What Lipo batteries are people using for the RRC3?

Rich asked me to take a look at these switching regulator devices and if they would be suitable for an RRC3.
There's no formal data sheet, however here's the spec summary for each:

TURNIGY 3A UBEC w/ Noise Reduction
Output: 5v/3A or 6v/3A (Selectable via jumper)
Noise: <50mVp-p(@2A/12v)
Input: 5.5v-23v (2-5S Lipo pack, 5-15cells NiMh)
Size: 41.6x16.6x7.0mm
Weight: 7.5g

TURNIGY 5A UBEC w/ Noise Reduction
Specifications:
Input: 7.2V-21V (2-5S Li-Po)
Output: 5V/5A
Dimension: 49mm*20mm*12mm (L*W*H)
Weight: 11.5g (wires included)

These look suitable for use if/when you want to provide a current limiter when using 2-5S LiPO batteries. Most low-current ematches have max all-fire currents @~1A, so these should be fine. Pre-measuring your ematch bridgewires for nominal resistances goes a long way in weeding out potential shorts, and there's one-less question to ask in any post-mortem failure analysis. Also the use of non-conductive ejection canisters reduces potential short paths.

The best 9V alkaline chemistries can dump about 5A max into a dead short...
The RRC3's are now using a 6A@25C SOT-23 FET.

The brown-out circuit keeps the mCU afloat for ~1.5 seconds when running a 9V power source.
ALL RRC3 events are activated for 1 second each.
A lower logic voltage reduces the brown-out hold-up time.

rharshberger said:

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

Click to expand...

Jim, thanks for looking into and responding to my request about the SBEC and UBEC. Mainly my concern for dead short situations comes from the two most likely scenarios, conductive charge wells and airstarts, 9v Alkalines will be my go to batteries for the most part. But there's something about tiny little LiPos that keep drawing me in.

Rich

Thanks Jim. Much appreciated. All good stuff. It looks like the airstart stuff is where it gets really challenging and demanding for batteries and altimeters.

Well I found the 9 volt dead short amperage right on page 5 of the RRC3 manual. Imagine that. Never hurts to reread the manual. I must have filtered that info when I read the first few times. Good to know though. Thanks again for the info. Jim. I might actually get to try my lipo and RRC3 out here soon.

Heads up folks, looks like the recommended LiPo from Sparkfun is finally back in stock.
See here: https://www.sparkfun.com/products/10718

I know lots of folks have been waiting for these for a long time. Here you go.

s6

stealth6 said:

Heads up folks, looks like the recommended LiPo from Sparkfun is finally back in stock.
See here: https://www.sparkfun.com/products/10718

Click to expand...

Thanks for the heads up on this! I received a RRC2+ and the 38mm sled for LiPo from Santa and this will complete the configuration.

V2rocketeer said:

And to add to that here is a voltage regulator from Turnigy that limits amps to 5a..

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=18521.html

Click to expand...

I am going to try the following regulator:

https://www.hobbyking.com/hobbyking/store/__18786__9V_4_5A_UBEC_2_5S_Lipoly_6_23v_.html

with either a 2S or 3S Lipo:

https://www.hobbyking.com/hobbyking/store/__23339__Turnigy_nano_tech_180mah_3S_25_40C_Lipo_Pack.html

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=23135

To power the ARTS1 or ARTS2 (or the RRC2+/3). I asked Jim Amos about this some time ago and he thinks it should work and provide the 5A protection.

-John

Tetrahedron said:

I am going to try the following regulator:

https://www.hobbyking.com/hobbyking/store/__18786__9V_4_5A_UBEC_2_5S_Lipoly_6_23v_.html

with either a 2S or 3S Lipo:

https://www.hobbyking.com/hobbyking/store/__23339__Turnigy_nano_tech_180mah_3S_25_40C_Lipo_Pack.html

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=23135

To power the ARTS1 or ARTS2 (or the RRC2+/3). I asked Jim Amos about this some time ago and he thinks it should work and provide the 5A protection.

-John

Click to expand...

I tested it today using my ARTS2 with two 7.4V Lipos in series giving me 15V and the regulator bring it down to 9V and 4.5A max.
It worked fine using the ARTS software diagnostic and fired apogee and main using two bulbs that I use when testing altimeters.
Next I will test fly it with Lipo using J-teks.



-John

Cl(VII) said:

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?

Click to expand...

I tested my RRC2 with the Lipo above that you mention and it fires the J-tek matches fine.

-John