Sabvoton SVMC 72150 doesn't do full power

[Sparfuchs]

Hello EV friends,

I built a e bike with a mxus 3k turbo, a (unlocked) sabvoton svmc 72150, a cycle analyst v3 and a 19s4p Samsung 40T/ 300A ant bms battery.

My plan was to get the mxus with ferrofluid and heatsinks to the max of its temperature but I'm not able to get more than 60 dc amps out of the sabvoton. The ca v3 is for now just a measuring instrument because I connected the throttle directly to the sabvoton. I did the hall angle test and it works "fine" but I just can't get more than 60 dc amps/about 5 kw/with full throttle step uphill and max 50 kph (flux weakening disabled) with a 24 inch tire.
As I "could" use up to 200 dc amps I just don't know why I can't ! I did the 36 combination test with manually set 120 and 245 hall angle but the results were best with the hall angle test (295 angle/unload 0,2 kw/68 kph...more details to the hall angle stuff in my last post).
I can't find any problem with my sabvoton settings (screenshot below) and I also checked the settings of my bms (screenshot below) and the real time current in the app and it was the same as on the ca v3.

Does anyone know what to do or what else I could try try to get the max out of my setup ??

Edit: and of course the three speed switch is permanent on high speed

Thanks for your help

 

[dominik h]

For me the settings of the sabvoton lock good.
Did you buy it unocked, or did you unlocked it with the unlock software? The settings in your pics is still 150 max current.

Does the limitation probably come from the battery or the wiring?
How much voltage sag do you see whilst acceleration?
Does your throttle reach the set 4,4V or does it stay lower?

 

[MountainLion79]

I am having the exact same problem as you but I have a 60v capable of 200amps continuous using a sabvoton 72200 locked with a QS205 V3Ti 5T, won't go over 43amps on full throttle, hitting no more than 30mph :x

 

[Sparfuchs]

I am having the exact same problem as you but I have a 60v capable of 200amps continuous using a sabvoton 72200 locked with a QS205 V3Ti 5T, won't go over 43amps on full throttle, hitting no more than 30mph :x

Have you connected the controller to a 3 speed switch or a wire from high speed to ground ? If not it's preset is on medium if you choose "3 speed switch"

 

[Sparfuchs]

For me the settings of the sabvoton lock good.
Did you buy it unocked, or did you unlocked it with the unlock software? The settings in your pics is still 150 max current.

Does the limitation probably come from the battery or the wiring?
How much voltage sag do you see whilst acceleration?
Does your throttle reach the set 4,4V or does it stay lowe

Thanks a lot for your reply,
I bought it as a unlocked controller and used the recommend software and also tried it with the app.. but it doesn't even do the "locked" 150 dc amps.

Possible.. but non of the battery settings explains that limitation. How could the wiring do limitation ? The 3 speed switch is the only thing i could think of and its allways on high speed with a wire from high to gnd.

The voltage drop is quite low as the battery is 4p of the Samsung 40t. Unload full throttle about -1 or 2 volt.

Throttle voltage is above full throttle setting.. so seems to be fine.

 

[dominik h]

Have you tried to set the low and middle speed to 100% to be shure that is not the problem?

Voltage sag seems to be ok, so wiring and battery should be ok.

Does the motor probably runs in reverse Mode?
Have you tried setting reverse to 100%

 

[Sparfuchs]

Have you tried to set the low and middle speed to 100% to be shure that is not the problem?

Voltage sag seems to be ok, so wiring and battery should be ok.

Does the motor probably runs in reverse Mode?
Have you tried setting reverse to 100%

Yes i did, and I also tried it with 20 and 40% and when I pulled out the wire it was at about 40% (so middle speed).
I had the motor at 01 direction to make it run right direction. But now a chose a wiring that was right direction with preset "0".
I also have a reverse switch and it works like it should. So no, not tried it with 100% yet.

 

[larsb]

I haven't tried a sabvoton, all the settings look understandable and logical but could be worth it to try and increase "current loop" kp in steps of, let's say 100.
it's not nice so if the throttle control starts overshooting so be careful with this and try it with wheel lifted first.

 

[Sparfuchs]

I haven't tried a sabvoton but could be worth it to try and increase "current loop" kp in steps of, let's say 100.
it's not nice so if the throttle control starts overshooting so be careful with this and try it with wheel lifted first.

Thanks for your reply larsb,
I'll definitely give that a try. I don't really know what the current loop ki does or if it explains why the motor only uses 1/3 of it's power, but I found explanations in the manuals like:

"If the driver feel shake obviously ,maybe we can modified the value to have a try. Generally ,for 10 inch hub motor ,use 1000 ,other type motor use 300" or "Generally, for 205 stator motor, set 999, for 273 stator motor, set 299"

Kathy from ES wrote in his thread (For Sabvoton sine wave motor controller users):
"For 12,13 or 14 inches motor ,the current loop kp is normally around 299,For 10 inches motor, the value is normally around 999.The parameter will be different for different motors as the technique and craft is different too. One could adjust the value by himself to suit their motors. But this value shall not exceed 3000."

So as the mxus 3k turbo and the qs205 both have about 244mm (9,6 inch) outer diameter I guess they both count as 10 inch motors ?
As the qs205 needs around 999 I guess that would be a better value for my mxus than my preset 300.
I'll try and do a hall test again and see what happens

 

[larsb]

Kp is most likely a PID regulation parameter for the current control.

If so:
PID parameters are called kp (proportional), ki (integral) and kd(derivative) constants. They each have their function in the regulation and only adjusting one of them will eventually lead to overshoot of the current. This means too high kp and you will get a surge of acceleration which might be uncomfortable or dangerous. With a too low kp the acceleration(=current) and speed will grow slowly so you’ll not see high currents.

The correct value depends on what you want your motor to do - fast and agressive wheel flipping or docile grocery getter or something in between?

In motor control the correct kp parameter will be dependent on kv ( if you’ve got a low motor with lot’s of torque per amp then obviously the acceleration will be higher for the same current ramp up.)

What i’m trying say is that it isn’t true that there’s a general kp for, let’s say, 10inch motors or even for a specific QS205. There might be a value that historically has suited many riders (or at least not annoyed them to the point of contacting seller) and this is what Kathy has described.

 

[DogDipstick]

Idk... I just put a Sabvoton 72150 on a QS205 clone motor and pulled 9,300w out at 123.4A. ON the first ride. Its got more too... It isnt my bike. I cannot abuse. 20 rim. Off the line its downright dangerous.

It will break 150A I bet. Its right there. You really gotta get on it hard to get in the 110A-120A range, I see alot of that on my datalogs. Alot of time spoent from 80A -125A... ish.

Out of the box. Just hooked it up and it did it. IDK. If there is anything I can check to help.. let me know.


Its still slower than my daily driver bike with the Kelly controller tho. ONly hit 55mph. Lol.

The voltage drop is quite low as the battery is 4p of the Samsung 40t. Unload full throttle about -1 or 2 volt.

Unloaded Vdrop is 1-2A.. that is good... but.. what about loaded Vdrop? that might be a problem. I dont see 4p of Sammysung 40T pushing out to many amps. I would imagine the sag would be significant. Under a 150A load.

I mean, I drop about 0.2v @ 2A... how many volts do you drop unloaded? 1-2v? If you are dropping 2v for 2A, that is alot in my opinion. I dont drop a half a volt under 2A.. not even a quarter volt.... let alone 1-2v.

Does that mean you drop 5v @ 5A? 10v @ 10A? Since you drop 2v @ 2A? Is it linear like that? If it does, this is not controller for you. This controller is hungy. Eats amps. it scares me. I am afraid I am going to loop this bike every time I hit the throttle. Super73 bike.

Have you actually seen your battery push more than 150A? I know my battery can double that with 300A easily in an instant.. Have you tested teh maximum output of your pack?

 

[larsb]

I missed that text. 4p of 40T is only 4*35A so 140A. It will sag quite a lot too at those currents.

 

[Sparfuchs]

Well, the Samsung 21700 40t is rated for a "continuous" discharge of 45 amps (with temp cut off) and burst/pulse of 70 amps.... So 45A*4 = 180 A (rated but not recommended discharge) and pulse bursts of 280A.
Even if I use the lower rating mooch got from testing (25/30 continuous) it wouldn't be explain why the battery limits to about 80amps bursts.. so 20 amps per cell.
I'll check all the bms settings again anyway.

 

[larsb]

True, you should be able to get higher max currents but this battery is too small to deliver them without penalty of shorter lifespan. Would be interesting to see what voltage sag you're getting at max load (full throttle from low speed in steep uphill).

 

[Sparfuchs]

True, you should be able to get higher max currents but this battery is too small to deliver them without penalty of shorter lifespan. Would be interesting to see what voltage sag you're getting at max load (full throttle from low speed in steep uphill).

I know that the rated values of the official datasheet like (2,5-4,2 V and 45 Amps continuous) aren't ideal for maximum possible lifespan... but as I keep each cell always between 2,6 and 4,1 V I guess it won't harm them if I discharge them with their rated 45amps for a few seconds from time to time And I also got two temp sensors to monitor and protect the cells... I should check those settings as well I guess..

 

[larsb]

A few seconds here and there shouldn’t matter :wink:

I’m curious about the kp tests, does it make a difference?

 

[Sparfuchs]

Unfortunately setting the current loop kp to 999 didn't get me better reluts or a different hall angle.. I guess the street performance was even worse with 999 instead of 300 and also far away from getting over 100 dc amps.
I'll try again with fully charged battery and setup via pc instead of app and I'll also check all the bms settings again.

Does anyone know a "easy" way without expensive measuring instruments to check if the bms could do about 150 dc amps without using the controller or motor ?

 

[minde28383]

my guess you bottle neck is battery. I know cell specs, you got them 4p. You don't see low sag so not much resistance. Logically thinking it should be not battery lack, but still, all looks good in sabvoton settings, i think it's battery.

you think bms is bottle neck which might be true too. I would try with another battery and if not than skip bms.
Maybe, how will you measure amps without a load, instruments. Go test without bms, directly, just keep temp sensors attached.

 

[larsb]

Bms is not bottleneck, either it works or it cuts power. I am leaning towards battery.

I think you can buy one of the chinese hall sensor current meters on amzon with reasonable delivery time - or aliexpress if you’d accept to wait some more weeks.

What happens if you set kp really high, like 2000/3000?

 

[Sparfuchs]

my guess you bottle neck is battery. I know cell specs, you got them 4p. You don't see low sag so not much resistance. Logically thinking it should be not battery lack, but still, all looks good in sabvoton settings, i think it's battery.

you think bms is bottle neck which might be true too. I would try with another battery and if not than skip bms.
Maybe, how will you measure amps without a load, instruments. Go test without bms, directly, just keep temp sensors attached.

Thanks a lot for your reply minde28383,
I agree that the most possible problem is the bms, as the cells could do way more than what the pack does.
I'm pretty sure the 300A Ant BMS "could" do what it should but the manuals are aweful...or not existing. And I chose this bms because it was the only 19s! bms with this current.
So even if I would "bypass" the bms and it works I'd know it's the bms but it still wouldn't solve my problem.

 

[Sparfuchs]

Bms is not bottleneck, either it works or it cuts power. I am leaning towards battery.

I think you can buy one of the chinese hall sensor current meters on amzon with reasonable delivery time - or aliexpress if you’d accept to wait some more weeks.

What happens if you set kp really high, like 2000/3000?

Well,the bms handles up to 300A and the datasheet of the cells says they can handle 45A (with 80℃ temperature cut). And it's known to handle bursts/pulse of 70A for a few seconds. So 45*4=180A continuous (with 80℃ temperature cut) and 70*4= 280A burst/pulse are possible for the pack... so let's just agree that max 70A is not caused by the limit bof the cells ?

 

[minde28383]

I have installed quite a few ant 20s bmses. They have amp limiting feature and if set accordingly they do limit power overall. So it could easily be the bottleneck but I too leaning towards battery because you checked bms settings and they are maxed I assume. Usually when people want high outputs we expect about 7p or even more parallel, with 2100 cells it could be few less parallel but 4p is on low side even if your specific cells have good specs. Their connections matters much too, specifically on high load.

 

[minde28383]

I acquaint had similar situation. He had even stronger motor 205 12kg 5t v3 hub with kelly 72v 300a phase. Battery was 6kg-7kg in weight so I think it was very similar to yours in performance big slightly bigger heavier but will less good cells, ut it had not cheapest cells too. No matter how we would accelerate we would not see more than 5kw consumption. Once battery was replaced with three times bigger one it was day and night difference in performance tacking into account acceleration and max speed with field weakening enabled.

 

[j bjork]

Why not just look at the app for the bms (maybe run screen recording) and see how much sag you get?

 

[larsb]

I have installed quite a few ant 20s bmses. They have amp limiting feature and if set accordingly they do limit power overall. So it could easily be the bottleneck but I too leaning towards battery because you checked bms settings and they are maxed I assume. Usually when people want high outputs we expect about 7p or even more parallel, with 2100 cells it could be few less parallel but 4p is on low side even if your specific cells have good specs. Their connections matters much too, specifically on high load.

You can set discharge current limit in the ant bms but does it really limit amps to this value? Do you have proof of this? I have run my ant bms up to 300A when set this high so there’s no general limitation.

I don’t think any bms really limits the current at a certain level, it cuts current to protect, limiting will be done by the controller.