Changing Controller, NCM Prague

[NcmPragueUser]

Hello Guys,

i have a problem with my NCM Prague+. Sometimes, it does not give any motor support, and the display changes from full charge to depleted suddenly.

I have decided to order a new controler and change it, since i feel that`s propably the cause. Maybe someone can help with how to do this properly? Or if you have any ideas what could cause the problem otherwise, that would also be welcome.

Specs:

• Display: Das-Kit, L6B,
• Controller: Das-Kit, CT-D5-44, 36V 15A
• Motor: Bafang, RX2, 36V

Thanks in advance!

I attached some pictures of the old controller, maybe someone finds something suspicious.

 

[NcmPragueUser]

Thanks for the reply, makes sense. Sorry , i`m new to the forums...

 

[lericain59]

Hello,

Did you end up changing the controller ? Did that solve you issue ? I ask because the same thing is happenning to mine albeit my battery is well over 5 years old.

Please let me know.

Scott

 

[indianajo]

You can check the voltage to the controller with a DVM. You can skin the wire & use alligator clip leads, or you can buy one with voltage display built into the hand throttle. You have to mount the DVM where you can see it safely while riding, of course.
A bad weld in the battery can cause sudden dips in voltage that shuts the controller off. Especially when demanding a lot of current, as uphill. Also there can be loose connections in the wiring from battery to controller input. I'm suspicious of those press to connect batteries that come with some brands. My battery is securely connected with crimp on insulated .250 flag terminals, Ideal, T&B, Panduit, 3M AMP or Dorman brand. The dorman terminal assortment made in ***** is the same garbage as all the other stuff made in *****. Individual packs of Dorman terminals tend to be made in ******. I bought a car at closeout price once because the customizer wired the ignition circuit with RadioShack flag terminals. When the current went over 25 A the terminal burnt off the wire every time. An T&B terminal was a permanent fix.