Raptor 2 - power system discussion

I’ve been thinking about your claims @onloop, and I found a flaw in your logic… You say the bottleneck right now is the vesc and while that is a bottleneck, what about the battery? At 10s3p, your getting a manufacturer rated 60a max which will sag heavily and drastically reduce the cels life. It’s really more like 40a max to have fair sag, 30a to have little sag. The current vesc v4.12s can do that already (even vedder said in his new video last week that the current vesc 4.12 can do 23 amps continuous, or 46 amps continuous between the 2 without heating up, which is exactly what my real world testing has shown me).

It seems like the real bottle neck is and still will be the fact your using a relatively low discharge battery made of 18650s, and you’ll be able to tap into only a fraction of the motors power with such weak batteries…

But you can’t even see this necessarily because you don;t even have working prototype yet. You’ll find out that there’s many surprises in working with hubs in general. I think you would have been better off waiting until you had your “upgraded” motor working, instead of rushing this release without even testing the “upgraded” motor.


We don’t use VESC. We developed a new version that is far superior, it’s called VESC-X. we also use 10s4p battery.

Dont hesitate to ask when you need some engineering help building your 4WD eboard with outrunner adapted hub motors and old style vescs.

Also if you could use sone advice on marketing your start up too im Happy to help.

1 Like

I’ve learned so much watching what you do already in marketing lol.

Still, even at 10s4p, 80 amps continuous rated by the manufacturer, 50 amps really to bring the sag down to a reasonable level. The current vescs can handle 25 amps each anyways (not forever, but for a few minutes, once your back under 23 amps, they start dropping in temp again).

The real problem is your still running relatively low amps li-ion batteries and hubs. I estimate around 150 amp continuous battery is what you want, as 100 amps (50 per vesc) is really what you want. Current vescs can’t do 50 con but the vesc 6 will, which might be out before your board ships.

You still have a bottle neck in your system.

Probably you miss that tread, and some reason why he use the vesc-x

I know why he uses the vesc x. My point is, I think the raptor 2 gains nothing from the vesc x, because the battery can’t do high amps. The current vescs can do the max con amps that battery can do. The whole vesc x is pointless (except in a mono drive) until he uses a battery with a higher continuous amps.

Can you please be a bit more precise why the battery should be the weak point? Maybe you can post a screenshot of your actual VESC settings and some details about your board to it (battery S and P, dual or single, street or AT) to bring some clarification here.

Everything you need to know about my board is here: http://www.electric-skateboard.builders/t/the-rocket-4wd-hummies-hubs-4x-chaka-vesc-10s4p-lg-he2-li-ion-cnc-milled-veneer-pressed-deck/8123

Right now, I limit my four vescs to 74 amps total (16 per vesc). The cells are rated to 80 amps max. The vescs 4.12 can do about 23 amps each without heating up at all, so 25 amps continuous is not an issue. For that reason, a battery that can push 100 amps without sagging would be ideal with the current vescs and 4WD.

The reality is, 4WD is more expensive, and won’t be practical for everyone. 2WD will save $200 of a boards price, which cosumers want. The problem with 2WD, is the vescs can’t do 50 amps con without major heat up and eventual shutdown. The vesc-x fixes this bottle neck (the vesc 6 will also, and there’s another guy working on an FOC esc (non vesc based) which can handle much higher amps), but, even if these new vesc-x’s can take 50 amps continuous without heat issues (which I know, testing says, we’ll see when my beta vesc-x arrives), the battery can’t supply the current needed. The current battery will likely be limited to 40-50 amps. Each VESC-X needs 40-50 amps to tap fully into the power of the motors (and for there to be a reson to have the VESC-X instead of the current VESCs). So you would need at least 2 space cells to supply enough current. The problem is, this battery was great for satellite drive, but it doesn’t convert over to hubs as nicely. You need a battery that can give higher amps, or the VESC-X is useless.

Bare in mind, the numbers I give are from testing at 12s. Since your at 10s, you need even more amps. Hubs love 12s, this has been stated by many in the community. This is the problem though with everyone preordering a board that hasn’t been build yet or tested. There is no working board right now, and I’m sure when he gets these motors, Jason will realize this, and try to come up with a solution. But right now, the only solution is lipos, which aren’t the best of solutions. Or a massive li-ion battery, like chakas free ride boards have. But a 10s4p is not a very large battery for 18650s and hubs.

The batteries are rated to 20 amps each which is 80 amps on a 4P setup. I don’t know why it should be less? I quickly read the thread you were writing about your board and i couldn’t see that you mentioned that the battery is too weak. You switched to 12S which is cool but i guess mostly because of the higher speed. I even have a 12S8P btw, but thats another story.

Then you are a heavy rider with a extreme ride style, you mentioned 38 mph. (<- respect). That means a 33 % higher gear ratio which results in 33% more amps to draw and you mention that you have a lot of hills in your area. I still don’t see something that shows that the batteries are not capable and also not in your boards thread where you say that they are the bottle neck. And there are a lot of test available that show that the batteries are capable of 20 amps continuous which we all don’t need when we ride. Nobody of us draws that continuous, maybe 10% of our ride if we drive hard, you maybe 25 % of the time if you drive really hard. But anyway i would be interested in your VESC settings for the motor.

From my testing, these cells (at least the LG HE2, which the graphs I’ve seen between these and 25r are very similar) can not do 20 amps continuous without major sagging. When I pull 72 amps (they are rated to 80 amps con), I will sag from 80% down to 20%. If I limit my amps to 40 across the entire board, the sag at 40 amps is less than 5%… So in reality, 40-50 amps continuous is what a 4p of these cells can do. (this is why my understanding is, the space cell 4p version has a 40a fuse)

If high amps aren’t what most people need, than the VESC-X is a useless improvement for dual drive boards (and only useful for single drive boards). If you only need 25 amps per esc, than the VESC v4.12 will do that just fine. If you want to do the extra amps the VESC-X can support, you need a battery with really double the continuous rating. Putting the VESC-X in the raptor 2 wouldn’t be much different than putting the VESC v4.12 with this battery. You can’t utalize the extra amps the VESC-X can do, because the battery can’t do the extra amps also.

1 Like

So you are measuring that via a battery meter which gives you a reading at no load. But you use it for load situations. That doesn’t mean anything. Most of them even have a linear calculation for the battery which is also wrong. When the battery is under load it is normal that the voltage goes down a bit. That is why they are rated to 3.6 V under load even when they are charged up till 4.2V. My 200 max amps continuous Lipo’s do that as well. So you would be very surprised that you have the same behavior with Lipo’s on your battery meter.

So please don’t try to make the battery’s bad when they work like they should work.

I can’t tell much if the VESC-X is necessary for a dual setup but it can’t hurt anyway. All i know is that most hub users say that hubs need more amps. But i have no experience with them yet that so i should be quiet for now.

1 Like

No offense, becuase I’m excited about your work with the vesc firmware and watt control mode. But you clearly haven’t followed any of my work, so let me fill you in…

I have built a bluetooth + iphone app system from the bluetooth communication code on up so I can see the data straight from the VESC while riding. I save data into sessions, so I can go back and look at both the graphs and my avg and max values for all important data the vesc keeps track of. I created a video overlay recorder in my app so I can see how my load changes while riding without the need of exporting data and using a second application to overlay it.

I collect data straight from the vesc while riding. I also have a panel of LCDs on my board to see what the voltage of every cell plus the overall voltage of my board is. These, I have found compared to the VESC’s data, to be somewhat inaccurate.

I tried watt meters, and compared to the vesc’s data, they are highly inaccurate. I trust the data the vesc sees and processes, as we are trusting it when we set all these limits (voltage cutoffs, max temp, max motor amps, max battery amps, ect.).

Here’s a diagram of what the 2 power systems could look like with the raptor 2, to highlight how pointless the vesc-x is with the current battery system:

As you see, you don’t utilize any of the extra amp capabilities of the VESC-X vs a VESC v4.12.

I am in no way saying the VESC-X is not an improvement, just that Jason said the main reason for the VESC-X is so the raptor 2 can do the higher amps the motors need. But the current VESC’s can already do the max amps the space cell 4p version can do, so it’s pointless besides the new BLDC tool for the raptor 2.

The reason cells sag is because your too close to the max discharge the cells can do. When you pull lower amps, like I said, 40 amps for the 4p config, you sag very little. This (and the fact your cells last longer the further you are from your batteries rated max amps) is why there has been a 40 amp fuse on the space cell 4p version.

If your lipos are sagging heavily, then the numbers the manufacurer gave you are bs. A great example of this is multistar lipos. They give normal lipo ratings (20c), but many in the online RC and even endless sphere have tested them and found they are a fraction of what they advertise (maybe only 4c instead of the 20c they advertise).

So even though these cells are rated to 80a, they will sag a lot and won’t last very long.

I will be testing with more lipos in the near future to highlight this, so watch out for some tests in the near future from me about this.

Also no offence from me. I am also only interested in the facts. i want to avoid that another myth is created because of misunderstandings. because there are already enough of them. I have also build a Android app to watch the live recordings to understand the VESC much better.

Your mentioned that the battery is going from 80% to 20 % at 80 amps. Please tell us the voltage for that because percentage values don#t make sense. Because i am quite sure that the voltage sag you are talking about is absolutely normal.

1 Like

I will be recording more video soon to highlight this, but my battery sags from 48.6 volts down to 42.2,which is not a good amount of sag. As a result, When I get down to 46 volts with no load, I have to stop riding, as I will sag it down to 38 volts or less at that point on a steep hill. Min I should go is 38.8, max is 50.4 volts. Evolve’s new Carbon GT has this issue. The reason, this is their first board with li-ion. They always used lipos before, and never had this issue. Before, when I used to use lipos, I never sagged like this. Chaka has talked a lot about sag in the 18650 thread, and recommended going up to a 12s6p (which is what he uses) to resolve the sagging issues I have. Jason is aware of them too, this is one reason why he doesn’t run cells close to their max discharge ratings. Some sag will always exist, but it’s ideal to get the sag as low as possible (preferably < %5)

1 Like

Im loving this and its going to go on for 6 months.


Also,if you want data about sagging, check out this poll I did: http://www.electric-skateboard.builders/t/lets-talk-about-voltage-sag-poll/12085

Bear in mind, the numbers I give in there are based off of readings from my built in volt meters and was before the app. Now that I have the app, I can see better and determine these things when I’m not going 25 mph and trying not to fall, lol. So I know now my sagging is actually much worse.

This poll confirmed to me that the sagging I’m seeing is not normal.

I don’t know why your against percentages… I get that batteries don’t discharge linearly, like percentages are calculated, but they are pretty close.

Also, regardless of whether this kind of sag is normal or not, the point is that you can’t run these cells that close to their max con rating without a lot of sagging, so again, the VESC-X solves nothing here, since the battery is the limiting factor.

Why is a sag from 48,6V to 42,2V (3,52 V each cell) not a good amount of sag? It#s just normal and what the battery is made for. When the battery is at 46V (aorund 30 - 40 % battery left) with no load then a sag to 38V (3,17 V each cell). Which is still or because the battery is rated to 2.5V minimum under load. So you still can go full throttle and have fun.

BTW: insead of not doing full throttle you could also set the VESC settings for battery cutoff start and end right because then the VESC is doing that for you. I let mine start to reduce the power at 3.2V and stop powering at 3.0 V. But that is because i run laptop batteries which are only rated for a max power output of 5 A and continuous at 2.5 A. So i overpower them drastically. And instead of my batteries the samsung 25R are build to do that. But even mine still do absolutely fine and don’t get hot. Because the battery temperature would predict the limit of the cells and even if i drive hard i use max amps for maybe 10 % of the time. On average i hardly ever use max amps. For example if you go full throttle all the time on the flat you don’t even get close to the max amps. Up a hill with your gearing, weight and speed you might do that.

And we don’t draw constantly the max amps so we are absolutely fine. I would even say it would be fine to draw max 100 amps from a 4P setup of those cells because they can stand the burst.

I’m not saying it’s not normal, but it’s just not desirable nor good. And there’s solutions to solve this issue, which are good lipos or higher p li-ions. @Jinra and @chaka are better people than me to talk about the details of voltage sag.

What lipos are you using btw?

The best lipos I used were the zippy flightmax 8000 mAh cells, and they sagged very little.

Don’t know the brand of my lipos? On my laptop cells I have a huge voltage sag. From 50 Vdown down to 32 V (not recommended) under heavy load (80 A) but they still do fine and the board is doing well and powers out 2500 watts which is enough for my weight of 80 kilos with clothes on. And I can bomb up my hills with 42 km/h. But I don’t know about the hills in San Francisco but I can imagine that they are a completely different level. But you could drive longer on your cells because you could go lower with the volt level under load. I am simply saying the cells are doing absolutely normal and they are not a bottle neck.

Regardless of whether they are doing what they should or not (since we seem to differ largely in opinion here), how can they not be a bottle neck? Your not going to be able to pull higher amps from those cells than the current VESC v4.12 can already do continuously, so the VESC-X does nothing to increase performance here…

Why shouldn’t you pull 80 continously from them when they are build for that. You said you only can do 40A or 50A from that pack and I simply say that this is not the case. Anyway, we should stop here.