FirePhoenix NL said:
but 1 led will prolly need ~3v.. how can 1 battery run 4 leds + fan then?
master chef: 4 12-16v leds running on 24v? how is that possible? =P
48v>24v or am i just thinking wrong
yup, u are ^^
it all depends on "how" u connect them. if u connect all devices in parallel, then the needed voltage won't go up. let's make this asumption:
u have 10 devices. each consume 3Volts and 100 Ma (Miliamps). if u connect all those in parallel (meaning, u attach the positive end of every device to the positive end of the power source, same for the negative) your entire system WILL consume exactly 3 Volts. however, it will consume 1 Amp (100 Ma * 10). in the contraire, if u hook them in series (meaning, from the positive end of the power source to the positive end of the 1st device, then from the negative end of that device to the positive end of the next one, and so on until u reach the negative end of the last device, and from there to the power source) the system will comsule exactly 30 Volts, and 100 Ma.
Now to further clarufy, it will depend on many things, the kind / brigtness / Power consumption of the leds u got, size of the fan, etc. for a quick reference, 1 AA baterry (1.50V) is more than enough to light a normal led (resistor needed). also 9V batts aren't your best choice here. i would get a rechargeable battery pack (12V) of at least 600 Ma (1AMP is way better).
Here's a scheme:
here are some good examples of what i would get (if i lived in the US that is T_T)
Battery Pack - Small
Battery PAck - Large
i hope this cleanses a few doubts ^^