Which Type Of Battery Is Best For HAB Use?
I'm often asked the above question and the answer depends on many things. Those with the knowledge and experience to select the best battery for a particular application, piece of equipment or HAB flight may choose something different for a specific reason, but Energizer Lithium Iron Disulfide cells are hard to beat for HAB use and the #1 choice by most, mainly because of their −40°C temperature rating and light weight.
Following is some other information from the Energizer Lithium Iron Disulfide, or LiFeS2, Cell Application Manual that I found interesting or good to keep in mind when using these cells.
I did some quick tests and calculations to determine how long Energizer Lithium L91 & L92 cells would power a RTrak-HAB V1.10 tracker with an active antenna which requires a minimum input voltage of 5.2V and ≈ 88 ma when idle and ≈ 310 ma transmitting. The 5.2V min. input voltage means only 4 cells are required and for a 30 sec. beacon rate with 1 sec. transmissions the average current works out to ≈ 95 ma which means:
I'm always looking for ways to reduce weight in order to reach the highest possible altitude so also did some quick tests with a SparkFun LiPower Boost Converter providing the tracker with 5.0V and with an input voltage of
Without knowing what the discharge voltage curve of a battery powering a RTrak using a converter would be it's not possible to accurately calculate how long it would last, but using the same formulas as used above for 4 cells:
A few grams have to be added for the weight of the converter of course. The converter output would also have to be made >5.2V to allow use of the tracker A/D converter which would reduce the times a bit, unless one bypassed the 5V regulator. And tests using L91 & L92 cells are needed to accurately know what operating times would be, but the calculated times at least help choose which power sources are most likely the best to test further which are:
Energizer Lithium cells aren't cheap so I don't plan on doing any actual battery life tests until one of the sources is used for a flight to allow simply leaving the tracker turned on and using the battery already used for the flight which would likely be discarded anyway with not knowing for sure how much longer it would last.
I also plan to check out using rechargeable Lithium Polymer Cells with a Sparkfun LiPo Charger/Booster which is simply a LiPower Boost Converter with a LiPo Charger to save having to remove a battery to charge it. Being rechargeable, this type of battery will allow some actual battery life tests to be done and having a number of cells of different capacity should provide a much better idea of how long L91 & L92 cells with a converter will last.
More to follow ........
|To BEAR Home Page|