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mtnmanak

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Incidentally, there is a lot of talk on the forum and in this thread about using LiPO batteries. Not trying to resurrect the LiPO vs 9 volt question, but I really had no idea what all the numbers and ratings meant on a LiPO battery and was a bit overwhelmed by all the various combinations of LiPO batteries, sizes, etc. Not to mention the arcane requirements for charging them. Anyone who has been working with LiPOs for a while probably is rolling their eyes at this, but I really knew nothing about them.

Have been researching it, and found these sites very good at helping me understand what all the terminology means and how to go about purchasing/using these batteries.


Granted, these sites cater to R/C hobbyists, but the info on the batteries still works
 

Banzai88

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Incidentally, there is a lot of talk on the forum and in this thread about using LiPO batteries. Not trying to resurrect the LiPO vs 9 volt question, but I really had no idea what all the numbers and ratings meant on a LiPO battery and was a bit overwhelmed by all the various combinations of LiPO batteries, sizes, etc. Not to mention the arcane requirements for charging them. Anyone who has been working with LiPOs for a while probably is rolling their eyes at this, but I really knew nothing about them.

Have been researching it, and found these sites very good at helping me understand what all the terminology means and how to go about purchasing/using these batteries.


Granted, these sites cater to R/C hobbyists, but the info on the batteries still works
No worries at all. Unless you come from an RC car or RC airplane background during the transition from NiCads to Lipos, or grew up in Drones that almost universally started with Lipos, there's really no other way to learn that to start at the beginning.

At least you got to miss the early years before good computer controlled chargers and frequent fires both in use and during charge! Almost never happens these days except with the RC car guys looking to squeeze $101 worth of performance out of a $100 battery.

The only real 'gotcha' about buying batteries the sizes that we use for rocketry is that there are plenty out there that have a current limiting board on them, and that is a NO GO for a deployment battery as it could cause a brown out of your flight computer during the drogue ematch firing sequence and cause a recovery system failure.
 

QFactor

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No worries at all. Unless you come from an RC car or RC airplane background during the transition from NiCads to Lipos, or grew up in Drones that almost universally started with Lipos, there's really no other way to learn that to start at the beginning.

At least you got to miss the early years before good computer controlled chargers and frequent fires both in use and during charge! Almost never happens these days except with the RC car guys looking to squeeze $101 worth of performance out of a $100 battery.

The only real 'gotcha' about buying batteries the sizes that we use for rocketry is that there are plenty out there that have a current limiting board on them, and that is a NO GO for a deployment battery as it could cause a brown out of your flight computer during the drogue ematch firing sequence and cause a recovery system failure.
IMG_8804.JPG
This was a Lipo-eating son-of-gun helicopter from the early days. This was before all the fancy power/battery controls. Drain the battery all the way down and see how quickly it "plumps". That was an expensive lesson in the first week I had the helicopter.
 

Banzai88

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View attachment 437031
This was a Lipo-eating son-of-gun helicopter from the early days. This was before all the fancy power/battery controls. Drain the battery all the way down and see how quickly it "plumps". That was an expensive lesson in the first week I had the helicopter.
Yep, that was my first helo. My second was Great Planes Real Flight (a computer simulator). Later, my first helo was MUCH happier that I spent some time on the sim!
 

mtnmanak

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Looking at all the LiPO battery options out there, it looks like I need a 2S battery (7.4V) for most altimeters, correct?

Is this little battery (it looks like it is physically smaller than a 9V) good enough?


Or do I need something bigger like this?:


Are the connectors standard or do you just cut them off and insert the wires into the terminals? I assume the chargers accept the connections these batteries have?
 

mbeels

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The first one (300 mAh 45-90C) is the one I've been using for altimeters and GPS transmitters, so far with good success.
 

Nytrunner

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Looking at all the LiPO battery options out there, it looks like I need a 2S battery (7.4V) for most altimeters, correct?

Is this little battery (it looks like it is physically smaller than a 9V) good enough?


Or do I need something bigger like this?:


Are the connectors standard or do you just cut them off and insert the wires into the terminals? I assume the chargers accept the connections these batteries have?
I like to use 2S 700 mAh batteries so I dont have to replace/charge/or worry about them on the pad over a weekend of launching, but 300mAh should be sufficient. (mAh is their energy capacity. Higher number means longer operation)

Dont cut off the connectors! Get a matching pigtail to wire into the altimeter terminals. The first battery has JST RCY connectors, so getting a pack of those pigtails should set you up for awhile

Oh, and get a voltage checker like the one below. You DO NOT want to let them run too low or they're toast.
I like them because they can show you the voltage of each cell and the overall voltage

 

Banzai88

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Looking at all the LiPO battery options out there, it looks like I need a 2S battery (7.4V) for most altimeters, correct?

Is this little battery (it looks like it is physically smaller than a 9V) good enough?



Are the connectors standard or do you just cut them off and insert the wires into the terminals? I assume the chargers accept the connections these batteries have?
The first one is perfect, it's my go to flight battery and has never failed me. Just get the matching pig tails to connect to your electronics and your all set.

Unpopular opinion: Batteries are consumables. If you get a season or two out of one, you're doing well. They're cheap enough and readily available that if you forget to put the 'storage charge' on them during the off season, they're easily replaced.

And because you're probably going to ask about chargers, almost all of them work off of a 12Vdc system. They vary from mild to wild, cheap to expensive, and amazing to H.O.R.R.I.B.L.E. This is the one that I use, and it'll do EVERYTHING you could ever think of doing. I have an adapter that goes into the cigarette lighter hole in my truck and has female banana plugs so that I can charge at the field if I find the need, and a 12vdc wall wart for use back at home with the same female bananas.

I charger 106
 

mtnmanak

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What is the difference between a "Discharge Plug" and a "Balance Plug"? What is the purpose for each? One for charging and one to hook up to the device?

Specs:
Capacity: 300mAh
Voltage: 2S1P / 2 Cell / 7.4V
Discharge: 45C Constant / 90C Burst
Weight: 19g (including wire, plug & case)
Dimensions: 45x17x12mm
Balance Plug: JST-XH
Discharge Plug: JST
 

Banzai88

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What is the difference between a "Discharge Plug" and a "Balance Plug"? What is the purpose for each? One for charging and one to hook up to the device?

Specs:
Capacity: 300mAh
Voltage: 2S1P / 2 Cell / 7.4V
Discharge: 45C Constant / 90C Burst
Weight: 19g (including wire, plug & case)
Dimensions: 45x17x12mm
Balance Plug: JST-XH
Discharge Plug: JST

Discharge plug is for powering your toy, the BALANCE plug has + and - leads to EACH CELL, and the charger dynamically keeps all the cells balanced with current flow and voltage.

You typically use both for charging, depending on your charger.

 

mtnmanak

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Discharge plug is for powering your toy, the BALANCE plug has + and - leads to EACH CELL, and the charger dynamically keeps all the cells balanced with current flow and voltage.
Got it, so I plug the JST-XH plug into the charger (assuming that is the white 3-pin plug) and get JST pigtails (assume that is the red plug) for the altimeter.

Sorry for another newb question, but went to look at chargers and it appears you need to buy a charger and a power supply, is that correct? The chargers don't have power supplies?
 

mbeels

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I bought the IMAX B6 that appears in the above video, and it came with an AC power cord. It's also a nice charger. It can do a battery discharge and recharge test to tell you how much capacity the battery has available so you can catch degraded batteries before they cause a problem. As Banzai88 pointed out, they do go bad.

Edit: I think it was this one:
 

Banzai88

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Got it, so I plug the JST-XH plug into the charger (assuming that is the white 3-pin plug) and get JST pigtails (assume that is the red plug) for the altimeter.

Sorry for another newb question, but went to look at chargers and it appears you need to buy a charger and a power supply, is that correct? The chargers don't have power supplies?
Some do, some don't. Most of the hobby world is very 'brand loyalty' centric, and many who use these things either already have a 12vdc power supply, or use the car battery adapters in the field.

Pretty much anything that can deliver several amps of 12vdc will do you for rocketry sized battery demands. There are wall warts, boxes...you name it, it's available. The only real limitation is 'how much money do you WANT to spend?", as long as you get something that'll deliver enough current to your charger for your charging needs. Most of us have 500000000% more than we need.

Lots of folks use something like this( power supply), the 6 amp is overkill, but more than enough head room, no need to spend more money, especially just starting out with a small battery load.
 
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mtnmanak

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Thanks for all the input everyone! Placing an order with Hobby King now, crazy lot of info to process, but hopefully this will be easy once I jump in and start using these things.
 

Banzai88

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Thanks for all the input everyone! Placing an order with Hobby King now, crazy lot of info to process, but hopefully this will be easy once I jump in and start using these things.
Once you step through it the first time with a video guide, you'll be a pro.

Might also want to consider a lipo charging bag Click here . Fire proof bag that effectively shields your stuff if a lipo goes bad during charging. Cheap insurance. YES, since lipos have become a 'thing' I've seen dozens go up in smoke/flames.

Some other thoughts:

DO NOT PIERCE A LIPO!!!!!!

Once it starts to 'puff', you are on borrowed time for lifespan and capacity. The surest way to prevent a puff is to charge ONLY on a good computer charger, and put a 'Storage Charge' on it when putting it away in lay up for a while. Saved lightly puffed batteries for ground testing and set up, use good ones for flight. Dispose of heavily puffed batteries ASAP, they're a fire hazard in that state.

Store in the fireproof bag.

Put a date label on each battery of when you bought it! Track accordingly. All things being equal, some batteries last seemingly forever, while another that you bought on the same day may die when you least expect it.

If you're NOT sure if the battery has a current limiter board in it, ASK BEFORE buying/flying. The last thing you want is a brown out/reset of your altimeter when the drogue charge fires.
 
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mtnmanak

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Once you step through it the first time with a video guide, you'll be a pro.

Might also want to consider a lipo charging bag Click here . Fire proof bag that effectively shields your stuff if a lipo goes bad during charging. Cheap insurance. YES, since lipos have become a 'thing' I've seen dozens go up in smoke/flames.

Some other thoughts:

DO NOT PIERCE A LIPO!!!!!!

Once it starts to 'puff', you are on borrowed time for lifespan and capacity. The surest way to prevent a puff is to charge ONLY on a good computer charger, and put a 'Storage Charge' on it when putting it away in lay up for a while. Saved lightly puffed batteries for ground testing and set up, use good ones for flight. Dispose of heavily puffed batteries ASAP, they're a fire hazard in that state.

Store in the fireproof bag.

Put a date label on each battery of when you bought it! Track accordingly. All things being equal, some batteries last seemingly forever, while another that you bought on the same day may die when you least expect it.

If you're NOT sure if the battery has a current limiter board in it, ASK BEFORE buying/flying. The last thing you want is a brown out/reset of your altimeter when the drogue charge fires.
Also ordered some fireproof bags on Amazon - thanks for the suggestion, would not have known to get them

Great advice on the date/tracking - once again, would not have known to be aware of the "puffing".

This LiPO battery thing is its own hobby! With all the requisite costs...
 

JoePfeiffer

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A real surprise to me was to learn many altimeters work just fine on a 1S cell -- notably Stratologger.
 

mtnmanak

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A real surprise to me was to learn many altimeters work just fine on a 1S cell -- notably Stratologger.
Good to know - I am using a couple Stratologger CF's in other rockets. A very small battery would be great to use in a CPR 3000 system from PML where space is at a premium in the altimeter bay.
 

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IMG_1785.JPGIMG_1786.JPGIMG_2135.JPGIMG_7761.JPG

This is the little charger I use on a 2000mAh LiPo for the T3 tracker.
 

Buckeye

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This LiPO battery thing is its own hobby! With all the requisite costs...
Indeed. That is why I avoided the whole thing for many years. I finally made the plunge and got comfortable with couple particular LiPo batteries, only for them to become unavailable or change their shape, and thus screwing up my av-bay layouts. That's my biggest gripe: There is seemingly no standardized form factor to Chinese LiPos.
 

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Good to know - I am using a couple Stratologger CF's in other rockets. A very small battery would be great to use in a CPR 3000 system from PML where space is at a premium in the altimeter bay.
If you go with a 2S in the SLCF, keep this in mind:

 

QFactor

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Where you pick that little guy up? I have a few really small, 110mAh, LiPo's.
IMG_1788.JPG
Here's the backside of the charger.

It's perfect for those little LiPos.

It's from Adafruit - and you have a choice of cable connections.

You have a Mini USB plug : https://www.adafruit.com/product/1905

And you have Micro USB plug : https://www.adafruit.com/product/1904

Choose wisely . . . . . Basically see which one is the most common USB cable in your household.

I use it, and others like it, with electronic projects that have micro controllers and micro computers.

You can also find them at Sparkfun : https://www.sparkfun.com/products/10217

I forgot to mention that Adafruit says their charger will only work with their LiPos. I haven't had any issues. But you want to be careful of the red & black leads (wires) on some of these dirt cheap liPos. They will have the red & black wires switched on the JST connector. Ran into that a time or two. But that was some time ago.
 
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Tyler P

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I like to use Lithium 9V batteries. I do own some rechargeable LiPo's, but I have found these lithium 9Vs to be excellent. They have a 10+ year shelf life and last a long time. I have a couple I have been using for at least a couple years now and they still show above 9V on the multi-meter. You should test your battery before every launch, regardless of what you are using.

Not in anyway "proof" of anything, but I pulled a couple 9V alkalines out of a brand new package and you can see below they are pushing about 8.76 volts. I tested one of the lithiums in my range box that is at least 2 years old and it still pushes 9.21 volts.

Once again, this doesn't prove anything - every battery is different, but I can say I have had great luck with the 9V lithiums. As an added bonus, they are 25% lighter than the alkalines. That weight may not affect your launch, but it does help keep the battery from wanting to launch itself around in your ebay.

LiFe packs are super reliable. I run 2S versions in my giant-scale aerobatic RC planes and it should be noted that RC turbine ECUs recommend the use of 9.9V LiFe packs too. I've been using the same packs in my plane for several years and they still charge, test, and perform as they should. LiFes are more stable than LiPos and should be ideal for use with rocket electronics.
 

Tyler P

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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.
That's where I'm at, too. I enjoy building maybe more than launching. I don't get to launch nearly as much as I'd like, so that might be part of the reason I enjoy the building so much. Gives me some attachment to the hobby while I can't be launching.
 

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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.
Would you recommend the RRC3 or RRC2L altimeter? I see eve RRC2L can be plugged into an LCD receiver and makes it easy to read flight data. I’m wanting an altimeter that’s not overly complicated but not the most basic so wondering what the recommendation would be. Purchasing the RRC2L with the LCD bundle makes it about $12 more than the RRC3
 

Nytrunner

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Would you recommend the RRC3 or RRC2L altimeter? I see eve RRC2L can be plugged into an LCD receiver and makes it easy to read flight data. I’m wanting an altimeter that’s not overly complicated but not the most basic so wondering what the recommendation would be. Purchasing the RRC2L with the LCD bundle makes it about $12 more than the RRC3
Up to you, which features do you want?

RRC3 has graphable data logging with the Data transfer unit, auxillary deployment channel, and interface with the RTX gps unit. (As well as in field adjustment using the dip switches and button or LCd interface)

RRC2L has the LCD interface, simple button program for main deployment, and beeps out last altitude/velocity readings. It also has a smaller form factor.

The RRC2+ has the dip switch programming and no LCD terminal. It is the simplest to use (if you know the switch positions)

I like data, so I use RRC3s and SLCFs.

Ill probably get a couple RRC2+s to use on simple flights in the future

If you get the RRC2L, you can use the LCD terminal for RRC3s or other RRC2Ls as well
 

Tyler P

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I chose RRC2+s for my first altimeters. I haven't used them yet, but I chose them because they're simple. I didn't want to clutter my mind with too many extra things to worry about, so these seem to fit the bill for my needs.
 

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Would you recommend the RRC3 or RRC2L altimeter? I see eve RRC2L can be plugged into an LCD receiver and makes it easy to read flight data. I’m wanting an altimeter that’s not overly complicated but not the most basic so wondering what the recommendation would be. Purchasing the RRC2L with the LCD bundle makes it about $12 more than the RRC3
Would you recommend the RRC3 or RRC2L altimeter? I see eve RRC2L can be plugged into an LCD receiver and makes it easy to read flight data. I’m wanting an altimeter that’s not overly complicated but not the most basic so wondering what the recommendation would be. Purchasing the RRC2L with the LCD bundle makes it about $12 more than the RRC3

Hi Steven,

I have been using the entire Missile Works product line for many years now. I’ve used both the RRC3’s and the RRC2+’s. They are inexpensive altimeters that perform really well. I have also installed one of the newer RRC2L’s in a rocket that hasn’t flown yet.

I preferred the RRC3’s because of the LCD connection. The plug in LCD makes it super easy to program the altimeter. The LCD also makes is easy to obtain flight data after your flight.

I would often use two RRC2’s in smaller rockets do to their smaller footprint. Now that Missile Works came out with the RRC2L with the LCD port you have the best of two worlds. The RRC3 does have a third output channel if that is of any use to you.

All the best,
Bob
 

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