florkk Posted November 8, 2019 Share Posted November 8, 2019 hello, since its unicycle forum, and i have bicycle, but everythink is the same, how motor work, how controller work ect. so... i have bicycle with KT controller sine wave. i damaged two kt controllers, one 48v 22A and one 48v 45A 18fet. i build battery pack 15s, with max voltage of 61.5v. Since i use this pack with cheap no name china controller and work great, but i want switch to sine wave, and i upgraded motor. so i have 15s with max 61.5V, caps inside both controller are 63v. first controller worked for 30km, i connect it to battery when i have about 57v, then i charge baterry and after full charge (61,5V) controller is damaged, so i think it happens, and i buy new one with more fet (18fet) and do the same, i make about 50km with about 60-61V, everything was ok till i charge battery to 61.5V RIght now i have two controllers both damaged the same. it power up, communicate with lcd, everything seems working, but when you press throttle nothing happend, is show no error, but wheel dont spin. But when you lift wheel and turn it backward, and it still turning slowly back and then press throttle everything work, it speeds up to max speed, when i press brake and give dummy load, it take 30A i can add and back throttle and its slows and speed , but if they motor slows too much, again i cant do nothing. when i stop and turn wheel again backwards and press throttle again it works. btw battery is still 61V.for sure motor is 100% works since i connect no name controller and it works flawless. what can be damaged ? iits looks like it dont wanna start, like missing one phase, or maybe controller dont see hall? but when i disconnect cable i get error about sensor position fault. maybe is some transistor fault or acs712? Quote Link to comment Share on other sites More sharing options...
Chriull Posted November 8, 2019 Share Posted November 8, 2019 22 minutes ago, florkk said: hello, since its unicycle forum, and i have bicycle, but everythink is the same, how motor work, how controller work ect. so... I moved your topic here. Your right - it works somehow with quite simular modules in principle. But in reality there are some differences/usances for which i would recommend you going to some ebike forum - there are enough and they should know much better all the details and quirks of your modules/setup. Some points: 15s li ion batteries have an max voltage of 63V (15*4.2V) - if you use li ion... Most BMS (if yours has one) need charging up to this voltage (at least from time to time) for balancing. Capacitors should have voltage wise some more safety margin. You have 48V ?kt? controller you operate with an 15s battery! I see no reason why a 48V controller should survive beeing supplied with 61.5V (63V). If you use a sine wave controller your motor has to be appropriate - ?some? need trapezoid commutation. But i don't know how this different operating modes are interchangable with different motors. With EUCs we have (as good as) no selfmade setups to gather such experience . Without more details on your used modules, batteries and how you connected them it's hard to solve any problem. And also with this details it's questionable if here are any people experienced with such modules/setups. Quote Link to comment Share on other sites More sharing options...
florkk Posted November 8, 2019 Author Share Posted November 8, 2019 ok, so i explain, i have custom bms where i can set all parameters i want, so my 15s pack when its full charged it have 61.5v so 4.1v per cell to extend life of 18650. this controller have 63v caps inside, and its work nice with 60-61v, and it still works, but somehow can not start, when i turn wheel backwards and then add throttle all works, so its something that cant start, its sinewave controller, and it have soft start, and i think they same type on controllers are used in unicycle. i see post of guy called esaj that wrote interesting think about acs component ACS hall based current sensors and i think maybe its good spot Quote Link to comment Share on other sites More sharing options...
Chriull Posted November 8, 2019 Share Posted November 8, 2019 8 minutes ago, florkk said: ok, so i explain, i have custom bms where i can set all parameters i want, so my 15s pack when its full charged it have 61.5v so 4.1v per cell to extend life of 18650. That's great! I'd like to have such possibities for BMS EUCs! 8 minutes ago, florkk said: this controller have 63v caps inside, and its work nice with 60-61v, and it still works, I'd take personally the next higher voltage (?84V?) to increase the safety margin. But that should not cause any of your problems - that's just for "lifetime" considerations. 8 minutes ago, florkk said: but somehow can not start, when i turn wheel backwards and then add throttle all works, so its something that cant start, its sinewave controller, and it have soft start, and i think they same type on controllers are used in unicycle. i see post of guy called esaj that wrote interesting think about acs component ACS hall based current sensors and i think maybe its good spot Could not remember/recall anything about ACS controllers? The brand EUCs have their own specific controllers, for the few DIY projects i remember mircoworks controllers were used. To get some members attention there are ways to notify them as described in the link in the forum rules - like asking for @esaj. 1 Quote Link to comment Share on other sites More sharing options...
florkk Posted November 8, 2019 Author Share Posted November 8, 2019 ACS is not controller itself but its like microchip inside of controller that sense current and i think also can be responsibility for starting turning wheel. i want ask him but i cant send him PM i got info that i can send 0 pm Quote Link to comment Share on other sites More sharing options...
esaj Posted November 8, 2019 Share Posted November 8, 2019 (edited) 7 hours ago, Chriull said: Could not remember/recall anything about ACS controllers? The brand EUCs have their own specific controllers, for the few DIY projects i remember mircoworks controllers were used. The ACS712 is a current sensor microchip using the hall-effect (magnetic field caused by flowing current) to measure the amount of current and output it as an analog voltage signal. https://www.allegromicro.com/~/media/Files/Datasheets/ACS712-Datasheet.ashx My best guess would be that the controller might go into some sort of overvoltage lockout if the motor isn't turning and it senses too high voltage (48V controller sounds like it's meant for something like 11S or 13S batteries). Have you tried discharging the batteries to a lower voltage to see if it then starts running? Then again, if it starts running without load (if you mean you turned the bike upside down by "backwards"), it might be related to the ACS712 (controller detects overcurrent when the motor's still stalled at start-up), in which case maybe a small voltage divider to drop the detected current value might work? EDIT: No, it won't work, the sensor's bidirectional, so it would move the offset away from the "zero current" -point at half the supply voltage, it would need a more complex set up with an op-amp or such... But I'm really just guessing... Either way, perhaps it would be best to get a controller that has suitable maximum voltage for the batteries? A better place to ask might be something like the Endless Sphere (e-bike) forums: https://endless-sphere.com/forums/ Edited November 8, 2019 by esaj Quote Link to comment Share on other sites More sharing options...
florkk Posted November 8, 2019 Author Share Posted November 8, 2019 i ask, on endless also, but somethink strange happend, its somehow fixed, i see tommorow, till now its on 61v and seems working Quote Link to comment Share on other sites More sharing options...
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