new Kelly brushless regen controllers

[fechter]

That sounds like a golden opportunity.

I probably don't really have time, but I'm willing to help.

I have lots of controller design and repair experience.

I would not be interested in becoming a dealer, but I know others who probably would.

I am excited about your controllers because there are not many controllers on the market at this power level, and most of those are too expensive. I've been looking for the ideal controller for the Mars brushless motor, and I'm getting too lazy to build the whole thing from scratch.

 

[flip_normal]

I got the job.

Doing the Kelly KBL Series Brushless Motor Controller User’s Manual now.

 

[GGoodrum]

I routinely hit 80-85A/5000-5500W with my setups. The motor gets warm to the touch, but not so hot that I can't leave my hand there.

 

[Nimbuzz]

Great -- cool news flip -- you too Good -- wowsers -- some power!

 

[Jay64]

I routinely hit 80-85A/5000-5500W with my setups. The motor gets warm to the touch, but not so hot that I can't leave my hand there.

Gary, you're getting those numbers with a Mars motor?

 

[GGoodrum]

I routinely hit 80-85A/5000-5500W with my setups. The motor gets warm to the touch, but not so hot that I can't leave my hand there.

Gary, you're getting those numbers with a Mars motor?

No, from a front-mounted 5303 on a 20" folding bike. It has a 4840 controller that Bob Mcree did the 4110 upgrade on and while he was "under the hood", I had him fill in some of the some of the shunt area with solder. That gave this controller an 87A current limit. The battery setup on this bike is two 10s4p a123-based packs in series, in a 20s4p 66V/9.2Ah configuration. There is a video here, but I have to warn you, the file is pretty big (150mb...). I used an EagleTree Systems MicroLogger to record the power being used. It has a PC-based replay feature that I overlayed onto the to video. Anyway, you cand see the amps and watts used.

On my 26" Townie, I have a rear-mounted 5304. It has a similarly modified controller, but the current limit on this one ended up at about 78A. With a 24s6p a123, or a 24-cell LiFeBatt configuration, it hits about 5000W peaks.

-- Gary

 

[GGoodrum]

I may have to take the plunge for one of these as well. The regen feature is just what I've been looking for, as I have one bike with a disc brake in back that won't work with the 5304 I want to put there. I've been contemplating trying to go the resistive route, but this would be so much easier.

-- Gary

 

[curious]

Great company ! If you live on the top of the large hill and you start downhill after full charge I'd still suggest a darlington clamp that I mentioned before in this thread (onsemi MJ11030 is a possible candidate) to insure you will not overcharge the batteries otherwise it is not needed. Still waiting for my controller to arrive.

 

[fechter]

Great company ! If you live on the top of the large hill and you start downhill after full charge I'd still suggest a darlington clamp that I mentioned before in this thread (onsemi MJ11030 is a possible candidate) to insure you will not overcharge the batteries otherwise it is not needed. Still waiting for my controller to arrive.

The Kelly is programmed to disable the regen if the battery voltage exceeds a set point.
It won't overcharge the batteries, but you could suddenly lose regen. If you did live at the top of a hill, you'd have to rely on friction brakes or do the voltage clamp thing at a level just below where the regen cuts out. In actual practice, I think this would be a rare event. With my Zappy, I didn't have to go very far on flat or uphill before enough juice was used out of the batteries to absorb a large downhill.

 

[curious]

You are right, the regen overvoltage threshold is programmable, I missed that in the manual. Even less priority for the clamp then.

 

[Jay64]

I don't mean to get too far off topic here, but I was under the impression that one of the bad things about regen was that it isn't good to give your batteries small little bursts of charges, it is better to let it run down a good ways, and then fully charge it back up. The point of my question was trying to figure out a way to extend battery life. I know at this point it isn't the best way to go, but I was thinking about a possible supercapcitor setup to handle the regen produced power, instead of having it give short bursts of charge to the batteries. But if I am mistaken, and it isn't that big of a deal to give the batteries short burst of charge, then I appear to be over designing it.

 

[GGoodrum]

So, are these available now, or not? Has it been shipped to you yet? I don't want ot order one yet, if they can't actually ship it.

 

[curious]

I've got the tracking number but have not received the package yet, they are shipping it directly from China via EMS. I'll let everyone know when I receive it. My understanding is that they are just ramping up the production and have sample quantities. I've ordered KBL72151 which is a bit of an overkill but I want to experiment a bit and see if I can run technical singletrack with it .

 

[curious]

Jay64 -
It depends on the batteries. A123 can take charge at multiple C-rate without damage. NiMH, SLA and LiPo/LiIon are much worse at it. This is part of the reason I decided on A123 packs.
The supercap is certainly ideal for regen but there is a major complexity involved in designing proper temporary energy storage. You will gain very little byu simply adding a supercap in parallel to the pack. Instead you need to fully cycle the cap from max voltage almost down to 0V to get the rated energy storage. We are talking biga*s DCDC converters here.

 

[Nimbuzz]

<< it is better to let it run down a good ways, and then fully charge it back up. >> There may be other details about regen charging but as I understand it this running it down and then full charging is left over from Nicad. Other chemistries can be cycled fully now and then to balance but not required as was Nicad.

 

[curious]

One more note on regen. Lithium batteries are extremely efficient at taking charge compared to other technologies. That means that recycling energy via lithium pack can probably exceed 90% (not including motor/controller losses of course).

 

[Nimbuzz]

Jay -- are there "Supercaps" available for ebikes?

 

[Jay64]

I don't know if they are available. I need to make sure they will work/are worth the effort before I go about trying to find them. Even if they aren't available now, if they are worth it, then they might be available in the future. But to be totally honest, I am not looking at this for my ebike, but rather for my emotorcycles. But this is the only catagory that has a technical section, and I was planning on using the Kelly with my motorcycles.

 

[curious]

It is an interesting engineering problem but too costly for ebike conversion. Do a search on +bidirectional +DCDC +converters +supercap on google and you will find tons of references. A full supercap regen implementation requires a very large bidirectional DCDC converter that continuously senses battery current and either pulls part of the current into supercap when charge current exceeds optimal for given battery technology or supplements the battery current from the supercap when the discharge rate exceeds optimum. The key here is that the supercap working voltage range is from zero to maximum cap voltage while the main battery operates in a very narrow voltage range therefore you need a very big (multiple kW) and efficient specialty DCDC converter to match the two.
I guess a simplified unidirectional scheme is possible were a separate regen circuit (like the ones discussed on this forum for non-regen controllers) charges the capacitor only and then a medium power conventional DCDC pumps the energy slowly from the supercap back into the battery. This is a one-way scheme, that is it prevents large battery charge currents during regen braking but does very little assisting the battery during rapid acceleration current surge.

 

[fechter]

Curious is right. You would need a humongous dc-dc converter as well as a capacitor that is larger and costs more than your batteries. Someone actually hooked up a Maxwell supercapacitor to a scooter a long time ago to see what it would do. It would be much more cost effective to just get larger batteries.

If you do the math (and ignore the price tag), you'll find that a Maxwell capacitor about the size of your battery pack will supply enough energy for about 10 -15 seconds of power. After that, it's excess weight.

The technology is not quite there yet for capacitors. Maybe next year...

 

[Jay64]

Well, I'm not planning on building my high performance race bike until next year anyways. :lol: I don't want to drag this thread off into a completely new direction. But I do really appreciate the input, and I will be thinking of ways to maybe use what you guys talked about.

 

[Drunkskunk]

Super Caps right now are basicly vaporware. They work, but not any better than the worst of the battery options. And they store voltage on a near linear ramp, so using the power from one can only be done with DC-DC converter, which isn't the most efficent way of using power.

if you're going with a cheaper barrery sorce for your main battery, you could probably replace the "super Capacitor" with an equil sized bank of A123 cells, and have a much better, and cheaper platform. The A123s could be setup to take all the regen spikes, and give high amperage boosts during acceleration.

 

[Jay64]

Well, I was thinking about using A123s for the high performance bike, but with the prices that I need to spend on those batts I didn't want to be shortening the life span if I could help it.

 

[Jay64]

I've got the tracking number but have not received the package yet, they are shipping it directly from China via EMS. I'll let everyone know when I receive it. My understanding is that they are just ramping up the production and have sample quantities. I've ordered KBL72151 which is a bit of an overkill but I want to experiment a bit and see if I can run technical singletrack with it .

So curious, what motor are you going to be running with the kelly controller?

 

[curious]

So curious, what motor are you going to be running with the kelly controller?

Just received 5304 on a 26" rear wheel. Will use 33V/66V switchable (series/parallel) pack.