Dumb as, you know... help?

[Blackgolem]

Hey this is gonna sound kinda mess up coming from an old man but I'm working on a e 300 scooter for a mobility scooter and for the life of me I can't figure out why it keeps going full on when I connect the battery. It runs through the speed controller. I have a 36 v motor/battery had a 36 v controller it blew then tried a 24 v( same architecture) both rated 500 w as is motor it worked for a second then went full on me not having turned on the ignition. Can anyone give me some help? I had checked FETS on the 36 v controller one was bad replaced off the 24 then I had to put it back all in all it still went open. What's funny is it was working fine then this. Could it be I have 12 gauge wire instead of 10? I thought 10 and 12 could handle up to 30 amps.

 

[harryS]

What controls the speed? Is there a throttle? Then look for a broken throttle or bad throttle connection.

On ebikes, throttle is a three wire control using a magnetic chip and a rotating magnet. Power, ground, signal. Power is 4.5 volts if you measure it. SIgnal changes from 0.8V when off to 4.4 volts when max. If the ground wire is broken, ebikes go full ON.

 

[rich c]

You'd be better off going to a scooter forum. This is all about bicycles. Could be you have a couple bare wires touching somewhere, completing a circuit.

 

[Sierratim]

As a general rule;

10AWG = 30A max
12AWG = 20A max

You can use 12AWG at higher currents if it has higher temp rated insulation, but the voltage drop goes up.

It does sound like a throttle problem.

You swapped FETs from the 24V controller into the 36V? Were they the same part number FETs?

Just to be clear, the 24V controller was hooked up to a 24V battery pack, right?

 

[Alex M]

This is not caused by 10/12 wire. If anything, higher resistance of a thinner wire will not increase the current flow. 12 AWG is rated 20A for safety but will handle 30A for some time before the insulation fails.
Ask at the Endless Sphere, in subsection for Scooters: https://endless-sphere.com/forums/viewforum.php?f=10&sid=4bab417719b577d4bf016fb896ac76b8

 

[Sierratim]

This is not caused by 10/12 wire. If anything, higher resistance of a thinner wire will not increase the current flow. 12 AWG is rated 20A for safety but will handle 30A for some time before the insulation fails.
Ask at the Endless Sphere, in subsection for Scooters: https://endless-sphere.com/forums/viewforum.php?f=10&sid=4bab417719b577d4bf016fb896ac76b8

To be clear, I didn't suggest that the issue was caused by AWG. I stated, and would still suggest, that it sounds like a throttle problem.

 

[Alex M]

To be clear, I didn't suggest that the issue was caused by AWG. I stated, and would still suggest, that it sounds like a throttle problem.

We're on the same page - wire is not a culprit, throttle possibly.
I prefer not to take wire ampacity ratings literally. The melt-down of AWG12 at the "official" 20A is not instant and depends on the insulation quality, while the OP noted high current running the moment he turned it on (or sounded like that).

 

[Blackgolem]

As a general rule;

10AWG = 30A max
12AWG = 20A max

You can use 12AWG at higher currents if it has higher temp rated insulation, but the voltage drop goes up.

It does sound like a throttle problem.

You swapped FETs from the 24V controller into the 36V? Were they the same part number FETs?

Just to be clear, the 24V controller was hooked up to a 24V battery pack, right?

Yes inside both the 24v and the 36v controllers they have same components just different capacitors

 

[Blackgolem]

We're on the same page - wire is not a culprit, throttle possibly.
I prefer not to take wire ampacity ratings literally. The melt-down of AWG12 at the "official" 20A is not instant and depends on the insulation quality, while the OP noted high current running the moment he turned it on (or sounded like that).

So if i understand it could be the throttle? I believe its rated at 30 amps

 

[Blackgolem]

You'd be better off going to a scooter forum. This is all about bicycles. Could be you have a couple bare wires touching somewhere, completing a circuit.

I hear you but shouldn't the controllers work same as each other? I don't think wires are touching but I'm going to check the case to see if anythings touching inside the case causing a contact short of some kind.

 

[Blackgolem]

What controls the speed? Is there a throttle? Then look for a broken throttle or bad throttle connection.

On ebikes, throttle is a three wire control using a magnetic chip and a rotating magnet. Power, ground, signal. Power is 4.5 volts if you measure it. SIgnal changes from 0.8V when off to 4.4 volts when max. If the ground wire is broken, ebikes go full ON.

Ok I will check I think this is rated at 30 amps not sure

 

[Sierratim]

Ok I will check I think this is rated at 30 amps not sure View attachment 55565

The throttle will be a signal level input to the controller. It won't directly control the motor current, that's up to the FETs in the controller. As @Blackgolem suggested, first check for broken wires.