Hi

I have 5 farad 2.7 supercapacitor

what is the minimum ameparage needed to start charging ?

because when i use a 1.5 v battery it starts charging but when i use a 2.5 volt solar panel nothing happen

 

The minimum amperage would be any current exceeding its leakage.
Of course charging at close to, slightly exceeding, its leakage would take
forever to charge it.

https://www.edn.com/design/power-ma...rging-a-supercapacitor-from-energy-harvesters

Regards, Dana.

 

what is the minimum ameparage needed to start charging ?

There is no minimum.

because when i use a 1.5 v battery it starts charging but when i use a 2.5 volt solar panel nothing happen

Then either your solar panel is defective, or you do not have it connected to the capacitor.

 

The minimum charge current is the supercapacitor self-discharge or leakage current.
The charging time 't' to 63% is another story.

t=VC/I
V= 2.5
C = 5F
I = charging current minus leakage current.

 

Please check your connections.
Arrrgh! Eurrrgh? Oh that's my amapeRAGE gland bursting again!

Any current will do: CV =IT more timage more volters.

bring back the neper!

 

The minimum charge current is the supercapacitor self-discharge or leakage current.

This omits a vital fact: the capacitor's leakage current is dependent on the voltage across it. At V = 0, leakage is ZERO. For small values of voltage (V << Vrated), the leakage current is relatively low; as V increases and approaches Vrated, it tends to increase dramatically.

Leakage current is NOT some sort of threshold which must be exceeded to begin charging the capacitor. Rather, it starts out at zero and increases non-linearly as the capacitor voltage builds up; and if the leakage current at any particular voltage exceeds the current capability of whatever is trying to charge the capacitor, charging simply slows down and eventually stops at that voltage.

The OP has said that when his supercap is connected to the solar cell array, "nothing happens." I take that to mean the capacitor is not charging at all, which rules out capacitor leakage as the culprit.

 

when i use a 1.5 v battery it starts charging