You will find this elsewhere in this thread and elsewhere in ECf. As a general rule, you can easily calculate watts. Volts squared then divide by ohms = watts. so: VxV/O=watts this is not exactly the most accurate but it is a convenient generalized guide to help you.
5 volts times 5 Volts divided by 3.1 ohms = 8.064 watts or 5x5/3.1=8.064
Some 5V devices use a regulator to bring the voltage down to 5 while others (GLV2) use a resistor. Most regulator style will meter read 5V at the connector. The GLV2 is designed to produce 5V under load so it is a bit stronger. Thus, you may find 3.1 ohms to be a bit hotter and you may want to try some 3.3 or 3.5 ohms rated attys and/or cartos.
5 volts times 5 Volts divided by 3.1 ohms = 8.064 watts or 5x5/3.1=8.064
Some 5V devices use a regulator to bring the voltage down to 5 while others (GLV2) use a resistor. Most regulator style will meter read 5V at the connector. The GLV2 is designed to produce 5V under load so it is a bit stronger. Thus, you may find 3.1 ohms to be a bit hotter and you may want to try some 3.3 or 3.5 ohms rated attys and/or cartos.