Looking for suitable controller, help wanted

qq4

10 µW
Joined
May 16, 2022
Messages
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Hello all. I have a 48v motor from this yescomusa rear hub motor kit and a 48v EM3ev jumbo shark battery with Panasonic PF cells, rated for ~29A Continuous, 38A Max Burst Current, as seen on the linked page. I am having trouble finding a suitable controller that will stay within my battery cell's specifications. I can not find the same controller in that kit, and I only need throttle, motor and power connections at minimum, although other features like lights or programmability would be nice. I don't mind soldering new cable connectors. The motor also appears to have sensors as there is a five fire connector alongside the three power connectors. I appreciate any help and can provide more details.
 
Fwiw, I am currently considering a Kelly KBS48051X controller. I am unsure about the 10 seconds boost attribute of the controller though, as it is 60A which is far above my battery's maximum burst current. If that current draw can be tweaked with software then I guess I'm okay. Unfortunately I'm a dolt when it comes to this stuff. I want to be more knowledgeable with electronics but alas I only have so much time.
 
Kelly does have software for thier controllers; I think Fany there is the most common technical contact for questions about that. The software does have quirks and may take some work to learn and get setup for your system. It's likely you'll end up using hte software to get the motor to run correctly with it even if you don't change current limits.

There's a lot of other generic controllers that would work; typically those that have a 30A current limit should work with your battery safely enough.

What was the original controller's current limit? (1000w / 48v is about 20A, based on the yescom info, but if it's marked it will give a more accurate number).


WHat kind of lights do you need?

Controllers don't typically provide power for or operation of "vehicle lighting", so if that's what you want, you'll need some additional bits like a DC-DC powered by your traction battery to provide constant lighting power, and some handlebar controls to turn them on and off, and possibly a blinker for turn signals if you want them and don't use self-blinking ones.

(there are a couple of (usually unavailable) controllers like Nucular and Adappto that have been able to provide lighting control, but they still use external DC-DC for the power itself)
 
For the old controller I assume about 20A for the same reason you do, but I'm not sure. The markings are 19EBE003-48V1KD-26R and LY-48V1000W P-19EBE-000002. I tried searching for those ID numbers and I only found links for the whole kit, and no new information.

I assumed lights would be common since every e-bike is already using a large battery. I don't need anything fancy, I would simply rather run a headlight and tail light off my battery instead of having to charge them separately.

I did notice a lack of support on the Kelly website, but maybe people get a lot of help here and on similar sites. I will try and contact Fany over at Kelly if I do go with one of their controllers. Thanks for the contact reference.
 
qq4 said:
I assumed lights would be common since every e-bike is already using a large battery. I don't need anything fancy, I would simply rather run a headlight and tail light off my battery instead of having to charge them separately.

It would be nice if they were common, but they're not nearly as much as they should be (and often what is used is either so bright it's blinding, or simply not very effective).

If all you want is headlight and taillight, there are some of them that run directly off voltages in the range of your battery.

But if you want good DOT lights like motorcycles or other road vehicles use, which can provide better visibility (both of you and by you) without blinding other road users, they pretty much all run off "12v" (really 13-15v). So you'd need a DC-DC converter from your battery voltage (call it 60v or higher for margin) to 13-15v (13.6v is commonly used), capable of enough amps to run whatever you hookup to it. There's a lot of these out there for scooters, golf carts, other EVs, etc.
 
Looks like the DC-DC converter is a good option. I'm seeing some examples online.

I found this controller on eBay that is about the size of the one in the kit. It's 30A and and seems like one of the generics you mentioned.
 
Note that it's specs say rated current is only 15A, max is 30, so as long as you aren't needing to use it at 30 all that much and mostly at the 15A range that would be ok.

If you really need higher continous usage power, you might need a slightly better controller. (this one might get hotter than it likes, doing that).
 
amberwolf said:
Note that it's specs say rated current is only 15A, max is 30, so as long as you aren't needing to use it at 30 all that much and mostly at the 15A range that would be ok.

If you really need higher continous usage power, you might need a slightly better controller. (this one might get hotter than it likes, doing that).

I am confused by rated and maximum current. When I go to find a 30A controller, that seems to mean a controller with a maximum current of 30A. All of the controllers I find have a rate current around half of the maximum. Should I be looking for a controller with a maximum of 50-60A then, which would likely be rated for 30A? I'm worried about the maximum current damaging my battery unless there is a way to limit it.
 
It depends on how the specific controller deals with it, and most sellers have no idea how what they sell works, making it difficult to be certain without testing yourself (difficult to do without wasting money on parts you don't use).

Some will only limit current at all at the "max" current, but may only be able to continously handle the "rated" current; how long they'll handle the "max" current is unknown unless it lists that.

Some will allow the "max" current for a few seconds (or less) and then limit to the "rated" current. I would guess that this is the most likely operation mode for most of them...but I don't know this for certain, or for any particular brand/model.

I don't know a good way to tell, from most advertisements, which is the case for a particular controller, unless it actually states how that one works.

All of the ones I have here, of various "brands" (as much as that term applies to these things), only list a single current limit number, which they all limit to within an amp or two, so I dont' have anything I can test for you to see which way is more common among at least a limited number of them.

If this exact current limit is critical to your system, then AFAIK, any of the KunTeng / KT controllers, especially those listed in the Open Source Firmware thread(s), should limit "properly" even with the OEM firmware, and if necessary you could install the OSFW on it and get more options.


Unfortunately for us, it is difficult to get exact specifications for these things. Because it is very common for ebike parts (and other things), especially batteries, often controllers, to be given maximum ratings that are only momentary capabilities, with a much lower continuous capability, sellers often appear to think it makes a better advertisement to show the maximum ratings (the continuous ones may or may not even be listed by the seller because that may make it look "bad" and not sell as well as a "higher rated" product). Most sellers know nothing about what they sell, which makes it worse--they may even just copy their ad from someone else's, and if they run out of a product they may just get soemthing similar and sell it using the same ad.
 
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