Another Newbie

[BuellGuzzi]

Hello, always been interested in electric propulsion and I have obtained a Cintura Dynamo chinese ebike 250w (I think) 36v 10amp (again I think) battery. pedal assist and a throttle. Battery sits at 42v charged. It has intermittent running problems either no go or max power when switched on with no throttle or pedalling. I've pulled the controller from the bottom bracket and cleared out the damp sand. I'll check all the connections once I identify where/what they do and hopefully rectify the problem. The front Wuxxing led light seems to have a component missing. It lights if I connect the wire (36v) to the back of the led circuit board however it appears that there should be battery or fuse installed between the wire and the board. This seems to be the size of a AAA battery but shorter. Can anyone shed any light on this.

Yes I really want a Stealth Bomber ;-)

 

[wheeliepete]

Yes I really want a Stealth Bomber ;-)

You don't know it yet, but you don't. Keep looking and learning. It sounds like you have the ability to build something yourself and save a HUGE heap of cash.
Oh, and welcome to the forum

 

[soundwave]

https://www.ebay.co.uk/itm/E-Bike-Frame-bicycle-Frame-Steel-155mm-dropout-for-Stealth-Bomber-Electric-bike/162208414047?hash=item25c45ff95f:m:mPSk7-ClvozpN_FODBuKGkw

http://www.hi-powercycles.com/hpc-5000w-hub-motor-complete-kit/

http://www.srsuntour-cycling.com/components/v-boxx/V-BOXX-GB10-VB-FR9-BAZ-5712.html

tho i have no idea if that gear box will fit on that frame but at the end it will be a 60kg bike and range wont be much good either esp at speed.

 

[BuellGuzzi]

Quite taken with a self build ie skint. This is my cheap (less than the battery is worth) 'gateway' Ebike to learn the electrical ropes and probably wheel truing.

 

[Nealh]

Sounds like there is a wiring issue/short or a controller short possibly to get power without pas or throttle use.
You will need a volt meter with buzzer for continuity test to find any wire fault.
I had a similar issue last year, once switched on the bike would take off just pushing it. I started with the throttle wiring and was lucky found the fault straight away with a broken wire ( I think mine was the signal wire which was intermittently connecting).

 

[wheeliepete]

Quite taken with a self build ie skint. This is my cheap (less than the battery is worth) 'gateway' Ebike to learn the electrical ropes and probably wheel truing.

'tis the way to go. Identify the throttle connector on the controller and disconnect it, then try the PAS. Throttle is often the problem. Sounds like it could be a fuse in your front light. Like Nealh says get a cheap multi meter with continuity tester if you don't have one, it's a vital piece of kit in this world.

 

[Deleted member 4366]

First thing to check is whether the motor is brushed (2 wires) or brushless (3 wires or more).

 

[BuellGuzzi]

Looks like three phases and hall senders

 

[Deleted member 4366]

View attachment 23353 Looks like three phases and hall senders

Good. It's a normal brushless motor. If you get power without pedalling or opening the throttle, there must be a short in the throttle wires on in the throttle itself. Disconnect the throttle and see if the bike works properly with the pedal sensor.

 

[BuellGuzzi]

I have a fluke to chase down dodgy wires. It has been suggested that the light may be a dynamo model pressed into service with 36v and the missing piece is a capacitor used for smoothing and momentary storage. What say the collective?