Bike electrics cutting out

[JES2020]

started at 51.4v pushed bike at pass 3. Two kilometers then died 50.8 v. Waited 2 mins started pass 1. no problem could ride 80 kilometers at low speed controller no problem,only when ask for more power at pass 3 the bike switches off.i can only think the controller cant deal with the request of more power and speed the power is there but it wont pass through the box at anything over the 18 amp cut off point. So I think its reduce the battery size or increase the controller size to handle at higher ampage

The confusing thing is, you say the battery has maybe 30 amps vs 30 amp hours.(remember the controller determines the amps to the motor NOT the battery).

But from what you describe, it sounds like a battery problem. Like severe sag. It could be a defective controller I suppose, but the controller shouldn't shut down the bike until the the low volt shutoff point is reached, on a 48 v controller that point can be somewhere between 39 and 43 volts. I assume you are using a 48v controller?
If I was confident in my battery, the next step I would take is to replace the controller.
You can go to a higher amp controller IF your motor wiring can handle it without burning up.

 

[Davie]

Thank you I will put in place a larger controller only 25$ then I will have peace of mind, then on paper I can use bigger batteries. Just have to relocate the bigger controller with the batteries in my saddle bags and just extend g the cables. Or reduce the battery size to 12ah.

 

[Gionnirocket]

I'm done here.

 

[EMGX]

I'm done here.

Wow, just wow.

 

[Gionnirocket]

Wow, just wow.

You can lead a horse to water. . .

 

[JES2020]

Thank you I will put in place a larger controller only 25$ then I will have peace of mind, then on paper I can use bigger batteries. Just have to relocate the bigger controller with the batteries in my saddle bags and just extend g the cables. Or reduce the battery size to 12ah.

No problem, let us know what the result is.

 

[Davie]

Built another battery 13s4p same bms. Did 43 kilometers, no problem. I think the controller could not run anything bigger. That's why only 12ah are sold for the bike. So now it's even cheaper, 52 cells instead of 78 cells. The bigger battery are for 1 kilowatt or bigger bikes.my next bike is on the way. So thank you I am shorted.

 

[JES2020]

Built another battery 13s4p same bms. Did 43 kilometers, no problem. I think the controller could not run anything bigger. That's why only 12ah are sold for the bike. So now it's even cheaper, 52 cells instead of 78 cells. The bigger battery are for 1 kilowatt or bigger bikes.my next bike is on the way. So thank you I am shorted.

That's probably a 35v controller. If you want to use a 48 v battery you will need a 48 v controller.
But then you have to watch out for burning up the motor.

 

[tomjasz]

Davie said:
Built another battery 13s4p same bms. Did 43 kilometers, no problem. I think the controller could not run anything bigger. That's why only 12ah are sold for the bike. So now it's even cheaper, 52 cells instead of 78 cells. The bigger battery are for 1 kilowatt or bigger bikes.my next bike is on the way. So thank you I am shorted.

That's probably a 35v controller. If you want to use a 48 v battery you will need a 48 v controller.
But then you have to watch out for burning up the motor.

Neither of you is making any sense.

 

[Gionnirocket]

Neither of you is making any sense.

Sure it does,

 

[Davie]

It's not a 35 v controller, is an engwe ep2 48 v 500 watt fat tire 20 " wheels. The controller is a
X008-aam003.with a cut off point of 38 v. And an electrical current limit of 18 amps. If I run 12ah not a problem, only s*it happens when I over double the ah on the bike problem solved.

 

[Davie]

Sorry cut off is 18 amps type o

 

[Gionnirocket]

It's not a 35 v controller, is an engwe ep2 48 v 500 watt fat tire 20 " wheels. The controller is a
X008-aam003.with a cut off point of 38 v. And an electrical current limit of 18 amps. If I run 12ah not a problem, only s*it happens when I over double the ah on the bike problem solved.

Yeah I had the same problem with my car... It came with an 18 gallon gas tank but when I tried to put a 30 gallon tank the fuel Injectors couldn't handle it.
You know anyone that wants to buy a 30 gallon gas tank?