|Dec 26, 2010, 04:14 PM|
Lightweight Hyperion packs for the UMX Beast, Sbach, and UM Stryker Q
Just finished making my lightweight Hyperion packs. I used two bare Hyp 180 cells, double-sided tape from a 3M window film kit to hold the cells together, the available pigtail w/stock JST 'PH' connector, a couple dabs of hot-glue between the tabs to provide some strain-relief and prevent shorting, a couple dabs of liquid electrical tape on the connections, a short strip of plastic for a tab, and a Velcro dot. I also built a 240 mAh Hyperion pack.
Weight & static RPM comparisons (RPM measured with a calibrated optical tach under natural light @ 30 sec into the run on a freshly-charged pack):
Eflite 2s 120 ----------------------------------------------- 9.45g; Static RPM: 10200
Eflite 2s 180 ---------------------------------------------- 12.92g; Static RPM: 10500
Hyp 2s 180 ----------------------------------------------- 11.84g; Static RPM: 11100
Hyp 180 'UM' cells x2 + RC-Connectors series harness -- 12.34g; Static RPM: 11000
Hyp 180 'UM' cells x2 + Eflite series harness ---------------- 13.01g; Static RPM: 10700
Hyp 2s 240 ----------------------------------------------- 14.51g; Static RPM: 11100
RPM data suggests that the stock 120 is a bit overtaxed in this application. Note the significant RPM increase with the Hyperion 180 pack. Also note the significant reduction in performance when using the Hyp 180 'UM' cells & the factory series harness - 400 RPM in this case. Interesting that there was no increase in static RPM with the Hyp 240 pack. The Hyp 180 pack may indeed be the ideal match for this plane - a significant power increase, yet lighter than Eflite's 180 pack.
A quick flight confirmed that my lightweight Hyp 180 packs provide a marked improvement in power as compared to Eflite's packs, and even the Hyp 180 'UM' cells + series harness. Vertical was very noticeably improved as compared to my vertical performance demo. I hope to test-fly with the 240 pack soon.
EDIT 12/29/10: I took the Beast up for some comparison testing between my 2s Hyp 180 & 240 mAh packs. I had no problem attaining a neutral CG setting with the 240 pack. The extra weight of the 240 was just barely noticeable on extended up-lines, however vertical performance was still essentially unlimited. Slow-flight was not affected enough to notice, and landings were as slow as ever. There was still enough power for extended verticals and large loops even 8 minutes into the flight. I'm waiting for my charge adapter harness so I can charge the packs on my BC8DX and post some usage data.
EDIT 01/02/11: Thanks to Habitforming for the static thrust data below, based on my static RPM measurements above:
Additional thrust as compared to the stock Eflite 120:
Hyp 180 'UM' + Eflite series harness -------------- +10%
Hyp 180 2s pack w/stock JST 'PH' connector -- +18%
My Hyperion 180 pack blows away the stock 120 mAh pack, and it also outperforms the Eflite 180 pack by a large margin; yet it weighs 1.08g less than the Eflite 180 mAh pack. My Hyperion 180 pack also outperforms the Hyp 180 'UM' cells + Eflite series harness by a large margin, and it weighs 0.76g less than the individual cells + harness. My Hyperion 240 pack also outperforms the Eflite 180 pack by a large margin and provides a significant improvement in endurance - yet it is only 1.6g heavier than the Eflite 180 pack. Flight-testing shows that the extra weight of the Hyp 240 pack over the Hyp 180 pack is barely noticeable. It is evident that if you want to unlock the true potential of the UMX Beast, making your own packs is well-worth the effort. If you lack the soldering skills, a pair of Hyp 180 UM cells with the series harness is the way to go until quality aftermarket packs are available.
I have received a series Y-harness from Glenn @ RC-Connectors.com for testing. I added the data above. Weight & static RPM tests show that Glenn's harness outperforms Eflite's harness by a significant margin (just 100 RPM lower than a 2s Hyp 180 pack); and at 0.53g, Glenn's harness is 0.67g lighter than Eflite's harness, which weighs 1.2g. The wires on Glenn's harness are much shorter, and the cell connectors appear to be of much higher quality as compared to Eflite's harness. Plus - Glenn's harness is $1 less than Eflite's.
For anyone wanting a plug & play high-performance battery solution for the UMX Beast, a pair of Hyperion 180 or 240 mAh 'UM' cells with Glenn's harness is the way to go.
Note: I made a mistake in measuring the weight of the loose cells with the Eflite harness. I forgot to include the weight of the extension tab that I used on the 2s packs. I have corrected the mistake, above.
Glenn @ RC-Connectors now has JST to Beast adapters. This gives those who already have 2s packs w/JST two-pin plugs, such as the Hyperion 2s 180 mAh or 240 mAh packs. Balance-charging is not possible with this configuration, however.
Marlin has put together a great pack-building pictorial & video. Check it out here: Marlin's pack-building pictorial & video
European source for the 3-pin JST 'PH' connector that's used on the UMX Beast packs. You want the 'Battery Lead for AR6400LBL': Micron Radio Control
RemE's Beast Modification thread (start at page one): http://www.rcgroups.com/forums/showthread.php?t=1349163
|Dec 27, 2010, 01:56 PM|
For those who are new to building their own packs, I will attempt to explain my method below. Unfortunately, I didn't take pics of the intermediate steps. I will document the steps when my next batch of cells arrives.
Warning: Use caution when building your own packs. Do not overheat or short the cells. Good soldering skills are required. If you are inexperienced, I suggest that you build them on a non-conductive, non-flammable surface that is capable of withstanding high temperatures. You may want to think about building your first few in the garage or outdoors, weather permitting. I present this for informational purposes only. The user assumes all responsibility for the use of the information presented herein.
Bare cell pics:
1) Attach a piece of double-sided tape to the back (side without printing) of one cell. Peel the backing, then stick the back of the second cell to the first one. You will now have a sandwich, with all tabs pointing in the same direction. Adjacent tabs will be of opposite polarity. The '+' tab on cell #1 will be closest to the '-' tab on cell #2, and the '-' tab on cell #1 will be closest to the '+' tab on cell #2. See the picture below.
2) Carefully trim the tabs.
3) Solder the '+' & '-' tabs on one end together, along with the white wire.
4) Solder the red & black wires to the remaining '+' & '-' tabs, respectively.
Caution: Be very careful to not short the cells when trimming and soldering the tabs.
5) Apply liquid electrical tape to all exposed connections, then let it dry.
6) Inject some hot-glue into the gaps between the tabs. Take care to not short the pack with the metal tip of the glue gun. For strain-relief, put a dab on the wires where they exit the pack.
7) Cut a strip from a plastic cover, such as a margarine tub. Attach a piece of double-sided tape to it, and stick it to one side of the pack, as shown below.
8) Apply a Velcro dot to the bottom of the tab, and your pack is ready for use. The pack goes in battery-first, and the tab should stick out far enough to allow for easy pack removal.
9) Install the pack, and measure the CG as described in the manual. Adjust the position of the pack accordingly. Here is an excellent guide for flight-trimming aerobatic planes, courtesy of the NSRCA: http://nsrca.us/index.php/all/flying/177-trimchart.html
10) Charge, fly, repeat!
Total: $9.90 + tax, shipping, misc materials
The stock charger will charge these packs; however the charge time will be long - especially with the 240 mAh pack. With the appropriate charge harness and an aftermarket charger, the Hyperion packs can be safely charged at 5c for hundreds of cycles with no loss in performance - provided that you land at the 80% discharge point or earlier.
Do not use SLVC (motor pulse) as your flight-timer. Doing so will damage your packs, as SLVC on most UM 'bricks' doesn't kick in until ~90-93% discharge. The best way to determine your usage is to time a few shorter flights using fresh packs, then charge them on a charger that reports the mAh required to charge the pack. Divide the charge mAh by the rated capacity of the pack, multipy by 100, and you have percentage of discharge.
With a 180 mAh pack, an 80% discharge equals 144 mAh. If you used 50% on a 5-minute flight, try flying for 6.5-7 minutes & check again. Set your flight-timer so that you'll land at the 80% discharge point on an aggressive flight. This will help to maximize the life of any LiPo - not just Hyperion.
Good luck, be safe, and happy flying!
ImagesView all Images in thread
|Dec 27, 2010, 02:21 PM|
This was MOST helpfull Joel! Please diss-regard my earlier PM asking about balancing, this explained it very well for me! The part about THANK YOU however stands! Thanks very much for this very helpfull information.
|Dec 27, 2010, 07:22 PM|
You are most welcome! Glad I could be of help. Remember that it is relatively easy to overheat these little cells. Manage the heat accordingly when soldering.
If you are relatively new to aerobatic planes, you may also find my post on flight-trimming useful: http://www.rcgroups.com/forums/showthread.php?t=1361350
|Dec 27, 2010, 10:17 PM|
Again, your posts are a wealth of knowledge for newer flyers, can't thank you enough. I will be pointing others this direction.
|Jan 04, 2011, 05:50 PM|
Many Thanks for taking the time to research and identify the best choices. My UMX beast is on the way and just ordered 6 bare cell hyperion 240 1C packs. Have been building my own packs for some time now for my micro helis so this wont be an issue for me.
|Jan 04, 2011, 07:15 PM|
You are most welcome! I am happy to help where I can.
Although I am a veteran fixed-wing pilot, I am relatively new to eflight. My first electric was a Wingo. I caught the 'UM bug' when the original Sukhoi 26m & mSR came out. It's been downhill since then! I received lots of great advice & assistance on the UM threads when I first joined RCG. Especially with the heli stuff, as the mSR was my first heli. Electronics (RF, in particular) is my profession, but I have always been strongly interested in mechanical engineering & aerodynamics. So, I am trying to do my part to help newcomers, as others did for me.
Good luck with your maiden! Let us know how it works out, and let me know how the packs work out for you.
Good luck & happy flying!
|Jan 07, 2011, 10:52 PM|
Joel - thanks for posting the info on here, I went ahead and soldered myself 3 new packs, 240mAh Hyperion cells x 6. I have a couple of tips that might help lighten packs as well as speeding up the job...
Instead of using hot glue/liquid tape, heat shrink the battery tabs after the appropriate wires have been soldered. Solder the two -/+ tabs together on the two cells first, slide a piece of heat shrink on the white wire, then solder the white wire on there, slide the heat shrink tube down the wire and over the soldered tabs, and carefully use a lighter or wand to shrink the heat shrink, keeping the flame away from the battery pack. You need to use a slightly larger heat shrink tube for the +/- tabs soldered together with the white wire, and smaller diameter heat shrink tube for the positive and negative battery leads on the other two tabs. The heat shrink provides strain relief on the battery tabs and prevents them from coming in contact with one another, it also adds next to no weight to the overall pack.
Definitely use nothing thicker than double-sided scotch tape to adhere the two cells to one another, I wanted to use double-sided foam tape at first, but the pack was just too thick to fit inside the Beast's battery compartment. With the double-sided scotch tape, it fits perfectly, pressure fits in there nicely.
Overall, each pack weighed about 13.7 grams, just a few grams heavier than the stock 120mAh 2S E-flite packs.
|Jan 08, 2011, 09:39 AM|
You're welcome! Your Hyp 240 packs weigh 0.8g less than the ones I built - most excellent! After using mine for awhile, I think the hot-glue is superfluous. I plan to omit it on my next batch, which will probably save 0.5g.
Did you do any static RPM measurements?
|Jan 08, 2011, 09:52 AM|
Joel - not yet, just charged the packs last night and plan on using them today at an indoor club fly event, I'll bring the tach to get an RPM measurement to check on it. Visually and audibly, I can tell the prop spins a bit faster on the Hyperion 240mAh packs vs. the stock 120mAh E-flite pack. I'll most look forward to the extra flight time.
How far back have you set your 240mAh packs to get a good balance? At a ~4g difference in weight, I don't think they'd need to go back more than a few mm, but I won't really know for sure until I fly this afternoon.
|Jan 08, 2011, 10:03 AM|
That's a very good question, and I surely don't mind. After all, the main reason I started these threads was to answer questions.
I trimmed the +/- power lead tabs to approximately 1/8" - just long enough to fold the ends around the wires. I left the balance wire tabs just long enough to provide an 1/8" overlap for soldering.
Be sure to stop back & us know how it works out.
|Jan 08, 2011, 10:16 AM|
Talk to you later, and thanks again Joel,
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