# Problem in charging 450v 680uf capacitors at the same time

#### farbod2089

Jul 3, 2023
3
Hi, I have five 450v 680uf capacitors. I'm trying to charge them to around 400 volts. For increasing battery voltage I tried using a 12vdc to 220vac inverter. Then I connected the inverter's output to a full bridge rectifier that I made it myself and it gave me around 300vdc. Then I charged up one single 450v cap and It charged up to around 300 volts without any problem. The problem is that I have a circuit that has five of these big caps and the rest are some diodes, resistors and LEDs. All of these caps should charge at the same time. I connected the dc power to my circuit but it didn't work! The voltage at the beginning of the circuit was zero but the voltage that was coming out of the rectifier was around 300v. I thought that the problem is current. So I connected two resistors is series before the power reached the circuit. The resistors were 220ohms 20watts but it still didn't work. My inverter is 500 watts and My battery is 16v 5A(Of course I decreased the voltage before connecting it to the inverter). I also tried some of the ZVS dc-dc 390v boosters but I ended up frying them too. I don't have any idea. Maybe I can use a transformer? I don't know.

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#### kellys_eye

Jun 25, 2010
6,229

Connecting a DC supply to a capacitor (using the correct polarity) will charge that capacitor to the applied voltage (in time, according to any circuit resistance and the value of the capacitor). If the capacitors are not charging then you either haven't connected them or have connected them incorrectly (or added something in-circuit to prevent it happening).

#### AnalogKid

Jun 10, 2015
2,843

Note that if you are drawing 5 A from a 16 V battery, that is only 80 W. After the inefficiencies of the inverter, that leaves around 50-60 W at the inverter output, only about 1/4 A at 220 V. A bank of discharged capacitors will draw way more than this.

ak

Jul 3, 2023
3
my schematic

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#### farbod2089

Jul 3, 2023
3

Connecting a DC supply to a capacitor (using the correct polarity) will charge that capacitor to the applied voltage (in time, according to any circuit resistance and the value of the capacitor). If the capacitors are not charging then you either haven't connected them or have connected them incorrectly (or added something in-circuit to prevent it happening).

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#### bidrohini

Feb 1, 2023
161
Make sure your inverter and power supply can provide enough current to charge all five capacitors in parallel.

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