I wanted to try Dual deploy to learn some basic electronics, but I feel like I need a masters degree in LiPo batteries

[Art Upton]

My best advice that everyone would likely agree with?...

YMMV, ground test, ground test, ground test.

Yes Ground Test, but hopefully not this type of ground testing

 

[Art Upton]

.. Already covered up above about polarity ...

 

[Art Upton]

Overall, DD is a pain compared to using a JLCR and motor eject. With DD, gotta futz with the altimeter in the payload, prep the charges, make sure the batteries are fresh, install the hard pins and the shear pins, and of course ground test. They're are several things that can go wrong.

OTOH, the JLCR is expensive and but the string of components coming down is an awesome sight.

I've been doing Dual "Chute Cannon' deploy since 2003 when I got a MAWD PerfectFlite altimeter. It was and is Futzy, and why I like the JLCR product. I was at the NARCON when John announced it, I was all in.

But you do have to do 'chute' testing, for example the red cheap Estes Nylon chutes don't like to catch air when released. I had a ton of those from lots of PSII kits I had built and flown and getting spares cheap from AC Supply. Guess what? These were used in my cheap mules. What I learned was don't use those , they can cause failure, but I still do not know exactly why and don't care to research it more.

My small stash of Top Flite chutes have been working well for me, but you do need to watch videos on how to fold/pack your chutes with a JLCR if you have not done it for awhile.

I have also used "Tethers", which I used the 'Defy Gravity' one on my L3 Rocket to hold the release of my Main in a Deployment bag, and used that method for a few other rockets as well, all out the top recovery. They seemed to have Futz.

But so far the JLCR for me is the least amount of Futz and lots of folks around me are also using them now. Not sure it really is that much more expensive if you lose one compared to an AV-Bay chute cannon total cost in an average rocket.

 

[kjhambrick]

I suppose the world has been spoiled the the plug-n-play of the modern USB and similar charging of our daily devices, but this LiPo battery stuff has me REALLY feel like I'm in waaaay over my head. Especially without an experienced person to work with and learn from.

How did YOU get comfortable with LiPo and charging?

Is there a repository here that has some solutions that "just work", that can act as a starting location?

I COULD just use JLCR, but part of what I love about the hobby is dabbling and learning. I'd REALLY like to move forward in the electronics area, but cant start w/o power

@dhurstell --

I've read this thread several times and I am more confused than I was before

I re-re-BAR'd in April 2023 after leaving the hobby in spring of 2000.

I was amazed at how far materials and methods and gadgets had progressed while I was 'away'.

There is no such thing as a 'one size fits all' electronics solution because different people are looking for different features in their electronics.

My advice is to read some of the interesting threads in the TRF "Rocketry Electronics & Software" and the TRF "Recovery" sub-forums.

Figure out what floats your boat ( oops, wrong hobby )

Ask Questions ( like you did in this thread ).

Then you'll find a specific gadget ( or gadgetry ) that sounds interesting and then get specific recommendations from the Manufacturer for powering your device(s).

As for general info on LiPo batteries, they're a little finicky but not too difficult.

This is a pretty good source of general care and feeding of LiPo's: The Drone Girl > HOW TO CARE FOR YOUR LIPO BATTERIES.

Check the sub-links too, if you care ...

This online PDF has a little more engineering data if you care: Renata Batteries > Guidelines:Ensuring long life operation of LiPo batteries

EDIT: And if you google: 'lipo battery best practices' you will find all kinds of info.

As for me, after following the path above, it was the Blue Raven that caught my fancy because it provides a full IMU, so I went with Adrian's recommendations for powering his gadgets.

Line @manixFan, I bought one of the Featherweight Dual GPS/Raven Battery Charger and It just works !

After reading a few 'best practices' articles like those I linked, I just make sure to not discharge the LiPo below 3.8 volts ( or so ), nor above 4.2 volts ( or so ) and so far they look fine ( no swelling ) and they perform OK.

Disclaimer: I only own 1S LiPo's ( a 1S LiPo is a single cell ) so I don't need to worry about balanced charging.

When and if I ever do get into multi-cell LiPo assemblies, I'll need to get into balanced charging and discharging and all that stuff.

But for now, I am all good.

HTH and I hope to see you at a Central / SE Texas launch sometime !

-- kjh

 

[thzero]

When and if I ever do get into multi-cell LiPo assemblies, I'll need to get into balanced charging and discharging and all that stuff

Its really not that hard. The chargers do it for you, i.e. they will balance the batteries, etc. The only thing I've found is that you do need to look hard at chargers to make sure they have a 'storage' option; I've run into a few that didn't have it which is annoying.

And if you follow the recommendations from the altimeter manufacturer for your altimeter, you should be good to go.

 

[KenECoyote]

I know that many here use and recommend 9v alkalines, but I personally prefer lipos because (among other reasons) I like to fully charge them just before launching and have confidence that they will last for hours.

Early on, I used 9v alkalines, but ended up having many dead and unsure of how much longer the rest would last.

So for those of you using 9v alkalines, do you use new ones each time?

 

[Art Upton]

I know that many here use and recommend 9v alkalines, but I personally prefer lipos because (among other reasons) I like to fully charge them just before launching and have confidence that they will last for hours.

Early on, I used 9v alkalines, but ended up having many dead and unsure of how much longer the rest would last.

So for those of you using 9v alkalines, do you use new ones each time?

I always did, a rocket was not worth the cost of a new Duracell at Costco bulk price
I have a box of the Amazon brand now and again, a new one each time.

I then use the used ones around the house for other items that might need one. Sometimes that part takes years to use them up.

I bought some LiPo for my stash of Perfect Flite Stratos, but found they are not recommended at all so will use the 9 volts.

Seems you need to add current limiting resistors in line with the matches if using LiPo on Perfect Flite

 

[Art Upton]

At $1.12 each

https://www.amazon.com/dp/B00MH4QM1S

 

[kjhambrick]

Back when I was working on the AltAcc I always flew Ultralife 9V Lithium Batteries.

Ultralife Batteries, Inc Long-life 9v Lithium Battery Smoke Detector

They worked great back in the day and I didn't hesitate to fly them more than once as long as the voltage looked OK ( don't recall my lower voltage limit any more ).

But they were certainly not $21.00 each ( and they were also not spec'd for Smoke Detectors back in those days ).

This week, if I needed a 9V, as @Art Upton recommended, I would go with the Amazon Basics 6LR61 ( 8-pack ) for $8.89 ( and today they're $1.11 each ) .

-- kjh

 

[Pilotx1]

the Performax 9v batteries from Menards are labeled as 6LR61 as well for $8.39 (1.40 each), a little bit more but it avoids amazon and you get it immediately

 

[KenECoyote]

Thanks for the 9v suggestions guys! I'll try them for my main altimeter (SLCF) and use the lipo for my backup Eggtimer stuff.

 

[cichlidgoob]

To answer the original question, this is the best thing I ever came across for a full and easy-to-digest explanation on LiPo batteries:

https://www.rogershobbycenter.com/lipoguide

When I made the switch from nitro to electric RC cars I looked for a “LiPos for beginners” primer, and this was the best by a long shot. If you read through this whole page you will know everything you need, and more, to be successful. You’ll also know more than most folks who actually use LiPos but don’t fully understand them.

I use 9 volt batteries for all my altimeters because they are so easy, reliable and convenient…but I do use LiPos for my featherweight trackers and RC cars.

I’d love to hear your feedback about the link above, but I think you’ll find it very valuable.

 

[cerving]

At $1.12 each

https://www.amazon.com/dp/B00MH4QM1S

IF you're going to use a 9V battery, that Amazon battery is a pretty darn good one. I've been using them in the EZ-DD rocket, about 20 flights so far this year on the same battery and it currently tests at 8.8V. Again, no matter what 9V battery you get, make sure it's marked "6LR61"... otherwise you're going to get pressed flat cells that are liable to fail in flight.

 

[Capt. Eric]

Thanks for the 9v suggestions guys! I'll try them for my main altimeter (SLCF) and use the lipo for my backup Eggtimer stuff.

I use 9v in my SLCF with no issues (knock, knock). I don't think you'll have a problem, as long as you check the voltage and make sure it's strong, which the SL does too (but I check before installing anyway).

 

[roytyson]

https://www.roysrockets.com/products/roysrockets-easy-apogee-sled
Getting into electronics doesnt get much simpler than this, and the battery charger is super simple.

 

[ac2fv]

Try one of these two... both charge from USB:

https://a.co/d/4H5w9R5

https://a.co/d/7My4k4W

The first one I personally like a lot (used in my L3 attempt rocket). The second one came highly recommended by an extremely experienced rocketeer. Both fit into 9v battery holders too.

Edit add: YMMV, ground test, ground test, ground test.

Ken, I’m working a build where I’m going to use Lipo batteries for the first time to power my altimeters. Is 800mah enough juice to power the altimeters, considering the usual time of sitting on the pad waiting to launch, then fire both altimeters? I found a 1200 mah 7.4 v that so about the same size as a 9v, but I really need something smaller in size. The 800 mah would be a better fit.

 

[KenECoyote]

Ken, I’m working a build where I’m going to use Lipo batteries for the first time to power my altimeters. Is 800mah enough juice to power the altimeters, considering the usual time of sitting on the pad waiting to launch, then fire both altimeters? I found a 1200 mah 7.4 v that so about the same size as a 9v, but I really need something smaller in size. The 800 mah would be a better fit.

Regular 9v alkalines have around 550mah, so you're already ahead with the 800mah (or at least even with them if capacity is overinflated).

I actually got the 800mah ones listed because they first within the dimensions of a 9v and fit into the 9v carriers I had on hand.

I found that they had plenty enough juice for a usual rocket "launch and find" episode, however some electronics are higher drain (especially if it has multiple functions like a GPS locator plus altimeter I would presume).

My L3 sat on the pads for a few rounds, got launched, then I had to wait for my L3CC to go track it down (his tracker and very windy day - it got dragged across some fields) and when we finally found it, both altimeters were working fine and this was about 4 hours running.

 

[thzero]

Ken, I’m working a build where I’m going to use Lipo batteries for the first time to power my altimeters. Is 800mah enough juice to power the altimeters, considering the usual time of sitting on the pad waiting to launch, then fire both altimeters? I found a 1200 mah 7.4 v that so about the same size as a 9v, but I really need something smaller in size. The 800 mah would be a better fit.

What does the manufacturer recommend?

 

[ac2fv]

Regular 9v alkalines have around 550mah, so you're already ahead with the 800mah (or at least even with them if capacity is overinflated).

I actually got the 800mah ones listed because they first within the dimensions of a 9v and fit into the 9v carriers I had on hand.

I found that they had plenty enough juice for a usual rocket "launch and find" episode, however some electronics are higher drain (especially if it has multiple functions like a GPS locator plus altimeter I would presume).

My L3 sat on the pads for a few rounds, got launched, then I had to wait for my L3CC to go track it down (his tracker and very windy day - it got dragged across some fields) and when we finally found it, both altimeters were working fine and this was about 4 hours running.

Ok, thanks. The altimeters are MW RRC2 altimeters. A friend recommended 180 mah batteries, which I am not comfortable with at all… I’ll go with the 800’s. See you at METRA!