Ezip Trailz only runs when plugged in

[jpkc97]

Just picked up this non running bike. It appears brand new, still had the owners manual taped to the frame.
It had no power but the green throttle light would come on and you can run the motor with the throttle when the battery is plugged into the charger.
I assumed the batteries in the pack were dead so replaced them without testing the old ones. When opening the battery pack, it appears the batteries were original and untouched so I replaced with the exact models. It had the same result so I double checked my connections. I tested the battery outputs and have 24.4v when unplugged and 28.4 when plugged into the charger. I also removed the fuse and have 0v unplugged and still 28.4v when plugged in.
The wiring has the wires from the charger going directly from the charge port to the terminals, with the batteries also connected so that's why it still runs without the battery circuit connected via the fuse.
I then figured it must be the controller, so ordered a new one. Just replaced and got the same result.
Any Ideas? When I unplug it, the green light turns red, then goes out, just like I switched the power off.

 

[gromike]

Lead acid batteries or Lithium?

 

[jpkc97]

Lead acid batteries or Lithium?

Thanks for replying...2 12v lead acid in series

 

[gromike]

I would focus on the wiring between the battery and the controller. A lot of time it's a bad connector, terminal, etc.
You could check the wires resistance from the controller terminal to the battery terminal.
You're reviving this bike as a hobby? Not much intrinsic value in it outside of being an ebike museum piece.

 

[jpkc97]

I would focus on the wiring between the battery and the controller. A lot of time it's a bad connector, terminal, etc.
You could check the wires resistance from the controller terminal to the battery terminal.
You're reviving this bike as a hobby? Not much intrinsic value in it outside of being an ebike museum piece.

Thanks, Yeah I guess I'll start digging into that. Weird how it's fine when plugged in.
I bought it from a guy for $150, hope maybe I can get some of my money back if I sell it.

 

[neptronix]

This is a very primitive system with no BMS so there's not much left to replace after what you've already replaced.
If you want to continue down the rabbit hole, i'd replace the throttle.

Also, does this bike have electric brake cutoffs?

 

[jpkc97]

This is a very primitive system with no BMS so there's not much left to replace after what you've already replaced.
If you want to continue down the rabbit hole, i'd replace the throttle.

Also, does this bike have electric brake cutoffs?

Yeah was thinking that next…Yes has brake cutoffs