RRC3/RRC2+ with 9V battery pad life?

[rocketgeek101]

Anyone know how long a MissileWorks RRC3 or RRC2+ with a fresh 9V battery can sit on the pad armed for flight before it would be considered unwise to launch it? Or alternatively what is the minimum voltage for a 9V battery you would launch with?

According to Google, a 9V battery has a capacity of ~550mah and from the RRC3 manual the nominal power consumption of the altimeter is ~6ma. That would allow for 550/6 = 91+ hours or just under 4 days of operation (though obviously you'd want to launch well before the battery is close to being spent). I'm thinking probably up to a few hours would be ok...

 

[StreuB1]

A very very very long time. Longer than any rocket would ever sit on a pad.

I have half a dozen RRC2+/2L/3 loaded up for MMWP this weekend and I think only 2 have fresh 9V batteries. I will fly when its >9.3-9.35V. I don't fly anything in the 9.2v or lower. Those values are entirely arbitrary on my part.

 

[user 30299]

The RRC2 and RRC3 have power saving modes that kick in after 5 minutes. So the power drain is minimal (negligible) .

If you have a quality 9-volt battery your rocket can sit on the rail all day - and not have a noticeable affect on the battery.
I had a rocket sitting in a tree, with an RRC2 and RRC3, and both still able to beep out their altitudes the next morning.

I usually set a battery aside once it gets to 8.5 volts. Again it's all about the battery quality. I currently only use Duracell Procells.
Every manufacturer has a couple of different 9-volt grades - so it's a challenge on the selection. "Heavy-duty" and "Industrial"
labels are deceiving. Not all 9-volts have the same Amp levels fresh out of the box. I have seen them as low as 2.5 and as high
as 5.6.

My 8.5-volt cutoff is just based on experience.

I can get 4 to 5 dual-deployment launches out of a Procell battery before the battery gets to 8.5 volts. So that means the battery
is running the flight computer, and then it sees two voltage/amp discharges in quick succession; Apogee and Main deployment.

 

[tim cubbedge]

I get at least 2-3 flights out of a 9volt with the RRC2/3. My cutoff is 9.0 volts but as you can see, everyone has there own opinion. Batteries are a lot cheaper than your rocket and I know some people who replace their batteries after even 1 flight.

 

[Bat-mite]

My 8.5-volt cutoff is just based on experience.

My rule is "8.8 'cause I'm a cheapskate!"

 

[mtnmanak]

As I have posted a number of times, these Energizer Lithiums last a long long time. The battery in the picture below has 18 flights on it powering an RRC3 and is still pushing 9.24V. At times, it has sat on the pad for over an hour. If you also consider that it can take up to 20-30 min or more to recover a rocket, I would estimate this battery has at least 20 hours of "on-time" powering an RRC3 and still going strong.

 

[Handeman]

I fly Perfectflite. I put a 9V battery in and don't open the av-bay until the altimeter reports less than 8.9V. That is usually 20+ flights and 3+ years.

 

[Steve Shannon]

We had a rocket with MW RRC3 and a Multronix Kate1 in it, sitting on the pad for 3-4 hours at ambient temperatures of about 48° last weekend waiting for clouds to clear beyond the 5/10 requirement. Kate1’s was down to 60% but everything worked fine.

 

[gary7]

I get at least 2-3 flights out of a 9volt with the RRC2/3. My cutoff is 9.0 volts but as you can see, everyone has there own opinion. Batteries are a lot cheaper than your rocket and I know some people who replace their batteries after even 1 flight.

I replace mine after every flight.