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e flite 7.4V 800 mah lipo? (blade cx)

Old 07-22-2006, 04:22 PM
  #1  
jcblough
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Default e flite 7.4V 800 mah lipo? (blade cx)

Last 2 flights, I've noticed some significantly lower flight times. Especially this last one - seems like I got like 5 mins tops. I got paranoid that maybe I had over discharged it but it measured 7.6V on my volt meter. I'm charging it on a balancing charger now - I had been charging it on my duratrax ice charger. Does it sound like the pack got over discharged at some point or am I just being paranoid?
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Old 07-25-2006, 03:11 PM
  #2  
redgiki
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The E-Flite LiPos are poorly matched to the Blade CX. I own four of them, and only one does a good job of keeping the heli in the air.

I recommend picking up a 15C or 20C 700mAh LiPo from Common Sense RC or another LiPo vendor to replace it. The "10C" E-Flite Blade CX LiPos just don't have the juice to keep the bird running... they are getting overloaded. This doesn't appear to affect their capacity, but it does affect their voltage under load, and eventually they won't fly it longer than 1-2 minutes before settling down into ground effect. Discharge tests on my Triton confirm they are still holding 800mAh, but they won't sustain enough voltage to keep it flying.

Altitude is a heavy factor. People who fly the Blade CX at sea level don't seem to report as many LiPo problems as those, like me, at higher altitude (around 5000' above sea level). It seems the BCX LiPos are just barely matched to the power system at sea level... any higher, and they're overloaded.

These days, I use these LiPos in parallel to power other stuff, and they work fine if I treat them as 6C LiPos... which seems to really be their actual discharge rating rather than 10C.
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Old 07-25-2006, 03:15 PM
  #3  
jcblough
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I'll look into it. I found out I had dinged my inner shaft which was eating up some juice. I will look into the other lipos though - thanks.
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Old 07-27-2006, 03:10 AM
  #4  
t. edwards
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I use a 2S 910 Thunder Power Pro Lite in my CX. Real improvement vs the E-Flite battery. Tom
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Old 09-05-2006, 12:55 PM
  #5  
redgiki
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I realize this is a very old thread, but I had to comment because of my earlier comment.

The "bad" E-Flite LiPo packs, while I still think they are marginal, in fact do fly the CX just fine if everything is mechanically sound. I did a partial mechanical rebuild on my CX tonight:
* Adjusted the flybar linkage so my upper rotor tracking was true
* Double-checked the balance of my rotor blades.
* Used some lubricant on my ball links.
* Replaced inner shaft and gear.
* Replaced outer shaft and gear.
* Replaced motors using a water break-in; I've been flying it regularly since January on the original motors on which I never used any sort of break-in.

I did each of these replacements one at a time, checked blade balance then flew it, replaced motors then flew it, replaced inner shaft then flew it, replaced outer shaft then flew it. Turns out the heart of my power problem was the outer shaft and main gear. It just wasn't turning true, but it took replacing basically everything else for me to be able to see the slight out-of-true wobble on the outer shaft itself at speed.

Anyway, after doing all that, re-greasing everything, putting oil on the bushing of the new motors post break-in, and making sure everything's true again, even the marginal batteries fly the aircraft fine at my altitude of 5,000 feet. They don't last as long as the two new batteries I bought today to see if they'd fix my problem, but they fly the bird just fine.

What's a man to do with five Blade CX batteries that all work now, anyway? I suppose I can just try to find creative uses for them in other aircraft.

The moral of the story? It pays to learn about your heli and all the things that can go wrong with it. Check your tracking. Check that your parts are straight. Really, just replacing the outer shaft and main gear was what "fixed" my heli, but having everything else working and true combined to make the heli run like it's new again. I had great fun hovering and practicing slow forward flight in my tiny living room. What a blast of a little heli! I remember now why I bought it.
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Old 09-15-2006, 04:14 AM
  #6  
redgiki
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Well, I'm eating my words again. 3 of my 5 BCX batteries worked fine... for the first 2-3 minutes. Then they dropped off in voltage.

Garbage! Less than 50 cycles each, only ever flown in my BCX.

Anyway, these motors can suck down over 4A each during a climb, plus servo draw. A "10C" 800mAh battery barely fulfills these requirements. I'm done buying the E-Flite batteries for my BCX until they get higher discharge batts to replace the current crop of crappy batteries.

I strongly suspect that most people flying the BCX don't put as much airtime on it as I do (daily flights whenever the weather is too bad to fly outside), or they fly at a lower altitude where the battery isn't strained as much.
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Old 10-22-2007, 06:34 PM
  #7  
constantCrash
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I've done everything by the book in taking care of my batteries for the BCX and one of them is starting to puff. one cell is just slightly squishy. I'm convinced E-flite charger combined with marginally suited batteries is causing premature failure.

I bought a CellPro 4s which when i plugged in my batteries they were both at least .2 volts out of balance. (The only other charger i have is the e-flite one which says something for have crappy they are at balancing).

Both batteries probably have 60-70 cycles on them and then went into storage for the past 4 months as i got into RC planes as I was sick of fixing my BCX2 (they were stored at 50% charge in a retaining wall brick in my spare room)
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Old 10-22-2007, 10:26 PM
  #8  
Ryan CSRC
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Originally Posted by constantCrash View Post
I've done everything by the book in taking care of my batteries for the BCX and one of them is starting to puff. one cell is just slightly squishy. I'm convinced E-flite charger combined with marginally suited batteries is causing premature failure.

I bought a CellPro 4s which when i plugged in my batteries they were both at least .2 volts out of balance. (The only other charger i have is the e-flite one which says something for have crappy they are at balancing).

Both batteries probably have 60-70 cycles on them and then went into storage for the past 4 months as i got into RC planes as I was sick of fixing my BCX2 (they were stored at 50% charge in a retaining wall brick in my spare room)

If your batteries start to get worn out and puff I recomend replacing them with something like 8c 800mah packs in the battery section of our website. They are only $12.00 and when used with a balancer should last you a long, long time.

Ryan Lefevre
www.CommonSenseRC.com
The Go To Guys For Electric Power
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Old 10-22-2007, 11:09 PM
  #9  
constantCrash
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Angry Almost worth a warning.

I thought about reporting your post. It's nothing but spam. If you had taken the time to read the thread you'd realize that we are already complaining about 10C 800mah batteries so advertising an 8C is not a good idea.If you are going to "advertise" in these forums, as a member I would applicate it if you at least understood the topic your posting to. Otherwise you make yourself, and the company you represent look bad.

Lipo batteries (if not abused) should see around 300 charge/discharge cycles. My e-flites are around 70 cycles and one is puffing.



Originally Posted by Ryan CSRC View Post
If your batteries start to get worn out and puff I recomend replacing them with something like 8c 800mah packs in the battery section of our website. They are only $12.00 and when used with a balancer should last you a long, long time.

Ryan Lefevre
www.CommonSenseRC.com
The Go To Guys For Electric Power
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Old 10-22-2007, 11:14 PM
  #10  
Ryan CSRC
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Originally Posted by constantCrash View Post
I thought about reporting your post. It's nothing but spam. If you had taken the time to read the thread you'd realize that we are already complaining about 10C 800mah batteries so advertising an 8C is not a good idea.If you are going to "advertise" in these forums, as a member I would applicate it if you at least understood the topic your posting to. Otherwise you make yourself, and the company you represent look bad.

Lipo batteries (if not abused) should see around 300 charge/discharge cycles. My e-flites are around 70 cycles and one is puffing.
Sorry if my first post gave the wrong impression. The problem with the eflite batteries is they are not 10c at all, they are more like 6c. True 8c packs outperform them, and will last the normal several hundred cycles. The being 6c thing was mentioned in this thread, I assure you, I read it.

Ryan Lefevre
www.CommonSenseRC.com
The Go To Guys for Electric Power

Last edited by Ryan CSRC; 10-23-2007 at 03:02 PM.
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Old 10-27-2007, 05:40 PM
  #11  
xcat
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please check the 800mAh pack
http://www.saibnpower.com/product_show.asp?keyno=945
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Old 01-25-2009, 10:00 PM
  #12  
Jacket Man
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We now have packs for the Micro Blade MCX.

http://www.commonsenserc.com/product...roducts_id=766

Bulk purchase discounts are available also.

Mike
www.CommonSenseRC.com
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Old 07-30-2009, 06:58 AM
  #13  
ray574
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Hi, your reply to this question leads me to belive you can answer mine. Can I replace my 7.4v 10c lipo with a 7.4v 15c lipo in my 4 channel Esky Douphin heli?
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Old 07-30-2009, 02:47 PM
  #14  
Matt Kirsch
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LiPolys are compatible as long as:

1. They have AT LEAST the same C rating as the stock pack.
2. They have AT LEAST the same mAh rating as the stock pack.
3. They have the correct connector to mate with the ESC.
4. They will fit in the battery bay of the aircraft, and don't weigh too much.

As long as the 15C batteries meet criteria #2-4 (they already meet criteria #1), they will work just fine.

Criteruim #3 can be fixed by swapping out the factory connectors (often non-standard) for a standard connector like the Eflite connector (easy solder) or the Deans Polarized Mini (smallest connector)
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Old 07-31-2009, 05:30 AM
  #15  
ray574
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Hey, thanks a lot. I really appreciate your help. I have already ordered some 15c for my 3 channel heli that cracket up so hard it broke the receiver electrics, I think, since heli won't respond to radio anymore. Not so bad, I got it for $5 on ebay, so not bad for a few hours of important lessons on what not to do. LOL. So I can use the new lipos for my new 4 channel now. Thanks again and have a great day.
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