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How to choose the correct power source for your EAGLE

EAGLE allows you to distribute power to many devices used in telescopes and astrophotography (such as computerised mount, cooled camera, electronic focuser, dew heaters, etc.), thus eliminating the need for many different power supplies. Since the EAGLE allows you to have a unique power source (battery or AC adapter), it’s important to select the correct power source to properly power all the devices you want to use. CAUTION: EAGLE must be powered with 12V regulated voltage. You can use a power supply with 12V output voltage or a field battery. If you use a battery, this MUST be provided with a proper voltage stabilization. In case of any malfunction, immediately unplug the power supply.

 

 

 

 

Which battery or power supply have I to use for my equipment?

The power supply or battery you need to use to power the EAGLE and all peripherals connected to it depend on the electric current needed to power all the instruments and the EAGLE. Let’s make an example by considering the EAGLE basic model:

– Computerised mount: 4A maximum consumption
– EAGLE: 1A maximum consumption
– Cooled camera: 4A maximum consumption
– Dew heaters: 1A maximum consumption

In most instances, devices like your filter wheel, focuser and guide camera won’t require separate 12V power since they get their power through the USB ports of the EAGLE.

Total maximum power consumption: 10A.

How to choose the correct power source for your EAGLE: field battery with 220V inverter and 12.8V AC adapter
How to choose the correct power source for your EAGLE: field battery with 220V inverter and 12.8V AC adapter

So, for this setup, you should use the 12,8V 14A AC adapter. If you want to use a battery (WARNING: The battery must have a 12V voltage regulator with protection system) that can power the entire system for 8 hours (for example for the duration of an astronomical night), you will need a battery with a capacity of at least:

10A (consumption per hour) x 8 (hours duration) = 80A

TIP: the EAGLE automatically switch off if the input voltage (measured at EAGLE’s input power connector) drops below 11,8V not only to protect the internal computer but also any devices that are powered through the EAGLE.

This also means that you have to consider the voltage drop caused by the power cables itself. Since, any length or size of electrical wire will have some resistance, if we assume a total current of 10A and the size of power cable of 1,5mm2, a power cable with 2.5 meter of length will create a voltage drop of 0,5V. So if you have a large power consumption, not only you have to have a proper power unit or battery, but also the appropriate power cable connecting your power source to the power IN port of the EAGLE.

This is why the 14A power unit for the EAGLE is already 12,8V instead of 12V. If you want to use a field battery, you could use a 12,8V inverter or, if you can’t find this option, you can add a 220V inverter and then the 14A AC adapter, also if the latter solution is of course less power efficient.