Help! Yosepower 350w kit - Fault Finding

[SteveMcG71]

Hello all,
Was wondering if anyone can help me out with my Yosepower 350w rear hub kit.

I’ve attached pictures of the offending problem, blown battery connectors.

I have two of these kits fitted to mine and the wife’s bikes, both covered around 1000 miles with no issues till now, it started with both bikes left with 70% battery charge and never used them for around 3 weeks, went to take them out and my bike had zero puff left, the wife’s had 70% left in it, I thought Hmm… strange, charged the battery and all was good.

2 weeks later, had both batteries out for charging and then went to fit my one, nothing from the display or the motor, fitted my wife’s battery to see if it was the battery and bang….. loud spark and blown the connectors on the battery.

Contacted Yosepower and they don’t know, they said maybe the controller…..

Where the 2 bikes differ is the backward rolling resistance, my bike (the broken one) is very stiff to roll backwards and forwards seems ok, the wife’s one rolls back very easily.

With the batteries off, both holding full charge, no sign in discharge.

Any thoughts on the issue? Blown / corrupt controller? It’s the built in downtube KT controller, if it is this, is worth fitting another downtube one, or get a separate one with the Juliet connectors.

Any help would be appreciated,
Steve

 

[vfr400]

It could be a shorted mosfet or two. You need a meter that beeps on continuity or some other way of testing continuity.

1. Test the middle leg of each of the 6 mosfets to the aluminium case. None should beep.
2. Test between the middle leg and the right leg of each mosfet. None should beep.
3. Lastly, check between the two battery wires. It shouldn't beep.

Left and right is determined by looking at the mosfet with the screw upward.

 

[SteveMcG71]

Thanks vfr400, I'll try that tomorrow, got a meter in the garage and report back the findings.

 

[SteveMcG71]

Morning,

Just tested the controller and found the below:

1. Test the middle leg of each of the 6 mosfets to the aluminium case. None should beep.
No beep with this test.
2. Test between the middle leg and the right leg of each mosfet. None should beep.
Two middle ones are beeping.
3. Lastly, check between the two battery wires. It shouldn't beep
It beeps between the battery wires.

What next? New controller required?

Thanks
Steve

 

[vfr400]

You have two blown mosfets. When you have two adjacent ones blown, it shorts the battery wires, since one is connected to the positive and the adjacent one the negative. Both are connected to a phase wire.

You will need a new controller that you can get from Topbikekit.

You seem to have missed the details in your story about what caused them to blow. Thet don't blow by themselves. To blow, they ned to be switched on, so connecting a battery won't do it. The only exception is when one isn't insulated to the case, but they passed that test.

 

[SteveMcG71]

Thanks for the reply vfr400,

I did suspect the controller was at fault, but the cause of it worries me for fitting a new controller to the system.

This is as much as i know, when i connected the battery into the holder and went to switch the system on via the handle bar switch, there was nothing, i then removed the battery, checked the female connectors on the battery side, re-fitted and still nothing, removed the battery and fitted my wife's battery and spark noise and smell of burnt electricals, that's as far as I've taken it till now. Other than spinning both motors in either direction, in which the broken one has far more resistance than the other.

Both systems are not abused, PAS 2-3 90% of the time, i maybe did notice slightly more noise from my system on the last ride out.

Also with the battery discharging fully, has this got anything to do with it?
Any tests i can do on the motor side to give confidence on fitting a new controller?

I have been looking on Topbikekit and they seem to have the best selection of Juliet controllers, is best to get a separate controller and will the 9 mosfets type give any more reliability to the system?

Sorry for all the questions, these kits are fine and dandy till something goes wrong.

P.S your handle vfr400 - i had one them, first "big bike", grey import 9,000rpm power band and 14,000rpm red line..... my dad had a go on it, needless to say a few swear words when he came back.

 

[vfr400]

It normally goes something like this. Owner doesn't put the motor connector in all the way to the line. During the ride, one of the pins in the connector breaks it's connection. That causes a burst of rough running and a rasping noise, which the owner notices, but doesn't do anything, unaware that the mosfets in the controller are getting tortured. As the connection makes and breaks, the noise comes and goes. Eventually, the mosfets get killed. Does that sound anything like what happened to you?

As I said, the mosfets can only blow while the motor is in use, not when parked up or when you connect the battery. They have to be switched on by the cpu in the controller, which is only active when the LCD is switched on. The cpu only activates the mosfets when the PAS or throttle is activated.

It's important to get to how they blew because the cause might still be there.

 

[SteveMcG71]

Definitely not, the motor cable was home all the way, i know this because i hate fixing them together, as they are a real pain to get right, they are like a 2 stage connection, 1st part is just getting past the waterproof and 2nd is actually engaging the pins.

The noise on the last ride was louder, but not to a point of "somethings wrong here" or else i would have turned the bike off.

I've just finished a Bafang mid drive bike build from the frame up, so I'm getting to know a few things with the electric bikes, but the in's and out's of the controllers and still new to me, so thanks for taking the time to post.

That's a pic of the new build attached.