I want to design a circuit to modify my electric bicycle controller so that it won’t turn off as a result of battery voltage drop which is the result of high current being drained by controller from the battery to the motor which is the result of throttle being fully pressed. If I fully press throttle the battery can handle high current drain for several seconds, but after that the voltage of the battery will rapidly drop under 30v and the controller will shut down. After several seconds the battery voltage will raise back and the controller will turn on back and I again can use it. This is very inconvenient behavior of the controller for me. I would like that the controller intellectually decreases current drain from the battery when the battery cannot supply the requested amount of current. That is evident by the battery voltage drop.
For example I am requesting relatively high power from the controller by relatively deeply pressing the throttle. The controller tries to get the requested amount of power from the battery but then sees the voltage on the battery drops too low (say under 33v) and understands the battery cannot provide the requested amount of power. And the controller modifies my request and drains from the battery the maximum amount of power that battery can safely provide at that moment without damaging itself.
Here is how I see the solution of the problem.
A circuit have to be designed which inputs throttle voltage V1 and battery voltage V2 and outputs voltage V3 which is the modified value of V1 based on the value of V2.
V1 range is from 1v to 4.2v.
V2 range is from 40v to 30v.
The circuit should function as follows.
As long as V2 is in the range from 40v to 34v V3 should be the same as V1.
For example if V1 is 1.8v V3 have to be 1.8v or close to it.
As long as V2 is dropped below 34v to 30v V3 have to be the progressively depressed version of V1.
Here are some values for example.
When V2 is equal or above 34v V3 should be depressed by 0% value of V1. That is for any value of V1 V3 should be equal V1.
When V2 is 33v V3 should be depressed by 25% value of V1.
When V2 is 32v V3 should be depressed by 50% value of V1. That is if V1 is 2v V3 should be about 1.5v. If V1 is 4v V3 should be about 2.5v
When V2 is 31v V3 should be depressed by 75% value of V1.
When V2 is 30v V3 should be depressed by 100% value of V1. That is for any value of V1 V3 should be about 1v.
V1 at any time may freely change from 1v to 4.2v.
Is it possible to design simple analog transistor circuit which would accomplish such a task?
I have basic understanding how transistor works but do not have enough knowledge and experience to design the circuit. I am asking for simple example circuit or any advice how I could design such the circuit. Thanks.
For example I am requesting relatively high power from the controller by relatively deeply pressing the throttle. The controller tries to get the requested amount of power from the battery but then sees the voltage on the battery drops too low (say under 33v) and understands the battery cannot provide the requested amount of power. And the controller modifies my request and drains from the battery the maximum amount of power that battery can safely provide at that moment without damaging itself.
Here is how I see the solution of the problem.
A circuit have to be designed which inputs throttle voltage V1 and battery voltage V2 and outputs voltage V3 which is the modified value of V1 based on the value of V2.
V1 range is from 1v to 4.2v.
V2 range is from 40v to 30v.
The circuit should function as follows.
As long as V2 is in the range from 40v to 34v V3 should be the same as V1.
For example if V1 is 1.8v V3 have to be 1.8v or close to it.
As long as V2 is dropped below 34v to 30v V3 have to be the progressively depressed version of V1.
Here are some values for example.
When V2 is equal or above 34v V3 should be depressed by 0% value of V1. That is for any value of V1 V3 should be equal V1.
When V2 is 33v V3 should be depressed by 25% value of V1.
When V2 is 32v V3 should be depressed by 50% value of V1. That is if V1 is 2v V3 should be about 1.5v. If V1 is 4v V3 should be about 2.5v
When V2 is 31v V3 should be depressed by 75% value of V1.
When V2 is 30v V3 should be depressed by 100% value of V1. That is for any value of V1 V3 should be about 1v.
V1 at any time may freely change from 1v to 4.2v.
Is it possible to design simple analog transistor circuit which would accomplish such a task?
I have basic understanding how transistor works but do not have enough knowledge and experience to design the circuit. I am asking for simple example circuit or any advice how I could design such the circuit. Thanks.