Controller Wiring question

[wbrproductions]

Hello -

Great site, metric tons of e-bike info. N00bie post, please excuse me if this has been answered...

I have a Wilderness Energy BD36 (brushed) kit that I ran with 2 sets of 3x12ah SLAs for a few seasons, then switched to LiFePO4 last season. The original controller seemed to work fine for a number of months, then I think I zorched it at the end of last year. The symtom - the wheel will spin fine w/o load, but as soon as I get on, pedal, then hit the throttle, the power drops to zero and the red light on the throttle fades out.

I assumed the controller was zorched, but if anyone thinks otherwise, please lemme know. I have not changed the brushes in the motor after 3 seasons of use (if that makes a difference).

So, I bought a replacement controller on ebay, but the wires don't match up. Based on this board, seems like a common problem. Uploading a pic of the controller, and the specs of the unit are listed on ebay in my signature line.

Anyone wired up this combination? I searched the wiring diagram topic, but didn't see that specific combo... Thanks in advance.

 

[yopappamon]

Does the battery voltage hold up when the system fades? Symptoms are similar to a very weak battery pack. Any connectors getting hot? Might be a poor connection.

 

[wbrproductions]

The battery voltage holds up fine - stays in the high 30s, but the voltage downside of the controller drops to 1-2 v. None of the connectors are hot...

 

[wbrproductions]

Reading the following post: http://visforvoltage.org/forum/5015-need-help-wiring-ecrazyman-brushed-controller, seems like I need to do the following:

• Black/Blue/Red on new controller ("Derailleur") to Black/White/Red to throttle, ignoring Purple for now (low-voltage indicator).
  Jump Black to Red on the "Power Locks" connector
  Large Black/Red connector to battery
  Large Blue/Yellow connector to Blue/Green motor wires (not sure which to which yet)

Make sense...?

 

[MrKang]

that connection is good.

what also could be your problem is your new LifePO4 pack.
if one cell is to low your BMS is cutting of the power..check al cell levels to see if that's an issue

 

[el_walto]

Battery probably has bad cell group and is cutting out. You could test by hooking the battery up to another load and seeing if it cuts out.

 

[dogman dan]

I agree, either your controller is hitting lvc or the battery is hitting lvc. Most likely the battery, since the controller lvc is low enough to use it with 24v sla's. The controller is fine, the battery is not. It could be just a faulty bms, but more likely the watt hog BD is hammering it. It's a 35 amp controller, so if you have a cheapie, or even a decent 10 ah pack, it's too small for the motor and controller.

Even if you have a bigger pack, like a 20 ah, a 35 amp controller is fairy hard on it, and any weak cells may have died, so that now the pack is smaller, and the rest of it gets stressed even more. I rode a BD36 2000 miles on a ping v1 36v20ah with no problems. But some of the round cell type packs have proved to be less durable.

 

[wbrproductions]

Another load, such as...?

 

[wbrproductions]

OK, thanks.

On a related note, how do I test each cell individually? So, there's a separate wire coming from each cell to the BMS (battery mgmt system?)?

 

[dogman dan]

Either on the bms itself, or the plug on the wires leading to it. One voltmeter lead on the end wire, and then the other on the next one. should be 3.5v. Move the second lead to the 3rd wire and it should be 7 volts, and so on. Then do subtraction to find the actual voltage of each cell. Do it after a full charge, to find if the pack is balanced. After a discharge, a very low cell will show up.

The best test would be a load test of each cell group. But that is not really a thing for a noob. You need to open up the pack and access each cells terminals, hook up a load, and measure voltage sag under load. The ones that sag a lot more are the bad ones.

As the paralelled cells in a group of cells begin to die, the remaining ones will get severe voltage sag, since the same amps is now being pulled from a very small battery. The bms sees this, and cuts out the pack. Not much fun to fix though, nearly impossible with a round cell pack, and a PITA on a pouch cell pack.

 

[Chillboy]

Battery probably has bad cell group and is cutting out. You could test by hooking the battery up to another load and seeing if it cuts out.

After a few strong but short rides I am also having this problem. I have good reason to believe I have a bad cell but keeping the faith and testing it on a scooter this weekend.
Question though I adjusted my controller to 40% output for only about 15A and brought top speed setting to 80% and it does the same thing. That's not a lot of demand but it still barely catches and then nothing. Turning controller on and off doesn't do anything. If I flip the battery switch on and off I will get that short burst again. Any insite?

 

[wbrproductions]

Dogman - thanks much, will run that test and report back.

 

[wbrproductions]

OK, ran the test on all 11 terminals. Starting at B1, and testing that against B2-B6, then starting again at B6, and testing that against B7-B11, each step added 3.7V X 5 = 18.5V per side X 2 = 37V. Testing B1-B5 against any terminal in B7-B11 yields open circuit, so it looks like this board divides the battery into 2 'master' cells with 5 'child' cells on each side. Make sense?

Each individual cell yielded 3.7V, so I'm not suspecting a bad cell. Is there some way I can test the old controller (Wilderness Energy), to confirm that it's burned out?

Thanks again.

 

[wbrproductions]

dogman - another question for you. I'm a n00b to working on my ebike, but not to electrical / mechanical work in general. if I'm able to connect up to each cell individually, can I run the ebike motor as a load for this test? Is there something else you can suggest in terms of connecting a load to an individual cell? I know how to measure the voltage drop...

Thanks,
wbrproductions

 

[wbrproductions]

OK, I've verified that the new controller works fine with this setup, tho I'm currently running in ON / OFF mode (37V or nothing), which is a bit hairy...

Also did a 5 mile test ride, averaging 25-30 MPH on straightaways with no problems, so the battery pack is 100% good.

The current mystery is this - I have 3 throttle wires coming from my new controller (pic in the first message in this thread), and 4 going to the throttle.

This configuration works (but gives on / off operation):

Controller: Throttle:
------------ ----------
Red > Red
Black > Black
Blue > White (with on / off switch)
? > Purple

Anyone know where purple needs to go to get proper throttle operation?

Thanks,

 

[jateureka]

There's a heap of info on here about how to test a throttle, so use the search function.
Basically for a hall sensor type you apply 5V to the + and - leads and turn the throttle and you will see a voltage swing on the sensor o/p lead. Most have red = +5V, some throttles have the +5V as white instead of red.

 

[wbrproductions]

jateureka - thanks for the reply. Sounds like you're suggesting applying 5v to Red and Black, then apply the throttle to check for a voltage swing on either purple or white (the 2 remaining wires from the throttle). Will search as well, thanks.

 

[jateureka]

yes, but if you don't get a swing on purple or white then put +5V on white and test for swing on red or purple, etc

 

[jateureka]

Did you have any luck with this?

 

[wbrproductions]

(Apologies for the very long delay between responses)

OK, tried all possible 5V permutations thru the throttle wires, and have now determined that no possible combination produces a voltage change. Pretty sure my throttle is zapped (may have been the original problem). Will take it off and look for obvious shorts or other issues. Recommendations for a 3-wire throttle from a particular seller?

Thanks again,