Crystalyte 3640 and 4840 controllers

I bought several of these (NOS) from a local bike shop. The 3640 and 4840 boards (EB212-A-5 ) and components seem identical except for one of the two power resistor (10w?). I assume it controls the LVC. 300ohm for the 3640; 330ohms for the 4840. Question #1: Can I change that resistor to make a 3640 into a 4840 or is more required?

I'm limited to 18 volt multiples (tool batteries) and use 54V batteries with 48volt controllers with no problems other than the LVC is lower than ideal. Question#2: Could I change Clyte controllers to a defacto 5440 with by changing that resistor to something higher?


I'm using the 4840 controller on a tandem that previously had a 30amp max. KT controller (died) with the LCD3 display/programmer. The KT setup with 5 power levels and automatic cruise control work very well for our style of riding. Level 1 in cruise would hold 20mph on flat with pedaling using less than 300w and automatically increase to 1000w as the bike slowed for the hill climbs. Downhill in cruise, the power used would drop to zero and resume to less than 300w on the flat. In Level 5, 30mph on the flat was no problem if needed.

The Clyte 4840 has a 3 speed switch, a more sophisticated cruise control and works better in all situations except one. Hill climbing; too much power. Both the 3 speed switch and the cruise control limit power only after a certain speed is reached. Climbing a long grade immediately pushes the power to 40-45 amps even in the low switch position and min. cruise setting. I can lower the power by holding the throttle in a mid position with cruise off, but that's difficult to do when busy with hard pedaling and frequent gear changing. Climbing a long steep hill at 20mph is a bad trade off for shortened range and heat build up in components and possible melt down.

I'd rather not use a CycleAnalyst. A little expensive to put on several bikes and it takes a lot of space on the handlebars. I prefer a simple watt meter and cell phone for speed and navigation.

Question #3: How can I limit or control the power output of the 4840 to 20-25 amps during 12 to 15 mph long climbs?

My ideas:
1. Permanent reduction of max. amps: Change or reduce the diameter of power shunts. The opposite of coating shunts with solder to fool controller into more power.
2. Some how adding a variable resistor to the throttle input. I assume cruise control would try go to max throttle voltage, but I think the pot would limit that.

Any ideas or comments would be appreciated.

Firedog said:

I bought several of these (NOS) from a local bike shop. The 3640 and 4840 boards (EB212-A-5 ) and components seem identical except for one of the two power resistor (10w?). I assume it controls the LVC. 300ohm for the 3640; 330ohms for the 4840. Question #1: Can I change that resistor to make a 3640 into a 4840 or is more required?

Click to expand...

the power resistors are not for lvc. they are to limit the current into the first stage of the lowvoltage power supply lvps that runs the mcu brain of the ocntroller, gate drives, hall and throttle power, etc.

you can calculate based on the ones you have what the volts per ohm is and extrapolate the ohms ou need for a higher voltage.


however, it is still possible that other components of the system can't handle the higher voltage when the batteyr is fully charged; you must check the specs of the individual parts, mostly capacitors and the fets that drive the motor. almsot everything else runs off the lvps so doesn't matter.

it's also possible the mcu is programmed to detect that higher voltage and then shut off to protect the controller (because voltage spikes in operation are often significantly higher than the battery voltage, and may be higher than the components are rated for and cause cumulative damage or immediate catastrophic failure, usually blown fets)

the mcu programming can be bypassed if you can find the pin that has a voltage divider on it to read the battery voltage. this is usually used to shutdown the controller for lvc, and will typicaly be at least a pair of smt resistors, one from that pin to ground, and one from that pin to battery voltage. there are usually no other pins on the mcu that lead to battery voltage at all, so should be easy enough to find. sometimes an opamp or transistor circuit is between the mcu and battery positive, to protect the mcu in case of overvoltage, but not always.

I'd rather not use a CycleAnalyst. A little expensive to put on several bikes and it takes a lot of space on the handlebars. I prefer a simple watt meter and cell phone for speed and navigation.

Click to expand...

cost notwithstanding, if youre only using it for control purposes, it doesn't have to be on the handlebars, you can put it anwyhere you want. if you need to chagne setitings while riding you can usaually use either a remote analog or digital control wiht presets or specific values. if space is really a premium and you never need to see the display, you can even cut the lcd off and use just the board inside, with a modification to add an led and resistor in series with the power supply as it's designed to use the one in the lcd to help regulate things somehow. then all programming is done within the pc or mac setup program.

it might cost more, but you could even ask grin if they can / already make or will make for you a smallscreen version of the cav3. then it would be around the size of the rc wattmeters.

The Clyte 4840 has a 3 speed switch, a more sophisticated cruise control and works better in all situations except one. Hill climbing; too much power. Both the 3 speed switch and the cruise control limit power only after a certain speed is reached. Climbing a long grade immediately pushes the power to 40-45 amps even in the low switch position and min. cruise setting. I can lower the power by holding the throttle in a mid position with cruise off, but that's difficult to do when busy with hard pedaling and frequent gear changing. Climbing a long steep hill at 20mph is a bad trade off for shortened range and heat build up in components and possible melt down.

Question #3: How can I limit or control the power output of the 4840 to 20-25 amps during 12 to 15 mph long climbs?

My ideas:
1. Permanent reduction of max. amps: Change or reduce the diameter of power shunts. The opposite of coating shunts with solder to fool controller into more power.
2. Some how adding a variable resistor to the throttle input. I assume cruise control would try go to max throttle voltage, but I think the pot would limit that.

Click to expand...

#1 is more precisely done using a pot on the opamp circuit that is between teh shunt and hte mcu, to adjust the proportion of response. it also means you can put a switch across teh pot to short it out for full current situations needs, with a bypass button on the handlebars or whatever.

#2 depends on the behavior you're after. if you want a constnat speed, cruise control on the common controller like these just outputs a constnat voltage. if you want to reduce that speed, then putting a pot in there will reduce the speed by reducing the pwm voltage applied to the motor by the controller.

whether that reduces current the way you want depends on the situation, but it shoudl reduce it.

you would put the pot between the controller and any throttle siganl coming into it. the pot would be wired so that one end of it goes to ground. the other end goes to the siganl that would otherwise go to the controller. the wiper center wire then goes to teh controller's throttle signal input.

then the pot simply attentuates the existing throttle signal, whatever it is at that moment, by whatever ratio the pot is set to.


it might be easier to operate by using a multipposition siwtch, toglge or rocker type, on the handlebars, and use different resisitive ratios on each position to divide the throtle signal up in different ratios. that way you are not fiddling with a knob to change currents, whcih is likely to be even more fiddly (because it's not already in your hand or on your thumb) than dealing with the throttle to control it.


but basically this kidn of control either pot or switch, is already done by most of the three speed switches on controllers like this--they commonly change the throttle response rather than any other function, for nonprogrammable "generic" controller designs like these. it might not change it as much as you want, but it should do something similar.




the cycle analyst specificaly has a mode that will automatically control throttle to limit current as needed to keep you within either watt or amp limits, while also obeying a speed limit, or a cruise setting, etc.

this can also be affected by a switch or a knob to change the value of the limit itself that the ca is obeying, or using a switch to change presets to affect multiple parameters at once.

it takes a fair bit of tuning the whole ca setup to make it operate ina particualr way, but it'll do a whole lot of things by itself without fiddling with the controller shunts, throttle signal wires, etc.

as you say, its' expensive, but it's designed to do what you're after already, although as you say the cruise fucntion doesnt' appear to be as sophisticated as the controllers' built in version; iirc it only holds a throttle output value that youv'e set with the throttle position. (what that throttle value actually is depends on what throtlte mode youv'e set, wehter that is speed, amps, watts, etc).

Climbing a long grade immediately pushes the power to 40-45 amps even in the low switch position and min. cruise setting.

Click to expand...

Amberwolf, I'm totally wrong on that report. What actually happen was I went full throttle to get up some speed ahead of a steep hill, set the cruise control, and didn't get the setting reduced before the 40 amp fuse blew. I didn't have a spare fuse, so we had a frustratingly long ride/walk home up hill with no power. Instead of retesting the problem, I jumped to the wrong conclusion on why it happened. My bad.

In reading your detailed response, I realized my first conclusion made no sense. I re-tested it today climbing some very steep hills. Taping plus or minus steps the cruise current up or down appropriately. Now that I understand how to use it, this set up will work very well for our needs.

Below is a picture of Crystalyte's cruise control and it works just fine to limit the current at any speed or grade..... if the rider is competent.

As always, thanks for you knowledge and patience.

Firedog said:

Amberwolf, I'm totally wrong on that report. What actually happen was I went full throttle to get up some speed ahead of a steep hill, set the cruise control, and didn't get the setting reduced before the 40 amp fuse blew. I didn't have a spare fuse, so we had a frustratingly long ride/walk home up hill with no power. Instead of retesting the problem, I jumped to the wrong conclusion on why it happened. My bad.

Click to expand...

nno problem; as other said a test is alwyas worht a thousand guesses.

fwiw, for at least testing situations, you might consider a dc-circuit breaker of equivalent rating to the fuse, that wires parallel to the fuse. then you can flip it whenever the fuse blows, and at least get home to replace the fuse. solar system breakers can be used for this safely, there are a number of threads about them.

i've also used powerchair breakers for lower voltage packs; proablaby wouldn't break the circuit on a high voltage one like 72v under load, though as most are meant for under 30vdc.

I re-tested it today climbing some very steep hills. Taping plus or minus steps the cruise current up or down appropriately. Now that I understand how to use it, this set up will work very well for our needs.

Below is a picture of Crystalyte's cruise control and it works just fine to limit the current at any speed or grade..... if the rider is competent.

Click to expand...

fwiw, that cruise cotnrol works on any system with a voltage-controlled-throttle input. (i have a couple here somewhere)

all it is is a sample-and-hold circuit inside along with an increment/decrement voltage fucntion, that take the throttle as input to it, and when the big button is pressed once it locsk that voltage in. then the + / - buttons will add or subract a little voltage (i think it's 64 steps? might be 32? i forget, it's been too long) on each button press. but anyway, they're really simple devices.


so it does not change the current, directly. all it does is change the throttle demand from the controller, which as a side effect in these pwm/speed-throttle type controllers like the crystalytes, happens to also lower current demand, depending on the situation.


btw, if you wire your ebrakes to them, then that will disable the cc when the ebrakes get engaged. if you dn't want to use the actual ebrakes you can use a separate switch, like a button right on your throttle or your handlebars next to your thumb, or even a separate button on the face of teh brake lever under one finger.

i don't recommend using *any* cruise control without some form of instnatly-accessible disable button that your finger already rests on all the time.

here's an old old thread about them
https://endless-sphere.com/forums/viewtopic.php?t=4250 but has some wrong info in it
this one
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=19742&start=0 is by me with tehcnical info on the itnernals, and links to another
https://endless-sphere.com/forums/viewtopic.php?t=17353
that has info on using htem on generic controllers but the pics are gone, but descritpions are enough to let you use it with them.
archived page
https://web.archive.org/web/20120409080405/http://www.electricrider.com/crystalyte/x-ctk.htm
has short usage description
this post
http://endless-sphere.com/forums/viewtopic.php?f=2&t=63288#p982627
has a wiring diagram

btw, the cycle analyst cruise control function can actually be more sophisticated than this one, because it cna be setup for autocruise once throttle is held for a certain number of seconds in one position, and you can set the amount of variation allowed while holding it.

not only that, but since the ca can be setup so throttle controls controller current or power rather than speed, the cruise can be used to hold a constant current or power rather than a constant speed.


if you want to be able to vary the throttle with a control after that, i think you can use the analog aux input and set it to this

ThrO Lim: The Aux control applies a scaling factor to the configured ThrO-> MaxOut voltage. With most controllers this has the effect of limiting speed by a means that is easier to tune but less precise than true speed limiting.

Click to expand...

and use a knob to do it, or use the digi aux input ans set it to this

Speed Lim: The Digital Aux control applies a scaling factor to further reduce the MaxSpeed limit.

Click to expand...

which does the same thin but lets you use buttons to change the value.

the catch is that those two things above remain in effect after crusie is turned off, and contineu to scal ehte max throttle, so you then have to turn the knob or push the buttons to get max throttle back where it used to be. so doesnt' do what the buttons on the crystalyte cc unit do.


https://www.ebikes.ca/product-info/cycle-analyst-3.html#ca31-setup-menu

[ ThrI->Auto Cruis ]*
Autocruise is a form of cruise control that automatically maintains a fixed throttle level. Holding the throttle steady for the configured time causes the throttle slider on the main screen to flash indicating that autocruise is engaged and the throttle can be released. That throttle level is maintained until autocruise is disengaged by braking or re-applying the throttle.

Off: Auto Cruise Mode is Disabled
2 Sec: Auto Cruise will engage after 2 seconds
3 Sec: Auto Cruise will engage after 3 seconds
4 Sec: Auto Cruise will engage after 4 seconds
5 Sec: Auto Cruise will engage after 5 seconds
6 Sec: Auto Cruise will engage after 6 seconds
8 Sec: Auto Cruise will engage after 8 seconds

IMPORTANT: Normal autocruise behavior maintains power after the throttle is released which can be alarming if unexpected. Ensure all riders are thoroughly acquainted with autocuise operation before enabling this feature.

[ ThrI->Cruise Hld ]
Sets the throttle voltage range for auto cruise to consider the throttle 'stationary'. Small numbers are more sensitive and can make engaging autocruise difficult. Large values reduce motion sensitivity but can cause unintended autocruise engagement.

Click to expand...