you could just use thicker wire your still gonna get a voltage drop but how much is 14 awg wire just saves some work of having to solder all those resistors in. you could also apply a step up transformer if your working with pulsed DC this just factor in .7 for a diode drop and place it were the voltage drops bellow your target goal starting off a bit high say 3.3 would also help but not any higher

also if your power supply is unregulated using a higher voltage and adding resistors will allow for a larger change in input power a regulated power supply will give 3 volts at almost no load and close to 3 volts at max load minis wire loss so the first LED might 2.95 assuming you start out at 3 volts knowing the exact voltage drop is gonna be tricky .

you could calaculate it in say blocks of 5 feet just average it out and expect the voltage at the end of one block will be close to the voltage of the next block and LEDs in the middle will be close to the total average of the entire block minis the expected wire loss to the end of the block as one block leads into the next it will have all the current for LEDS in current block and all past blocks you could try to calculate this one LED at a time but that all depends on the exact placement of the LEDs on the wire any any defects in the wire quality of the splicing for something like this I would take the typical math and add 5 percent to that total

Your can expect increased loss so that 5 v Power supply should be more like 5.05 or even 5.1 is not gonna hurt heck 5.2 would remain within spec .

most wall warts do not allow you to adjust them like this a meanwell LED power supply will allow for this type of adustment and they are fairly non expensive in the current range your looking at likely not any more then a walwart once you do all your math put the parts togather apply power at 5 volts measure the voltage across each LED .
If your math was off the ones at the end will be a bit lower then expected. Raise voltage slightly you could also run 2 or more sets of wire to reduce current say first wire has 15 feet of 40 second set has slightly less 10 feet of 40 3rd set has 7 feet of 40 then 4th set has 5 feet and the last set has 3 feet yes that string will have 40 feet of LEDs but more then 40 feet of wire as each set of LEDs will have blank wire until the set before it ends this setup will allow for 3.3 volts to be used.
Note the first few LEDs will run a bit high all others will be within spec. If your running 18 small wire still need to know the current draw of the LEDs. These things run off a button cell battery so they should be pretty small but large numbers it will add up to a bit

You could just use thicker wire - your still gonna get a voltage drop but how much is 14 awg wire. Just saves some work of having to solder all those resistors in.

You could also apply a step up transformer if your working with pulsed DC this just factor in .7 for a diode drop and place it were the voltage drops below your target goal starting off a bit high say 3.3 would also help but not any higher

Also if your power supply is unregulated using a higher voltage and adding resistors will allow for a larger change in input power. A regulated power supply will give 3 volts at almost no load and close to 3 volts at max load minis wire loss. So the first LED might 2.95 assuming you start out at 3 volts knowing the exact voltage drop is gonna be tricky .

You could calculate it in say blocks of 5 feet just average it out and expect the voltage at the end of one block will be close to the voltage of the next block. LEDs in the middle will be close to the total average of the entire block minus the expected wire loss to the end of the block. As one block leads into the next it will have all the current for LEDS in current block and all past blocks. You could try to calculate this one LED at a time but that all depends on the exact placement of the LEDs on the wire any any defects in the wire quality of the splicing. For something like this I would take the typical math and add 5 percent to that total.

Your can expect increased loss so that 5 v Power supply should be more like 5.05 or even 5.1 is not gonna hurt heck 5.2 would remain within spec .

Most wall warts do not allow you to adjust them like this. A Meanwell LED power supply will allow for this type of adjustment and they are fairly non expensive in the current range your looking at. Likely not any more than a wallwart once you do all your math put the parts together apply power at 5 volts measure the voltage across each LED ..

If your math was off the ones at the end will be a bit lower than expected. Raise voltage slightly. You could also run 2 or more sets of wire to reduce current say first wire has 15 feet of 40 second set has slightly less 10 feet of 40 3rd set has 7 feet of 40 then 4th set has 5 feet and the last set has 3 feet yes that string will have 40 feet of LEDs. But more than 40 feet of wire as each set of LEDs will have blank wire until the set before it ends this setup will allow for 3.3 volts to be used.
Note the first few LEDs will run a bit high all others will be within spec. If your running 18 small wire still need to know the current draw of the LEDs. 
These things run off a button cell battery so they should be pretty small but large numbers it will add up to a bit

you could just use thicker wire your still gonna get a voltage drop but how much is 14 awg wire just saves some work of having to solder all those resistors in you could also apply a step up transformer if your working with pulsed DC this just factor in .7 for a diode drop and place it were the voltage drops bellow your target goal starting off a bit high say 3.3 would also help but not any higher

also if your power supply is unregulated using a higher voltage and adding resistors will allow for a larger change in input power a regulated power supply will give 3 volts at almost no load and close to 3 volts at max load minis wire loss so the first LED might 2.95 assuming you start out at 3 volts knowing the exact voltage drop is gonna be tricky you could calaculate it in say blocks of 5 feet just average it out and expect the voltage at the end of one block will be close to the voltage of the next block and LEDs in the middle will be close to the total average of the entire block minis the expected wire loss to the end of the block as one block leads into the next it will have all the current for LEDS in current block and all past blocks you could try to calculate this one LED at a time but that all depends on the exact placement of the LEDs on the wire any any defects in the wire quality of the splicing for something like this I would take the typical math and add 5 percent to that total your can expect increased loss so that 5 v Power supply should be more like 5.05 or even 5.1 is not gonna hurt heck 5.2 would remain within spec most wall warts do not allow you to adjust them like this a meanwell LED power supply will allow for this type of adustment and they are fairly non expensive in the current range your looking at likely not any more then a walwart once you do all your math put the parts togather apply power at 5 volts measure the voltage across each LED if your math was off the ones at the end will be a bit lower then expected raise voltage slightly you could also run 2 or more sets of wire to reduce current say first wire has 15 feet of 40 second set has slightly less 10 feet of 40 3rd set has 7 feet of 40 then 4th set has 5 feet and the last set has 3 feet yes that string will have 40 feet of LEDs but more then 40 feet of wire as each set of LEDs will have blank wire until the set before it ends this setup will allow for 3.3 volts to be used note the first few LEDs will run a bit high all others will be within spec if your running 18 small wire still need to know the current draw of the LEDs these things run off a button cell battery so they should be pretty small but large numbers it will add up to a bit

you could just use thicker wire your still gonna get a voltage drop but how much is 14 awg wire just saves some work of having to solder all those resistors in. you could also apply a step up transformer if your working with pulsed DC this just factor in .7 for a diode drop and place it were the voltage drops bellow your target goal starting off a bit high say 3.3 would also help but not any higher

also if your power supply is unregulated using a higher voltage and adding resistors will allow for a larger change in input power a regulated power supply will give 3 volts at almost no load and close to 3 volts at max load minis wire loss so the first LED might 2.95 assuming you start out at 3 volts knowing the exact voltage drop is gonna be tricky .

you could calaculate it in say blocks of 5 feet just average it out and expect the voltage at the end of one block will be close to the voltage of the next block and LEDs in the middle will be close to the total average of the entire block minis the expected wire loss to the end of the block as one block leads into the next it will have all the current for LEDS in current block and all past blocks you could try to calculate this one LED at a time but that all depends on the exact placement of the LEDs on the wire any any defects in the wire quality of the splicing for something like this I would take the typical math and add 5 percent to that total

Your can expect increased loss so that 5 v Power supply should be more like 5.05 or even 5.1 is not gonna hurt heck 5.2 would remain within spec .

most wall warts do not allow you to adjust them like this a meanwell LED power supply will allow for this type of adustment and they are fairly non expensive in the current range your looking at likely not any more then a walwart once you do all your math put the parts togather apply power at 5 volts measure the voltage across each LED .
If your math was off the ones at the end will be a bit lower then expected. Raise voltage slightly you could also run 2 or more sets of wire to reduce current say first wire has 15 feet of 40 second set has slightly less 10 feet of 40 3rd set has 7 feet of 40 then 4th set has 5 feet and the last set has 3 feet yes that string will have 40 feet of LEDs but more then 40 feet of wire as each set of LEDs will have blank wire until the set before it ends this setup will allow for 3.3 volts to be used.
Note the first few LEDs will run a bit high all others will be within spec. If your running 18 small wire still need to know the current draw of the LEDs. These things run off a button cell battery so they should be pretty small but large numbers it will add up to a bit