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Calculating size of pre-charge resistor

Posted: Fri May 14, 2021 7:37 am
by Mamosa
I am trying to calculate the size of required pre-charge resistor for my 2x60AHV powered with 48V Li-ion battery.

According to the documentation, capacitor bank is 2820uF. I guess one second of precharging would be enough for me. Using the formula "(charging time / 3) / capacitance in farads", I get a result of 118 ohms. I will take 120ohm or 150ohm. But, how will I know how many watts I need?

Will 20W do the job? Maybe some link?

Thx!

Re: Calculating size of pre-charge resistor

Posted: Wed May 19, 2021 1:45 pm
by Basicmicro Support
118 ohms is reasonable. 1/4 watt is more than sufficient. 1/10watt would probably work in most cases as well.

Re: Calculating size of pre-charge resistor

Posted: Wed May 19, 2021 2:05 pm
by Mamosa
Thx!