ITS REAL Cobra CX5e production model

[Swank171]

Well I picked up one of the first of its kind for the little guy. There bikes rip and they are oil cooled….not liquid. Guess it has a mineral oil not a coolant for the motor coolant.

Cobra killed it. If anyone is interested let me know. I know of 3 more that are coming but other than that they will be hard to get.

They have a holeshot mode

Hot swappable battery

Quick and slow charging option

Already way outlasts my sons ktm e5

Has top off charging mode

6 ride modes 2 are low traction modes, not like husky where it only gradually gets slower.

Hope you guys enjoy….these things are awesome.

 

[mr.skywalker]

The battery looks way different than the one on the website. Also interesting that you say the range is better but it has essentially same capacity as the ktm/husky/gg (0.960kwh vs 1kwh). Do you know the voltage? Maybe thats where the efficiency improvement is coming from

 

[Swank171]

The battery was reduced to save weight for production models. The pre production battery was quite heavy. It’s quite noticeably faster too. We have had the bikes side by side riding.

Not sure voltage, could be motor efficiency, it is oil cooled so less heat less energy loss.

Not sure if you have had much experience with the ktm/husky/gasgas but that motor gets very very hot in a competition setting.

 

[mr.skywalker]

Battery size reduction makes sense from weight but it just seems small for racing to me, id think 1.5kwh minimum would be needed for really fast kids riding outdoor tracks.

I havent had any experience with the production bikes(own a mod surron and did qs138 build with tc65) but I have heard of the heat issues with the ktms. I know the ktm is 48V so Im curious if this is 52v/60v/72v as that would reduce the amps needed which means less heat and more efficiency. I think the cooling doesnt improve efficiency as much as reducing amps unless the motor was way under spec'd then it wouldnt be in its efficient operating range.

 

[Swank171]

There’s always going to be a balance between battery, size, weight, and run time. These little kids and the center of gravity are easily disrupted by a little bit of weight up high on the bike.


I’d say on the voltage and amperage it will make a difference. I don’t think it will make as much of a difference as you were alluding to. Using a surron as an example I have had a 60 V high amperage set up and also a 72 V high amperage set up, my run time was not noticeably different. I’d attribute that to it being air, cooled and heat. My motor temperatures were almost identical. I would say that the oil cooling makes more of a difference than you think. The reason you would reduce amperage in this set up an increase voltage is to maintain the same power level or watts and reduce heat. Amperage creates heat, by cooling the motor you’re reducing heat. Any electric application you will be trying to conserve energy by controlling heat.

Sorry for the multiple edit, speak to text makes a lot of mistakes

 

[mr.skywalker]

The reason to reduce amperage is to reduce heat, heat is an efficiency loss so if keeping the same power the high voltage is more efficient like you said. The cooling is to reduce heat which is just a way of removing the heat that came from an inefficiency so lower amps and lower heat means less heat that needs to be removed. The question is how much loss is from heat in the motor(motors loose efficiency with heat) plus the energy loss to run the pump vs the efficiency increase from say 33% reduction in amps going from 48v to 72v. Of course if both are combined it could be drastic improvement

In my experience my 72v setups are way more efficient than my 60v at the same power levels. I built my own batteries so 60v63ah vs 72v42ah both get the same range at 8kw, but the 72v gets better range at higher than 10kw

 

[Swank171]

That’s exactly what I said….Amps are heat. Cooling reduces heat. A bike running exact battery with cooling will run more efficient. Not sure what is being lost in translation here. I’m not trying to know everything, just giving real world application and my experience with these bikes is pretty in-depth. Your previous statement about cooling not making a difference and reducing amperage being the best way isn’t the case.

I’ve had both setups, I’ve tested them extensively on the same bike swapping 60 and 72. There is a difference but not as noticeable as having a motor with a cooling system. There is a sacrifice here with the torque/hp riding characteristics. That’s why there is a sweet spot with the voltage:amperage when using the same amount of power.

I’d say having a well cooled 60v would see more improvement than gong simply from 60-72v (maintaining the same wattage) with bad cooling. This is backed up by theory as well as real work application in my personal experience.

Regardless of the specs this bike has, it’s faster and has a longer run time. I’d attribute that to the motor being cooled down. Controlling heat is the name of the electric game. From a transformer on a pole that feeds your house to an RC car your kid is driving in a backyard.

A transformer with the same kva rating with less oil in the tank overloads and fails drastically faster than one with more efficient cooling. This all translates to battery usage and efficiency too. It’s all relatable…

 

[mr.skywalker]

I think you are assuming the cooling is to improve efficiency, its not entirely the case, its only a small portion. Same concept for gas engines, liquid cooling allows you to run at higher performance levels(ie more amps/power) without overheating the system. You still have you inefficiency(heat from amps) but you have a way to remove it which is in itself another loss(pumping coolant) so you are even less efficient but stable. The tradeoff is you can sustain higher power without running into heat issues and dial back the power when it overheats or run less power to prevent heating in the first place. Maybe thats where the difference is in what we are saying.

The only way cooling could possibly be more efficient is if it keeps the motor in its efficient operating temp but that difference would have to be larger than the draw of running the pump for it to net an improvement in efficiency.

 

[Swank171]

I think you are assuming the cooling is to improve efficiency, its not entirely the case, its only a small portion. Same concept for gas engines, liquid cooling allows you to run at higher performance levels(ie more amps/power) without overheating the system. You still have you inefficiency(heat from amps) but you have a way to remove it which is in itself another loss(pumping coolant) so you are even less efficient but stable. The tradeoff is you can sustain higher power without running into heat issues and dial back the power when it overheats or run less power to prevent heating in the first place. Maybe thats where the difference is in what we are saying.

The only way cooling could possibly be more efficient is if it keeps the motor in its efficient operating temp but that difference would have to be larger than the draw of running the pump for it to net an improvement in efficiency.

Okay…..splitting hairs here. My statements are based on an evaluation of a production bike. This matters due to the context of the situation. You are trying to make a point by getting into engineering facotrs that have been ironed out in a procudtion model. These have been taken into account and balanced.

The bike has the same kw rating and has better performance. The product in this application has field proven to be superior.

We can debate theory….in fact we could do that all day through introducing new factors. I’m speaking of real world tests on real bikes I’ve had hands on. I’m not using my bias to bend theory into my favor. I’m simply doing real tests, taking real results and applying my experience in evaluating that.

If you wanna Be right then you win and you are right. I’m just sharing my experience on the bikes and at work.

The bike is great and we are fortunate enough to have both bikes side by side so I can give you real world test results.

 

[mr.skywalker]

But from what I can tell there are no published specs on the output, only battery size. With the liquid cooling and possible voltage increase(would be easy for you to measure as you have one) then we could see part of where their efficiency and power are coming from.

I wasnt debating to be right, I was just inquiring as to what voltage was or how they are getting more power and more range simultaneously as that is hard to do.

 

[Swank171]

I have that I will for sure be getting the voltage of the battery when I get back to the house.

I gotcha. Then sorry if I blew up hahah.

 

[Swank171]

Battery size reduction makes sense from weight but it just seems small for racing to me, id think 1.5kwh minimum would be needed for really fast kids riding outdoor tracks.

I havent had any experience with the production bikes(own a mod surron and did qs138 build with tc65) but I have heard of the heat issues with the ktms. I know the ktm is 48V so Im curious if this is 52v/60v/72v as that would reduce the amps needed which means less heat and more efficiency. I think the cooling doesnt improve efficiency as much as reducing amps unless the motor was way under spec'd then it wouldnt be in its efficient operating range.

Nearly full charge we are at 50v so I don’t think we are looking at a voltage increase over the husky. Also it’s running the bac 4k controller.

 

[mr.skywalker]

Woah thats strange they are using a BAC4000, wouldnt think that would be ok as their plugs arent water sealed(I got rid of my BAC 4k for that very reason as it cut out on me when it got wet). That does explain a bit of the efficiency though as I bet the ktm doesnt have FOC which does improve effciency and generates less heat.

Is it at full charge for 50v? 48v(13s) packs are typically about 54v so maybe its 12s pack

 

[Swank171]

Woah thats strange they are using a BAC4000, wouldnt think that would be ok as their plugs arent water sealed(I got rid of my BAC 4k for that very reason as it cut out on me when it got wet). That does explain a bit of the efficiency though as I bet the ktm doesnt have FOC which does improve effciency and generates less heat.

Is it at full charge for 50v? 48v(13s) packs are typically about 54v so maybe its 12s pack

It thought that was crazy too…..my bac 8k was erratic with water as well. I’ll be keeping an eye on that for sure. They nailed the tuning on it.

I’m just off full charge, it’s about 95% I’d bet it’s 54 at full charge…that’s prob right on point

 

[Garsink]

It thought that was crazy too…..my bac 8k was erratic with water as well. I’ll be keeping an eye on that for sure. They nailed the tuning on it.

I’m just off full charge, it’s about 95% I’d bet it’s 54 at full charge…that’s prob right on point

Hi, i have ordered CX5E for my little guy as well. We live in europe though and have 240V outlets here. Would it be possible for you to take some photos of the charger’s specs, which came with the bike? Just want to start preparing a solution for that .
Many thanks!

 

[Swank171]

Hi, i have ordered CX5E for my little guy as well. We live in europe though and have 240V outlets here. Would it be possible for you to take some photos of the charger’s specs, which came with the bike? Just want to start preparing a solution for that .
Many thanks!

I’ll get a few pics of the charger for you today!

 

[Garsink]

I’ll get a few pics of the charger for you today!

Thanks! And waiting for the pics

 

[Swank171]

Thanks! And waiting for the pics

Sorry about the wait! Got called out for work!!

I keep it stored in a crate and at the track I flip the crate and put it in top of it to keep it out of the dirt and in the shade by the generator.

 

[Garsink]

Sorry about the wait! Got called out for work!!

I keep it stored in a crate and at the track I flip the crate and put it in top of it to keep it out of the dirt and in the shade by the generator.

Great! Many thanks, now I know what i need to do

 

[Swank171]

Let me know if you need anything else, if I can help I will!