KT controller on 15s, strange thinks happend.

Electric Motors and Controllers
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florkk   10 mW

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Joined: Oct 24 2016 12:39pm

KT controller on 15s, strange thinks happend.

Post by florkk » Nov 08 2019 7:32am

i have problem and maybe someone know how to solve it. 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 happends, 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 whell 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.
Right now i open controller and give throttle, nothing happend and i check voltage on phase wires on pcb, and blue and green have about 11.04V when i max throttle, but yellow one have 0.0V wheel dont spin. Then i spin whell backwards and its run then stop and measure again and now yellow wire respond to throttle giving 11v but other two phase wires now are 0.0v, when i spin wheel backwards again and repeat my test again yellow 0.0 other phases wire 11v.

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stancecoke   100 kW

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Re: KT controller on 15s, strange thinks happend.

Post by stancecoke » Nov 08 2019 7:52am

Do you use a direct drive motor? It is well known, that the mosfets die with stock firmware, if you do regen with a nearly fully charged battery. If the BMS of the battery cuts the connection to the controller due to overvoltage protection during regen,you get very high voltage peaks on controller side, that kill the mosfets.

regards
stancecoke

florkk   10 mW

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Joined: Oct 24 2016 12:39pm

Re: KT controller on 15s, strange thinks happend.

Post by florkk » Nov 08 2019 8:43am

no i use geared hub motor, also if i get shorted fet that wheel will be spin very fast even with load ? if i backspin wheel and then add throttle then it spins normal, reaching max speed, even if i brake i can give load about 30A of controller since i see current A on bluetooth bms.

florkk   10 mW

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Joined: Oct 24 2016 12:39pm

Re: KT controller on 15s, strange thinks happend.

Post by florkk » Nov 08 2019 9:04am

also mine controller have TK150E09NE fets on datasheet its sould be fine up to 85V

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stancecoke   100 kW

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Re: KT controller on 15s, strange thinks happend.

Post by stancecoke » Nov 08 2019 9:39am

Seems to be a hallsensor problem.
two phases on same level and one at a different assumes Block commutation. Normal for Startup.
Try to swap two hall wires.

regards
stancecoke

florkk   10 mW

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Joined: Oct 24 2016 12:39pm

Re: KT controller on 15s, strange thinks happend.

Post by florkk » Nov 11 2019 7:25am

but before it works flawlessly , its looks like hall related problem but before it works, and on second controller it also works, this sinewave dont have learn cables, what i measure that, in i put throttle wheel dont spin and i measure voltage in phase wires both green and blue get about 11v but yellow dont respond to throttle movement , but when i turn back the wheel, add throttle wheel dont spin now yellow have about 11,5v and rest two phase wires dont output anything.
it can be faulty ACS 785 Hall-Effect-Based Linear Current Sensor?

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stancecoke   100 kW

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Re: KT controller on 15s, strange thinks happend.

Post by stancecoke » Nov 11 2019 10:44am

Can you check the voltages behind the LM317 and the CJ78L05 voltage regulators.

https://opensourceebikefirmware.bitbuck ... ematic.pdf

regards
stancecoke

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