Need help diagnosing!

[Paulmyoung]

Hi —
I own an Ecotric Rocket 36v and am having trouble diagnosing. I turn on display and as soon as I turn throttle, display dies and bike has no power. Display stays on when I turn pedals only and don’t touch the throttle. Tested battery, battery wires and controller output with a voltmeter and all three showed 42v. Attempted to replace the display with no luck. Any suggestions on where to look next or what could be wrong?

 

[harryS]

How old is the battery? Can you ride in the highest PAS w/o it also shutting off the bike? What display is it, LCD or LED?

 

[indianajo]

You need a continuous voltage reading. Something you can both ride and watch the voltage. I bought two bad batteries. One would read nominal voltage (41-54.6) sitting still. Performed fine on flats. As soon as I climbed the first hill it would drop to 7 v. It would stay at 7 volt after I rode back to base, so I got my money back from Amazon.
The other would read nominal voltage until I climbed the first hill, when it would collapse to 11.3 v. As soon as I cut the throttle back, it would bounce back to nominal voltage. I had to bring that battery to town and rig up a test jig involving 500 W resistors that would waste 10 A while I read the voltage, to catch the battery voltage collapsing. This took 90 days so I didn't get my money back from e-bay.
I bought a throttle that had a voltage indicator on it. Works whether bike is turned on or off. Lacking that, you need to wire a voltmeter on an ever-hot wire like the alarm power or something similar. If the voltage from battery is staying nominal under all conditions, then the wiring is bad to the controller, or the controller is bad, or the display is bad.

 

[Paulmyoung]

You need a continuous voltage reading. Something you can both ride and watch the voltage. I bought two bad batteries. One would read nominal voltage (41-54.6) sitting still. Performed fine on flats. As soon as I climbed the first hill it would drop to 7 v. It would stay at 7 volt after I rode back to base, so I got my money back from Amazon.
The other would read nominal voltage until I climbed the first hill, when it would collapse to 11.3 v. As soon as I cut the throttle back, it would bounce back to nominal voltage. I had to bring that battery to town and rig up a test jig involving 500 W resistors that would waste 10 A while I read the voltage, to catch the battery voltage collapsing. This took 90 days so I didn't get my money back from e-bay.
I bought a throttle that had a voltage indicator on it. Works whether bike is turned on or off. Lacking that, you need to wire a voltmeter on an ever-hot wire like the alarm power or something similar. If the voltage from battery is staying nominal under all conditions, then the wiring is bad to the controller, or the controller is bad, or the display is bad.

Awesome thanks for the info. I will try and let you know how it works

 

[Paulmyoung]

How old is the battery? Can you ride in the highest PAS w/o it also shutting off the bike? What display is it, LCD or LED?

Battery is about 2 yrs old — bike shuts off as soon as you pedal or use throttle. Not sure what display is but it’s pretty basic

 

[harryS]

I've owned Ecotric. That happened with my battery after 25 months. Shut off several miles after a full charge to 42V. It was reading about 40V when it shut off. It was extremely unbalanced.

What can i say. They and many of their competitors use cheap cells that start to wear out around 25 months.
|
Replacement is the only option.