Crystalyte 408, 4-Series with X5 Controller 72V 35A, 40A

[broloch]

Hi ES'ers,

Just wondering if anyone has a Crystalyte 4-Series motor that they hooked up to a 72V 35A, or 40A controller?
Have you tried it at 72V? Does it work well? Is there any sign that the motor may not be able to handle it?

What exactly does the Amps on the controller mean? e.g. 72V20A, versus 72V35A? Does this mean the amount the controller "can" take, or does it mean that the current will always be higher on the higher amp controller? For instance, for someone going 0-35mph, when someone pulls on the throttle, will a 72V35A controller always make the bike accelerate more quickly than with a 72V20A? (F=ma) (T=Fd) more torque with 35A, hence better acceleration? But what happens as each bike reaches 35mph, on the flats and doesn't need to accelerate?
Then would the current draw from the 72V35A drop to the level that is similar to the 72V20A? Am I making sense here?

Is the 72V35 controller gonna use electricity from the battery pack faster, even if I try to go easy on the throttle to make it accelerate as lightly as possible, kinda like if I were riding a bike with a 72V20A controller? (for instance if the 72V20A bike accelerated at 8km/(h/s) at full throttle, and I was magically able to pull on the throttle of the 72V35A bike to accelerate at the same 8km/(h/s), would the 72V35A controller draw the same amount of electricity?

 

[adrian_sm]

I have a 408, with a 35A controller, but only run it at 48V.

I would recommend having a look at this simulator, and adjust the battery voltage, and controller amp rating, and see the effect on speed and torque.

Basically the amp rating on the controller is the maximum current that the controller allows the motor to draw from the battery. This has the biggest impact on the torque from low speed.

As for how quickly you use the battery up, energy is energy. Assuming you can be restrained and not use the more available speed or torque by going a higher current, or voltage, you can acheive essentially identical efficiency. As it takes the same amount of energy to push through the air, and accelerate the mass. But in reality as soon as you have more power on tap you will use it, so expect higher energy use per distance travelled.

Finally about running the 408 at 72V I don't have the experience so hopefully someone else will be able to answer that one for you. But I am pretty sure you can do it successfully. But you will have to be more carefull about overheating it.

Hope this helps.

Adrian

 

[dogman dan]

It may take awhile to understand what the simulator tells you but it is a fantastic resource. Over at Ebikes.ca there are also some really great explanations of how motors controllers and batteries work.

A few simple things to remember here though.

A battery able to put out 20 amps will not magically put out 35 just because you put on a bigger controller. Well, actually it will, but it will die trying.
So a high amp controller needs to be matched with a battery pack that can handle it.

At a given speed, a given motor at a given voltage is going to use a given amperage. So if your 408 or whatever uses 14 amps while cruising at 20 mph with a 36v battery and a 20 amp controller, it will use the same amps cruising at 20 mph using a 36v battery and a 35 amp controller.

While acellerating, or climbing a hill, or riding into stiff headwind, the 20 amp controller will use less power than the 35 amp one. Under heavy load, the higher amp controller will supply more amps when the motor demands it. Unless the rider uses less throttle.

As stated above, some smart imput from the rider can make riding a 35 amp controller just as efficient as riding the 20 amp, with the benefit of having more power when you occasionally need it. Trouble is, we tend to use whatever power we have avaliable. The EV grin can make economical riding hard to actually do.

 

[broloch]

For a battery to discharge at 20A, would that mean that the battery must have at least a 20Ah capacity? Is that how the capacity is usually rated - 20A discharged for 1hour?
Or can a 15Ah battery still discharge 20A but still be safe, e.g. discharging 20A, but only for 40 minutes?

how many dogs do you have?

 

[broloch]

good info to know guys.

it would depend on my ride i guess.
if i were to go a long distance, i would try to slow it down a bit, and assist with pedalling

 

[broloch]

Also, I have a big crank installed, something like 58t or 60t for higher speeds

i will have to buy pings later on

my current battery is useless almost, takes me like 4 miles

 

[dogman dan]

The discharge rate a battery can do varies by lots of things. Some, like lifepo4 come with a bms that will theoretically protect it from delivering too many amps for it's own good. But the bms is not always perfectly matched to the battery, or may have not so accurate settings and not shut down as soon as would be best. Lots of variables.

In the currently offered lifepo4 there are about three grades of batteries based on the c rate. For a 10 ah battery 1c discharge rate is 10 amps. For a 20 ah battery, 1c discharge rate is 20 amps and so on. All the lifepo4 on the marked now can stand a 1c discharge rate, so your statement that a 20 ah battery can discharge 20 amps is correct. Pingbattery for one can take 2c discharge rates, but any battery will last longer at 1c discharge than it will at 2c.

But up the ante from the ebay duct tape battery and the amps you can use go up. For example, the headways are said to be 5 c batteries. So a really conservative discharge rate for that battery would be around half that. Use a 10 ah headway at 3c, and you get 30 amps of discharge rate, and are still in the "safe zone".

Move up to A123's, and they are, I think, 10 c or somethig? So a 10 ah A123 pack could easily deliver 50 amps and still be in the "safe zone"

Right now I'd say if you buy pingbatteries, discharging at 1.5c would be safe enough for the battery to last long enough. So if you bought a 48v 15 ah, you could do continuous 30 amps without too much worry.

If you bought cheaper ebay duct tape like a vpower battery, you might be wise to aim for .75c discharge rate, so the same 48v 15 amps may have you aiming for 10 amps of power.

If you do get a big ol 5304, then you really need to get 30 ah of ping, or 10 ah of headways. I'd get the headways.

Oh and, right now I'm down to only 3 dogs, two Bloodhounds and a St Bernard. For a few years I was doing rescue work with agressive bloodhounds and had up to the legal limit of 7 dogs for inside city limits with a kennel licence. I was saving the dogs from euthanasia after a man bite, not saving people with trained dogs. Then one got loose on me and bit a neighbors child, and I had to get rid of the mean ones and stop getting more. Just the three sweeties left now, the last mean foster dog died of natural causes last summer.

 

[broloch]

Good to hear about saving the dogs.

I haven't looked into upgrading to a 5304 as yet. Is there an advantage to doing so from a 408?

I am looking to end up with a 24V 15Ah and a 36V 15Ah pack and go upto 60V 15Ah. LiFePO4.
This would put me in the 28mph top speed. My current controller is a 20A controller. I don't suppose I should have to upgrade to a different one?

Perhaps a 72V 35A controller?

 

[itselectric]

Broloch:

Here is a sample 408 motor with 72v 25amp, it went perfect in every way, with dual 37v 8.2ah batteries

http://www.youtube.com/watch?v=M7kYZlL6zUY

When you start putting 35amp or 40amp controller onto 408, it provide very good low speed torque, we have installed this type configuration on an xtracycle with 300lbs total weight. It really needed the 35amp controller for hill climbing. However a few of our customers just push the throttle all the way non-stop at the maximum speed and going up the hill, the motor started to heatup, one of them actually melted glue and the magnet came off inside the motor.

So if you want lighter weight (16lbs 408), lower price, a bit more low speed power, and short running top speed, a 408 with 35amp controller is perfect.
If you want a lot more power, accepting the heavy weight (23lbs 5304), much higher top speed, a 5404 with 35amp controller is for you.

Ken

 

[dogman dan]

Assuming the battery will be ping or equivilant, you will want to stick with the 20 amp controller. A 35 amp will push the batts past 2c discharge too much. And as pointed out, the 408 can dish out the power with higher volts, but will melt itself after x number of miles if you push that wattage continuous enough.

The advantage of the x5 is the larger diameter gives it more tourqe for the same watts, and it can take more heat before the magnets melt off. The disadvantage is you need to double the cost of your battery to have any range and or have the battery survive.

If you overvolt your 408, for sure you want a motor thermometer on the handlebars. Buy a cheap car indoor outdoor thermometer and put the sensor on the end of the axle, and enough tape to insulate it some. Then add 40f to the reading to get the actual inside temp. Ride till it hits 180F(140F on the readout), and if it climbs further, stop! Below 170F, I garantee your motor will not get damaged.

I need to get back into fostering dogs, they kill 70 a day at the local shelter. But at the moment we are still trying to pay off the costs from the one that bit a neighbors kid. I staved off a lawsuit, and paying $50,000-70,000 but only by getting a loan and heaving a big chunk of cash at the victim. No more dogs with a man bite history now. I need a place further out in the sticks for that. Besides, getting bitten yourself several times a year gets old. People can visit my house again now too.

 

[lifepo4ever]

you can look my video also of my 72 volt crystalyte here: http://www.youtube.com/watch?v=XLdeJC57xAw

look all the video you will see difference between 36 volt and 72 volts

this motor 406 as less torque but top speed


408 as less top speed but more torque

x5 series as lot more torque but drain energy if you open the trottle


my new project now is a 2807 rear wheel 9c and at 72 volts ping batterie I will be able to reach easy 60 kph

 

[lifepo4ever]

like dogman say the 408 can over heated but I never have problem going at 40mph with my 406 because it can handle it

anyway at 40mph you don't want a ride for a long period of time so the motor cool off , after 2 minute ride I release the trottle to give him a chance

also the controller have to handle it because of the heat build inside the case depend on where you put on bike , mine have lot of drilling hole so the air can pass

next summer I will try with a barbecue sensor in the wheel like doctorbass do