The computer that is built in into the EAGLE is able to boot when you connect the EAGLE to a power unit or a battery with voltage starting 10V up to 15V. Please remember that voltage is not power capacity and, when selecting the correct power source for your EAGLE, you have to provide also the correct current, based on the devices you power through the EAGLE. For example, a typical telescope setup composed by goto mount, cooled camera and other accessories requires usually 5-8 Amps (that’s why the EAGLE’s power unit is 14A) and if you power your EAGLE with a field battery you will need at least 50 Ah battery.
An important fact to consider is that the EAGLE distributes, to the power out ports, the voltage you provide to the power in port: this means that, if you provide (for example) 14V, you will have at the power out ports a voltage that is a little bit lower than 14V (because of the small voltage drop caused by the power distribution) and you will have to check is the devices that you power through the EAGLE are able to work fine with this voltage. For this reason the power unit for the EAGLE is set at 12,8V.