation, or ignition of
flammable material. The Battery Management System must provide a feedback loop to
the charging system to disable charging in the event that a cell or group of parallel
connected cells exceeds the charge voltage limit specified by the cell manufacturer.
Additionally, the motor controller must interrupt power supplied to the motor (s) if the
overall pack voltage is greater or less than the cell manufacturers charge voltage limits,
calculated by dividing the overall pack voltage by the number of series connected cells.
Battery Management System Recommendations
It is recommended, although not compulsory, for the Battery Management System (BMS)
to provide a cell balancing function. Cell balancing is an automatic function of a BMS unit
to control the charging process, with the purpose of ensuring that all cells connected in
series achieve an identical State of Charge (SOC). Normally, the BMS will accomplish this
by identifying the cells at the highest SOC and then reducing the SOC via a small load,
thereby allowing the charging process to continue until all cells have an equal SOC. This
process improves the performance of the pack, life cycle of cells and safety during
charge/discharge processes.
Temperature monitoring of cell modules via BMS or other supervisory control system is
recommended to provide safety interlocking to motor controllers, charging systems, and
issue audible and visual warnings of cells in danger of operating outside the
manufacturer’s thermal limits.

[frodus]

you don't need onboard balancing, but I'd recommend some sort of way to balance them at some point, or your $4k in batteries may go up in smoke.

Maybe consider something like Elithion or Orion BMS for something full featured.

[jonescg]

Jay - Awesome stuff. I will be watching this thread closely

Just thinking in words here, but 7.5 kWh is way more than enough to complete a 27 km race on a pair of Agnis. I found my continuous battery power use was closer to about 36 kW, with peaks of 55 kW on occasion. But let's say 7 kWh is your goal, that's 40 Ah at 170 V. The problem is getting a controller that can tolerate these over-volted conditions. All Kelly controllers are rated to 144 V, but can be pushed to about 165 V at the absolute maximum - as Ripperton found out at Winton last year.

So 40 cells in series would get you there, and if you had the 5Ah cells you would need 8 in parallel. I imagine 8 of the 5S packs would be easy enough to purchase? It makes for a bit of a spaghetti junction, but a GSXR600 has so much room in the frame you will fit it all in and still have room for your lunch. Especially since you will have two motors hanging out the sides so you can fit even more cells between them. I'd say using a simple bus bar system like AussieJester or Jozzer has used would work fine.

For LiPo it looks like Method's boards are the way to go for HVC and LVC, but you will need some kind of balance tap arrangement conveniently located on the pack so you can balance them in the evenings before the race weekend. At 40 Ah, it's going to take a looong time, so start early .

And definitely build some crash protection in!

Oh, when joining the motors at the shaft, use a solid lump of steel with keyed 19 mm holes at either end. Some folks would have you believe you need a lovejoy coupling or something, but the forces are too big for any such coupling to survive.

Good luck!

[grindz145]

Remember you can always push a little more current, with a quick shot of liquid nitrogen....

This thing is going to be a beast, I'm really enjoying seeing you progress so quickly on your builds. If you need any battery help man, always feel free to drop me a line to run something by me

[Jay64]

Chris, thanks for your insights. I think I may be going with the 8ah packs. But I guess I will have to see what is available and what the pricing is when I actually get around to buying. After talking with Steve, I think I might try to go about 168v. I'm definitely going to have to hit up some sponsors for this build.

Troy, It will definitely be a beast compared to anything that I have built so far, but I think it will be a little lacking compared to the Lightning's 200mph. I think the new Agni's that are set to come out very soon will be closer to the current standard. But I need to get in the game and run what I currently have, learn from some experiences and make improvments.
I will probably definitely take you up on the battery stuff.

[drewjet]

Awesome Jay. Are you going to be building in Tampa or Orlando? If Orlando i could help out here and there. I have a small lathe and Mill and am a hack machinist.

[Jay64]

I haven't decided yet. The Off The Grid guys are interested in helping, but I usually get more work done when I'm not there. They tend to get too side tracked with all the little things going on and take a long time to finish projects. Maybe it's because of all the little co-eds running around getting drunk.
If you could help out here and there with some lathe and mill stuff, that would be AWESOME. My angle grinder and cordless drill just leave me a bit short on ability sometimes. I would definitely be willing to bring it up to your area when you have time.

[drewjet]

Sounds good Jay. I am currently only working part time, so I have plenty of Play time. If you need predcision down to .001, that is not me, but I can get better than an angle grinder and cordless drill:)

[Jay64]

I think the only part that I would need real good precision would be for making the motor mounts, to make sure that the shafts are aligned as perfectly as possible. But there is a lot of others stuff, that the angle grinder and drill would be good enough for, and lathe/mill would just make it that much better. So maybe we can outsource the motor mount stuff. Outsourcing everything gets a bit much, but only one part is doable.

[Jay64]

I got an offer this weekend to buy a ride on a Lightning bike. Full bike with signage rights on the bike for the full year and a Lightning tech at all the races. Boy, that would be cool to race on a 200mph bike. I'm really tempted, and still in talks about the whole deal. But at the same time, with the amount of stuff I already have in house, I can build a bike for less than it would cost me to rent a bike for the season. It also looks like I wouldn't get any test time on the bike, just races. I don't think I have time to build a 200mph bike for that cost before the first race. But I think I could build a pretty fast bike that will be a lot of fun to race. I think I would rather race my own build, and see if I can at least give them a run for their money. But, as of right now, the offer is still on the table, just in case I can't get a bike built in time, I might try and go that route.
So in the spirit of building my own race bike, I've been checking out some batteries. Is there a major difference between Zippy Flightmax, Turnigy Lipoly, Turnigy nano-tech? I think the nano-techs have a higher C rating, but I'm thinking a 20c rating should be pretty good. I'm looking at getting a 40ah pack and the Agni's should only get about 400a max at lower than 5K rpm, so I shouldn't need much more than 10c. But having more in the back pocket is always good. But at the same time, I don't think I need 50-90c. I was thinking of nano-tech this whole time, but if I don't need the really high c rating, are the others cheaper and just as good in the other areas?

[jonescg]

My A123 pouches (3p, so 60 Ah) were never being used at more than 600 A, which is about 10C max. No need to go for the Nano-Techs, and if keeping weight down is your objective, go for 7 kWh worth of Zippies. I think these guys have the best energy density of all the LiPo brands.

And you have to BUY a ride on the Lightning bike? WTF? I guess there's a lot more demand in the US. I couldn't even give my ride away!

[Jay64]

Another thing that I noticed while comparing them is that the nano-techs have a higher charge c rating. 5c compared to 2c. How big of a difference would that make in trying to charge up a 168v40ah pack at the track between practices and races? They also say that the nano-techs don't sag as much under high discharge rates, but if I'm only pulling 10c, would there be much of a difference between them?

Chris, it would probably be cheaper for me to just fly out there for the races and race your bike.

[jonescg]

You are most welcome to visit any time mate! It's not a very nice bike to ride, I'll warn you.

Charging fast is important, but the limitation will be the size of your charger and the supply. I paralleled three Elcon chargers together (4 kW) and ran them from two different circuits. I charged my bike from 1/3rd to full in just under an hour. This was really important for me as I needed as much track time as possible to get to know the circuits. Still, 32 amp charging was only 0.5 C. These pouches are good for 1C I think? So yeah, the cells are not the limitation. Burning the pits down is more of a concern.

[Jay64]

Screw the pits. J/K. Well, I already know the tracks. Well, the one track I have never ran yet is Portland International, but it is scheduled as a conflicting date with the AMA Pro Roadracing event for my gas racing. I'm probably going to have to skip that one, but I am playing it by ear because there are a few different scenarios that might play out where it will be more beneficial to skip the AMA race and go to the TTXGP race. But if I do go to that race, maybe I can bring one of my gas race bikes and race in some of the gas events to get more track time. But thanks for the break down on how long it too you charge etc.

[Jay64]

Do Zippy Flightmax battery packs need to have compression on them when in use? About how often would I need to balance charge them? Could I just balance charge before the race weekend, fast charge over the weekend, and then balance charge after the event is over?

[drewjet]

Another thing that I noticed while comparing them is that the nano-techs have a higher charge c rating. 5c compared to 2c. How big of a difference would that make in trying to charge up a 168v40ah pack at the track between practices and races?

Jay
2C should mean a 30 minute charge but in reality closer to 35 or 40 as the charge slows at the end. 5C Should be 12 minutes but probably closer to 18 to 20 minutes. Really it is a matter of getting a charger to output enough amps, and in the high amp arena they start getting expensive. If trying to charge a 7KW batter at 5C you would need 35KW output. I doubt it exists. A 1C one hour charge would still need 7KW output charger. Each 110V socket are usually only 1500 watts or so. 240v socket are good for a lot more somewhere around 8000 watts I believe if 40 amp breakers.

[fechter]

You could use Methods' HVC/LVC boards as a BMS or it's possible to use 'bicycle' sized BMS boards with an interface to the throttle and charger (fairly simple). There just aren't many good ones out there.

[Jay64]

Getting the batteries ordered today. ZIPPY Flightmax 5000mAh 5S1P 20c packs. 72 packs in 9s8p configuration for 166.5v40ah. Still trying to figure out if they have enough for me at the moment. Going to go with the Kelly controller and Dual Agni's in Serial for right now, need to try to get to the first race in about 30 days. Am looking at some options for upgrades after the first race.

Fechter, yeah, I was actually thinking about Methods board for LVC and HVC. One thing I am getting a little caught up in is that the packs are actually series, then I'm going to parallel the packs into subpacks and then series the sub packs together. Normally I could just monitor each paralleled subpack, but since they are series first, would I have to monitor all 75 cells individually?

[Nuts&Volts]

Jay maybe you could go with these Zippy http://www.hobbyking.com/hobbyking/stor ... _Pack.html

They are ~169 wh/kg and would make wiring a lot easier. Go with a 40s 8p configuration for 6.8kWh and only 90lbs. Very excited to see this guy get built.

If you wait on the page the price should go down to ~$112 per pack. Or $3600 for 32 packs. However I guess shipping may be more in since its not in the US warehouse...

[Jay64]

Yeah, I was looking at a few different size batteries, but those will come out to be about $700 more than the same power of batteries that I ordered....and 50 of them are already ordered. We had to order them up in separate sets, something about weight limits or something. Also, they are in the US warehouse, so they don't meed to be shipped from China, which is good for cost reasons and the time constraint issue. Yes, it will be more wiring. But it came down to saving money with some extra work and possibly getting the bike built in time, or not having enough funding to get the bike built before the first round.