Power & Weight

Zephyrus 1's balloon doesn't have much lifting power. To achieve a satisfactory altitude, the maximum payload weight is just 580 grams. Working to such contraints isn't easy and every gram counts. At the same time, our avionics are going to be demanding on power. Running just a GPS chip alone draws 100mA. That might not sound like a lot, but it'll drain a 9v PP3 battery in about 2 hours. To make matters worse our expected drain is closer to 300mA which will kill it in just minutes.

After finding that the PP3 battery performs so badly, especially under load, it has been decided that AAA size batteries will power our GPS receiver and radio gear. We'll also be using Lithium batteries rather than alkalines as they provide better longevity in high drain applications and as an added bonus they are also significantly lighter. An average AAA battery weighs in at 12 grams - whereas the Lithium counterpart is just 7.6 grams (Energizer L92). Since we need 4 to power our telemetry package thats a saving of close to 18 grams.

Our camera will also be powered by Lithium batteries (probably Energizer L91) as they weigh just 14 grams compared with 23 for alkalines. Since the A560 takes two AA's we will be saving another 18 grams here.

Simply changing from alkaline to Lithium batteries will shave a massive 36 grams off of our payload and come the final weigh-in that could be vital.