My 48 v 1000 watt ebike kit isnt working!

Unfortunately I can't get a warranty because this was bought last year.
The item came from ebay and they don't seem to want to offer help.
Usually I hook up my bike with 4 sla (12.9) volts each and it is a pretty heavy load.
Recently iv. Been adding a 6 volt sla of the same amps hours as the the other 4.
It has worked well just until now. Maybe I was pushing the voltage to the Max??
But I doubt this was the cause. I think it comes from the batteries being extremely heavy.
Theres so much weight on the motor that something got cooked from hIggy amps.
I think it was a burst of high amps coming from the motor trying to accelerate that killed a fet.
But the problem stems from the weight of the bike.

Again, I'm not totally sure if this its the real problm.

I do want to replace a mosfet. Can anyone help me with the first step I should take?
I think I need to identify which mosfet it is first?? ??? But how??
Then determine the type and then purchase it.

A fully charged SLA cell is 2.3 volts
2.3 x 6 x 4 =55.2 volts
2.3 x 3 = 6.9 volt
Total = 62.1 volts

Most 48 Volt controllers are built with components rated for 60-63 volts (in particular the capacitors). So yes, you were likely pushing the limits of the controller.

ronbrown629 said:

I do want to replace a mosfet. Can anyone help me with the first step I should take?
I think I need to identify which mosfet it is first?? ??? But how??

Click to expand...

I will echo the advice that you received earlier "This is not a task for the inexperienced". Even if you find and replace the blown MOSFET there may be other components that were fried as well. For most people it is more practical to replace the controller.

The MOSFETS should have a number(s) imprinted on the exposed surface. Then you need to get the data sheets for the MOSFET. Testing each one them is going to require a minimum VOM meter and a power supply (probably 5 volts) as well as an understanding as to how they work. Basically it is an electronic switch. You apply a voltage to the "gate" and that closes the switch to allow current to flow between the "source" and the "collector".

You might want to start here http://www.electronics-tutorials.ws/category/transistor

OK so I did find which mosfet it was. I basically did the same thing as before but to each individual fet
It totally makes sense because the dead fet that doesn't work is very close to the yellow phase wire which is causing problems.
I think the only problem is the bad fet.
Its only 1, the others are in good condition.
The front of it says

SM 7002N
VN66E

So here comes the hard part, actually replacing it.
And I'd rather not buy another controller because I like learning about electronics and I'm on a budget.

Hmmmmmmm ... something sounds off: https://en.wikipedia.org/wiki/2N7000
Note the voltage limit is 60 volts

The problem is I think that you should be looking for a FET in a TO-220 package but the only thing that I can find with those numbers is surface mount or TO-92
I am out of my depth here ... someone else needs to step in :|

Possible Sources:
http://www.digikey.com
https://www.arrow.com

Yeah thanks for the help lewtwo
I wonder if they all have to be the same to work?

Np, they don't have to be the same identical part, but they need to be of similar voltage and current capability and the 7002N part number you put up doesn't refer to a power MOSFET. In any case, if you replaced it with the same part and went back to your higher SLA battery array, the voltage would blow it or one of the others out in short order.

Did a search and some users here as well as the lyen controllers like the IRFB 4110, which is a 100V Mosfet. You can buy them at mouser for about 4 bucks each plus maybe 10 bucks shipping. Or you can get the right part number off your blown MOSFET and order that.

Add the cost of a solder sucker, and some wicking braid .... maybe a new controller is cheaper.

I'm going to borrow solder a friend and the iron.
Can someone show me a link of what I can buy?
I will take a look at the mouser.com but it might be hard to find a good part.
What specifications should it be?
65 volt ? What else?

What if I replaced them all with 100 volt fets?
What would happen if I ran it at 90 volts?
I know this is a silly question but I'm curious

Why does it cost 1 dollar for 5000!?
And 3 dollars for 1!!!????

How many Fet's on your controller ?

I understand you being on a budget, I am also
However
Sometimes it is best to spend a little more and get a good product, it can cost the same in the long run.

If you have a 6 Fet controller, with a 1,000 watt motor I would want to be running minimum 9 fet, but better to get a Good 12 Fet Controller.
Infinenon Controllers are good,
For a 1,000 watt motor, I am using a Infineon 12 Fet IFRB 3077,
if there is something as good and cheaper, someone reading this will probably tell you what and where to buy.

This is where your credit card can come in handy.
On a 1,000 watt ( you will be using more on take off from a light, etc. ) a good controller is a better deal.

How do you know how many fets?
Do you just count each individual one?
In that case, there are 15 INDIVIDUAL FETS on the board.
There grouped a little.
2 + 3 + 2 + 3 + 2 + 3 = 15 total fets

The place you buy the kit from states the information on the controller.
I have never opened up my controller, never needed to.
Besides, from what I have seen from circuit boards when I opened up a generic Chinese charger that I had that stopped working, I do not have the skills to fit a soldering iron in there to fix anything without affecting a nearby component.

A side note. I like Infineon Controllers that have the plug to directly/easily plug in a Cycle Analyst should you want to get one of those in the Future. I have two different display's and prefer the Cycle Analyst.

ronbrown629 said:

Unfortunately I can't get a warranty because this was bought last year. ... from ebay and they don't seem to want to offer help....

I do want to replace a mosfet. Can anyone help me with the first step I should take?
I think I need to identify which mosfet it is first?? ??? But how??
Then determine the type and then purchase it.

Click to expand...

Replacing the mosfets in your controller is a doable job, but a bit challenging, mostly because you'll need special equipment that you don't have. In particular its fine de-soldering & soldering work, so you'll need fine point solder guns and various means of sucking up the solder before it shorts the board, like solder suction devices and flux clothe and what not. I don't suggest it. You'll spend more money for that equipment, unless you can beg or borrow.

Instead, check out the 6 fet IRFB3077 Infineon Controller (Motor With Hall Sensors) from em3ev, for $60+. These are top line controllers with the superior IRFB3077 mosfets. If you do, you may also want their throttle controls, which will correctly fit the pin set.

ronbrown629 said:

OK so I did find which mosfet it was. I basically did the same thing as before but to each individual fet
It totally makes sense because the dead fet that doesn't work is very close to the yellow phase wire which is causing problems.
I think the only problem is the bad fet.
Its only 1, the others are in good condition.
The front of it says

SM 7002N
VN66E

So here comes the hard part, actually replacing it.
And I'd rather not buy another controller because I like learning about electronics and I'm on a budget.

Click to expand...

Even so, problem with these low-cost hub motor sets is that they've slacked on cost for better mosfets. Go ahead and get the experience. But be prepared to buy a replacement controller when you find yourself without a working eBike months from now.

ronbrown629 said:

I'm going to borrow solder a friend and the iron.
Can someone show me a link of what I can buy?
I will take a look at the mouser.com but it might be hard to find a good part.
What specifications should it be?
65 volt ? What else?

What if I replaced them all with 100 volt fets?
What would happen if I ran it at 90 volts?
I know this is a silly question but I'm curious

Click to expand...

If you proceed, the trick is to replace all the fets, not just one, so they all have exactly the same electrical characteristics, necessary to balance the charge/discharge cycle.

So you're telling me they all have to be the same but another person provided a link to a different type of fet?

ronbrown629 said:

So you're telling me they all have to be the same but another person provided a link to a different type of fet?

Click to expand...

mosfets are like capacitors, only controlled by a magnetic field for they're firing, so digitally controlled. The motors are three phase. So its why controllers have a number of mosfets by factors of three - typically 6, 9, 12 and 18. They're paired together. Your controller probably has 6 mosfets, so 2 x 3. Its the capacitance that matters - they have to be more or less balanced. You get that when all the mosfets are identical. They're not that expensive, so replace them all. Its just the time to solder them in place that's expensive.

Regarding the FET testing. They are all soldered into the board in parallel (within the 3 groups). How do you manage to test one out of circuit?
Thus far you have not identified the controller/motor/kit brand if there is one.
You have also not identified the rating for the controller: 10, 15, 20, 25, 30 ....N amps (or I missed it).

ronbrown629 said:

So you're telling me they all have to be the same but another person provided a link to a different type of fet?

Click to expand...

That is because the number that you provided did not come back to a proper part (or at least one that could be identified)... which is always a risk with items that were manufactured in a country where counterfeiting electronics is prevalent. It is true that the FET do not need to be exactly the same. Many manufacturers make components with the same specifications and sometimes even the same part numbers. The FETs do need to have matching specifications/operating characteristics ... or at least VERY close.

Another thing to consider. High amperage controllers have more FETs. A 12 FET quality controler is considerable more expensive than one is likely to find in a unbranded generic kit. A "12 FET IRFB4110 INFINEON 40 AMP CONTROLLER" would cost you on the order of $100 plus shipping. If all 15 FETs are being used for phase current then they must be very low spec parts ... what does that say for the specs of the other parts?

You can not upgrade the board to 100 volt just by replacing the FETs if all the capacitors are only rated at 63 volts ... you would need to replace them as well. Think of it as replacing all the 12 inch tires on a car with 15 tires and keeping the 12 inch rims. So then you change the rims as well. Now what about the fender clearance, springs, etc ??

Replacing a defective FET (or group of them) may be practical for someone with the experience, tools and parts access. However for someone without those items and on a limited budget I highly recommend that you get a cheap 48 volt, 20-30 amp square wave controller (ebay ?) and save the rest of your money to invest in a different power system. Even a cheap LiPo pack will radically decrease your bike's weight and increase your range.

Well we'll see what happens. I might just do it to see if Im capable and then I'll post back into this for with a video or something.

Let's drop that subject for now.

What do tight guys think about me running 100 volts and 16000 mah (or 16 amps same thing) to my current motor.
My current motor never failed me. Its a 1000 watt motor.
Now 16 X 10 is a bit more than 1000 watts.
Iv heard people running there motors higher than their original rating.

If I do this im safe because I can just buy another motor with a higher rating.
You know what Ill just post my original supply list here. It might be confusing but here's goes.

Bike parts list https://lunacycle.../xt90-to-banana-plug-charge-lead-adapter.html

Here's the motor but it's optional if I can get everything to work on my current motor.

Motor http://em3ev.com/store/index.php?route=product/product&product_id=253 430$$$


Part of the reasoning of me being hesitant to buy this is that I'm not sure if it will stay in my back wheel dropouts.

ronbrown629 said:

What do tight guys think about me running 100 volts and 16000 mah (or 16 amps same thing) to my current motor.

Click to expand...

16 amps is a measure of current, like how fast you use up your batteries.

16Ah (16000mAh) is a measure of capacity, like how much battery you have.

So they actually mean completely different things.

If you use 16Ah batteries, at 100V, then you have 100V x 16Ah = 1600Wh (1.6kWh) of capacity.

If you use 16A of current at 100V, then you are using 1600Watts (1.6kW) of power.

Now 16 X 10 is a bit more than 1000 watts.

Click to expand...

It's actually 1.6 times that, or more than half again...so it is quite a lot more than 1000W.

However, your motor will probably handle it fine if you don't run it constantly at that level. Usually you only see peak power during acceleration and hillclimbing.


All that said, the controller itself is the limiting factor for both voltage and current. There is a limit to what voltage the controller can handle, and if you exceed that it can blow up the FETs, capacitors, and other components. SOmetimes a bunch of things all at once, and sometimes it's fixable, and sometimes it's not. (or at least, not worth doing).

There is also a limit to the current a controller can handle, but for that, it has a built in limiter, so there's not much worry about damaging it from that (unless you have it in a bag or unventilated area). So the controler's current limit (usually printed on it) is what will determine the current your system draws from the battery, not the size of the battery.

ronbrown629 said:

Well we'll see what happens... What do tight guys think about me running 100 volts and 16000 mah (or 16 amps same thing) to my current motor.
My current motor never failed me. Its a 1000 watt motor.

Click to expand...

You need amps to run a motor and for amps to be maintained continuously, you need volts. Yes, watts = V * A, so it can be confusing to think you can up the volts and drop the amps, but its more complicated than that. While you think its OK, its your controller that's going to determine how many amps are delivered, or not. Stick with the amperage rating of your controller, probably, what, somewhere between 22 and 30 amps, I expect. It'd be terribly wasteful to up the volts of your battery beyond what's needed. 1000 watts / 25 amps is 40 volts, so 48 volts, which is what the motor/controller were designed for.

LYEN Controllers

6 FET 4110 Mini Monster Programmable Controller LYEN Edition $79

6 FET 4110 Sensorless Mini Monster Controller LYEN Edition $89

9 FET 72V Infineon Brushless Controller (LYEN's Edition) $89

12 FET 4110 Mark II Extreme Modder LYEN Edition Controller $129

12 FET 4110 MOSFET MK2 sensorless Controller LYEN Edition $149

12 FET 84-132V High Voltage Racing Controller - LYEN $199

18 FET Low RDS MOSFET Overclocker Ready LYEN Controller $199

18 FET Low RDS MOSFET Overclocker Ready Sensorless LYEN Controller $209

18 FET 4115 MOSFET 84-132V Real Highway Speed Controller $259

24 FET 10000Watts Muscular High Current LYEN Controller $299

24 FET 4115 MOSFET 84-132V Freeway Speed Controller $349

Which controller is best suited for my application?
16 Ahr battery and 100 volts
With 1000 watt motor?

I just emailed lyen. He will let me know.

If you had a little patience, people here could help you better.

You do know that as you run more power, things tend to break more often, that will include your motor.

I don't understand why you're putting your equipment at risk when budget is a problem. I also don't think you understand how heavy batteries are cause 100V batteries of 14ah of any type is going to be pretty heavy (and expensive).

I used the most energy dense batteries I could get a hold of (multistars - their energy density is comparable to good 18650s). 150v 16ah, include a case, connectors and cable (0 AWG) and its 15kg easy.

Doesn't sound heavy? Try puttinf 15kg anywhere except low centre and the bike and your handling will badly suffer.

I just find it hard to believe anyone with a 1kw kit - even over driven, needs that much energy. Unless you're running 100km between charges, I don't see the need.