Shocked

[motovita]

On 9/28/2021 at 9:44 AM, djr said:

Wow , I think I will be sticking with 2 stroke power ,

all this talk of - 50+volts , 800A fuses, mixed with heavy rain , is not convincing me that electric is the future.

Good luck, I hope its a simple fix

 Do you know what the secondary voltage is on your two stroke? Shocks from kill buttons used to be common in the rain, fortunately there are better kill buttons availble nowdays.

[djr]

On 10/1/2021 at 3:40 AM, motovita said:

 Do you know what the secondary voltage is on your two stroke? Shocks from kill buttons used to be common in the rain, fortunately there are better kill buttons availble nowdays.

Yes . I do know the secondary voltage on my 2 stroke ,

but I am sure the ignition hasn't enough power to do welding. ( which has been quoted for the electric bike concerned in this post )

Thanks, I will take my chances with the kill button

[austini]

Spent a lot of time in the wet on my epure and haven't experienced any shocking experiences, I was also curious as to why em put a light on the lanyard kill switch when any magnet will work. I am no electrician and any piece of electric string that isn't 12VDC scares the **** out of me, Q: will the fuse fitted on the bike blow if the short is that serious? Could the shock of been through static there's a lot of nylon in riding gear?

[Joule]

45 minutes ago, austini said:

Spent a lot of time in the wet on my epure and haven't experienced any shocking experiences, I was also curious as to why em put a light on the lanyard kill switch when any magnet will work. I am no electrician and any piece of electric string that isn't 12VDC scares the **** out of me, Q: will the fuse fitted on the bike blow if the short is that serious? Could the shock of been through static there's a lot of nylon in riding gear?

I haven't taken kill switch apart so am speculating; light looks to be red LED. They only need about 2V to emit light. Usually a resistor is in series to limit current so maybe 5V is supplied to the lanyard? The big fuse in the ceramic holder at the rear of the bike is listed at 300A in the parts schematic at Central Powersports Distribution. Given a 50V battery, for the 300A fuse to blow the short is going to need to be about 0.2 ohms or less (V=I*R, R=V/I=50V/300A=0.2 ohms) . 

 

[trapezeartist]

4 hours ago, austini said:

Spent a lot of time in the wet on my epure and haven't experienced any shocking experiences, I was also curious as to why em put a light on the lanyard kill switch when any magnet will work. I am no electrician and any piece of electric string that isn't 12VDC scares the **** out of me, Q: will the fuse fitted on the bike blow if the short is that serious? Could the shock of been through static there's a lot of nylon in riding gear?

I think the answer to why EM put a light on the lanyard is "Because they can". Just like the white light at the front and the red light under the rear mudguard. It just makes the bike stand out a bit.

[Joule]

I think this is the right power connector for the battery. They've got a cover for it. I'm thinking of printing a cap so when I pull battery out of bike the terminals are protected.

 

ds-sb120.pdf

Edited November 9, 2021 by Joule
mistake

[JPATTmaui]

I just did an underwater river crossing this past weekend lol. Now you guys have me scared! I really need to get more educated on electrical stuff but for what it's worth, I ride in the pouring rain and regularly cross 2' depth water on this thing. The only time I ride my 300 2t now is on longer, faster rides away from my house.

[Joule]

On 1/18/2022 at 12:24 PM, JPATTmaui said:

I just did an underwater river crossing this past weekend lol. Now you guys have me scared! I really need to get more educated on electrical stuff but for what it's worth, I ride in the pouring rain and regularly cross 2' depth water on this thing. The only time I ride my 300 2t now is on longer, faster rides away from my house.

I have not performed a "turn-on turn-off" experiment with my EM to prove root cause of the shock I received. I did make measurements of resistance (ohms) at many locations on the motorcycle and think I know what happened.

My measurements:

How I measure:

I use a hand-held multi-meter (DMM) and do not know how many volts the DMM applies when it measures resistance. Other hand-held DMM's I've used would apply about 2V when operating in resistance measurement mode. I will assume the DMM I used also applied about 2V to make the resistance measurement. (For readers who are wondering about this: Ohms law is V=I*R or in words the voltage drop across a resistance is proportional to the magnitude of the resistance multiplied by the amount of current flowing through the resistance. The DMMs I've used apply a voltage and measure the resulting current, then do the math to get the resistance.)  Maximum resistance range on my DMM is 2M*ohm.

I used the standard probes that came with the DMM. My probes have a sharp tip, like a small nail. All measurements were made by either lightly pressing the tip of the probe to metal on the bike or, for comparison, grinding the tip of the probe into the metal to break through the anodization.

What was measured:

Motor case to motor case. The motor case is natural looking aluminum and I assumed it has the thinnest layer of anodization. DMM probes lightly placed on the motor case returned essentially 0 ohms probe tip to probe tip. I did this at many locations on the motor case and conclude the motor case is a reasonable ground point. This also taught me how much pressure was required to get a good contact to the motor case from the probe tips.

Handle bar to handle bar where the bars are anodized (black anodization). Lightly pressing the DMM probes tips to the anodization returned an open circuit measurement on all resistance settings of the DMM. I conclude the anodization is a good electrical insulator for small voltages. 

Handle bar anodization to motor case: Pressing one probe tip from black anodization region of handle bar with other probe tip on motor case returned open circuit on all DMM resistance settings. I tried many anodized locations on the handle bars and several spots on the motor case. All returned open circuit. 

Grinding probe tip into handle bar anodization to motor case: Grinding a probe tip into the anodization on handles bars with one probe tip to the other probe tip on the motor case returned less than 100 ohms. 

Clutch lever to motor case: Probe tip to clutch lever (aluminum lever) with other probe tip on motor case returned open circuit. Note: I have teflon plumber's tape wrapped on handlebars so clutch lever has a chance to rotate if I drop the bike. 

Kill switch attachment screw to motor case: One probe tip on the head of the screw of the clamp that holds kill switch to handlebars other probe tip on motor case returns less than 100 ohms. I have kill switch on left side, clutch side, of bars.

My guess about what happened:

I received a shock at an event where it was raining off and on. Bike had less than 20 hours on it. The battery level indicator is a voltmeter and full battery voltage is routed to it, so full battery voltage is available at handlebars. I suspect water, sweat, mud, formed a conductive layer on the surface of the handlebars. The bars were in pristine condition with no scratches through the anodization. I suspect the layer of water made a path connecting clutch lever to some electrically hot point inside the battery level indicator. I was discussing the bike technology/features with the trials master when shock occurred and suspect (but don't really remember) that I pantomimed pressing a button for regen braking by pressing thumb into clamp of kill switch. I suspect this because that is exactly the kind of thing I would do while talking with someone, gester with my hands. So: Goo on outer surface of handlebar and clutch makes connection to hot terminal in battery level indicator. Handlebar surface electrically isolated from ground, clutch lever electrically isolated from ground, finger on clutch, thumb presses into ground connected screw completing the circuit. 

I have not done an experiment to try and prove the above and know it is a lot of handwaving.

I have dropped the bike a bunch in rocky terrain and the anodization on the handlebars is no longer pristine. There are many points on the bars that measure low resistance to the motor case. If it looks like I'll be riding in the rain I plan on making sure levers are well connected electrically to the motor case. The easiest way to do this in my opinion is to rub off the anodization on the handlebars at all clamp locations. I may try and add some insulation under the battery level indicator, like a piece of inner tube. I have about 100 hours on the bike and have had just the one incident.