What Lipo batteries are people using for the RRC3?

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Ok, thread necromancy.

Has anyone had any first hand experience with the RRC3 using a Lipo other than the Sparkfun one yet? Because that Sparkfun one has been out of stock for awhile.

I was thinking this one: https://www.hobbyking.com/hobbyking/store/__24218__Turnigy_nano_tech_180mAh_2S_25C_Lipo_Pack_E_flite_micro_series_compatible_USA_Warehouse_.html

It is 180 mAh and 25C, so I believe that makes it 4.5 Amp maximum which is within the RRC3 window of 5 Amp. I know that is a safe maximum, and not necessarily the true maximum. Assuming I don't have a short and the e-matches go how likely am I to get a spike over that? Also, assume I am not using these for air starts which I understand can lead to a "short" due to the conductivity of the gases at ignition.

Also, for anyone with the lipo-RRC3 3D printed sled what are the battery compartment dimensions?
 
I have used the battery in your link, as well as the 120 mAh version, and have not had any problems.
 
ben said:
This is the battery the printed sled uses
https://www.sparkfun.com/products/10718 which I have used without any problems.

You really don't need a 7.4 volt lipo battery.

Ben
Click to expand...

The Sparkfun battery has been out of stock for months. That or it was briefly in stock and I missed it before it went back out of stock. I know I don't need the 7.4V, but it gives me some versatility as it will be cross functional with some other devises I already have, and I'm betting that next tiny featherweight altimeter will like a 2S lipo for instance. The 1S batteries kind of limits the applications, and I like to standardize across devises as much as possible.

That being said I would probably just order the Sparkfun one if it were available for the compatibility with the 38mm 3D printed sled alone. I have two of the 54 mm 9V sled version and they are really nice and quite robust. I had a 50G flight last week with no show of failure or stress with a 9V. That alone tells me that if I get the battery weight down 2-3x I am good for even the zippiest of flights on that sled.
 
I had a pretty good experience from Sparkfun customer service on getting info on when that battery would be back in stock. Such as "it's on a boat due to dock in the US in 10 days" and "it got held up in customs for a week" and "It's shipping in 3 days".
 
Zebedee said:
I had a pretty good experience from Sparkfun customer service on getting info on when that battery would be back in stock. Such as "it's on a boat due to dock in the US in 10 days" and "it got held up in customs for a week" and "It's shipping in 3 days".
Click to expand...

That is incredibly detailed. Is Sparkfun a one or two person operation? How does customer service know that? Thanks for the heads up. I'm so accustomed to customer service being useless that I don;t even bother to contact about such things anymore.
 
Honestly - I have no idea, they may have been spinning me a line the whole time, but they gave me updates when I asked for them, were polite and responsive and it eventually arrived (took approx 8 weeks though).
 
OK- so good discussion of battery theory, expensive circuit protectors etc. BUT...

I did some testing using resistors to limit the current.
I make my own ematches - I use 36g nichrome and a home dip kit. My matches test pretty consistently 1.1 to 1.3 ohms. I used an 800 mah 7.4v 20-40C LIPO for the test.
With the 10 feet of extra wire, each of my matches was 1.9 ohms before test. I tried a 10 ohm resister - no burn, with a 4.7 ohm resistor (6.6 ohm total ) it took 3 seconds before burning and it "sounded slow". With a 2.4 ohm resistor, 4.3 ohms total to the battery, it popped immediately.

A 1 or even 1.5 ohm resistor without the extra wire in a rocket is about half that total resistance and should fire without problem. If there was a short, the resistr would limit the current to 7.5 or 5 amps. I used 1/4 watt resistors -didn't get hot or blow - which will survive short bursts of high current and 1 watt resistors are still small and cheap. ( I know 7.5 amps in 1 ohm is 7.5 watts- a very large resistor) If a resistor blows it will open not short and still protect your altimeter. Also though I certainly wouldn't guarantee it for an altimeter, MOSFETs will generally survive higher than rated current for short bursts anyway and many altimeter outputs are limited to one second firing.

As usual - TEST your own matches and resistors
 
Hello All

I'm looking at pages 8 and 9 of the RRC3 manual where it describes "Dual Battery Wiring" Does this wiring setup save the altimeter in case of a short where a lipo may have a great deal more Amperage than 5a?? If one was using 2 lipo batteries wired in this manner would the scenario of a short at the ejection charge be ok or would the logic battery still being a lipo dump it's charge through the altimeter.

Thanks in advance

Chris
 
Just looking at my local dealer and found these and was wondering if this this the solution to providing a decent power supply to the RRC3 or other Altimeters and limit the current the lipo can produce.
 
Input voltage for that regulator listed is 8v minimun, I would do further research on it before using it with anything less.

Just went an did a little reading about the v-regulator linked in the post above, it might work pretty well, as some people were using it with 2S LiPo's.

Did some more researching, anybody know if a SBEC or UBEC could be used in our applications, from what I have read about ones like this:
https://www.hobbyking.com/hobbyking/store/__33297__TURNIGY_3A_UBEC_w_Noise_Reduction_USA_Warehouse_.html or
https://www.hobbyking.com/hobbyking/store/__33290__HobbyKing_HKU5_5V_5A_UBEC_US_Warehouse_.html
 
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V2rocketeer said:
I guess that was my thinking and running 2s or even 3s batteries.
Click to expand...

Good idea a 2s or 1s for the logic and a 2s or 3s for Pyro. I'm looking for more input on this one. The amperage limiters look good (SBEC and UBEC), does anybody have experience with set up like this?
 
I recently got an RRC3 and ordered the lipo sled. After much deliberation, for my pyro battery I may resort to taking apart a 9V, arranging the cells to fit my head end ignition canister and re-soldering them. I'm doing an airstart and am concerned about shorting a fet. I can still use the lipo for the flight logic.
 
I was looking at some CR123 batteries by Tenergy that have a PTC built in to limit them to 5A, with two of them in series its about the same weight as a 9V but you can get a better amperage without blowing the electronics if they work as they say.

https://www.all-battery.com/tenergycr123alithiumphotobatteryhighcapacitypropel.aspx

Edit: Energizer LA522 Lithium Advanced 9V has a PTC, have to read spec sheet for its Amp limit.

Edit again:its 1A max for the LA522 per thread https://www.rocketryforum.com/archive/index.php/t-63249.html
 
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Here is what I have learned, for whatever it is worth. I make no claim to know much about Lipos, which is why I started this thread. To date, I have only used my RRC3's with a single 9V battery. I have a minimum diameter 38 mm project which is very space limited, and will not currently be able to use a 9V battery. After the discussions in this thread, I purchased the 2C Lipo from Hobby King and the cheap recommended charger, an HKE4. The details are in this thread, but I can look up if necessary. The charger does not come with a power supply. Fortunately, I had one. Immediately, I was never able to charge the 2C lipos with either my power supply, or my car battery. The lipos had some charge, and I was able to power up my RRC3 and LCD. The lipos are now discharged, and I have no way to charge them. This coupled with some of the components taking a long time to arrive from Hobby King, I decided to dump this approach. Dpatel has successfully used the 1C Lipos sold by Adrian A. at Featherweight with his RRC3. Dan Patel looks to me to be a high end flier, and may have been a RRC3 beta tester. That is good enough for me. I would have purchased from Featherweight, but wanted to also purchase a charger. I got this charger from Fruity Chutes. It is a Tenergy:

https://fruitychutes.com/buyachute/.../wall-charger-for-37v-mcx-batteries-p-61.html

I purchased two 120mAh, 1 Cell, 3.4 V, 14C LiPo E-Flite batteries from Fruity Chutes also. The website photos show Tenergy batteries, but they are E-flight.

https://fruitychutes.com/buyachute/...c-11_17/37v-120mah-10c-lipo-battery-p-60.html

The website should be changed to reflect the correct batteries, however they are good. I can power up my RRC3 and LCD fine, and I can recharge them just fine. I have had these for some time, and they still charge fine and power up the RRC3 and LCD. The batteries are considerably smaller than the 2C batteries. I have yet to fly these, as I focussed on my 54 mm Space Cowboy. I am pretty happy with this setup, and believe that it will work well. I don't know much about all of the discharge limiters, and everything else, but these are good enough for Adrian A. for the Raven, and people have used them for the RRC3. This is what I have found, I hope this helps in some way.
 
4kids49 said:
I don't know much about all of the discharge limiters, and everything else, but these are good enough for Adrian A. for the Raven, and people have used them for the RRC3. This is what I have found, I hope this helps in some way.
Click to expand...

Has this approach been tested into dead short or used for airstarting a motor?
 
I should have been more clear. I was referring to the batteries. I am not sure what has been done with the RRC3 in your type of high end application. Adrian A. knows a lot on this topic with lipos and Raven in airstarts. His knowledge may help translate to RRC3. You might also contact Jim Amos directly. He is very knowledgeable and answers emails pretty quickly. My post was mostly directed at the typical RRC3 user and lipos. There seems to be a lot of reinventing the wheel in some of the threads, and for me, some of the suggestions did not work.
 
For what it's worth:

I use my Raven - with the standard 1s 3.7 LiPo that Adrian supplies - for my sustainer in a two stage rocket. That battery fires the separation charge (ematch), airstarted motor (CTI ematch), apogee charge (Q2G2), and mains charge (Q2G2). Handles all four events no problem. This IS with a Raven, and not an RRC3, but still.

s6
 
Binder Design said:
@stealth6 Is this the battery you are talking about?: https://shop.featherweightaltimeter...7728.m1plqscsfapp02?productId=14&categoryId=1

I fried a parrot fet on an airstart with that battery.
Click to expand...

Interesting. Here is a thread: https://www.rocketryforum.com/showthread.php?52649-Let-s-talk-Lipo-s-for-a-minute

In posts 6 and 54, Adrian talks about these batteries not being able to damage Featherweight altimeters even in a short situation. There is another good thread on this topic that I am looking for.
 
That's why I like the sparkfun lipo's - because they are 2C instead of 10C or 20C the max amps they can put out is unlikely to damage anything.
 
4kids49 said:
Interesting. Here is a thread: https://www.rocketryforum.com/showthread.php?52649-Let-s-talk-Lipo-s-for-a-minute

In posts 6 and 54, Adrian talks about these batteries not being able to damage Featherweight altimeters even in a short situation. There is another good thread on this topic that I am looking for.
Click to expand...

Yes however the Raven's output FETs are able to withstand 30amps and 9amps while the RRC3 is only rated at 5amps. So what works for the Raven isn't necessarily the best for the RRC3. I'm space challenged as well and doubt I can get a 9volt in the bay, not to mention I have yet to find a 9volt connector that I feel total confidence in High G situations. That is why I'm looking at a lipo replacement. I just need a way to limit the current so that in a short circuit situation I do not lose the altimeter.

Cheers

Chris
 
V2rocketeer said:
Yes however the Raven's output FETs are able to withstand 30amps and 9amps while the RRC3 is only rated at 5amps. So what works for the Raven isn't necessarily the best for the RRC3.

/QUOTE]

I get that. What is the max amperage of a 9 volt battery in a short situation? The recommended battery for RRC3 is a 9 volt.
Click to expand...
 
Binder Design said:
It was a parrot. Not sure if the fets are different from the raven.
Click to expand...

I believe you, I am just learning from this thread. I am not doing an airstart, so demands on batteries and altimeters is much less than in your shorting environment. One of the reasons I was interested in the 2 cell 7.4 volt lipo for RRC3 was because initially Jim Amos recommended getting a voltage closer to 9 volts. The larger 2 cell battery would seem to be able to generate a higher amperage if shorted out. Adrian's posts have recommended going to smaller single cell lipo batteries. I can't seem to find the correct short amperage for a 9 volt battery. I would be curious to know what the battery experts opinion on this is. Do you have any thoughts on the battery that you might use?
 
4kids49 said:
I am just learning from this thread. I am not doing an airstart, so demands on batteries and altimeters is much less than in your shorting environment. One of the reasons I was interested in the 2 cell 7.4 volt lipo for RRC3 was because initially Jim Amos recommended getting a voltage closer to 9 volts. The larger 2 cell battery would seem to be able to generate a higher amperage if shorted out. Adrian's posts have recommended going to smaller single cell lipo batteries. I can't seem to find the correct short amperage for a 9 volt battery. I would be curious to know what the battery experts opinion on this is. Do you have any thoughts on the battery that you might use?
Click to expand...


We are all just learning mate. I certainly do not have the answers. Even if you only use the lipo to fire ejection charges if your charge wires short together that can cause a shorting scenario. Here is a great breakdown of a different problem but related to what we are talking about.

https://gag.com/bdale/blog/posts/Batteries_and_Pyro_Circuits.html

In your 2cell 7.4 lipo what is your C rating and Mah?? Take the C rating and multiply that by your mah and that is what your battery is happy to deliver until it is discharged. So if you have a 1000mah battery and it is rated at 25C (common rating) then on paper it can give you 25000ma of current or 25 amps.. WAY more than the 5 amps the RRC3 is rated for. Adrian's post says no more than the 165mah 3.7 lipo for the power perch and sells it with a 130mah battery. Not sure of The C rating as I overcharged that battery last year and had to dispose of it. (soaked in salt water for a week) If you look at this battery.

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11893

you will see that the burst C rating is 40 which in effect means this little bad boy can put out 6.4 amps and still be within its design limits (not a short) Remember the RRC3 is limited at 5amps

I was hoping Jim might pop back in and put in some words to this. On pages 8 and 9 of the RRC3 manual there is a diagram for 2 batteries. I'm looking at the Diagram and wondering if that would offer some protection to the RRC3.

I hate 9volt battery connectors and I am so space limited in this project that a lipo a quarter of the size would fit and the 9volt will not. ARRRRRGG

Cheers

Chris
 

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