Battery Amps low at acceleration, slow acceleration

Hello ESK8 Builders, I am using a Maytech VESC and a Maytech MTO5065-70-HA motor in combination with a 10S3P battery with own BMS.

I have set the Motor Max to 55A and the battery max to 40A. Using the app of Ackmaniac I can see that during full acceleration the motor Amps are not going higher than around 20A. The acceleration is very slow also. Shouldn’t the motor amps not achieve more or less the max amps defined in the VESC? I wonder why the amps are not getting higher even if push the remote control to 100%.

I calibrated the remote control in the VESC, so I believe this is not the issue.

Any hints or explanation from you guys is highly appreciated.

Thanks & Regards Frank

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How about the voltage ? Does it sag a lot, under acceleration ?

No voltage sag during acceleration.

Hi! Which cells are you using for the battery? Ackmaniac software usually works based on the watt instead of current. Could you please post your setting in the VESC tool or VESC app? Anyhow the max value you set will be reached only during really fast accellaration or on steep hills. I also never reach the max values set and in any case it will be just a peak of current. In order to understand you can also post a telemetry data if you use the app. Other thing to know is if you use the BMS for charge only or also for discharge. If it’s also for discharging which one are you using? Specs? Third thing single 5063 motor is rest her small so you can not aspect a speedster from it. I hope you are light otherwise you can think to move to a single 6374 motor. Let we know.

I appreciate a lot your feedback. I will post the settings from the BLDC tomorrow.

My main question is if I should see when starting from zero speed and fully accelerating for a few seconds the max motor current as programmed in the VESC or not? If yes, can it be because of the small motor that the maximum programmed motor current is not achieved?

Thanks for the advice of the 6374 motor. Do you know if there exist any torque diagrams for these kind of motors in general?

Thanks a lot and Best Regards Frank

you also need to calculate the wh of your battery since ackmaniac throttle is centered around that.

Sorry, maybe for clarification. I just use the Ackmaniac app to see the live data. I am still making the programming in the BLDC tool. I have not changed to Watt Mode.

Which remote are you using? My remote has a slow mode on it that basically cuts the amperage the motor receives by half what I’ve got my FOC Box programmed at. Screenshots of your settings would be helpful.

I use this remote from Maytech… I put it on the “fast mode” LED flashing with higher frequency and in this Setup I am adjusting the bandwith in the BLDC Tool to ensure it reaches 100% & 0%. This should be fine or?

My main question is if I should see during acceleration that the maximum motor amps are achieved or if it is normal that the values I see in the datalogger are way below?


In my case I never reach the max watt or current I set. I have seen people reached with belt drive system but I am using hub motors and they are not capable of the power the battery can provide. It is true that what matter is the battery current, because that is where the limit is. I would say that for a single motor 5063 you probably saturate the stator without the need of drain all the current available, that’s why your motor amp doesn’t reach the max value even during hard acceleration. You should also check the battery amp, maybe you reach the max value there. Covering the motor mapping curve you won’t find anything like that in the datasheet. Although what matter is the stator size so 6374 bigger stator = more wattage. There are plenty of good motor. You can find also second hands one on the forum and you save some money. Torque Board, HobbyKing, BKB, Maytech, Esk8 motors are all good.

That’s the same remote I have as well. Alternate between slow and fast mode to test it. Watch your real-time amps at full acceleration in each mode to see how they differ. Obviously the motor will pull less amps when remote is in slow mode.

I am trying to figure out the same thing. How can one achieve better acceleration? Volts are according to speed so I cannot do anything there and my focboxes are not reaching max motor amps, nor max battery amps. The thing is even when accelerating from a standstill under full throttle I only get like 45 amps into my motors. I thought max throttle means max possible amps into the motor (as pre-set) My wattage is set to 15000 as default as I don’t need to limit that but how does it show on the remote that is “watt” based and not amp based. In other words how the hack do I make my board use more motor amps? :slight_smile: My max wattage according do vesc data was around 1800w. I ride 12s dual 6355 3500w motors with preset 70a for each motor and 30a battery amps for each motor. So I am reaching a little over half of the power I have set.

Sometimes you don’t need that much amps to do the job, from a standstill it might be 45a, from a standstill on a hill going up it may be more. 6355 motors don’t feel as torquy as 6374 motors from my experience, I was never able to get to a full stop on dual 6354 motors (190kv). Now I run my pneumatics and dual 6374’s, geared at 60t/18t and I can get to full stops.

Some motors can’t do the job efficiently especially 50xx motors and just make heat instead of actual work. Think you should consider having bigger motors, the same concept for hub motors. Hubs are smaller in general, only Hummies, R-spec hubs are the biggest hubs on the market imo that have a major impact. If you are looking to break the 40km/h barrier then bigger motors are the way, because after that much speed you need more amps from the battery to keep the motor accelerating faster. (also bigger motors means they can handle much more current) And that’s why I tell all my diy friends that the most expensive part of a board is batteries because it = torque in the end game.

For reference I run 10s5p 30Q cells, dual 6374 motors and 6" Haggy pneumatics. I’ve gone past 55km/h as of recent with this set up, definitely will be more during warmer weather.

Thanks for the reply, bigger motors definitely will do better. And I agree with what you are saying but still what you say about motor amps doesn’t make sense to me. If my unit would give more amps to my motor If I was going more uphill than there would be some kind of acceleration limit cause it shouldn’t care whether I am going uphill or not. It should give max power with max throttle, it shouldn’t decide what to give, that wouldn’t make sense. How would anyone be able to achieve anything over 2000w If the voltage stays the same and amperage in motors doesn’t go above 40-50 amps and battery amps barely reach 50 when they are set to 60… Everything has room yet the power available is not being achieved so something somewhere must be limiting that. I am running 12s4p 30q, 6,5 inch trampas so we are really close. 18/62t

so 40amps of play per motor maximum, but still like I said, to actually DO the work to get you up to speed takes much less amps because the motor is bigger. That being said, the only thing that takes up more amps on an esk8 is start up, but even then once it gets up to speed it takes less amps to ramp up depending on your throttling. On my Focbox Unity I run batt 50/-20 and motor 60/-55, which is plenty of torque in my opinion when I don’t get voltage sag. It doesn’t take 2000watts to get you from 0-100, the bigger the motor the more efficient it is because it produces less heat and more work done than having a smaller motor.

Smaller motors will produce more heat under a load which causes them to lose efficiency. If you pull a heavy load then the motors will probably put out more wattage. AmpsxVolts = Watts. Reguardless, if you program your vesc for much higher settings (+60 amps) you will feel much more power/torque but remember that they are just limits to what you program your board to do.

Voltage - Think of it like how big a muscle is Amps - Think of it as how much energy you can send to that muscle

You don’t need more amps if your muscles are already big, but if you put in more amps then the work will be done faster but energy depleting faster. There is no acceleration limit, you just need to adjust your throttle curve up to give your self more power for acceleration

My problem is not not having torque :slight_smile: My problem is wanting more and more torque and I still don’t understand why the motor doesn’t get more amps. I get all the stuff about bigger motors and heat loss (though it would be nice to see some data cause there are many facts and many of them are not important… For ex. the difference in power loss due to heat built up the moment I start accelerating between 6355 and 6374 might be really negligible. But I don’t know so data is needed) Pulling a heavier load will consume more watthours but it should have nothing to do with how many amps are given to motors when full throttle is applied. The only difference should be me, as a lighter guy, accelerating faster. Motor outputs whatever it outputs, it doesn’t discriminate between light and heavy guys or one going uphill or downhill. If I am applying more power than using the motor amps/battery amps should keep raising. With 100% throttle I should be getting maximum of what is capable. You get what I am saying right?

Ye I understand, maybe it’s just that you don’t have that amounts of amps to give yourself the full power you desire. If you ran Lipos then you would probably get what you want because of the amount of amps it can output. 12s4p doesn’t sound like it will get you more torque than you can already/have achieved.

The only thing that would make sense to me is that my battery is not capable of giving more than 50 amps at a time… Is it possible? 4p 30q samsung. Does the immediate discharge value go down over time as well and do you know how much?

It should be 60amps continuous and 80amps maximum

But then there is the fact that when you are accelerating from a standstill since you are only getting like 0,5v to your motors then 70amps should be no problem to give to the motor. the battery amps are only like 10 per motor at the beginning with full throttle.