Dude. We need more humans like this gentleman on this earth. I have a Blix Vika+ that failed on me and I called the manufacturer. Talking to them was about as useful as talking to a sack of potatoes. This dude knows exactly what he is talking about.
Thank you for the video! Helped me find and switch out a bad mosfet that went bad after a month. FWIW the replacement part for mine was IRFB 3607. Mine also was a negative mosfet but different location than in the video. Moving the mosfet back and forth until it broke off made it a lot easier to hold one leg with pliers and then heat it on the back side until it could pull out. Cleaned out the hole with Chem-wik, right stuff for the job, and in with the replacement. I was able to isolate the correct phase wire by disconnecting each phase wire in turn while rolling the bike backwards. Once the correct phase wire was disconnected, bike rolled backwards easily. Prior to that rolling backwards required more effort indicating a problem (as well as an E9 error code) Bravo - Thank you for your instructions!
I had a broken motor controller a couple of years ago, and thanks to this instructional video I managed to fix it. Now I got another one, immediately found this video and fixed the controller. Thank you!
If possible, its often easier to cut the legs and remove one leg at a time. Might not save everyone a lot of time in cases like this, but its safer and easier for those unskilled or working with less than ideal tools. A weak 15W soldering iron or an oxidized tip might end up taking too long, and before you know it the traces just come right off the board. Nice video. Blown FETs is a common problem and fixing it is something most will be able to handle. Especially if they have some soldering before.
hello, if I give full throttle (freewheel) or put a little load on the engine, everything turns off. When I then disconnect the battery, I measure 32v on the controller side which then slowly drops. And reconnecting the battery (note a spark at the battery contact), I can start up again. could it be that my battery is too small 36v for 11max20A controller 36v direct drive motor. thank you.
Some controllers are potted which makes things like mosfet repair a lot more challenging. But first you should confirm if you do actually have a blown mosfet, using the technique in this video or just by plugging it into a motor and spinning the motor with no power applied to see if there is heavy chugging resistance that goes away when the controller is unplugged.
On my Aventon the mosfets are ok but the speed is not displayed on the unit & I'm getting am E30 error. Spoke to Aventon & they thought the controller is bad so I thought I'd open it up to see if it was something obvious.
My brand new controller is connected but doesn't work and has resistance on the wheel but if i disconnect the eyellow wire the resistance is gone any combination with the yellow connected has resistance
good video, the diagnostics in the beginning were helpful. I would recommend replacing the heat sink compound or at least mentioning it as this is very important in an electrically isolated heat sink. also, the wattage of your gun is important with mosfets as a lot of heat is sucked away by the large traces and the center leg. probably would have fallen out if your gun was hotter. :)
ok... just to be sure here... my controller doesn't have red and black wires that connect to the battery (as @ 2:01), it has a wire with male phase pins. So to do the testing, I have to connect the female phase connector to the male phase pins... is that right?
Great video. I have the same controller as in the video and my motor just shudders and then stops when powered up. I get about 5 kohm's between battery -ve and 2 of the phase wires but only 1.8 kohm on the 3rd phase wire. Is this too low and could one of the mosfets be my problem? Resistance builds as expected on all 3 pahses against battery +ve. I've checked hall sensors and windings on motor itself and they are all good. Thanks for any help.
Phil help!! our display unresponsive we have go trax R1 folding ebike we connect blue and red wires from display to bypass still nothing! Display out of stock!! WHAT can we do to simply operation the ebike fir school and work thanks!!
Question... I shorted out my controller by touching the positive and negative wires together on the controller. I opened it up and there is a black burn spot next to the positive and negative area inside the controller. Now my controller no longer works. What could be problem? Thank you
When I do continuity from positive to decide which ones are positive and negative I get continuity on all 12 mosfets to battery positive and none beeps on the negative, what's that indicate?
i just taken a reading on all 6 of my mosfets.. 2-6 all have a climbing voltage reading. but number 1 has a voltage spike on first contact and then begins to fall? is this the problem im having? when the system is live, its feeding 5v to all phases at the same time.. even when i apply the throttle, the voltage on all phases just sags to 0.3v and the motor makes a tiny humming sound.
How about no power on a sabvoton controller? Worked for ever and now no power. Switch wire when touched to positive battery line, minisparks but it doesn't kick sabvoton on anymore. Any where I should look first?
Probably not the mosfets which is what this video is about. Putting V+ accidentally on your control signals can wreck all kinds of havoc on the logic board so you should probably be looking at where you can buy a replacement unfortunately.
Hello, I have a controller 36V with one Mofset dead exacltly like you show in your video. The mofsets inside this controller are called S68N08R-A from Si tech. I don't have another one here and I don't know where to find one to replace the dead one. But I have 12 mofsets from a destroyed overboard wich are called 100N8F6. Do you think it is possible to use one for replace the dead S68N08R mofset?
After have take a look at the datasheets, the RDSON is almost similar 6,5 milli ohm for the S68N08R vs 8 milli ohm for the 100N8F6. But for the 100N8F6 the total gate charge is 100A (instead 80A for the original Mofset) and the rating voltage is 80V (instead of 68V). Knowing that, do you think it is possible to replace the S68N08R by the 100N8F6? (Sorry if the answer is obvious, but I am not an elelctronician so I need some help to be sure). If not I thougt at an another solution. Do you think it is possible or better idea to replace the 6 orginals mofsets by 6 mofsets 100N8F6 so that they are all identical?
So, I got no response but I made it and it works fine. 100N8F6 moffset taken from an overboard can replace a S68N08R moffet. I hope it can be usefull to somebodies. Bye
Good to hear. Normally there is a decent allowance of mosfet specs that will work on a given controller PCB and a given gate drive. No harm in just trying out a substitute fet with similar-ish specs if that's what you have.
Have an issue with my controller, once you twist the throttle then let go, the hub motor does not stop running, cruise wire is not connected nor enabled. Any diagnosis on this scenario?
The pedal assist wiring shows positive +5V and signal wire + 4.6V. Please any help. What can I replace? The throttle works fine. Except the pedal assist not working. Please advice.
I've got same issue, I've established the issue is on yellow phase however my multimeter is ancient and has no beep noises... what should I be looking for on screen in terms of finding the offending mosfet? There are 5 per phase on my controller
I have a swagtron envy bike I think the motor is only 200 watts it has a small motor controller in it. I was having problems with it when I got a 14 amp battery at 36 volts that battery that came with it was only a 4.4 amp battery at 36 volts mine keeps cutting off the power and the display malfunctioning going crazy then I noticed the controller was getting hot is it because the battery has more amps in it how will I lower the amperage do you think I might need a new motor controller
That speed controller looks like it has good solder lines across the board. I and wondering how can I mod a speed controller to have a good line like that. I have a Kugoo Kirin G3 electric kick scooter. And 2 speed controllers failed on me. There are burn marks at a couple mosfet solder joints. And it looks like the trace on the PCB along the mosfets is what burnt apart to a no connection.
Yes the stock traces are often quite underspec'd for required phase current. You can easily beef them up with a piece of straight copper wire soldered on top of the trace.
My controller has two wires each for the brakes(the brakes are on when i short the wires of one brake) and i want to use one of the brake's wires with relay to control with arduino is this possible ? If not what should i use?
Im trying to diagnose my nanobot d4+ 2.0 scooter. This problem does not happen in the cold morning on my first ride but happens in middle of day when it is warmer. Im in NM. What happens is both motors cut out when I'm in dual mode and when i go full throttle, and also sometimes when i try to just accelerate quickly. when it cuts out i does not come back alive by simply backing off a little on the throttle but i have to totally go back to 0 or no throttle and then the motors start if i re-engage the throttle more gently incrementing the speed. It does not happen in single mode when in just rear hub drive. When in single mode i can press the throttle fully and as quickly as I like. If I think of the thumb throttle as a clock that goes clockwise from 12 to 6. it is at the 5 when the motors cut out. It also happens if i got from 12 to 3 very very quickly. I'm pretty techy and i can replace of fix most anything but I like to diagnose first. I did have an extra thumb throttle speed controller so i did decide to replace that (because a year ago i brew out its usb power port when making a dual charger for a camera i have) but changing that speed controller had no change in the symptoms. Do you think there is a short somewhere in the system on full power or is it a hall sensor. Is it overheating and the bms cutting out? There are two controllers in the scooter with a communication wire between them, could one of the controllers be off. Both motors shut off when this happens. What tests should i run to see where the problem is? I have opened up the scooter before because I silicone sealed everything to protect from water. but actually moved to NM where there is little rain and I do not ride it in mud or water anyway. Any help appreciated.
My controller to 4000watt motor does not seem to work. When new throttle was added. Then even the old throttle did not work. This is due to mosfetts need to be replaced?
If you watch the video, you will see the diagnostic step to determine if a mosfet is shorted and if so which one. That will tell you if this is the source of your issue or not (most likely it is not)
Exactly. That's a blown high side mosfet, but the replacement procedure and the replacement mosfets are identical whether they are on the high side or low side.
Not sure if you will even respond but. I ran a test on the controller with a ebikes tester it showed all ok when I use my Ohm meater Ground prong to controller to 3 phase (green 9.07) (yellow 9.06) (blue 9.04) neg prob to positive controller the 3 phase wires all read 00.0 bad Controller??
my battery cable fell of so the kers burned anything on my controller. sadly i dont think that replacing mosfets will help if the esc just does nothing anymore, even the scooter doesnt turn on anymore. I have a functioning replacement controller but it's from a german 20 kmh m365 clone, and just the tail light flashes ... so i have to replayce broken parts but what for parts?
I have a 48v Brushless Razor mx650. My problem is the motor only runs when you rotate the drive gear to a certain point. Do you think I might have a bad mosfet in my controller?
Hi. I have a scooter on Ms energy neutron n2 plus which has a 36V 15A controller. There is a problem it will not turn off on the button. You have some idea how to solve this. Thank in advance.
I’ve got zero ohms to positive battery when probing the phases, is this also bad ?. They’re fine to ground, but phases are zero to positive, but only a certain polarity.
hello guys im having an issue find the same controller was thinking to try fix it or can i use another one and put the right conectors and how do i trace wires if there diffrent colours?
In most cases it will still work fine, in some cases you can run into shoot thru currents and other issues if the mosfet driver isn't fast enough. In other cases you can have high amounts of electrical ringing that can cause voltage spikes on the fet and complete failure even if you are nominally below the max voltage.
I have a motor that has a white wire included with the 5 hall sensor wires. My replacement controller does not have a white wire. after connecting everything power but the motor does not move.
Usually the white wire would be an internal wheel speed sensor if you are running a geared motor that freewheels. It shouldn't be required for the controller to run the motor.
Great. Thanks! Maybee A stupid question: Does it still make sense to adjust the 2 shunt sensors, i mean by soldering make it wider, bridging. You sure know what I mean. I have an escooter with 2x 45A controllers (1 controller per wheel) and the BMS also offers 90 or 100A. The BMS circuit board on the battery pack can only spend as much as it says, no more?! I hope someone can tell me whether that still makes sense or not. Thank you all 😊
Doing this will increase the battery and phase current limits of the controller, but it will also increase the likelyhood of frying your controller mosfets. If you have a 90A BMS and each controller is 45A battery current limited, then if you went any higher on the controllers you'll trip the BMS overcurrent cutoff when you try to run full power.
Hello maybe you can help me I have a problem on the headlight of my e-bike: it is always on but weak, when I turn off my bike, the light is a little bit stronger but still very weak, it is impossible to turn off the light unless I remove the battery. When I put the battery back, the light is again always on and weak. Is it a problem from the headlight or from the controller ? My bike is a Lankeleisi X2000+ Any help is very welcome, thank you in advance.
Hi, awesome video thanks, I use an Hover 1 alpha E scooter so two days ago I was changing the accelerator of the scooter, and in the process of assembling it together i found out that the beeping device was lose but before I could touch it one part it's poles mistakenly touched the pole of the display panel which resulted in some weird noise and the break light blinking and unfortunately the Scooter went off and wouldn't come on again not even charge any longer , do you have any idea what could be the issue Thanks..
Does anyone know why my 1000 watt 48 volt front hub keeps going into reverse? It'll spin properly for a bit then inexplicably reverse. PI cannot figger it out.
Likely an intermittent signal on the fwd/rev input of the controller. Could be from water ingress messing with the digital input signals, or from stray stands of copper around the connector.
Hi, excelent video thanks a lot. i have a question. i have a controller that PAS works fine but throttle doesn't. i already tested throttle in another system and works fine. also made this test (fase and + or -) and it is working fine. do you know what more test can i do to the controller?
There may be two blue wires that connect together and cause the controller to limit your speed to 20 miles an hour. If you disconnect those two blue wires. You will be able to override the 20 mile per hour limit.
Hi my girlfriend has an old bateribike which stopped working. we have tried a new battery , no goog we think it is the controler, ? any help would be good. Harry
@@harryhughes5868 hi it could be several issues. i teach in my channel how to try step by step, sorry it is in spanish! th-cam.com/video/--YcASeLvNA/w-d-xo.html
Hi, are all the mosfets the in the controller the same? or are there 3 negs and 3 pos? I have an ebike controller with 1 mosfet blown and all mosfets have same number on them, I cannot find these to replace, the number is ZJ7080. The controller is for a 48v 250w bike, controller says 15amp max current.
There are 3 high side mosfets, and 3 low side mosfets, but usually they use the same part number for both. Most likely you what we would consider a pretty crappy mosfet in a low current controller like that, typically 8-10 mOhm of on resistance.
I am worried I blew my new Kelly KLS 7275H. It was working, but when i wired the potentiometer, there was a ZAP and now I dont have power to the phase wires. Can it be fixed?
Anything can be fixed if you have the ability to identify what is wrong and replace it. But very few people have that skill set for random bldc motor controllers. Generally your first course of action if you don't have those skills would be for you to contact Kelly controllers or the vendor you bought from, and see if they offer repair services.
@@GrinTechnologies thanks for the reply. yes few of us study BLDC motor controllers that in depth. I thought perhaps you had some troubleshooting steps to narrow it down. Kelly hasn't responded yet.
i have a minimotors controller shorted because the accessories wire positive and negative touching, i tried replace the fuse but lcd only turn on for split second, motor also a bit weird when spinning by hand, but if i unplug the yellow wire motor turn smooth by hand. any idea how to fix it?
I have an ebike just come in been standing in his shed 6 months, has no light on display, battery is good fully charged all wiring and connections are controller connections all good bike is only 18 months old , any pointers please ??? could be controller but all looks new condition
You know what i never ask for help but... please does anyone have any ideas! I have a scooter i purchased $100 secondhand broken! Its a replica of the s11 leqismart, i got a new battery and the controller flashes red slowish speed, when the power button is pressed. Upon release nothing! No display no deeps nothing! If i hold the pwrbttn it keeps flashing aslong as i hold it😅
I have a question about the replacemnet Mosfet. Should it be exactly matching the old. Or I can use something with in range? I have 6 mosfet controller 32V, 250W controller. Can I use 49A 55V Mosfet?
In general it's a good idea to try and match or do better for the Rds ON resistance, and also the total gate charge or gate capacitance. Both or these specs are well documented in the datasheet for any given mosfet model. What you don't want to base in on is nominal amperage. Saying 49A doesn't mean anything really since the current handling depends massively on the extent of heatsinking, you want to look at the fet's actual electrical characterization.
Hi dude, i have bad controller, but i check 3 phases and there is no problem. So i try check resistence betwen mosfet legs and i find one with diferent resistence - shorted circuit with no resistence. you think that mosfet is broken? And when is 80V/170A i need stick with these volts and amps or can be different? how much if yes? 75V/160A? Rds same or lower and Total GATE charge same or lower? thats all what i need to know when replace this mosfet? thanks dude
Hi, I have a question to ask. Today I was going to charge the battery of my 72v 40amp 8000w and once I plugged it it short circuited, are you able to tell me what is gone? So I turn on the scooter and the volt meter on the scooter is going down really really fast? Can you help me? Thank you Sir
My scooter suddenly turned off while riding and the motor wheel isnt rotating, the screen won't come on, it won't indicate charging so this would mean my controller is bad and needs to be replaced but the motor is fine?
If the screen and controller don't turn on it is most often a battery issue. But if the controller has a fully blown MOSFET bridge it creates a short that effectivity suits off the battery the moment it is plugged in.
If you swap out mosfets for ones that have 1/4 the RDs ON resistance, reduce the resistance of the current sensing shunt by half to effectively double the effective amperage of the current sensing feedback loop, and reinforce all the conductive traces on the power bus, and add more electrolytic bus capacitance, then in some cases yes you could do this.
Adding more in parallel is kindof an ugly hack job and you really need to check if the mosfet gate drive is up to it. Replacing stock mosfets with others that have lower ON resistance is doable for sure, but you then have to make other changes to the controller to allow it to actually pass a higher current.
What will be the result if I replace 85v 150A mosfet ( k150e09ne- 18 nos) & 63v caps with 100v 200a (SSF1006 mosfet) & 100v Caps. Controller is 48v 45a...
Most controllers are made to be RoHS compliant for the CE sticker and so are using lead free solder, which yes is a PITA to melt and work with. Use flux and use the hottest iron setting with the largest tip. When you resolder on new mosfets you can use the much easier to work with lead/tin stuff.
Thank you for this video. After seen this video, I’ve found that is my problem. MOSFET. But they are 24 . It is a little bit hard for me to fix this. Can you do for me?
Nope. If doing it yourself is outside of your skill set or comfort zone then we'd recommend you get a replacement motor controller form the company who sold you the system in the first place.
In principle yes but in practice it would be pretty messy as there isn't any additional room on the heatsink for a parallel mosfet, you'd need to do extension lead wires to a floating heatsink and mosfet bank somewhere else in the motor controller. There is also the question of whether the gate drivers on a single mosfet controller have enough current to turn on and off more fets in parallel without shoot-thru problems. It's much easier and more sensible just to start with a controller PCB that is meant for higher number of mosfets.
hi i tested my controller in resistance mode like your tests and one reading is zero on red power side does that mean mosfet blown?controller not that old from alixpress 48v 1500watt on a 1000watt hub motor and 54v 18650 samsung.had throttle problem before so bought this new controller and throttle kit.lcd display lights up ok had last ride and motor died and seemed to run rough the wheel with motor in.ride before that was intermittment power.
how does this work when you have 9 mosfets? there are only 2 polarities and 3 phases, though my mosfets are in apparently banks of 3 and there are 2 the same and 1 different in each bank, i am getting shorts accross the power rails and the 3 middle mosfets are all shorted across all 3 pins, the other 6 only show continuity on the middle pin, i am assuming it is only the 3 in the middle i need to change, great info, but a bit of elaboration on if there are more than 6 mosfets (which fit into the + - of 3 phases) would be helpful, cheers
When there are multiple mosfets they are always hooked up in parallel. Much more common than 9 fets would be to have 12 mosfets, where every mosfet is doubled up. With 9, it means that either the high side or low side fet is doubled while the complimentary (low or high side) is single. If the failure is on a paralleled mosfet, you can't tell until removing the fets which one of the two is damaged. The easiest thing to do is just remove and replace them both, but if you remove one first and see that the short is gone, it usually means that the problem was only with the mosfet you took out and the 2nd one can possibly stay in place.
My 3 speed settings wont work how do i go about diagnosing that? Ive tried jumping it with a wire. It went out after my charge port shorted but everything else seems to work fine
Unfortuantely we've never worked with controllers that have a 3 speed setting input so can't really comment on what might or might not have been done to break functionality there. But generally as a starter when troubleshooting a digital signal you would look at the voltage and see if it alternates between 0V and 5V when the switch is toggled.
i only have 5 mosfets on my controller, of wich 2 have continuity with ground wire (on the top aluminum part of the mosfet) how do i determine wich one is faulty. the way i measured as in the vid, i have no ground connection on either colors measured on the print board?
you must have 6. Also another option is that you have 3 mosfets that consist of HIGH and LOW side mosfet in one package. The other 2 are for power for example.
My KT sine wave controller has 18 mosfets. Looks like the blue phase is shorted. Now, looks like I have to de-solder 3 of those fets? Oh boy. CRST041N08N and where to buy?
Yup, only one may be blown but you can't easily tell which it is. No need to use an identical replacement, a comparable mosfet with similar gate capacitance or gate charge and similar or lower rds on will usually work fine as a substitute.
hey! how can I find the rating of the motor controller if the label removes from the motor controller mosfet? is there any way to get this number using multi meter ?
Thanks for this great guide, the biggest problem to find the right china mosfet, in my case it is a brainpower control. DC52V (the scooter is a Speedway 4 clone + no dualtron 1x800w motor) the mosfets(to 220) have the designation: K M ..9Y ....... 19x 2452 ..... L12 .... K3475N .. Unfortunately I could not find a data sheet to find comparable replacement mosfets. does someone have a tip?
It's not too bad if you solder the mosfets all at the same height and all with their legs vertical. Failure to do that though, and you could be in for a small alignment challenge...
The process is quite similar, yes. Single quadrant brushed controllers will have just 1 mosfet, brushed controllers that can do regen but only go in one direction will have 2 mosfets equivalent to a single half bridge in a 3 phase controller, and brushed controllers that can do forwards and reverse will have 4 mosfets, equivalent to two half bridges.
Hi I got 15 MOSFET 1000w 48 v motor controller, I followed the above instructions, I notice my yellow phase wire resistance on battery +ve side is faulty. I.e black probe on yellow connector and red probe on battery red shows 0 ohms. I opened the case and checked it has 5 MOSFETs for each phase.. how can I can find the faulty MOSFETs, is there any instructions for controllers with 15 MOSFETs
A 15 mosfet controller would typically have groups of 2 mosfets on the non PWM side of the bridge and 3 mosfets on the side that is doing active PWM. Until you separate the parallel connection you have no easy way to know which mosfet in the parallel group of 2 or 3 is actually blown. One way you can tell though is to force current though the short with a power supply and use a thermal camera to see which one is heating up from the current flow, or use a multimeter to in the mV mode to probe the voltage drop across the traces. Usually though it's fasted just to take them all out (2 or 3) than trying to identify which specific one is the culprit.
@@GrinTechnologies Thanks for taking time to reply.I am non-electronics person but learning about them, I have ordered for the mosfets will try to troubleshoot.I am ebike enthusiast and started to retrofit few bikes.Looks like fault finding is key to sustain the interest :)
Thanks Phil for the video. I have identified several blown Mosfets after seeing your video. I have a chinese controller with 12 Mosfets. No markings to identify them. Can you tell me what Mosfets I need, and where to get them? I have a 48V, 26amp controller.
Dude. We need more humans like this gentleman on this earth. I have a Blix Vika+ that failed on me and I called the manufacturer. Talking to them was about as useful as talking to a sack of potatoes. This dude knows exactly what he is talking about.
Thank you for the video! Helped me find and switch out a bad mosfet that went bad after a month. FWIW the replacement part for mine was IRFB 3607. Mine also was a negative mosfet but different location than in the video. Moving the mosfet back and forth until it broke off made it a lot easier to hold one leg with pliers and then heat it on the back side until it could pull out. Cleaned out the hole with Chem-wik, right stuff for the job, and in with the replacement. I was able to isolate the correct phase wire by disconnecting each phase wire in turn while rolling the bike backwards. Once the correct phase wire was disconnected, bike rolled backwards easily. Prior to that rolling backwards required more effort indicating a problem (as well as an E9 error code) Bravo - Thank you for your instructions!
I had a broken motor controller a couple of years ago, and thanks to this instructional video I managed to fix it. Now I got another one, immediately found this video and fixed the controller. Thank you!
Awesome!
And this helps me 6 years later :) Thank you very much for explaining!!
Hey glad to hear that! Mosfets in motor controllers aren't going away any time soon so this kind of info is fairly timeless.
Great repair guide. Justin and the team from Grin Tech are the best in the industry!
Oh yeah I have just come across GRIN channel and viewed a few of the content all worth the time so subscribed to validate my appreciation 👏
If possible, its often easier to cut the legs and remove one leg at a time. Might not save everyone a lot of time in cases like this, but its safer and easier for those unskilled or working with less than ideal tools. A weak 15W soldering iron or an oxidized tip might end up taking too long, and before you know it the traces just come right off the board.
Nice video. Blown FETs is a common problem and fixing it is something most will be able to handle. Especially if they have some soldering before.
hello, if I give full throttle (freewheel) or put a little load on the engine, everything turns off.
When I then disconnect the battery, I measure 32v on the controller side which then slowly drops. And reconnecting the battery (note a spark at the battery contact), I can start up again. could it be that my battery is too small 36v for 11max20A controller 36v direct drive motor. thank you.
Sounds like a tripped BMS. 32V is quite flat for a 36V nominal battery pack so you might want to try charging the battery first.
Many thanks for the nice video. The way you described the symptoms at the beginning is perfect. Now I can fix my bike thanks to you
Awesome video, didn't realize these could be opened up. Tried on my Aventon, got the end covers off but its sealed in a clear,flexible material.
Some controllers are potted which makes things like mosfet repair a lot more challenging. But first you should confirm if you do actually have a blown mosfet, using the technique in this video or just by plugging it into a motor and spinning the motor with no power applied to see if there is heavy chugging resistance that goes away when the controller is unplugged.
On my Aventon the mosfets are ok but the speed is not displayed on the unit & I'm getting am E30 error. Spoke to Aventon & they thought the controller is bad so I thought I'd open it up to see if it was something obvious.
My brand new controller is connected but doesn't work and has resistance on the wheel but if i disconnect the eyellow wire the resistance is gone any combination with the yellow connected has resistance
good video, the diagnostics in the beginning were helpful. I would recommend replacing the heat sink compound or at least mentioning it as this is very important in an electrically isolated heat sink. also, the wattage of your gun is important with mosfets as a lot of heat is sucked away by the large traces and the center leg. probably would have fallen out if your gun was hotter. :)
Super helpful video! Lots of good information for working with mosfet controllers in general. Thanks!
Thanks for putting these videos together, very useful!
This might be the problem I have with Urban Drivestyle bike. Extremely helpful video.
ok... just to be sure here... my controller doesn't have red and black wires that connect to the battery (as @ 2:01), it has a wire with male phase pins. So to do the testing, I have to connect the female phase connector to the male phase pins... is that right?
Via a multimeter, correct
Excellent educational video but would have liked to see the heatsink compound replaced.
Great video. I have the same controller as in the video and my motor just shudders and then stops when powered up. I get about 5 kohm's between battery -ve and 2 of the phase wires but only 1.8 kohm on the 3rd phase wire. Is this too low and could one of the mosfets be my problem? Resistance builds as expected on all 3 pahses against battery +ve. I've checked hall sensors and windings on motor itself and they are all good. Thanks for any help.
Phil help!! our display unresponsive we have go trax R1 folding ebike we connect blue and red wires from display to bypass still nothing! Display out of stock!! WHAT can we do to simply operation the ebike fir school and work thanks!!
Question... I shorted out my controller by touching the positive and negative wires together on the controller. I opened it up and there is a black burn spot next to the positive and negative area inside the controller. Now my controller no longer works. What could be problem? Thank you
@@jb9072 controller was not connected to the battery.
How can I find out what kind of electric scooter I have would it not be in marked on the scooter or the blame it all
When I do continuity from positive to decide which ones are positive and negative I get continuity on all 12 mosfets to battery positive and none beeps on the negative, what's that indicate?
thank you so much. Good Job. You just made a horrific challenge into a simple fix.
My e bike mobility scooter has no brake lights and no reverse, could a bad controller be the cause.?
i just taken a reading on all 6 of my mosfets.. 2-6 all have a climbing voltage reading. but number 1 has a voltage spike on first contact and then begins to fall? is this the problem im having? when the system is live, its feeding 5v to all phases at the same time.. even when i apply the throttle, the voltage on all phases just sags to 0.3v and the motor makes a tiny humming sound.
How about no power on a sabvoton controller?
Worked for ever and now no power.
Switch wire when touched to positive battery line, minisparks but it doesn't kick sabvoton on anymore.
Any where I should look first?
Probably not the mosfets which is what this video is about. Putting V+ accidentally on your control signals can wreck all kinds of havoc on the logic board so you should probably be looking at where you can buy a replacement unfortunately.
Hello,
I have a controller 36V with one Mofset dead exacltly like you show in your video. The mofsets inside this controller are called S68N08R-A from Si tech. I don't have another one here and I don't know where to find one to replace the dead one. But I have 12 mofsets from a destroyed overboard wich are called 100N8F6. Do you think it is possible to use one for replace the dead S68N08R mofset?
After have take a look at the datasheets, the RDSON is almost similar 6,5 milli ohm for the S68N08R vs 8 milli ohm for the 100N8F6. But for the 100N8F6 the total gate charge is 100A (instead 80A for the original Mofset) and the rating voltage is 80V (instead of 68V). Knowing that, do you think it is possible to replace the S68N08R by the 100N8F6? (Sorry if the answer is obvious, but I am not an elelctronician so I need some help to be sure).
If not I thougt at an another solution. Do you think it is possible or better idea to replace the 6 orginals mofsets by 6 mofsets 100N8F6 so that they are all identical?
So, I got no response but I made it and it works fine. 100N8F6 moffset taken from an overboard can replace a S68N08R moffet. I hope it can be usefull to somebodies. Bye
Good to hear. Normally there is a decent allowance of mosfet specs that will work on a given controller PCB and a given gate drive. No harm in just trying out a substitute fet with similar-ish specs if that's what you have.
What causes the mosfet to fail? is a lesser amp controller more likely to fail than a bigger ah controller?
Have an issue with my controller, once you twist the throttle then let go, the hub motor does not stop running, cruise wire is not connected nor enabled. Any diagnosis on this scenario?
We don't do tech support on TH-cam. Could be a throttle issue and a simple swap out... if it's our system please contact our warranty department.
My scooter have 12.6v but no power could this be the problem with it ?
Good mr. please my throttel not run maybe lost mosfet or short ?
The pedal assist wiring shows positive +5V and signal wire + 4.6V. Please any help. What can I replace? The throttle works fine. Except the pedal assist not working. Please advice.
I've got same issue, I've established the issue is on yellow phase however my multimeter is ancient and has no beep noises... what should I be looking for on screen in terms of finding the offending mosfet? There are 5 per phase on my controller
Hello
I have a controller but k1 and k2 to increase speed not working, when is the problem
Why are all of these videos from over 2 years ago when these scooters are more popular now than ever?
Because thats when these all came out
I have a swagtron envy bike I think the motor is only 200 watts it has a small motor controller in it. I was having problems with it when I got a 14 amp battery at 36 volts that battery that came with it was only a 4.4 amp battery at 36 volts mine keeps cutting off the power and the display malfunctioning going crazy then I noticed the controller was getting hot is it because the battery has more amps in it how will I lower the amperage do you think I might need a new motor controller
That speed controller looks like it has good solder lines across the board. I and wondering how can I mod a speed controller to have a good line like that.
I have a Kugoo Kirin G3 electric kick scooter. And 2 speed controllers failed on me. There are burn marks at a couple mosfet solder joints. And it looks like the trace on the PCB along the mosfets is what burnt apart to a no connection.
Yes the stock traces are often quite underspec'd for required phase current. You can easily beef them up with a piece of straight copper wire soldered on top of the trace.
Sir i m not getting the same mosfet G067N07 n-channel what should i do
how to tell if a mosfet is bad for a treadmill? will the same apply if the treadmill motor is showing resistance if you spin the belt by hand?
My controller has two wires each for the brakes(the brakes are on when i short the wires of one brake) and i want to use one of the brake's wires with relay to control with arduino is this possible ? If not what should i use?
Im trying to diagnose my nanobot d4+ 2.0 scooter. This problem does not happen in the cold morning on my first ride but happens in middle of day when it is warmer. Im in NM. What happens is both motors cut out when I'm in dual mode and when i go full throttle, and also sometimes when i try to just accelerate quickly. when it cuts out i does not come back alive by simply backing off a little on the throttle but i have to totally go back to 0 or no throttle and then the motors start if i re-engage the throttle more gently incrementing the speed. It does not happen in single mode when in just rear hub drive. When in single mode i can press the throttle fully and as quickly as I like. If I think of the thumb throttle as a clock that goes clockwise from 12 to 6. it is at the 5 when the motors cut out. It also happens if i got from 12 to 3 very very quickly. I'm pretty techy and i can replace of fix most anything but I like to diagnose first. I did have an extra thumb throttle speed controller so i did decide to replace that (because a year ago i brew out its usb power port when making a dual charger for a camera i have) but changing that speed controller had no change in the symptoms. Do you think there is a short somewhere in the system on full power or is it a hall sensor. Is it overheating and the bms cutting out? There are two controllers in the scooter with a communication wire between them, could one of the controllers be off. Both motors shut off when this happens. What tests should i run to see where the problem is? I have opened up the scooter before because I silicone sealed everything to protect from water. but actually moved to NM where there is little rain and I do not ride it in mud or water anyway. Any help appreciated.
My controller to 4000watt motor does not seem to work. When new throttle was added. Then even the old throttle did not work. This is due to mosfetts need to be replaced?
If you watch the video, you will see the diagnostic step to determine if a mosfet is shorted and if so which one. That will tell you if this is the source of your issue or not (most likely it is not)
@@GrinTechnologies well my motor wont run and throttle goes on but does not twist. Must be the mosfets?
mine is shorting from possitve to yellow phase cable is the the same prossess only this time swap poss mosfet?
Exactly. That's a blown high side mosfet, but the replacement procedure and the replacement mosfets are identical whether they are on the high side or low side.
What if any is the risk to replace only the 2 blown mosfets out of 6, with ones that are quite close in values V, A, Rdson?
Not sure if you will even respond but. I ran a test on the controller with a ebikes tester it showed all ok when I use my Ohm meater Ground prong to controller to 3 phase (green 9.07) (yellow 9.06) (blue 9.04) neg prob to positive controller the 3 phase wires all read 00.0 bad Controller??
my battery cable fell of so the kers burned anything on my controller.
sadly i dont think that replacing mosfets will help if the esc just does nothing anymore, even the scooter doesnt turn on anymore.
I have a functioning replacement controller but it's from a german 20 kmh m365 clone, and just the tail light flashes ... so i have to replayce broken parts but what for parts?
I have a 48v Brushless Razor mx650. My problem is the motor only runs when you rotate the drive gear to a certain point. Do you think I might have a bad mosfet in my controller?
Hi. I have a scooter on Ms energy neutron n2 plus which has a 36V 15A controller. There is a problem it will not turn off on the button. You have some idea how to solve this. Thank in advance.
Yup, but it's not really related to the controller mosfets or mosfet replacement.
I’ve got zero ohms to positive battery when probing the phases, is this also bad ?. They’re fine to ground, but phases are zero to positive, but only a certain polarity.
Generally yes, this is bad as it would be a short of the high side mosfet
@@GrinTechnologies I’ve taken all mosfets off and they’re fine. If I switch the probes though it goes away.
hello guys im having an issue find the same controller was thinking to try fix it or can i use another one and put the right conectors and how do i trace wires if there diffrent colours?
Does anyone know where i can purchase the controller? I have a model # ST027A-ST890-800A The capacitor blew up and damaged the circuit board.
What will happen if you use same spec mosfet but not the exact same as other ones?
In most cases it will still work fine, in some cases you can run into shoot thru currents and other issues if the mosfet driver isn't fast enough. In other cases you can have high amounts of electrical ringing that can cause voltage spikes on the fet and complete failure even if you are nominally below the max voltage.
what does the letters and numbers refer too on the solder side of the controller
I have a motor that has a white wire included with the 5 hall sensor wires. My replacement controller does not have a white wire. after connecting everything power but the motor does not move.
Usually the white wire would be an internal wheel speed sensor if you are running a geared motor that freewheels. It shouldn't be required for the controller to run the motor.
@@GrinTechnologies Thanks, I was able to connect the controller without the white wire and it worked.
Hi Would you know of a replacement for these mosfets AB431A M317
Great. Thanks! Maybee A stupid question: Does it still make sense to adjust the 2 shunt sensors, i mean by soldering make it wider, bridging. You sure know what I mean. I have an escooter with 2x 45A controllers (1 controller per wheel) and the BMS also offers 90 or 100A. The BMS circuit board on the battery pack can only spend as much as it says, no more?! I hope someone can tell me whether that still makes sense or not. Thank you all 😊
Doing this will increase the battery and phase current limits of the controller, but it will also increase the likelyhood of frying your controller mosfets. If you have a 90A BMS and each controller is 45A battery current limited, then if you went any higher on the controllers you'll trip the BMS overcurrent cutoff when you try to run full power.
@@GrinTechnologies Thanks
Hi my ebike motor is working fine off the ground but when I seat on it and under load will be cut off the power . need help with this issue
If it works unloaded then you do not have a blown mosfet and this video won't be of much help I'm afraid.
@@GrinTechnologies Could you please help me what is the problem because I checked my battery with similar bike and it was fine .
Hello maybe you can help me I have a problem on the headlight of my e-bike: it is always on but weak, when I turn off my bike, the light is a little bit stronger but still very weak, it is impossible to turn off the light unless I remove the battery. When I put the battery back, the light is again always on and weak. Is it a problem from the headlight or from the controller ? My bike is a Lankeleisi X2000+
Any help is very welcome, thank you in advance.
You are best to get support from the store who sold you the ebike. They should know the internal wiring and have access to necessary replacement parts
Hi, awesome video thanks, I use an Hover 1 alpha E scooter so two days ago I was changing the accelerator of the scooter, and in the process of assembling it together i found out that the beeping device was lose but before I could touch it one part it's poles mistakenly touched the pole of the display panel which resulted in some weird noise and the break light blinking and unfortunately the Scooter went off and wouldn't come on again not even charge any longer , do you have any idea what could be the issue Thanks..
Well it's most likely not a blown controller mosfet ;-)
@@GrinTechnologies Wow Thanks for replying really appreciate,
So what could it be then :•{
Fantastic! Very helpful. Do you have a video for checking 5v regulator transistor in the controller?
Does anyone know why my 1000 watt 48 volt front hub keeps going into reverse? It'll spin properly for a bit then inexplicably reverse.
PI cannot figger it out.
Likely an intermittent signal on the fwd/rev input of the controller. Could be from water ingress messing with the digital input signals, or from stray stands of copper around the connector.
Hi, excelent video thanks a lot. i have a question. i have a controller that PAS works fine but throttle doesn't. i already tested throttle in another system and works fine. also made this test (fase and + or -) and it is working fine. do you know what more test can i do to the controller?
There may be two blue wires that connect together and cause the controller to limit your speed to 20 miles an hour. If you disconnect those two blue wires. You will be able to override the 20 mile per hour limit.
Hi my girlfriend has an old bateribike which stopped working. we have tried a new battery , no goog we think it is the controler, ? any help would be good. Harry
@@harryhughes5868 hi it could be several issues. i teach in my channel how to try step by step, sorry it is in spanish! th-cam.com/video/--YcASeLvNA/w-d-xo.html
Hi, are all the mosfets the in the controller the same? or are there 3 negs and 3 pos? I have an ebike controller with 1 mosfet blown and all mosfets have same number on them, I cannot find these to replace, the number is ZJ7080. The controller is for a 48v 250w bike, controller says 15amp max current.
There are 3 high side mosfets, and 3 low side mosfets, but usually they use the same part number for both. Most likely you what we would consider a pretty crappy mosfet in a low current controller like that, typically 8-10 mOhm of on resistance.
I am worried I blew my new Kelly KLS 7275H. It was working, but when i wired the potentiometer, there was a ZAP and now I dont have power to the phase wires. Can it be fixed?
I see power between B+ and B- and at the end of the fuse between + and B-. I just don't see power anymore between B- and the phase wires. Please help!
Anything can be fixed if you have the ability to identify what is wrong and replace it. But very few people have that skill set for random bldc motor controllers. Generally your first course of action if you don't have those skills would be for you to contact Kelly controllers or the vendor you bought from, and see if they offer repair services.
It's very unlikely that anything you did to the potentiometer input signal would have blown the controller MOSFETs, which is what this video is about.
@@GrinTechnologies thanks for the reply. yes few of us study BLDC motor controllers that in depth. I thought perhaps you had some troubleshooting steps to narrow it down. Kelly hasn't responded yet.
I need a new motor controler. Where do i get 1
i have a minimotors controller shorted because the accessories wire positive and negative touching, i tried replace the fuse but lcd only turn on for split second, motor also a bit weird when spinning by hand, but if i unplug the yellow wire motor turn smooth by hand. any idea how to fix it?
I have an ebike just come in been standing in his shed 6 months, has no light on display, battery is good fully charged all wiring and connections are controller connections all good bike is only 18 months old , any pointers please ???
could be controller but all looks new condition
You know what i never ask for help but... please does anyone have any ideas! I have a scooter i purchased $100 secondhand broken! Its a replica of the s11 leqismart, i got a new battery and the controller flashes red slowish speed, when the power button is pressed. Upon release nothing! No display no deeps nothing! If i hold the pwrbttn it keeps flashing aslong as i hold it😅
I have a question about the replacemnet Mosfet. Should it be exactly matching the old. Or I can use something with in range? I have 6 mosfet controller 32V, 250W controller. Can I use 49A 55V Mosfet?
In general it's a good idea to try and match or do better for the Rds ON resistance, and also the total gate charge or gate capacitance. Both or these specs are well documented in the datasheet for any given mosfet model. What you don't want to base in on is nominal amperage. Saying 49A doesn't mean anything really since the current handling depends massively on the extent of heatsinking, you want to look at the fet's actual electrical characterization.
Any link to where I can buy these Controller Mosfets
So my board has 12 mos total, can it run on 11? Don't have a replacement
I mean it could as long as you keep the current limit to half the normal maximum
Hi dude, i have bad controller, but i check 3 phases and there is no problem. So i try check resistence betwen mosfet legs and i find one with diferent resistence - shorted circuit with no resistence. you think that mosfet is broken? And when is 80V/170A i need stick with these volts and amps or can be different? how much if yes? 75V/160A? Rds same or lower and Total GATE charge same or lower? thats all what i need to know when replace this mosfet? thanks dude
Hi, I have a question to ask. Today I was going to charge the battery of my 72v 40amp 8000w and once I plugged it it short circuited, are you able to tell me what is gone? So I turn on the scooter and the volt meter on the scooter is going down really really fast? Can you help me? Thank you Sir
My scooter suddenly turned off while riding and the motor wheel isnt rotating, the screen won't come on, it won't indicate charging so this would mean my controller is bad and needs to be replaced but the motor is fine?
If the screen and controller don't turn on it is most often a battery issue. But if the controller has a fully blown MOSFET bridge it creates a short that effectivity suits off the battery the moment it is plugged in.
Thanks, I replaced the motor controller, the scooter now turns on and runs but only in 1st gear what did I doo lol
Are you able to turn 60v 50a into a 100a controller?
If you swap out mosfets for ones that have 1/4 the RDs ON resistance, reduce the resistance of the current sensing shunt by half to effectively double the effective amperage of the current sensing feedback loop, and reinforce all the conductive traces on the power bus, and add more electrolytic bus capacitance, then in some cases yes you could do this.
Can I add more to my controller to make it better. Or up them
Adding more in parallel is kindof an ugly hack job and you really need to check if the mosfet gate drive is up to it. Replacing stock mosfets with others that have lower ON resistance is doable for sure, but you then have to make other changes to the controller to allow it to actually pass a higher current.
I’ve only built 2 ebikes, but have already replaced 2 controllers. Now I’ll see if I can fix them!
How do I get a mosfet?
sorry mate i dont have reading on any phase with positive conector, any idea?
What will be the result if I replace 85v 150A mosfet ( k150e09ne- 18 nos) & 63v caps with 100v 200a (SSF1006 mosfet) & 100v Caps.
Controller is 48v 45a...
Nice video interesting, just replacing a faulty mosfet, don’t know what solder they used but quite a job trying to melt the solder with very hot iron
Most controllers are made to be RoHS compliant for the CE sticker and so are using lead free solder, which yes is a PITA to melt and work with. Use flux and use the hottest iron setting with the largest tip. When you resolder on new mosfets you can use the much easier to work with lead/tin stuff.
Thank you for this video. After seen this video, I’ve found that is my problem. MOSFET. But they are 24 . It is a little bit hard for me to fix this. Can you do for me?
Nope. If doing it yourself is outside of your skill set or comfort zone then we'd recommend you get a replacement motor controller form the company who sold you the system in the first place.
Great video, thanks. Is there a procedure for the Baserunner Baserunner_Z9 ?
Is it possible to upgrade the controller by adding mosfet? Some controller have 3 or 4 morfet per phase.
In principle yes but in practice it would be pretty messy as there isn't any additional room on the heatsink for a parallel mosfet, you'd need to do extension lead wires to a floating heatsink and mosfet bank somewhere else in the motor controller. There is also the question of whether the gate drivers on a single mosfet controller have enough current to turn on and off more fets in parallel without shoot-thru problems. It's much easier and more sensible just to start with a controller PCB that is meant for higher number of mosfets.
I have a e-bike that wont change speeds, only the low speed works. the cluster shows when i switch speeds but no change in the motor, any thoughts ?
You should probably contact the vendor who sold you the ebike or the manufacturer that made it.
shorted yellow phase of sabvoton to positive. replaced fets but the power light wont even come on... help? will pay for a working soloution
hi i tested my controller in resistance mode like your tests and one reading is zero on red power side does that mean mosfet blown?controller not that old from alixpress 48v 1500watt on a 1000watt hub motor and 54v 18650 samsung.had throttle problem before so bought this new controller and throttle kit.lcd display lights up ok had last ride and motor died and seemed to run rough the wheel with motor in.ride before that was intermittment power.
how does this work when you have 9 mosfets? there are only 2 polarities and 3 phases, though my mosfets are in apparently banks of 3 and there are 2 the same and 1 different in each bank, i am getting shorts accross the power rails and the 3 middle mosfets are all shorted across all 3 pins, the other 6 only show continuity on the middle pin, i am assuming it is only the 3 in the middle i need to change, great info, but a bit of elaboration on if there are more than 6 mosfets (which fit into the + - of 3 phases) would be helpful, cheers
When there are multiple mosfets they are always hooked up in parallel. Much more common than 9 fets would be to have 12 mosfets, where every mosfet is doubled up. With 9, it means that either the high side or low side fet is doubled while the complimentary (low or high side) is single. If the failure is on a paralleled mosfet, you can't tell until removing the fets which one of the two is damaged. The easiest thing to do is just remove and replace them both, but if you remove one first and see that the short is gone, it usually means that the problem was only with the mosfet you took out and the 2nd one can possibly stay in place.
My 3 speed settings wont work how do i go about diagnosing that? Ive tried jumping it with a wire. It went out after my charge port shorted but everything else seems to work fine
Unfortuantely we've never worked with controllers that have a 3 speed setting input so can't really comment on what might or might not have been done to break functionality there. But generally as a starter when troubleshooting a digital signal you would look at the voltage and see if it alternates between 0V and 5V when the switch is toggled.
Ok thanks for the input. Ill pull it apart one day and inspect it
i only have 5 mosfets on my controller, of wich 2 have continuity with ground wire (on the top aluminum part of the mosfet)
how do i determine wich one is faulty. the way i measured as in the vid, i have no ground connection on either colors measured on the print board?
you must have 6. Also another option is that you have 3 mosfets that consist of HIGH and LOW side mosfet in one package. The other 2 are for power for example.
My KT sine wave controller has 18 mosfets. Looks like the blue phase is shorted. Now, looks like I have to de-solder 3 of those fets? Oh boy. CRST041N08N and where to buy?
Yup, only one may be blown but you can't easily tell which it is. No need to use an identical replacement, a comparable mosfet with similar gate capacitance or gate charge and similar or lower rds on will usually work fine as a substitute.
hey!
how can I find the rating of the motor controller if the label removes from the motor controller mosfet?
is there any way to get this number using multi meter ?
Thanks for this great guide, the biggest problem to find the right china mosfet, in my case it is a brainpower control. DC52V (the scooter is a Speedway 4 clone + no dualtron 1x800w motor) the mosfets(to 220) have the designation:
K M
..9Y ....... 19x
2452 ..... L12
.... K3475N ..
Unfortunately I could not find a data sheet to find comparable replacement mosfets. does someone have a tip?
Can I replace 3 mosfets from 1500w 60v 10 mosfets controller to a 2000w 60v 15 mosfets controller ?
In general most likely yes.
So, how much time to line up the long bar that locks down the mosfets? That part can be a bear to put back in.
It's not too bad if you solder the mosfets all at the same height and all with their legs vertical. Failure to do that though, and you could be in for a small alignment challenge...
Does this go for brushed controllers also?
The process is quite similar, yes. Single quadrant brushed controllers will have just 1 mosfet, brushed controllers that can do regen but only go in one direction will have 2 mosfets equivalent to a single half bridge in a 3 phase controller, and brushed controllers that can do forwards and reverse will have 4 mosfets, equivalent to two half bridges.
My scooter shuts down and have a Undervoltage protection error, Any advise what causes this? thanks!
Check if you have Bad battery, replace it.
Hi
I got 15 MOSFET 1000w 48 v motor controller, I followed the above instructions, I notice my yellow phase wire resistance on battery +ve side is faulty. I.e black probe on yellow connector and red probe on battery red shows 0 ohms. I opened the case and checked it has 5 MOSFETs for each phase.. how can I can find the faulty MOSFETs, is there any instructions for controllers with 15 MOSFETs
A 15 mosfet controller would typically have groups of 2 mosfets on the non PWM side of the bridge and 3 mosfets on the side that is doing active PWM. Until you separate the parallel connection you have no easy way to know which mosfet in the parallel group of 2 or 3 is actually blown. One way you can tell though is to force current though the short with a power supply and use a thermal camera to see which one is heating up from the current flow, or use a multimeter to in the mV mode to probe the voltage drop across the traces. Usually though it's fasted just to take them all out (2 or 3) than trying to identify which specific one is the culprit.
@@GrinTechnologies Thanks for taking time to reply.I am non-electronics person but learning about them, I have ordered for the mosfets will try to troubleshoot.I am ebike enthusiast and started to retrofit few bikes.Looks like fault finding is key to sustain the interest :)
how I tell what kind of electric scooter I have when it's not identified on the frame
Thanks Phil for the video. I have identified several blown Mosfets after seeing your video. I have a chinese controller with 12 Mosfets. No markings to identify them. Can you tell me what Mosfets I need, and where to get them? I have a 48V, 26amp controller.
good luck