Current Cycles Prototype Buildlog...

Hello All,
I am in the process of building a similar bike to the Stealth, although I am trying to keep MY budget under 1000-1500 bucks. I am a skilled fab guy that just found out how cool these E-bikes can be and decided to build the Kicker of all AMERICAN BUILT E-bikes. I know its very similar to the Stealth, but I am in no way copying their design, I have only seen them and liked the lines, this bike will have a standard crank, and derailleur w/gears and should hopefully do over 45MPH!I am going to start around 80 volts and move up to 100 if the motor will take it. I am new to this dc motor stuff and appreciate any help you have to offer, and thanks to the guys who have already helped out on other threads! Here is the chassis thus far, I am still fine tuning the design to make it all fit nicely and be as light as possible. I am shooting for well under 100 LBS but we will see!

Nice solid works design. I don't think you have to worry about copying the stealth. A frame made from plate steel was not invented by the stealth designer, most mopeds have similar frame construction.
One idea: consider the new lithium polymer batteries sold on the forum. I just got one and was surprised to find that a 6"x6"x2" battery weighing 7lbs is enough for me to ride across town and back and another short trip. This could alter the size of the cavity you design into the center of the frame. The big cells on the stealth take up a lot of space for the capacity and need a special egg crate frame to hold all the cells in place. New prismatic cells are much more compact either Lithium Iron Phosphate or Lithium Polymer prismatic cells are the way to go, in my opinion.

Thanks! I am looking at the Foxx cells right now, approx 20AH @ 80 volts will easily fit with room to spare, what do you think of those? Do you have a link to the ones you are talking about? How much $$ are they?

extreme green on the forum has lipos. $700 for 48v 10 ah with balancer. I bought my lifepo4 (lithium iron phosphate) prismatic pack from hi-powered cycles. $800 for 48v 10 ah with charger.

I don't know about fox cells but both of the options I have listed above may not work for you since you will be running 80v. I'm not sure if 48v packs can be run in series without damaging the internal BMS circuits. Definitely the charger cut off would not work right.
Maybe get a quote from ping batteries:
http://www.pingbattery.com/servlet/StoreFront

nothing at 80v listed on his sight but ping is famous for being able to build different pack configurations even for one unit orders.

WOW, there has got to be a cheaper way to get a decent battery than 600-1200 dollars! Why are his soo expensive? I see them on ebay for at the most 400 and that is a 20AH 48 volt??

that is the one thing that is still very expensive. I could easily pay more for a good battery/charging solution than I paid for my bike, motor kit,lead batteries and charger, and new tires combined. Sad but true if I want any range without hauling 50 + lbs. of lead around.

I originally had some problems with my credit card and HobbyKing when trying to order batteries so I searched for an alternative for weeks. I ended up calling my bank and having them help me get HK paid so I could get their batteries. I was hoping to deal directly with manufacturers but they don't seem to want to do business with anyone really. Even at wholesale, manufacturer direct, the cheapest quote for enough LiPo cells for 44V 20AH was over $2200. With HobbyKing, I got the pack for a little over $600 including shipping. It's the best option almost everyone on the board has come up with and I support their opinions. I'm definitely keeping an eye out for LiPo manufacturer that's not trying to recover their entire development budget in two years by charging crazy prices. I'm looking for the one that realizes that if they make batteries affordable and sell a ton of them, they'll make a bunch of money and help get an amazing thing going...the EV movement. Right now, it seems that they're all waiting for big money all at once, when there will be NO big money if environmentally friendlier means of transportation are not implemented on a mass scale soon. Bottom line, regardless of ethical, political, environmental, geographical, economic, etc. issues, Hobby King sells the best batteries for your money right now.

Here are some thoughts about your budget. I was initially hoping to build a bike with similar specs as yours. I priced a cheap DS mountain bike, a huge motor(agni), a big kelly controller, and a bunch of Kokam batteries. Once the project got serious, I started looking into it a little deeper and realized that it takes some relatively beefy stuff to travel safely at 45mph. As a test, I took my Diamond Back Coil, lower to medium quality mountain bike to a big hill and had my girlfriend follow me for some speed testing. I was able to pedal up to 38mph and coast to 45mph on the hill I'd chosen. At 38mph, it was already a little scary. The frame was flexing causing wobbles, suspension was actually bottoming out on two inch bumps in the road......not good. I tried a good brake test at the bottom and probably took 120 feet to safely stop, and probably used half of the life of the brake pads. The brakes could have grabbed harder and faster, but the contact patch on the tire couldn't hang. What if the brake was bigger, and tire wider? The rims, spokes, and hub will be next to fail. Get where I'm going? I'm working on something with basically the same stats you're shooting for and have been getting some pretty humorous advice about only having a $5K parts budget. As it sits, I'll be $1K over budget once all of the parts are ordered. I'm not trying to be negative at all. If you can do it for $1500, that's great. Just think about all of the different aspects of going fast, not just how to go fast.

I hear ya, I am lucky in the fact that I can build the chassis, but I need all the little stuff just for the bike and that is eating into my budget right there, I would be happy with 10AH to be honest right now, but even that is going to be a lot of coin, but with the motor I am using just for now, I think it will be fine. I don't need HUGE power, just something that will give a good kick in the shorts as far a torque goes and then get me close to 40MPH top speed. I am trying to get the bike as light as possible so there is less to haul around, thus giving greater mileage/acceleration with less motor/juice. That being said, I think I can get it under 75LBS if I can find a decent LiPo or LiFePo4 batt for at least a few hundred bucks. That is where I am stuck right now. So I am still looking. I actually considered NIMH batts because they are cheap, but I am not sure they would give the life I am hoping for cyclically.

Thanks for the help!

I don't need much power, just enough for 40 mph. :wink: Like the rest of us, you'll be doubling or even tripling the budget. 30 mph is realistic though, and more within the capabilites of bike brakes etc. Nothing wrong with aiming high with a good budget though.

LOL....You know I have to try, but I would be happy in the mid 30's.... That's only like 490RPM I need out of it!

Hey crazy Idea, but what about this? I could get nearly 8AH out of this with 56 volts, and easily upgrade later, they get 2000 cycles and great shelf life? Could these be charged together if I wired them in parallel for charging purposes and then in series/parallel for the discharge, thus allowing me to charge them with a single charger? I understand it would take longer, but I am fine even if it takes 4-8 hrs to charge.....Just an Idea?? Don't go buying them all up if its a good idea though, it was mine!! LOL! 300 bucks for 56 volts and 7.2AH sounds fair to me!

Whiplash said:

Hey crazy Idea, but what about this? I could get nearly 8AH out of this with 56 volts, and easily upgrade later, they get 2000 cycles and great shelf life? Could these be charged together if I wired them in parallel for charging purposes and then in series/parallel for the discharge, thus allowing me to charge them with a single charger? I understand it would take longer, but I am fine even if it takes 4-8 hrs to charge.....Just an Idea?? Don't go buying them all up if its a good idea though, it was mine!! LOL! 300 bucks for 56 volts and 7.2AH sounds fair to me!

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What about what?

What are you planning on for a motor? Hub or RC? If you said on other threads I forgot. The budget 30 mph motors are the 9c 2806 and the Aotema. Both do 30 mph on 48v (56v hot off the charger). If you went the lipo route, you could start with 4 6s packs running them 12s with a stock kit controller. (48v) Then later add a 72v controller and 2 more packs to go 18s (66v). Or using 5s packs, go straight for 72v with 4 5s packs. Add 4 more later for a 10 ah 72v pack.

I have decided to go with the Conhis Motor on ebay, I can get the whole setup for 300 bucks shipped and I have been in contact with someone who has run 72 volts through it with no problems at all and has over 1000 miles on it. Sorry for not posting what I was talking about, I got sidetracked at work, I am looking at the Dewalt 28 volt packs, they are 2.4AH and 28 volts and I can get 6 of them for 300 bucks! They are Lifepo4 style I think and with 6 packs, I can get 56 volts and 7.2 AH and add to that as I go with more packs. My question is, is there a way to charge them all at once or do I need to charge one at a time? I thought if I had a charging wiring config. putting them all in parallel, I could charge them with one charger, it would just take longer right? then unplug that setup and plug in the power wires somehow....Any ideas? This looks to be far cheaper than doing a duct tape battery as I can't seem to find one cheap that will output more than 20 amps continuous, and I have heard these will easily double that and then some...I am thinking of doing 56 volts and 60ish amps if I can find a controller to do it...

Whiplash said:

I hear ya, I am lucky in the fact that I can build the chassis, but I need all the little stuff just for the bike and that is eating into my budget right there, I would be happy with 10AH to be honest right now, but even that is going to be a lot of coin, but with the motor I am using just for now, I think it will be fine. I don't need HUGE power, just something that will give a good kick in the shorts as far a torque goes and then get me close to 40MPH top speed. I am trying to get the bike as light as possible so there is less to haul around, thus giving greater mileage/acceleration with less motor/juice. That being said, I think I can get it under 75LBS if I can find a decent LiPo or LiFePo4 batt for at least a few hundred bucks. That is where I am stuck right now. So I am still looking. I actually considered NIMH batts because they are cheap, but I am not sure they would give the life I am hoping for cyclically.

Thanks for the help!

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Just an FYI. I've got less than $300 in frame materials and supplies and 80% of that is going to get milled into tiny chips. It's all the little stuff that added up to the other $5700. Just order some Turnigy packs and start building. I got mine in the mail today. It only took a few weeks. Make sure and order something else besides lipos with your order though. They threw my batteries in the smallest box they would fit in with absolutely no other packing materials. The box was totalled after it's trip across the ocean but all of the batteries miraculously made it OK. I heard they pack things better when you order some odd shaped stuff with your batteries.

The only thing with the Lipo's is the cycle duty, I don't want to have to buy batts every year, that raises the cost of ownership a TON! These packs from Dewalt, if they work out right, will cycle over 2000 times according to the manufacturer and that is quite a few years of use, even if you charge them every day!

Nevermind on my Turnigy advice anyway. I should have tested the packs before I posted that they all survived the shipping. One pack was either bad from the start or disconnected in transit. HK won't answer the phone or return emails. Search elsewhere.

Whiplash said:

The only thing with the Lipo's is the cycle duty, I don't want to have to buy batts every year!

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Wont happen, your using multiple packs never getting anywhere near their limits, to further increase the
number of cycles you can charge to 4.05 or 4.10v volts. I have read of members here with Lipos few years old still showing no signs of
decreased capacity. If your flying 3d in a rc chopper its another story 6 or 8 packs in an e-bike totally different.

KiM

My lipos didn't make a year

Which ones? Did you use a BMS?

The overwhelming evidence shows that, indeed, lipo declines during "ordinary usage" over 200-300 cycles. Mark A_W, Hyena and many others can attest to that. Many cell phone and laptop users can also attest to that, where the chemistry is identical, and the current-usage / "c-rate" ratio is comparable if not better.

However, "a year" is kind of vague. If someone only rides their bike 40-100 times a year (The sunny warm weather type of rider), well then, yeah...

Four cheap ebay 2500mah lipos, in parallel as a booster pack with a 36v LiMnSO4 pack.


Charged with single cell chargers (4.15v) every time.

They did not have a BMS, but the pack they were in series with did have a BMS. They did have a meter on their overall voltage.

My current draw was about 20A, so only 5A each.


I ride the bike to work 3 or 4 days per week.


So they lasted about 200 cycles, but from 150 on they were very sad, requiring charging twice per day, instead of once. At the end they swelled up like sausages.



I'm sure Lipos are better now. But LiFePO4 is better for the environment, and buying Lipos does not build a market for batteries that could be used in cars. Lipos will never go in cars.


My Headway LiFe pack is two years old now and showing no sign of degradation (still get 9Ah out of it, same as new).


But my brother's very early Headway pack (lots of little 2Ah cells) is starting to struggle, after almost 3 years of weekday commuting.

Hard to beat A123's. Hard to afford em too. If using the stock controller from that hub kit, you might start looking into a pingbattery for the starter kit. 48v 15 ah is still only about $600 including the shipping to USA, weighs 16 pounds and will take you full throttle 20 miles or more. Should last 10,000 miles of riding ( possiblly 20,000)if no problem cells or broken bms wire problems crop up. Good for 25 amps continuous for sure, without compromising cycle life too much.

Make the hole in the center of the frame 13" long and 6.6" tall and a 4" thick 48v 15 ah pingbattery will fit perfectly into the space. Later on, an A123 pack can fit in the same space, of smaller ah.

Well guys, I decided to give Conhis motors a try since I got the kit really cheap and that was about all the money I have right now. I got the whole kit for 275 shipped to my door and I have a friend on Youtube that has this exact kit and has used it at 72 volts and he said the motor did not even get warm so I am giving it a try. He also had a 6x10 9C motor prior to this kit and he said the 6x10 had only a tiny bit more on initial takeoff and after that the Conhis was faster by a good margin. These were both tested at 48 volts and he gets 33MPH out of the Conhis at 48 volts and a 27amp controller, so I figure with 72V and around 40-50A I should be good to go at around 40 no? We will see and this is just the first go round so I am not really too worried about it...I hope it shows up this year though...LOL!

OK, I got my kit ordered and I am now ready to decide on the batteries, I think I will go with the LIPOs but I am not 100% yet, because for now I need to run 48 volts and the controller is setup with the low cutoff for 48 volts. What would be the best way to achieve the correct array of batteries to make sure the low volt cutoff works properly? Will the cycle analyst work with any controller to cut the power if you go below the low volts? I know it does this but I want to be sure it will work with this cheapo controller for now until I get some more money together for the good 72 volt controller...

I found some good deals on batteries on fleabay for (8) 18.5 volt LIPOs for $349.00 shipped! but I am not sure this will work because it will not add up to the 48 volts I need.

SOOOO, what I am considering doing, is getting the Dewalt packs I found ($300 for 6 packs brand new) and trying to cut them up and build (3) 24 volt packs and then wire two packs in series to get 48 volts and then add the third when I am ready to go to 72 volts...Does this make sense? This is the last piece of the puzzle I have yet to figure out for sure, I REALLY like the idea of doing the Dewalts, because I know it will fit my bike and make GREAT power, I am just not sure how to balance/charge them... Can I get some help on this from someone who actually has used them??