Throttle cuts off at high speeds,

[kevo]

I just got my 72v 45ah 12kw qs273 sabvoton 150a stealth bomber from Alibaba, (boneng) I took it out for the first full ride. It operates great till i got to about 40% battery left, i was pushing about 50-60mph and the throttle just cut out and came to a rolling stop. I turned it off and let it sit a minute then back on, it drove fine for a mile and did it 2 more times when i was going about 45 to 55 (in traffic-kinda scary!) I'm thinking the controller is hitting a self protect mode. Anybody have any ideas what could be happening and what could fix it? Thanks

 

[Freddy1]

Could be 3 things I reckon. The battery BMS protection. The Controller low voltage protection. The controller overheat protection.

I'd start with the controller overheat. How hot is it getting? If its not getting a good airflow eg. stuffed inside a box or bag, that's the first thing to address before chasing other possible problems. Don't know you set up, but if it inside a sealed compartment, can you just hang it somewhere in the air draft to test.

 

[HumanPerson]

Heya @kevo Welcome to the forums


Is it possible that the pack is not even really 45ah...

 

[Freddy1]

Looking at a picture of the bike ... the 72V 200A controller has to be located in that vented panel under the battery, held in place by what looks like 4 screws, one in each corner. What I would do is remove that cover, cable tie whatever is necessary to keep all the wiring and controller temporarily in place with the cover removed, and then take it for a spin.

 

[kevo]

Heya @kevo Welcome to the forums


Is it possible that the pack is not even really 45ah...

They said it was, model # N7245

 

[kevo]

That's a

Could be 3 things I reckon. The battery BMS protection. The Controller low voltage protection. The controller overheat protection.

I'd start with the controller overheat. How hot is it getting? If its not getting a good airflow eg. stuffed inside a box or bag, that's the first thing to address before chasing other possible problems. Don't know you set up, but if it inside a sealed compartment, can you just hang it somewhere in the air draft to test.

Good idea to eliminate variables, the controller is mounted inside the frame on the top with no ventilation. Thanks

 

[kevo]

I

Looking at a picture of the bike ... the 72V 200A controller has to be located in that vented panel under the battery, held in place by what looks like 4 screws, one in each corner. What I would do is remove that cover, cable tie whatever is necessary to keep all the wiring and controller temporarily in place with the cover removed, and then take it for a spin.

I agree, i think that's the next step to try to figure out what component is failing. That controller is so big it won't fit in the bottom ventilated compartment. I may have to modify the compartment. I'm trying to find more information on accessing the controller settings thru the Bluetooth adaptor. I have not done anything with that yet. But adjusting the settings may cause damage to the controller. But the bike cutting off in heavy traffic at 60mph may cause damage to my life .

 

["A"]

I'm pretty sure riding 60 mph among traffic on public roads is dangerous
and likely to cause damage to anyone's life when accidents happen, regardless what vehicle you operate.
Be safe, no need to give ebike operators bad rep & endanger yourself at 60 mph, keep it on the track if you like to speed.

 

[Freddy1]

the controller is mounted inside the frame on the top with no ventilation.

That's where I'd be looking first. My little 25A controller in a sealed bag would do exactly what your describing if I was working the bike hard. Since putting a lot of holes though the bag (with grommets to make it look neat) and get some decent airflow across the controller the problem hasn't reoccurred.

 

[Tacticooldennis]

I have the same problem with my bike, it can't handle continuous operation. I put a meat probe on the controller and its to about 160 degrees F and cuts off, wait for cool and ride again. Vendor for alibaba is looking into it.

 

[Hoggdoc]

That's a

Good idea to eliminate variables, the controller is mounted inside the frame on the top with no ventilation. Thanks

I agree I think the problem is heat related either the BMS in the battery pack or the controller with no air flow. What is the fix, use maximum power/speed for short bursts.

 

[Tacticooldennis]

Here's a vid I made about it so far.

I think the best solution would be to put the controller on the outside to help cool it, but I am limited by space upfront If you bottom out the front suspension it hits the extra cage on the outside, knowing the controller is taller means it would hit a lot more often so its not a viable solution. Im thinking about making some extra side panels with vents or adding USB fans inside but its a balance between letting in Mud, and water debris. along with cool air.

 

[kevo]

Thanks for the video! I'm tempted to cut some slots near the head tube and maybe by the seat or side panels. I'm thinking of ways to try to make the vents closable and weather tight, still trying to figure that out. Carrying some duct tape or flex seal might work in a pinch. I like your idea of adding a fan and temp monitor. I removed some foam padding i had around the controller and my last ride wasn't bad, 20 miles of moderate riding with no issues, until i got . 25 mi from my house. But it was only 72°f and i stopped a few times to enjoy the beach. I can feel a lot of heat up high where i have the controller mounted, and like you, not much at all by the battery and motor. Let me know when you figure out a cold air induction system with ram air tubes!

 

[Tacticooldennis]

Here's a guy that mounted the controller near the seat bolts. He cut some slots and brought the temps down about 30 degrees. I wonder if you could just get some vehicle magnet signs for a car. and just move them over the vents when the weather gets rough or puddles.

 

[lee venning]

ive got holes drilled in my side panels from previous owner i hate it and ive seen plenty of bikes run fine without doing this .does youre battery have thick cables running out and what amps are youre bms rated to .give the bms a little headroom .id rather put fans in than cut holes esp in uk or move it outside and modify the cover .this is what im planning to do let that heatsink do its job .and have more room inside to manovre battery or fit larger one

 

[kevo]

I have two 8awg in parallel from 150amp bms 72v 45ah battery. I've been riding it recently and a long as i don't hold it wide open at 65mph for too long i haven't had a prob. I'm thinking a little air flow would do a lot.. it looks like a lot of work to relocate controller. I'm at an impasse....