Accidental regen on non-compatible controller?

[mrzed]

Hi all,

I am running a ebikes 9C front kit with crystallyte 20A pedal first controller (no regen) and a ping 48v/15ah battery. Today on the regular ride, I'm heading down the steepest section of my ride. Very shortly after releasing throttle, I notice a strong shuddering. It felt a little like the stuttering I get from the motor when starting up at low speeds and full throttle, but stronger, and in reverse.

I pulled over right away, as I though I may have lost a spring on the front brake or something else that may have impeded forward motion. The rest of the ride was normal.

I have never felt anything like this before - I take the same route every day, and normally I can just feel a slight smooth regen drag down this section once I get up to speed.

Any thoughts on what this may have been and if it is a concern?

 

[dogman dan]

You may have blown something in the controller. It still works? I'm told by ping that regen is ok with the V2.5 battery so don't worry about the battery.

Seems like this has happened to others, but I don't recall the thread name. I'd definitely ask Justin about it since you bought the stuff from him.

 

[Holz2010]

You may have blown something in the controller. It still works? I'm told by ping that regen is ok with the V2.5 battery so don't worry about the battery.

Seems like this has happened to others, but I don't recall the thread name. I'd definitely ask Justin about it since you bought the stuff from him.

Just a caution on the regen with Ping's BMS as discussed here http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=14583&start=15
with the V2.5 Ping batteries, but Mrzed may not be using a BMS (?)

If so though the diode diagram from Ping is attached and on the last page of Ping's download here: http://www.pingbattery.com/usrguide/Wiring%20Guide%20V2.5.pdf

Rumor was that Ping would have a BMS out about now that accepted regen...maybe after Chinese New Year!

 

[mrzed]

The controller works as normal, as far as I can tell. I put about 12Km since the issue this morning. The only other component in the system is a cycle analyst, which did not show anything out of the ordinary, though admittedly, I was not reading it while heading down a steep hill with the motor shuddering.

I wonder if the wiring for regen diagram applies here, as the controller is not set up for regen. The only reason I brought it up is that it felt almost as if the motor momentarily turned into a generator. I am using a BMS, as it is a Ping 2.5 like Dogman suspected.

 

[HTB_Terry]

It sounds like the controller got a jolt of high voltage causing it to loose sync and turn on the wrong mosfets. Maybe the processor reset. I'm sure the mofets got hot but you lucked out and they didn't blow. That was smart to stop right away.

On the Ping drawing, the charge inputs are connected to the controller to receive the charge which is what you want. You don't want it reversing into the discharge path. The purpose of the diode is to prevent that. The charger input will disconnect (mosfet shuts off) if any of the cells receive an over-voltage. I wouldn't want my last line of defense used to protect against regen spikes but theoretically it would work. No protection against over current, thus the 5A warning. An alternative would be to switch the controller to the charger input with a relay controlled by the brake switch. It would be safer to add an external current and voltage clamping circuit.

 

[Tiberius]

I agree with Terry; it sounds more like the controller losing the plot and firing the phase wires with the wrong sync.

I had something similar once when I overheated a motor. It damaged one of the Hall sensors so that when the motor was warm it sent the wrong signals. The effect was a severe juddering followed by the controller shutting down.

Of course, if its a sensorless controller its even more likely that it loses sync when the throttle is closed.

Nick

Edit: Just read OP again. It is a sensorless controller.

 

[dogman dan]

Interesting that it didn't blow the controller. I've never had any of my High Tech Bikes sensorless controllers behave like that on me, in thousands of miles of riding. Lots of hill riding too.

Another possibility could be an intermittent loss of connection on a connector somewhere. Any chance a wire rubbed on a wheel? Or a pin on a molex is partly pushed out?

When I asked ping about regen, I was asking about a battery I just got this month, mabye I have the new bms. I did tell him I wasn't getting more than 5 amps of regen though, so his reply indicated that it was ok. He didn't tell me to look at that diagram, possibly since I wasn't making more than 5 amps. He did caution me not to use the regen down a big hill if the battery was full though. He knows I live on a hilltop. Fortunately for me the steep part is still 5 miles from home.