Hi everyone,

I am struggling with one of my design right now. The voltage supply is fluctuating a lot.

How it work is the system battery is constantly being recharge by an alternator. This battery will then power a copper bus located inside an electrical box and then this copper bus will power different equipment. One of our equipment is a computer which draws lots of current and have lots of current spike. Those current spike cause the voltage to spike a lot.

I was looking at decoupling capacitor, but I am not sure how am I suppose to make a choice for those capacitor. The current peak is around 30A the power the entire system.

Should I just add a fairly big decoupling capacitor between the copper bus and the ground inside the electrical box? Will this help?
The system battery was added to try to smooth the voltage, but it's not enough. Voltage drop too low and equipment are shutting down and restarting during operation.

 

Voltage drop too low and equipment are shutting down and restarting during operation.

Then it would appear that either the battery is too small, or the circuit wiring resistance is too high.

It would likely take a huge capacitor to smooth out those voltage drops otherwise.

 

I was looking at Capacitor they used in audio application in car. Like those capacitor : https://www.amazon.ca/PLCAPE50-Fara...65&mcid=aad2c9d0096b3b45ac36cec2777497ca&th=1

Would something like this help?

 

Would something like this help?

Depending upon the length of the current spikes, it may.
It should if placed near the equipment power input with large gauge wires connecting it.