Because you want to replace incandescent, so at least the following requirements:
Brightness should be very incandescent usually talk about wattage and not talk about the number of lumens. Although the LED also can talk about wattage, but due to the efficiency of LED streetlight bulbs are still evolving, saying only that the wattage does not mean that its lumen. The most commonly used incandescent lamp wattage of 15 watts, 30 watts, 45 watts, 60 watts, 75 watts and 100 watts. If you talk about the number of lumens, you can use incandescent light efficiency. Incandescent lamp luminous efficiency of 7.5-12lm / W The higher the wattage the greater the efficiency.
If using LED to replace, and can draw the appropriate wattage. However, because the led high bay luminous efficiency in the rising, it is difficult to give an accurate figure. Assumes the usual LED1, its luminous efficiency of 100lm / W, if the highest luminous efficiency of the LED2 is its luminous efficiency of 130lm / W (warm white light efficiency will be lower than this value). Can be drawn on the wattage of the two luminous efficiency LED. LED streetlight bulbs require constant current source, the constant current source efficiency is assumed to be 85%, In addition, because the LED can not adopt a transparent blister, but only using the milky foam shell. The transmittance of about 85%. They are multiplied together equal to 0.72. After considering the above factors can be drawn and incandescent lamps of equivalent wattage. Can be seen from the table, LED2 in the same brightness can save approximately 10 times the power. It should be of special note.