Need help on charging supercapacitor

[tattee]

You are talking about the wrong caps. These are no supercaps! A supercap starts at 500F and goes up to 600F, 700F is under development.

Really? coz i thought the supercap are anything with the Farad range. I mean 1F to as high as 500F or greater. Even 0.1F I thought was considered a supercap. I got mine from cooperbussman and i guess they'll disagree with what you said as well. They have a wide range of capacitors in there all are considered supercap.

 

[mneary]

Supercap or not, the added value is from extracting energy from the source (battery) at an efficient rate and delivering the (peak) current demanded by the load.

If, when a (super)cap is in the circuit, the battery is still overstressed, the cap might not help much with service life.

 

[kchriste]

I fail to see the need for a supercap at all. 2100mAh NIMH batteries will have no problem supplying 600ma or even 1000ma and will be fairly efficient at these discharge rates:
https://www.electro-tech-online.com/custompdfs/2008/07/nh15-2200.pdf
And look at Figure 13 (Effect of Discharge Rate on Capacity) on page 13 of this pdf:
https://www.electro-tech-online.com/custompdfs/2008/07/nickelmetalhydride_appman.pdf
And you'll see that NiMH batteries are very efficient at rates below 1C (less than 2100ma in your case).

 

[Boncuk]

one F is the capacitance which allows 1A of current flow for a time of 1 second per volt of final voltage

Of course, just forgot to mention it. Beg your pardon.

 

[Boncuk]

Really? coz i thought the supercap are anything with the Farad range. I mean 1F to as high as 500F or greater. Even 0.1F I thought was considered a supercap. I got mine from cooperbussman and i guess they'll disagree with what you said as well. They have a wide range of capacitors in there all are considered supercap.

I guess WIMA will totally disagree with cooperbussmann and and call them simply high-capacitance caps. WIMA is the patent holder of super caps.

 

[joygupta]

supercapacitors charging

hi frnds...am having winter project this year, topic:
"LED Lighting Systems based on Solar Power and Ultra-capacitor as Storage"
i have selected a room of 3m * 3m,aim was to lighting the room for 24 hours. The LED’s am going to use are of 1 watt each. So for 24 hour lighting i need
(1 watt * 24 hours) / 3 volts= 8 amp-hour/day.
using batteries i have done all of my calculations.( ex- how many batteries i do need to use 4 solving dis, wt sd b deir ratings , again 3 days stored battery charge etc etc); bt am gettin confuse wid d supercapacitors.Cn nebudy help me out......wt i need is to supply contionuous mode of current to S.Caps. and i need to use 5 banks of S.Caps.
among them 3 sd b stored for imergency supply(bad wheather) and rest of 2 will get charge and discharge in alternative days.
how to calculate S.Caps in terms of farads. and how to connect them?
reply plz.

 

[Ubergeek63]

8AHr/day + conversion losses + charge losses + leakage losses = 14Ahr/day assuming you are using switchers for everything... and the leakage losses vary with the capacitor.

 

[giftiger_wunsch]

I'm afraid I wasn't able to decipher most of that message, but my understanding of your project is you're charging a bank of supercapacitors (of apparently undefined capacitance?) using solar power, and using the energy stored in these supercaps to power LED lighting during the night? Is that a correct interpretation of your project?

How big are these "supercapacitors" exactly? And what do you mean how do you connect them? If you connect the capacitors across the power supply (in this case a solar panel I assume) you will charge the capacitors. When the voltage across the solar panel drops the capacitors will discharge.

In future please create your own thread if you need help with a problem, and try to make your question as clear as possible.

 

[audioguru]

I think you should look at the datasheet of an Energizer Ni-MH AA cell.
Its capacity at a current of 1A is almost the same as at 10mA.