Is over amping dangerous?
Posted by freebobuxmanlol@reddit | ebikes | View on Reddit | 14 comments
I have a ridstar q20, and the battery pack says its rated for 35 amps discharge, if I put a new controller that can draw 80a is it going to end badly? Im curious because a 80a controller seems like a cheap way to get extra power.
Laserdollarz@reddit
Here is exactly what to do, hope this helps!
SeparateArtichoke458@reddit
So... Can it be rewired and use a different battery? 🤔
Laserdollarz@reddit
Sure just replace the battery and all the wires, including the one that goes into the motor. You'll probably need to swap the controller and display to work with your new wiring harness.Â
This will be more expensive than the bike originally cost.
atlasraven@reddit
It's sorta like making the fuselage of an airplane bigger without changing the wings or engines...
Just-Smart-Enough@reddit
Err, not the best analogy...
No-Plan6610@reddit
Unpopular opinion, however I am quite advanced in electronics: the max current after the battery is limited by the motor, max power theoretically and practically also by the controller limitter. Controller reacts on the sensor input and open/close PWM, like a "valve", to regulate power. 80A vs 35A means the valve "pipe diameter" is 2+ times bigger, so it can flush more current, but if it is connected to the motor "pipe" of 35A "diameter", current won't flow faster than 35A.
My concern is how the input of a sensor of an old 35A controller, I believe, will be interpret by 80A controller? If to assume the sensor is the same, than the 80A "valve" will be open for 35A already by a half sensor voltage what probably will be felt like max support level when min selected. Also if sensor is torque based, cadence will be not in sync... that could be aided by appropriate resistor on the sensor output. What is appropriate? - try and error.
tldr: will it burn the battery if motor is the same? I doubt. Will it work out-of-the-box as supposed? I would give 50/50 chance.Â
Just-Smart-Enough@reddit
You are putting a lot of faith in your battery's BMS. As best, you'll get a soft overcurrent shutdown. Slightly worse, and you'll get a permanent disconnect or accelerated cell aging, and, if your BMS is low quality, you could possibly burn your house down.
KevinRatz@reddit
Following
AdBoring4472@reddit
Understand I2R heating, and you will have your answer.
Ohm_Slaw_@reddit
Think of your ebike has having three parts. Battery, controller and motor. These parts need to be matched up. A high amp controller will pull too much power from the battery. The BMS will shut it down, or it will burn. The controller will push too much power to the motor. It will burn. Find out the ratings of all three components. Don't exceed the ratings.
nobullshitebrewing@reddit
The controller dont push anything to the moter. The motor pulls what it can/wants.
Bad terminology can lead to bad things
edrock200@reddit
Yes. It is dangerous. You want your controller to be the first line of defense against over amperage, not your battery.
FrenchFatCat@reddit
The battery is pretty much the only thing on a bike you dont really want to fuck with brother.
acezoned@reddit
Your battery wont work if its rated at only 35amps It should shut it self down when you push it over its limit, if it doesnt it will overheat and over heating leads to the battery failing