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MW products are top notch. The reason that they print for a 9v is that a LOT of the rocket community still uses the 9v. I know at least two guys that put fresh 9v in their Dual Deploy rockets at the start of the season, and literally do not change them out until the end of the launch season.....and they never have an electronics related failure.

For us newer tech folks, there are literally a dozen different LiPos that are almost exactly 50% the size of a 9v and will fit in the same pocket quite easily, so it's an easy 'standard' battery box size to default to.
 
I am wondering why they design them to hold a standard 9v battery? Isn’t such a battery considered inferior for more than a flight or two and should always be fresh? I prefer a 7.4v lipo to power my altimeters. I wish they’d print a sled for such a battery. I’d be curious to know how many of you actually use just a standard 9v for your flights?
I agree.

Despite clear evidence that a 9v battery is inviting disaster — particularly from not being replaced on every launch — I too am amazed that any prototype example dual deployment implementation uses them, including from Apogee Components.

One possible excuse is that there are multiple shapes and sizes of 2S 7.4v lipo batteries and only one 9v battery size. But this is no justification for implicitly advising people to use them. Dual deployment is difficult enough to get right without putting your rocket at risk with a poor choice of battery.
 
And what is your "clear evidence?"
For example the Duracell 9v alkaline battery has a capacity of 580 mAh. This capacity goes down dramatically at high current rates.

Assuming that an altimeter dual deployment computer can apply 4 volts to a 1.5 ohm igniter, the current is about 2.7 amps. If the burned out igniter doesn’t instantly open circuit before the computer cuts off the power, 2 seconds of 2.7 amps will significantly reduce the battery capacity.

Online 9v battery test data indicates that at 0.5 amps, (a current that the battery was never designed for), the capacity drops to 170 mAH. A 2.7 amp draw is so high that there isn’t any listed data.

The user’s manual for the Eggtimer Proton I use says:

“While we’re on the subject of 9V alkaline batteries, DO NOT, repeat, DO NOT use a 9V battery to power the Proton. At all. 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 WiFi range starts to rapidly decrease, and the Proton will appear to become unresponsive”.
 
For example the Duracell 9v alkaline battery has a capacity of 580 mAh. This capacity goes down dramatically at high current rates.

Assuming that an altimeter dual deployment computer can apply 4 volts to a 1.5 ohm igniter, the current is about 2.7 amps. If the burned out igniter doesn’t instantly open circuit before the computer cuts off the power, 2 seconds of 2.7 amps will significantly reduce the battery capacity.

Online 9v battery test data indicates that at 0.5 amps, (a current that the battery was never designed for), the capacity drops to 170 mAH. A 2.7 amp draw is so high that there isn’t any listed data.

The user’s manual for the Eggtimer Proton I use says:

“While we’re on the subject of 9V alkaline batteries, DO NOT, repeat, DO NOT use a 9V battery to power the Proton. At all. 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 WiFi range starts to rapidly decrease, and the Proton will appear to become unresponsive”.

I have attached Page 5 from the Missile Works manual for the RRC3. This will give you a little more info on the 9-volt battery condition. And if I remember correctly, in the early days LiPos didn't have a stellar record for current control/discharge - which was not favorable to the flight computers. I'm sure some legacy conditions have carried forward. Not all electronic product's are designed the same - so requirements & performance varies.
 

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Newer items, like Egg products, with BT and wifi, consume a tremendous amount of power....and thus one can posit that they were designed around the use of a lipo. Ergo, a 9v would be an obvious bad choice for those electronics. That in no way invalidates the 9v as a valid choice for other electronics.

Empirical evidence suggests that, no matter how much someone disbelieves that there are suitable 9v batteries out there for rocketry, that they perform in quite yeoman fashion in the field day in and day out with a WIDE variety of other DD altimeters and trackers.

In fact, MW and SL both call out the 9v as the battery of choice. Could they BOTH be wrong? I mean, those two alone probably account for 75% of the flight computers at any given field that I fly at, so they must be doing something right?

Let's also not forget that there are quite a few lipos out there that have current limiting in them. That's not always called out in the specs of the battery. I've seen even experienced rocketeers make that mistake. In fact, I've seen way more of that type of failure than I've ever seen of 9v failures. The guys that I know that are 9v exclusive......never have an electronics related failure....and one of those guy STILL uses flashbulbs!
 
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Newer items, like Egg products, with BT and wifi, consume a tremendous amount of power....and thus one can posit that they were designed around the use of a lipo. Ergo, a 9v would be an obvious bad choice.

Empirical evidence suggests that, no matter how much someone disbelieves that there are suitable 9v batteries out there for rocketry, that they perform in quite yeoman fashion in the field day in and day out with a WIDE variety of other DD altimeters and trackers.

In fact, MW and SL both call out the 9v as the battery of choice. Could they BOTH be wrong? I mean, those two alone probably account for 75% of the flight computers at any given field that I fly at, so they must be doing something right?

Let's also not forget that there are quite a few lipos out there that have current limiting in them. That's not always called out in the specs of the battery. I've seen even experienced rocketeers make that mistake. In fact, I've seen way more of that type of failure than I've ever seen of 9v failures. The guys that I know that are 9v exclusive......never have an electronics related failure....and one of those guy STILL uses flashbulbs!

That is a very good point about the current limiting LiPos and how this spec is not always called out. I think it's one of those word-of-mouth conditions, and that's how I learned of them.
 
That is a very good point about the current limiting LiPos and how this spec is not always called out. I think it's one of those word-of-mouth conditions, and that's how I learned of them.

Unless you're crossing over from a drone/RC car/RC airplane hobby where that spec is common(especially in low end products to protect the consumer from himself and from destroying the battery and device), there is almost no other way to know, or to even know to ask the question.

Same with chargers. NiCads were relatively simple to understand, but once we got into Lipos and computer chargers.....well, for a while it was like re-living learning how to program the clock on a 1984 VCR.

Thankfully, most of the current crop of battery chargers adjust easy enough with just a few simple button pushes and menu selections, especially as the market has moved into a HUGE amount of consumer toys. That's probably what made the chargers easier, folks in the market gravitated towards something that you didn't need a phone book sized manual for. But it's VERY easy to destroy a lipo by improper use, storage, or charging.
 
I looked into the pre printed sleds on Missileworks site that you mentioned. I love the idea of the ease and accuracy of using one of them in the future. I am wondering why they design them to hold a standard 9v battery? Isn’t such a battery considered inferior for more than a flight or two and should always be fresh? I prefer a 7.4v lipo to power my altimeters. I wish they’d print a sled for such a battery. I’d be curious to know how many of you actually use just a standard 9v for your flights?

Also are the RRC2+ and RRC3 considered to be good altimeters? I’ve never had one of these particular ones. Like I said, I love the idea of a printed sled (looks to me like Missile Works only offers a sled for these two altimeters currently) for electronics with mounting areas already integrated into it for ease.

Missile Works RRC3 & RRC2 altimeters are easy to use, inexpensive, and very reliable. There customer service is fantastic.

I prefer the RRC3 because it accepts an optional LCD plug in controller. This device allows you to setup the altimeter with extreme ease. At the end of the flight you can plug in the LCD panel to get read outs of all of your flight data.

I’ve used RRC3’s on all of my certification flights including my Level 3. They even work well past Mach 1 speeds.

As far as the 9 volt batteries go, I use them most of the time. You don’t have to worry about charging them up. They hold there charges for years when not being used. I also use the 7.4 volt LiPo batteries. See the attached picture.

One great feature of the printed 9 volt battery box is that they hold two of the pictured 7.4 volt LiPo’s! I utilize one of MAC Performance’s printed sled boards with the attached printed 9 volt battery box in 3” and smaller rockets. I’ll do this to be able to install two altimeters for redundancy.
 

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Missile Works RRC3 & RRC2 altimeters are easy to use, inexpensive, and very reliable. There customer service is fantastic.

I prefer the RRC3 because it accepts an optional LCD plug in controller. This device allows you to setup the altimeter with extreme ease. At the end of the flight you can plug in the LCD panel to get read outs of all of your flight data.

I’ve used RRC3’s on all of my certification flights including my Level 3. They even work well past Mach 1 speeds.

As far as the 9 volt batteries go, I use them most of the time. You don’t have to worry about charging them up. They hold there charges for years when not being used. I also use the 7.4 volt LiPo batteries. See the attached picture.

One great feature of the printed 9 volt battery box is that they hold two of the pictured 7.4 volt LiPo’s! I utilize one of MAC Performance’s printed sled boards with the attached printed 9 volt battery box in 3” and smaller rockets. I’ll do this to be able to install two altimeters for redundancy.

The first photo shows two Missile Works RRC2’s mounted on a MAC Performance 3” sled. The sled has one 9 volt printed battery box on it. Two 7.4 volt LiPo batteries are perfectly installed in the one 9 volt battery box. The last picture is of the 7.4 volt LiPo battery that fits perfectly in the battery box.

The Missile Works printed sleds are less work to install because they are pre drilled for their product line. You can purchase their sleds for 4” rockets with provisions to mount two RRC3’s with two separate 9 volt battery boxes.

I use the MAC Performance sleds with the RRC altimeters when I want redundancy in smaller rockets. One of the pictures has two RRC3’s mounted on a 4” sled. This is more work than using Missile Works dual 4” sled. However I like MAC Performance’s red pushbutton switches better than the rotary switches that the Missile Works sleds are setup for.

Best of luck with your project,
Bob
 
I have attached Page 5 from the Missile Works manual for the RRC3. This will give you a little more info on the 9-volt battery condition. And if I remember correctly, in the early days LiPos didn't have a stellar record for current control/discharge - which was not favorable to the flight computers. I'm sure some legacy conditions have carried forward. Not all electronic product's are designed the same - so requirements & performance varies.
Thanks.

The RRC3 is a popular DD controller and had I been familiar with it, I wouldn’t have been so negative about 9v batteries.

But I’m totally sold on Eggtimer Proton and Quantum DD controllers, especially for their Wifi wireless configuration, arming, data downloading, and channel testing. No more need for ladders to arm a DD controller.

But the 9v battery is viable for the RRC3.
 
+1 for missileworks. The RRC3 is the first DD altimeter I used and has never failed me.

I'm also like you and like to use 7.4v li-po batteries rather than 9v. But I always carry a pack of 9v and connectors for them if I need them in a pinch.
 
Missile Works RRC3 & RRC2 altimeters are easy to use, inexpensive, and very reliable. There customer service is fantastic.

I prefer the RRC3 because it accepts an optional LCD plug in controller. This device allows you to setup the altimeter with extreme ease. At the end of the flight you can plug in the LCD panel to get read outs of all of your flight data.

I’ve used RRC3’s on all of my certification flights including my Level 3. They even work well past Mach 1 speeds.

As far as the 9 volt batteries go, I use them most of the time. You don’t have to worry about charging them up. They hold there charges for years when not being used. I also use the 7.4 volt LiPo batteries. See the attached picture.

One great feature of the printed 9 volt battery box is that they hold two of the pictured 7.4 volt LiPo’s! I utilize one of MAC Performance’s printed sled boards with the attached printed 9 volt battery box in 3” and smaller rockets. I’ll do this to be able to install two altimeters for redundancy.

In your picture that has the RRC3's - are those bread board wires at the terminals?
 
In your picture that has the RRC3's - are those bread board wires at the terminals?

Hi QFactor,

What you are seeing in my pictures are ferrules installed onto the ends of my wiring. You can purchase altimeter wiring kits from Dog House Rocketry with the ferrules pre installed. I bit the bullet and ordered the ferrules from an electronics supply company. The ferrules are very inexpensive. Unfortunately the specialty crimping tool that they require is expensive. I cannot remember exactly what I paid for the tool - something like $250.

The ferrules provide you with a better connection on the terminal block than a soldered wire end. Dog House Rocketry, now owned by Binder Design Rocketry, wiring kits are great. I use their wiring kits. Since I purchased the ferrules crimping tool, I can custom cut the wiring to the exact lengths that are needed.

I will take a picture of the tool and loose ferrules later and post it here later today.

All the best,
Bob
 
Hi QFactor,

What you are seeing in my pictures are ferrules installed onto the ends of my wiring. You can purchase altimeter wiring kits from Dog House Rocketry with the ferrules pre installed. I bit the bullet and ordered the ferrules from an electronics supply company. The ferrules are very inexpensive. Unfortunately the specialty crimping tool that they require is expensive. I cannot remember exactly what I paid for the tool - something like $250.

The ferrules provide you with a better connection on the terminal block than a soldered wire end. Dog House Rocketry, now owned by Binder Design Rocketry, wiring kits are great. I use their wiring kits. Since I purchased the ferrules crimping tool, I can custom cut the wiring to the exact lengths that are needed.

I will take a picture of the tool and loose ferrules later and post it here later today.

All the best,
Bob
Thanks for the info. Very helpful. I'm always looking for ways to improve on the wiring. And the wire terminations at the blocks - I always checking them to see if they have loosened any. The ferrules would help in that area.
 
Hi QFactor,

What you are seeing in my pictures are ferrules installed onto the ends of my wiring. You can purchase altimeter wiring kits from Dog House Rocketry with the ferrules pre installed. I bit the bullet and ordered the ferrules from an electronics supply company. The ferrules are very inexpensive. Unfortunately the specialty crimping tool that they require is expensive. I cannot remember exactly what I paid for the tool - something like $250.

The ferrules provide you with a better connection on the terminal block than a soldered wire end. Dog House Rocketry, now owned by Binder Design Rocketry, wiring kits are great. I use their wiring kits. Since I purchased the ferrules crimping tool, I can custom cut the wiring to the exact lengths that are needed.

I will take a picture of the tool and loose ferrules later and post it here later today.

All the best,
Bob
Do you know off hand what are the most common ferrule sizes you use with your rockets?
 
Do you know off hand what are the most common ferrule sizes you use with your rockets?

They're wire gauge dependent, within a narrow range for each gauge AND length.

I bought a spool of red, white, black, and blue 20 gauge that I wire everything with and purchased ferrules accordingly. I generally use 6mm length.

Eventually you end up with all sorts of stuff!1603899534927776200645442771680.jpg16038997063182401941663839112516.jpg
 
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Do you know off hand what are the most common ferrule sizes you use with your rockets?

Yes. Twenty Two AWG is the most common altimeter wiring gauge. This is the gauge wire that Dog House Rocketry uses.

You can purchase the ferrules from Pacer Group. Their website is www.pacergroup.net. Their phone number is 1-800-634-5031.

You will need part number TFRL22-6MM-100. The 22 gauge ferrules utilize a 6mm collar. I have attached pictures.

Good Luck,
Bob
 

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Yes. Twenty Two AWG is the most common altimeter wiring gauge. This is the gauge wire that Dog House Rocketry uses.

You can purchase the ferrules from Pacer Group. Their website is www.pacergroup.net. Their phone number is 1-800-634-5031.

You will need part number TFRL22-6MM-100. The 22 gauge ferrules utilize a 6mm collar. I have attached pictures.

Good Luck,
Bob
Once again - all good info. Thanks
 
Ferrules on an RRC2L. They are grey as I used 20AWG silicone wire for this install'

IMG_20200726_124445324.jpg
 
Yes. Twenty Two AWG is the most common altimeter wiring gauge. This is the gauge wire that Dog House Rocketry uses.

You can purchase the ferrules from Pacer Group. Their website is www.pacergroup.net. Their phone number is 1-800-634-5031.

You will need part number TFRL22-6MM-100. The 22 gauge ferrules utilize a 6mm collar. I have attached pictures.

Good Luck,
Bob

22 AWG and 20 AWG are perfect for almost everything - Only exception I would note is if you use the PML CPR 3000 DD kits, 22 & 20 won't fit through the little slot you need to feed the wire to get to the switch. 24 AWG works, but even that is pushing it. PML uses 24 AWG in those kits of you use their switch. I keep 20, 22 and 24 AWG on hand.
 
Still can't believe you put this together that quick.

Sorry I haven't posted on it lately, it is all painted and ready to go, just need to ground test the altimeter and deployment charges - been busy with work this past week. Plan on getting all that done this weekend and then flying it next weekend - will post some picks this weekend and, hopefully, after launching next weekend!
 
Still can't believe you put this together that quick.

Also, I guess I wouldn't include the electronics in the build time since none of them are included. However, building out this ebay was quick since I did not install redundant systems. Although the ebay is already built out, I did order one of the MIssile Works printed sleds, since I am using an RRC3+, so I may switch out the plywood one prior to game time.
 
I I have watched the instructional videos on putting this thing together twice but that was a long time ago so I think I'm going to watch the whole thing again before I start mine. I'm pretty sure I just want to build it exactly like the video shows as I will only be flying this rocket maybe twice, three times at the most, built the way the video shows I would imagine that it will hold together well enough for three flights
 
I just got done watching all the build videos this past week but haven’t purchased it yet. I’ve had my eyes on it for a long time among other kits so we’ll see. TVM takes some short cuts that I wouldn’t, but maybe with his experience he knows where he can and can’t cut corners. That is the reason I get so much time wrapped up in my builds. I would spend more time on adding fillets to centering rings, measuring instead of eye balling, wedging the fins between CRs, etc. Does it come faster, guys the more you build or does a guy just get more particular as he learns lol? I’ve only built a handful of hpr rockets so far
 
I just got done watching all the build videos this past week but haven’t purchased it yet. I’ve had my eyes on it for a long time among other kits so we’ll see. TVM takes some short cuts that I wouldn’t, but maybe with his experience he knows where he can and can’t cut corners. That is the reason I get so much time wrapped up in my builds. I would spend more time on adding fillets to centering rings, measuring instead of eye balling, wedging the fins between CRs, etc. Does it come faster, guys the more you build or does a guy just get more particular as he learns lol? I’ve only built a handful of hpr rockets so far

Unpopular opinion: TVM is a nice guy, but I don't like how he builds. I prefer a more precise build approach with an eye towards a more robust assembly.

For me, the process of building and finishing is part of the hobby, but not everyone in rocketry is here for the same things.

As long as the flight execution is safe, it's all good.
 
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