Is Charging a 2.7V, 350F Supercapacitor with a 10mA, 20V Source Safe?

[cosmos1226]

I have supercapcitor 2.7V, 350F. I want to charge it by 0.001mA 20V power source. Is it safe?
Thanks you!.

 

[davenn]

hi
welcome to the forums

well its a 2.7V capacitor ... what do you think ?

Dave

 

[NascentOxygen]

I have supercapcitor 2.7V, 350F. I want to charge it by 0.001mA 20V power source. Is it safe?
Thanks you!.

What arrangement will you use to charge it? How do you know your power supply is limited to 0.001mA?

 

[willem2]

A 350 F capacitor charged to 2.7 volt contains a charge of 2.7*350 = 945 Coulombs.
If the current is really limited to 0.001mA, it would take 945 / (10^-6) = 9.45 * 10^8 seconds = 29.9 years for it to charge to 2.7 volts, so you'd be ok for a long time.
In practice there will be a lot more leakage current than 0.001 mA and the capacitor would never charge to 2.7 volt.

 

[cosmos1226]

I'm experimenting power supply 20V for charging 27V capacitor 350F. Supercapacitor is loaded, but does know it safe?

 

[NascentOxygen]

I'm experimenting power supply 20V for charging 27V capacitor 350F. Supercapacitor is loaded, but does know it safe?

Is the capacitor rating 2.7V or 27V?

 

[cosmos1226]

Is the capacitor rating 2.7V or 27V?

. maxwell supercapacitor 2.7V 350F. thánks you

 

[NascentOxygen]

You could connect a pair of resistors as a potential divider to reduce your 20V down to a safe level, say 2.2V. Then the supercapacitor could be safely left to charge unsupervised, and you'd know that in a few decades it should be almost fully charged to 2.2V

You haven't answered why you want to charge it at 0.001mA, and I presume that is not the figure you intend.

 

[cosmos1226]

You could connect a pair of resistors as a potential divider to reduce your 20V down to a safe level, say 2.2V. Then the supercapacitor could be safely left to charge unsupervised, and you'd know that in a few decades it should be almost fully charged to 2.2V

You haven't answered why you want to charge it at 0.001mA, and I presume that is not the figure you intend.

Although the voltage is 20V but only amperage 10mV (it as a leak). so, I do not want to pass any parts change any power consuming.

 

[NascentOxygen]

amperage 10mV

10mV is not a current

In theory, you could connect a parallel 2.2V zener diode to limit the capacitor's voltage at 2.2V, but a practical zener would have significant leakage current below a capacitor voltage of 2.2V.

 

[cosmos1226]

10mV is not a current

In theory, you could connect a parallel 2.2V zener diode to limit the capacitor's voltage at 2.2V, but a practical zener would have significant leakage current below a capacitor voltage of 2.2V.

I'm sorry, 10mA

 

[NascentOxygen]

I'm sorry, 10mA

So it's 10mA now!

Up until this, it has been one-thousandth of a milliamp (0.001mA).

Are you sure it's 10mA??