Crystaylte with Lifepo4 Setup Question

[TylerTrinh]

I wanted to get a recommendation on the e bike that I am building. Any advice is greatly appreciated. Now there are alot of different variables involved when trying to calculate speed and power (weight, terrain, motor, ect). It seems that the crystalytes provide the torque and speed I'm looking for. ( no pedals on this design) Between the 5303,04, and 05 I think I'm going with the cruiser 5304. I'm looking to get 35-40mph. I really like the lifepo4 batttery because of size, weight and life cycle. EVessemble has Headway 12ah cells with BMS that I'm looking at but I'm not confident will be a good fit. I spoke with someone from electric rider that sells crystalyte about battery recommendation. He stated that they have yet to find a lifepo4 manufacturer that can deliver 40 amp continuously. It's also on thier website. They have tested lifepo4 and that are experiencing cells that fail. Is it just to new for lifepo4 to handle x5 motors? If they can will I sacrifice range? To sum it up 5304 motor. 36-48v 12ah lifepo4 48v 40 amp crystal controller. Is this a good setup?

 

[swbluto]

I wanted to get a recommendation on the e bike that I am building. Any advice is greatly appreciated. Now there are alot of different variables involved when trying to calculate speed and power (weight, terrain, motor, ect). It seems that the crystalytes provide the torque and speed I'm looking for. ( no pedals on this design) Between the 5303,04, and 05 I think I'm going with the cruiser 5304. I'm looking to get 35-40mph. I really like the lifepo4 batttery because of size, weight and life cycle. EVessemble has Headway 12ah cells with BMS that I'm looking at but I'm not confident will be a good fit. I spoke with someone from electric rider that sells crystalyte about battery recommendation. He stated that they have yet to find a lifepo4 manufacturer that can deliver 40 amp continuously. It's also on thier website. They have tested lifepo4 and that are experiencing cells that fail. Is it just to new for lifepo4 to handle x5 motors? If they can will I sacrifice range? To sum it up 5304 motor. 36-48v 12ah lifepo4 48v 40 amp crystal controller. Is this a good setup?

Depends, terrain? What kind of performance expectations do you have for your terrain? In particular, hills. What kind of range are you looking for? At 40 wh/mi. at 35 mph, you're looking at ~14-15 miles with a ~600 wh pack (48 volt 12 Ah battery). If you go 25 mph, you may expect nearly double the range.

Also, I might advise caution with stressing the full C-rate of a battery if you're concerned about longevity, especially Headways.

If you want to reach up into 40 mph on flat land, I might advise the 5303. The simulator predicts ~36 mph on flat land with the 5304 with a "48 v" lifepo4 battery.

 

[icecube57]

All the major companies have cells that can do 40A continuous. The pack size you would want is a 60v 20AH or a 72v 20AH. That will give you your targeted speed and range. Ping Battery sells 40A continuous packs. Thundersky sells 20AH 2C(40A) continuous 10c Peak (100A). Headway 8/10/12ah cells are capeable of 40A easy. PSI are capeable of 40A. Cellman on this forum sells 40A capeable cells a123. There is always Bosch Packs and Dewalt Milwalkee and Makita batteries that are capeable of 40A discharge. Lifebatt with their expensive ass can deliver 40A. Ductape ebay packs can deliver 40A if you get a good one.

The main thing you need to look for is a pack that is 20AH minimum. 9/10 they can deliver 40A. Some of the more expensive companies can deliver 40A out of 10-12AH cells. (Headway is an example)

 

[ryan]

I can't speak for other combos, but I get 35-40mph continuous on flats with my 5305 with a 72v20Ah Headway pack. At WOT I can get about 20 miles on a single charge. Or if I'm thoughtful about amperage, I can stretch that to 50 or more.

When I was looking at my first build I also found electric rider's site confusing with their preference for SLAs. But folks here steered me in the right direction.

 

[TylerTrinh]

Yea I know. Electric rider made me feel like they didn't know what was going on. So I thought I give you guys a shout who are actually doing this. Thanks alot

 

[dogman dan]

Headways, A123's, 15c lipo, all good for a big x5. But the motors are a bit watthog for a ping. Sure lots of batteries can do 40 amps continuous, but the question is for how long. Running any chemistry at it's max c rate is gonna cost you lots of cycles.

In the case of lower c rate cells such as pings, I'd consider 30 ah to be a minimum size to reliablly put out 40 amps. So you'd have the range, with 72v 30 ah, but it would also weigh 60 pounds! So the higher c rate cells such as headways are generally a better match for the big x5's. 72v 10 ah would get you pretty far, and weigh a LOT less.

A good way to start out though, would be with a 48v pack. 30 mph is cheap, but 40 is twice as expensive, especially for the bike itself. I don't know what your need for speed is for, but on the street 48v is already an illegal bike most places. A 40 mph bike just might be noticed if you plan on street riding it. In my town the cops could give a damn till you hit somebody or get hit, then they'd go boy, what the hell are you riding? But at that point, I'd get enough tickets to wallpaper the house with em.

 

[TylerTrinh]

Dogman,
Total size of the battery is important. I'm looking for speeds 35-40 mph. I consulted with EVessemble last night. 60v 12ah lifepo4 Headway will require 20 cells. This is the size I'm looking at. With trying to maximize range and using 60v 12ah, which motor would be better for normal commute terrain, e bikekit motor or x5?

 

[cell_man]

You're not gonna get far doing 35-40mph constant on a 60V 12Ah battery. I reckon you need to budget at least 30-40Whrs/km, so maybe 20 or 25kms, maybe 15 miles range or maybe a touch more. You don't want to run the battery flat all of the time so you would want to leave a bit in reserve. Also 40mph on a bike is pretty fast and you would really want a full suspension bike for sure. A123, even just a small pack with just a few parallel M1 2.3A would handle 40A no bother. The A123 prismatics, no problem. LiPo no problem. Headway with just 10 or 12Ah, you are pushing them a bit but they should be ok.

My bike has dual geared hub motors which are not probably not as efficient at high speed. I use somewhere between about 2500 and 3000W to maintain about 40mph. The power needed to increase from 30 to 40mph is very significant. You might only need about 1000W to maintain 30mph.

 

[morph999]

I have a 5303. With 48v, it makes a difference what kind of tires you have and how much you weigh as to how fast you will go. I got bad tires and I weigh 250lbs and I just barely hit 35 mph after about 50 seconds of constant acceleration. With better tires and a lighter rider, you could probably hit 35 mph much easier.

 

[morph999]

if you are planning on 35 mph - 40 mph, a 5303 is the best motor for doing that because it won't overheat no matter what you throw at it. If you plan on doing that kind of speed, I'd get some Schwalbe Big apple, Schwalbe Fat Frank, or some Maxxis Hookworm tires. Also, your wheel base is a factor. You should measure the wheel base of your bike. The longer the wheel base, the better. I have a GT Outpost trail bike and it has a 1 1/2 inch shorter wheel base than my huffy so I feel less safe on it than I do my Huffy.

* big fat tires like 26" x 2.35 or 26" x 2.50 would be good
* long wheel base
* and maybe even a suspension would be good but I've been told that fat tires can actually be better than a suspension

 

[dogman dan]

I'm finding it takes about 1000 watts to maintian 27 mph on an ebikekit 9x7 at 48v. Making it to 40 mph will take more than double that I bet.

But I'm not the guy who knows that one. Since I've never commuted my 15 mile ride faster than 27, I have no idea how long you could ride 40 mph on the same motor.

But my gut feeling is that for any kind of long distance at 40 mph, you will need the brute strength and heat tolerance of an x5. Or better still, something chain driven that can have fan driven cooling in the motor. But we still have no idea how long he wants to go 40 mph. 5 miles pretty easy, 10 getting harder but can be done, 20 miles good luck if you live in a warm climate.

 

[TylerTrinh]

if you are planning on 35 mph - 40 mph, a 5303 is the best motor for doing that because it won't overheat no matter what you throw at it. If you plan on doing that kind of speed, I'd get some Schwalbe Big apple, Schwalbe Fat Frank, or some Maxxis Hookworm tires. Also, your wheel base is a factor. You should measure the wheel base of your bike. The longer the wheel base, the better. I have a GT Outpost trail bike and it has a 1 1/2 inch shorter wheel base than my huffy so I feel less safe on it than I do my Huffy.

* big fat tires like 26" x 2.35 or 26" x 2.50 would be good
* long wheel base
* and maybe even a suspension would be good but I've been told that fat tires can actually be better than a suspension

What would be a good wheel base?

 

[dogman dan]

Exactly the same as a motorcycle that goes at least 60 mph. My roketta scooter is just about 18" longer than a typical mtb and goes 60 mph nicely.

I don't think you have to go to a cargo bike though, just something a bit longer than a bmx.

 

[TylerTrinh]

Dogman,
The longer wheel base is something I can do to redesign the frame. This concept bike will be made from raw materials and welded. Mix of aluminum 6061 and steel forks for strength. Lower center of gravity and aero dynamics is why your other bike flys right? Alright I am going to decide on 5304 and redesign the frame. Right now the design will accept 20 Headway 12ah cells. With the redesign of a larger frame I might be able to squeeze extra cells to 72v 12ah.

 

[ryan]

Now you're on the right track. Sounds like a plan! If you're going without suspension, I recommend leaving extra room for fat tires. I have a high quality suspension system and I still feel the bumps. When you're up over 35mph, that's the last thing you want to feel.

 

[cell_man]

My pretty standard full suspension bike is pretty stable at speeds around 40mph but could be better. Doesn't corner so good, but it's a cheap bike. Definitely need full suspension or at least really fat tyres (biggest you can find, I've seen 3") to do much over 30mph on a bike I reckon. With a real big motor in the rear, even more so. If you're gonna go really big tyres you mighgt be better with a 24" rim as it will give you similar rolling rolling radius as a 26" with standard sized tyres. Disk brakes are of course a must have.

 

[icecube57]

i do 30-40 regularly with 26x1.75 at 50-60psi. This is on a front wheel drive with rigid front Surley Instigator Fork and a rear suspension.

 

[TylerTrinh]

Ryan,

Funny that you mentioned about the tires. I was working on the wood model for measurements. I was looking to move to 24" x 2"-2 3/4". 26" seem to big for this design.