Merida ebike modification

[soyjim]

Below is a link to a site that discusses modifications I would like to do to get some hands on work with electric bikes. The modification are listed in the second response to the post. I have this ebike but the batteries have always been a source of dissatisfaction. I have some of the parts now or on order. I think I can follow the instructions to do the job. I have found that there are throttles with a built in gauge that I might like to try. that gives me some problems in figuring out how to wire up the controller, gauge and throttle. Not sure how I will proceed.

I did test the motor with the battery 36v 20 amp lifepo4 battery from ebay and got the motor to run thru the bikes 24v wiring but after fully charging the battery and making permanent connections in the battery case I cannot get the motor to run. I am hoping that the running problem will be solved when I put in the new controller. Power is getting thru the bike and registering as if the battery is half full. When we measured the battery voltage it showed about 44 volts. When I pedal to start the motor the bike shuts down. I think there is a click somewhere. The ebike technician I was working with in New Mexico seemed to think the problem was in the controller based on the way it was acting. He is the one that did the hard wiring and modified the case to put the lifepo4 battery in. I am now home and still willing to drop time and a few dollars into getting this bike to run. Right now I am to the point where I need to get a throttle. I just have to decide if I can figure out how to wire in one with a gauge or just follow the instructions I have got.

I took the bike to NM cause my Brother in law was willing to show me how to wire the bike to test if the motor still worked. Once satisfied that it could be fixed I replaced some broken spokes. The fact that the bike no longer worked after hard wiring and fully charging battery was disheartening. I am now back home and largely on my own figuring out how to proceed. Have a controller and brake levers on order and hope they are here soon.

Have been reading and enjoying the forum now for a while. Any advice on how to proceed would be appreciated.

http://visforvoltage.org/forum/2562-merida-modifications

 

[dogman dan]

Is home in NM? I think when you fully charged the battery, it then has enough voltage to trip the high voltage protection cutoff on the bike.

 

[soyjim]

Great to get a response from the famous dogman dan.
I live in Illinois. My sister lives in Albuquerque and I go out there every so often and go on bicycle rides with them. Mainly along the Bosque which is a flat trail. I took this bike out there this year instead of a regular bike so that I could determine if it was possible to get it to work with Granpa Chas's throttle install. I figured that it was worth buying the 36v battery Lifepo4 battery as I got it on ebay last year for about $180 dollars. I now know it is one of the ones with the soldered connections that may be a problem. Albuquerque is a great place to ride a bike most of the year. Lots of bike lanes and little rain or snow. Goat heads though. (Lets keep this quiet) One of the guys at a bicycle shop on Montano (Fat tire cycles I Think) did some work on modifying the battery box for me. Not sure if I should mention his name, but he seemed to do good work. He is the guy they have designated to work on electric bikes.

Hope you are right about the high voltage cut off on the bike being the problem. Did not test voltage on battery when we the got bike to run. It had been setting for a while and never charged. the charger was left on overnight and definitely took several hours to charge. Installing the new controller should solve that problem, right? I am leaning towards getting a three plug thumb throttle. no gauge for now as that would be the simplest to connect. I could run the bike without a gauge and worry later about what and how to hook up a gauge. The 36v JC 116-3 controller, I have on order from aliexpress, has a 3 prong throttle plug. I am of 2 minds about going forward with this. I want to make the project simple, one step at a time and I would like to get the completed job done right without having to keep coming back to do more modifications.

I think I like the idea of a thumb throttle. The bike has a right hand 4 speed twist grip shifter. Putting both of these on the right hand would pretty well force me to let off on the throttle which I think is something that should be done when shifting Shimano internal gears.

Not looking forward to taking the bike apart but am looking forward to riding it.

 

[soyjim]

My controller arrived today. Basically the only instructions with it were most of the wires coming out are labelled. Below is a key to where I got it and it has some info about the controller there.

http://www.aliexpress.com/item/BRAND-NEW-36-Volt-Controller-Scooter-Parts/355515542.html

The instructions I am trying to follow for hooking up this controller are below after the ***** (star) line. When I started this project the electric bike did not work with the fully charged battery. I thought I could sort of start in the middle of the instructions to see if I can get it to run with the new controller. The first six steps of instructions are about putting stuff on handle bars. I have got the covers off and can see most connections. I thought I would see if the bike will run through the new controller.

I need to figure out what wires to connect to the new controller. The instructions after the second star line make reference to a diagram but that is no longer available. It is the instructions after the second star line that indicate what connections that need to be made. Four are listed as required.

Throttle- this would be plugging in the new throttle to the three pin prong on my 36v controller that is labelled derailleur. Green, black, and red wires are on that plug. I do not have the throttle but they appear to be red, turquoise, and white probably in that order in the picture. Connecting that would make for a red to red. black to turquoise and green to white connections. I will post the colors when I get the throttle.

Key switch or power switch- Not sure about this. There is a connection on the new 36v controller labeled "lock." It has two blue wires running to the connector. Is that likely to be the power switch connection on the controller? Again not sure how to identify the power switch line on the bike, but it seems like I should be looking for a line coming out of the battery case because that is where the off and on key is located. The terminals on the bike for receiving from battery box are Black on one side and red and white wires on the other side. I think I need to look closely at this to see if I can figure out how that white wire goes into the old controller as that must be related to the switch. Any advice on what to look for and how that connection is made?

Battery connection- Hopefully this one is pretty obvious- wires from the battery receiving terminals and hopefully the bike will have a red and black connector that connects to the 36v controller connector with the red and black thicker wires. This is not labeled on my 36v controller but corresponds in location to the battery connection in the sales diagram.

Motor connection- This one is a yellow and blue connector on the bike going to the motor. It plugs into the unlabeled yellow and blue connector with heavier wires on my 36v controller.



After making these connections the ebike should work with the throttle or I need to figure out what the problem is. I do not think I need to attach the controller to the bike to test to see if this gets it running. hopefully it will work and I can proceed with getting the thing back together again.

********************************************************************************************************************************************************
Step 7: Remove the lower left cover from the bike. Note there are 2 screws holding this cover on, take care not to loose the small nut in the lower housing cover.
Step 8: Remove to old controller. There are 2 small nuts on the backside. They can be reached with a nut driver if you let some air out of the rear tire.
Step 9: unplug all the connectors from the old controller. You should not remove the 2 sensors on the bottom of the gear housing. This would allow dirt and gravel to get into the gearbox. Just tuck their wires up out of the way.
Step 10: Mount the new controller. There is a hole in the frame where the old controller was mounted that should work fine.

**********************************************************************************************************************************************************

Now it's time to connect the electronics.
Follow the diagram and connect each of the connections.
_________Required_________
Throttle
Key switch or Power switch
Battery connection
Motor connection
__________________________
_________Optional__________
Brake Levers
Tail Light (Brake Light)
_________________________
Now put the covers on and ride.