No throttle, wrong Grin hub?

[fxsvelo]

A friend gave me his old Grin conversion ebike and everything works fine except that the throttle kills the system. Black screen and you have to restart.

If you hold the wheel off the ground, the throttle does power the wheel. But put any load on it and it quits. Black screen/restart.

Looking at it with Phaserunner suite you can see the Amperage spike over the 30A setting.

What I'm suspecting is that the wheel is wrong for this bike. It's a Grin GH-0215 19.34 RPM/Volt. So high speed/low torque.

Baserunner: V6 L10
firmware: V6.025
Motor: GH-0215
Battery: 36 volt original Grin LiGo stackable.

Any ideas?

 

[E-HP]

A friend gave me his old Grin conversion ebike and everything works fine except that the throttle kills the system. Black screen and you have to restart.

If you hold the wheel off the ground, the throttle does power the wheel. But put any load on it and it quits. Black screen/restart.

Looking at it with Phaserunner suite you can see the Amperage spike over the 30A setting.

What I'm suspecting is that the wheel is wrong for this bike. It's a Grin GH-0215 19.34 RPM/Volt. So high speed/low torque.

Baserunner: V6 L10
firmware: V6.025
Motor: GH-0215
Battery: 36 volt original Grin LiGo stackable.

Any ideas?

Can you measure the voltage of the battery after the system dies, but before cycling/restarting?

 

[fxsvelo]

Very interesting...

BTW the batteries are stackable and connected in parallel so you can use any number

Trying it just now, I now get some boost before it cuts out on max throttle. This is on 2 batteries @ 37.6.

Switched over to 3 fully charged batteries @ 40.7 and I got boost even at max throttle.

So it seems like some connection wasn't good, somehow got better?

And, having full voltage on 3 battery packs makes a difference. That makes sense if you have a weak battery that's not putting out enough voltage you have to increase the amp draw to make the power.

The bike sat for a long time so connections oxidized? Maybe it needs going through all the connections and cleaning contacts?

 

[fxsvelo]

And I think the 3rd aspect of this is that the wheel is 19.34 RPM / Volt so higher speed / less torque.

Does that make sense? The combination of the three:
Poor power connection
Lower battery voltage
Higher speed / lower torque wheel

 

[E-HP]

What was the voltage of the battery after the system dies, but before cycling/restarting?

 

[offGridDownUnder]

The Grin Ligo modules are 36V each. Adding more increases the available current, not the voltage.

For your symptoms, it appears that you are using too few modules to provide the current your motor requires.

How many modules do you have, and what happens when you use all of them?

 

[E-HP]

The Grin Ligo modules are 36V each. Adding more increases the available current, not the voltage.

For your symptoms, it appears that you are using too few modules to provide the current your motor requires.

How many modules do you have, and what happens when you use all of them?

Based on his 2nd post, it sounds like initially 1, and adding a 2nd allowed it to run, but not at full throttle. The specs say 10A continuous and he pulled 30A, so the symptoms point to the BMS tripping, however he won’t confirm the voltage after the screen goes black which would support that diagnosis.
The battery lights should indicate if there’s an issue, and what it’s related to.

 

[fxsvelo]

I was testing the throttle under different battery sets. 2 - 5 batteries. And yes, they're in parallel of course, not series. But when the voltage drops with a partially charged battery, to get the same wattage, you increase the amperage, no? Amps x Volts = Watts. So if you lower the Volts you need to increase the Amps.

I saw no drop in voltage when it tripped, but that's just from a multimeter. I'd have to set up the oscilloscope or some sort of capture device that I don't have.

The first test where I reported that it powered the wheel but cut out at full power was on partly discharged batteries. Second test that didn't fault was with 3 fully charged batteries.

On my initial test ride when I picked up the bike, it always faulted no matter what batteries.

In any case, I do think that it's mostly a power lead connection problem exacerbated by the 19.34 RPM / Volt wheel. In moving the batteries around in the frame bag this morning I'd disconnected the power lead from the batteries to the baserunner and reconnected it. That's when it started functioning more normally.

I've stripped the e-stuff off the bike since it's not my size. They even installed an NTCE torque sensing BB, though they never hooked it up. Someone went to a lot of trouble to do that too. You have to solder/splice the cable back together and heat shrink the whole thing. Only to cap it off. ???

I'll build it back up on another bike and take extra care that the connections are good / low resistance.

 

[marty]

BMS tripping

Think it's called "low voltage cutoff" Prevents lithium batteries from draining too low. If voltage goes too low, lithium batteries die as in dead to never recover. Tie a volt meter to handle bars. Watch if volts drop right before and or after screen goes black.

Sad story about alcohol, and collage students. Group of students told 1 guy to exercise. He exercised till he died. This happened a few years ago, near my house. Poor guy had no BMS.

 

[marty]

Battery: 36 volt original Grin LiGo stackable.

What is age of batteries?

 

[offGridDownUnder]

Grin GH-0215

"Grin GH-0215 bicycle motor" does not return any search results. No similarly named motor is listed in the Grin Simulator.

Can you confirm how you determine this is the designation for the motor you have, please? Is a picture available?

 

[fxsvelo]

"Grin GH-0215 bicycle motor" does not return any search results. No similarly named motor is listed in the Grin Simulator.

Can you confirm how you determine this is the designation for the motor you have, please? Is a picture available?

Yes! Let’s talk about this motor and whether this is a good choice or not! And yes, I found that odd as well. Nothing shows up googling <grin GH-0215 ebike>

What I can add is that this was apparently a Calfee conversion. And that may explain why the special 19.34 RPM / Volt motor. Calfee, as manufacturer of sport bikes, seems to have intended this for faster speed riding.

This is a kit that’s been passed down from friend to friend in our local bike club. The person who I believe to be the original owner is off on a BAC (Bicycle Adventure Club) ride in Switzerland. I should be able to get more details from him when he’s back. He originally had it on a coupled bike he used for overseas trips. Hence the stackable airline-friendly batteries.

Something? Just the conversion kit? Was passed down to another friend who used it to power his loaded touring bike. So a completely different frame and reinstallation of the kit.

The batteries are certainly old. They’re the original LiGo that are now discontinued. They all charge up to a good voltage but I don’t have any way to assess the capacity other than using them.

There was no drop in voltage that I could see with my multimeter. Though there was a clear spike in amperage seen in the phaserunner software during testing.

What is clear from all my testing is that evidently there was a poor power connection when I first received the bike. Once the power cable connector (HiGo L10 locking) was unplugged/plugged the problem started to go away.

Thanks to all for their insights!