the igniter essentially dead until near deployment (except for a tiny trickle current that’s used to
test continuity). For the igniter to fire, both sides have to be activated independently, and this
can’t happen until you’re in the air and the low-speed deployment enabling logic has been
triggered. It’s a nice safety feature because it virtually guarantees that you cannot have a
deployment charge fire on the ground.
However, you may still decide to use a mechanical power switch, either because your club
requires them or because you want to close up your AV bay beforehand and power off
everything until you’re ready to fly. (We get it… flight day isn’t always the best time to be
fiddling with your AV bays…) It also saves power, too… which allows you to charge all your
batteries up and close up your AV bay several days ahead of time since there’s no battery drain.
Whatever switch you use, make sure that it can handle the expected G forces that you expect the
rocket to experience during flight. We recommend screw switches, because they lock down
tightly and generally can’t come loose in flight. Rail-Buttons.com, Featherweight Rocketry, and
Missile Works make good small screw-type switches, they use a screw to positively lock down
the contacts and completely eliminate any possibility of the switch being jarred open. A lot of
people like the Fingertech mini screw switches too, but those require a hex key to actuate so
they’re not always as convenient.
Quasar Battery Options
The Quasar is designed for a 2S 7.4V LiPo battery. We recommend using one rated at least 500
mAH, since the Quasar draws about 130 mA on average after you connect to the Status Page,
however it can pull over 300 mA under some circumstances, and typically draws about 250 mA
during flight when it’s transmitting constantly. You CAN get away with smaller batteries, IF
(and ONLY IF) you connect the fully-charged battery up right before flying. We’ve used
batteries as small as 180 mAH in testing with model rockets, but we have several fully-charged
batteries on-hand and we change them out with a fresh one after each flight. With a larger
battery, you can take your time… an 800 mAH 2S LiPo is about the same size and weight as a
9V alkaline battery, and will last all day. That’s what we use for all but the skinniest of rockets.
For 54mm diameter rockets, we like the skinny packs used for Airsoft guns… they’re about
100mm x 18mm x 12mm, so it’s easy to fit them on the back of the sled, and they have a lot of
capacity… over 1000 mAH.
While we’re on the subject of 9V alkaline batteries, DO NOT, repeat, DO NOT use a 9V battery
to power the Quasar. At all. Even for testing. They don’t source much current, especially
compared to a 2S LiPo. While it will appear to work fine once it’s new, it will quickly drain, and
you will find that the range starts to rapidly decrease, and the Quasar will appear to become
unresponsive, or it will reset due to low current. WiFi and RF telemetry takes a lot of power, so
make sure you feed it well.
In addition, recommend that the current-sourcing (“C”) capacity of the battery should be at least
5x the all-fire current of the igniter, to prevent any chance of the voltage dipping (although the
drivers will shut off the deployment load if the voltage drops below 5V, preventing a “brown
out”). To get that number, multiply the capacity in mAH by the “C” number of the battery. For
example, a 300 mAH battery rated at 20C will easily put out 6,000 mA, or 6A. If your igniter is
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