20A vs (30A vs) 35A X-lyte controllers

I've been reading up on Maytag and Deecanio's builds and was wondering if someone could explain in simple language the differences between the x-lyte 36-72V controllers. IE at 20A and 35A (the 30A is a mod that knoxie talked about)

It seemed that Knoxie was modding a 20A controller for D to run at 72V along with suggesting a mod that Steve did for his Dirt Monkey to bring it up to 30A.

Maytag ran into trouble with a 35A controller when going for the 40 MPH club I think it was.

Ypedal seems to be using a 20A controller at a higher voltage as well but I think that is with a 4 series motor.

I believe it was Knoxie who also suggested that the 20A controller was more robust and was perhaps a "simpler" conversion than the 35A controller.

Fechters excellent tutorial on modding controllers lends me to think that I could tackle the work involved ,but I'm a bit confused as to the better base unit to start with.

Also does anyone know why X-lyte isn't building these higher voltage controllers and selling them?

Crystalyte makes 20 , 35 and 40 amp controllers. ( the 35 and 40's are just about the exact same, not exactly regulated to 35/40 exactly.. but close , they go slightly more.. ie: my 20 amp controller will alow 25 amp peaks)

Both the 4 and 5 series motors can handle the 40 amps.. it's the batteries that have a hard time in most cases.

The 36v controller will handle 48v.

The 72v controller will handle 72v , up to 95v....

By adding a bit of solder or a few strands of copper to the controller's current bus bar you can bump it up a bit.. but you void your warranty :wink:


What you can also do is replace the FET's from the stock controller with better one's and also bump the voltage to 100+ v without causing smoke. I plan to try this soon, but it's not that easy.

Batteries, if using SLA, 12ah bricks will delivedr 40 amps.. but not for very long. you shorten your range considerably, With NIMH/NICAD, you need to have high-rate cells or enough AH to keep below 3C, so you need 13ah + and canot use the 8ah cells without burning them up .

Some of the lithium packs out there can deliver the juice, but again $$$$$

You wanna play, you have to pay !

To add to this.

On most bicycles, 20 amps is sufficient, honestly, unless you have hills to climb that will stall your motor at 20 amps , there is no valid reason to go with the higher rated controller.

I"m using 72v 20 amps on a 20" wheel in 409 and can climb any hill in my area, i do live in fairly flat terrain, but i've went looking for the biggest hills i could find, and have not yet found a road that the motor will not climb on it's own.

Off-road i've managed to stall it, but with a bit of leg power, each kick was like superman pedaling along with me, and i could keep my ass on the seat all the way up where the MTB guys struggled to make it up at a crawl speed.


if you go to the X5, then you really should go the 40 amp route, as the motor basically chokes at 20 amps.. but as you probably know.. the X5 is a freakishly large monster..

Ypedal said:

To add to this.

On most bicycles, 20 amps is sufficient, honestly, unless you have hills to climb that will stall your motor at 20 amps , there is no valid reason to go with the higher rated controller....

if you go to the X5, then you really should go the 40 amp route, as the motor basically chokes at 20 amps.. but as you probably know.. the X5 is a freakishly large monster..

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I have an ammeter on my handlebars and have run my X5 at voltages from 30 volts to 84 volts; my opinion on this: The X5 doesn't choke at 20 amps, it just takes a good 1500 watts plus to get that 25lb hunk of metal rolling off-the-line at decent clip (especially if off-the-line is also up an incline). In what manner it receives that power is not nearly as important. 72V 20A will do the trick; 48V 35A or 40A will do the trick too. If it can't be fed at least 1500 watts, I see no reason to choose the X5 over the lighter 400 series. If it can be fed over 1500 watts, there's many reasons to choose the X5.

Boy this stuff makes my head hurt :?

So if the X-lyte controller will work at 72V and 35 or 40A and is usable up to approx. 95V why are the boys modding their controllers? In Knoxies case is this due to the Puma/X-lyte controller differences?

I guess I was interested in running a 5 series at 72V with a 35A controller but have begun to look at its weight. The Puma/BMC intrigues me mostly because of its weight and torque as I am having a blast riding around on my new bike

http://www.rocky-mountain.com/bikes/2007/sport/trailhead.aspx

and I am not convinced that I want to add all of that weight (the X-5)just to make the hill climb easier.

Perhaps I am just too greedy :lol: I want a light weight bike that when I remove the batteries handles almost like a MTB without a motor on it. Am I dreaming?

Gaston, are you suggesting that I might want to look at something like a 4011 @ 72V over the 5 series? Hmmmm.....

gwsaltspring said:

Boy this stuff makes my head hurt :?

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This stuff makes my head happy!

So if the X-lyte controller will work at 72V and 35 or 40A and is usable up to approx. 95V why are the boys modding their controllers?

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Four reasons I'm aware of:
1) There's quite a bit of manufacturing variance with the mosfets, and how they're attached to the heatsink. Some people's (Maytag is one) 72 volt controllers fried at well under the theoretical 90-95v limit. The better quality mosfets fix that problem. Some mosfets being used (like by knoxie) are good for 150 volts. The X5 has about a 120 volt limit.

2) The better mosfets allow for more amps. The popular IRFB4110s turn a 72 volt 35 or 40 amp controller into a reliable 96 volt 60 amp controller if the current-sensing shunt inside is also modified.

3) These mosfets are also more efficient. So the controller heats up less, and wastes less battery energy.

4) Some people just like screwing with perfectly good equipment.

I guess I was interested in running a 5 series at 72V with a 35A controller but have begun to look at its weight. ...
and I am not convinced that I want to add all of that weight (the X-5)just to make the hill climb easier.

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If weight is a primary concern, and all you want is to make your hill climb easier, you'd probably be happier with a Puma, or a higher-winding 400-series (like a 409, 4011, or 4012) run at 72 volts and 20 or 35 amps.

Perhaps I am just too greedy :lol:

Click to expand...

Ain't we all...

I want a light weight bike that when I remove the batteries handles almost like a MTB without a motor on it. Am I dreaming?

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Sounds feasible. I want to fly around the sky and through space in a vacuum-sealed wet suit at supra-luminal velocities using featherweight, lace-on anti-gravity boots. Am I dreaming?

For my 32km/h efficiency test, I ran a 10 amp current limit via the CycleAnalyst. The bike behaved just like any other low powered ebike, and the 5304/24" didn't seem to mind at all.

Quote "
Gaston, are you suggesting that I might want to look at something like a 4011 @ 72V over the 5 series? Hmmmm....."

Well, Yes i am. in a way.

Unless you weigh 250 lbs + , or need to haul a heavy trailer up some NASTY hills.. and even then.. the 4 series could still do that job.

Some people are ok with a fast car.. others like to supercharge a Corvette and add Nitro for the hell of it.... what kind of person are you ?

Thanks for the clarifications guys.

With your assistance I am slowly gaining clarity.

I'm not saying that my speedo is the most accurate but I clocked 89.6KPH coming down the mountain today. Obviously not all the way, but basically it is a fun down hill ride into town. The uphill pedal is another matter, there are two all too short dips on the way up and for the rest of the way it seems pretty much an uphill slog.

For the most part it seemed that I was able to maintain about a 10-12 kph climbing rate on the steepest parts but I forgot to reset the speedo in town before starting the climb so I'm don't know what my average speed was going up. Next time.

Next up is the inclinometer test for the steepest section and an accurate distance along with reclarifying the elevation gain so that I have my parameters lined up.

Now back to the initial questions I was curious about.

Xyster, thanks again for the clarifications.

Is it fair to suggest then that any of us who are looking to run higher voltages would do well to think in terms of upgrading the mofsets?

Is it possible to take some precautions before changing out the mofsets?
eg. has changing/upgrading the screw/rubber tubing mofset hold down been enough to make a difference alone?

V x A = W correct?

So the higher Volts combined with the increased Amps leads to greater Watts to the motor. correct?

Is this the important achievement? Is there a preferred method to get to the higher Watts? (if this is infact the end goal) eg 100V x 20A = 2000 W, 72V x 30A = 2160W, 60V x 35 A = 2100 W, 50V x 40A = 2000W (I gather 40A continuous is not sustainable with the current batteries )

If the motors are rated in Watts, how does this relate to the above formula?

So quality of the original build is part of the issue.

Oh I get the notion of messing with perfectly good equipment. I have to admit I do it all the time with clients houses. "If we just move these walls over here I think you will be much happier with your design" Some times I just can't help myself :lol:

So are you saying that I am just dreaming if I want a bike that can act just like my bike before conversion after I have done the conversion? The Nerve of some people :wink:

Lowell;

I always appreciate your comments but I don't understand the significance of your efficiency testing data. I'm sure there is something for me to learn here, perhaps you would be willing to phrase it in a different manner for me to be able to grasp its significance.

Gaston

Ok, at least I was following you. Thats a relief.

I grew up riding around in a Jag and later learned to drive the same car. Never felt the need to mess with the thing, it was temperamental enough as it was. Same with my TR6 that I got after University.

I drive a Toyota SR5 4X4 cause it is reliable and does what I need it to do.

My dad is still messing with Jags and complaining about the trouble they are.

So I think that might just put me in the fast is good but once it is set up leave it alone camp. "If its not broken why fix it eh?"

I do appreciate your thoughts though, good one.

gwsaltspring said:

Now back to the initial questions I was curious about.

Xyster, thanks again for the clarifications.

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Ok, I've got my thinking cap on....

Is it fair to suggest then that any of us who are looking to run higher voltages would do well to think in terms of upgrading the mofsets?

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Yes I believe other people's experiences with blown controllers demonstrates a risk reduction benefit that increases exponentially with voltages over 60 volts on a 72v controller.

Is it possible to take some precautions before changing out the mofsets?
eg. has changing/upgrading the screw/rubber tubing mofset hold down been enough to make a difference alone?

Click to expand...

That's covered to some extent in Fechter's controller rebuild thread.

V x A = W correct?

Click to expand...

Correct.

So the higher Volts combined with the increased Amps leads to greater Watts to the motor. correct?

Click to expand...

Yes, as would either higher volts, or higher amps -- within the range of the mosfet's voltage/amperage rating (as well the other components), maximal wattage (power) is achieved by increasing both to their maximums.

Is this the important achievement? Is there a preferred method to get to the higher Watts? (if this is infact the end goal) eg 100V x 20A = 2000 W, 72V x 30A = 2160W, 60V x 35 A = 2100 W, 50V x 40A = 2000W (I gather 40A continuous is not sustainable with the current batteries )

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When all else is equal, I'm partial to increasing voltage first, amperage second. Increasing amperage takes more of a toll on the batteries, and increases resistive losses (heat in the wires and components from the "friction" of additional electrical current), whereas increasing the voltage alone does not. Within the bounds of the motor's voltage rating, more voltage gets you higher RPMs and so a higher top speed. More amperage gets you more torque. Power -- the "power" to climb a hill better, or the "power" to accelerate faster -- is a function of both RPMs and torque. Power = torque X rpms. And Power = Amps X Volts. Therefore, torque = amps, and rpm = volts. (I'm using the equals sign as an "is equivalent to" sign).
So raising volts (rpm's) gives you higher top speed, AND more power to climb hills better and accelerate faster. Whereas increasing amps (torque) gets you more power to climb hills better and accelerate faster, but unless gearing is altered too, not more speed.

If the motors are rated in Watts, how does this relate to the above formula?

Click to expand...

I'll have to think about that. Hopefully more of a motor expert will answer first

So quality of the original build is part of the issue.

Click to expand...

Yes.

Oh I get the notion of messing with perfectly good equipment. I have to admit I do it all the time with clients houses. "If we just move these walls over here I think you will be much happier with your design" Some times I just can't help myself :lol:

Click to expand...

It's fun. I imagine you have to be much more careful when it's somebody else's stuff you're feeling like you want to experiment with just for the heck of it.

So are you saying that I am just dreaming if I want a bike that can act just like my bike before conversion after I have done the conversion? The Nerve of some people :wink:

Click to expand...

"Just like"? Yah, that's a dream. "Close to" is possible. My comfort bike handles nothing like it originally did. But on balance for my riding style, I find the heavy X5 and 30lbs of batteries a trade-off well worth it.

gwsaltspring said:

Lowell;

I always appreciate your comments but I don't understand the significance of your efficiency testing data. I'm sure there is something for me to learn here, perhaps you would be willing to phrase it in a different manner for me to be able to grasp its significance.

Click to expand...

I was saying that an X5 can run ok at low power levels, the only problem is it behaves just like a low powered motor, but with a bunch of extra weight.

Xyster wrote:

It's fun. I imagine you have to be much more careful when it's somebody else's stuff you're feeling like you want to experiment with just for the heck of it.



Houses are just large sculptural pieces to my eyes at times, so with trust, a client will usually indulge me.

You are correct though, a certain amount of care is required as the project amounts are starting in the tens or hundreds of thousands of dollars.

As Picasso reportedly responded when asked which was his favourite painting "My next one", my designs evolve from one to another. I steal shamelessly from my own work and that of others

As an aside, I was listening to an architect today speak of the lack of artististic freedom with the field of architecture and how many are turning to other fields to express themselves. I was feeling that today for some reason. Oh well.... tomorrow is another day. :wink:


Now back to the topic at hand, controllers. Any comments on the notion that I believe Knoxie posted about Steves' Dirt Monkey controller being a 72V 20A modified to 30A over modding a 35A contoller or did you respond and I have just forgotten. ( the trouble with having company over the weekend ) I believe Knoxie thought that it was an easier mod with only 6 FETS to change out.

gwsaltspring said:

Now back to the topic at hand, controllers. Any comments on the notion that I believe Knoxie posted about Steves' Dirt Monkey controller being a 72V 20A modified to 30A over modding a 35A contoller or did you respond and I have just forgotten. ( the trouble with having company over the weekend ) I believe Knoxie thought that it was an easier mod with only 6 FETS to change out.

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Fechter, Knoxie, Lowell and the others who've done this procedure would know the answer much better than I. Due to limited fine hand dexterity, I haven't done any FET surgery. When it comes time, I'll pay somebody else to do that particular mod for me.
I'd rather start with the highest rated controller which fit size and budget constraints, then do the FET/shunt upgrade mod if more amps are required, and/or use the CycleAnalyst to limit the amps if fewer are desired. That way, if I didn't find 30 amps enough after doing the 20A-->30A conversion, I wouldn't be stuck buying another controller, and possibly do the mod all over.

Thanks X

Kind of what I was thinking, though I must admit that I like the compact size of the 20A controllers (there, spelt it correctly this time).

I had forgotten about the current limiting capabilities of the new CA.

From reading some other post I think Deecanio wound up with a 35A controller in the end anyway so that is probably the way to go if I wind up with a Puma/BMC.

I've been running Crystallite 408's from a 20A / 36-48V controller with 56V of LiPO without any trouble.

The same controller and battery setup seems to fry FETS using a Puma Motor if you do multiple full power starts, as happens when you get handbraky mania in a KMX kart, but I'm not yet 100% sure of the cause...

rhubarb said:

I've been running Crystallite 408's from a 20A / 36-48V controller with 56V of LiPO without any trouble.

The same controller and battery setup seems to fry FETS using a Puma Motor if you do multiple full power starts, as happens when you get handbraky mania in a KMX kart, but I'm not yet 100% sure of the cause...

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Where is this info from? I was under the impression that only the recent 35A (not the 20A) controllers have been blowing at higher voltages, and not only for puma motors!
Seems relevent as I will be doing just this in my KMX by the weekend!

36 and 48v controllers have 55v rated FETs, so if you're running a 15s lipo it could very well blow up.

A 20 amp controller could easily be turned into a 35-40 amp, while maintaining the same thermal load on components by using IRFB4110's. I would only do that if space is really an issue though, as having MOSFETs in parallel seems like a much better idea.