SOURCEFORGE » RALF » 2015 Satellite emergency small terminal

h1. Integration of a battery

We were told by Arnaud Glin that the optimal autonomy for the Microbox would be 3 hours (or more). Our first working plan included the purchase of a battery, but we abandoned this due to time and budget issue.

First, we wanted to buy a "GoalZero":http://www.goalzero.com/p/164/goal-zero-yeti-150-solar-generator battery. This battery has the advantage to be "plug and play" : upon receiving, we put it in the suitcase and case use it directly. It can provide 150 Wh, which is enough for our use : the phone use 5x1,2 = 6 W, the router uses 3W and the Raspberry Pi maximum use is 6W. So we need 15W per hour, so the Microbox would have an autonomy of around 10h.

But it is very expensive (229 $) and heavy (5.5 kg). Also, we need to rethink to box to fit it in.

The efficient solution (but more difficult) would be to buy built the power supply ourselves.

We can use a "lithium-phosphate battery":http://www.apexbattery.com/app07l2-bs12-lithium-iron-phosphate.html This battery would fit in our box (we still have space below the wooden stand), and it provides 84 Wh, which can supply the Microbox for more than 3 hours. 

The raspberry needs a 5V input, as for the phone. But, the router needs an input voltage of 6 to 12 V. So we would need to make a circuit board which would supply the necessary voltage to each equipment.