LED hook up question

[The Mechanic]

i got some 5mm green LEDs, the asorted pack of leds, a round battery holder and a 3V litium battery and a very small 8 button switch from radioshack to use on my micro crawler. i plan on hookin at less to leds to one switch and have the one 3V battery to power them all and im just not sure what i need to do to hook them all up. help with this would be appreciated.

[SMR 510RR]

You need to look up what voltage and current your LED needs to operate on. From what I am looking at a "standard" 5mm green led with a 20* angle needs 4v and 20ma to power it.

If that is the same as the specs on your LED's then you will need to step up to a bigger battery to run them. What I do is just pull power from my receiver (coming from either a external BEC or from the ESC) and use that to power the LED's. The Micro crawler's RX and ESC are one unit but it does supply power to the servo, you could use a Y harness off that to power your LED's.

Once you have all the specs listed above then you find a LED calculator online (just search google) and it will tell you exactly what resistors you need to add to get the power to the correct level.

This one will tell you if you can run them in parallel or series and if you can do it without resistors or if you still need to add them in. LED series parallel array wizard