cbdane
06-22-2009, 06:29 PM
Okay fellow 700E'ers. I think most everyone is familiar with the "$118 flight pack" thread where it was suggested that the new HobbyCity (or HobbyKing) Turnigy 6s1p 5000mAh 15-20C packs are really incorrectly labeled 20-25C packs, comparable in performance to the Zippy-H's that we know and love.
Here's the thread that first got my attention: $118 per 700e battery - HeliFreak
I ordered 4 of these to round out my collection of 6 Zippy-H packs that have been performing flawlessly in my 700E.
The good:
1. $59 each. :shock: Yes, boys and girls, 1/5 of the price of the 6s1p packs that I first bought for my 600E two years ago. 4 packs, with EMS shipping (about 4 days), set me back right around $300 for a real price of $75 each shipped.
2. These packs rock. Easily as powerful as the Zippy-H. I've never run some of the new uber packs (Hyperion v3, etc.) but I'm very happy with the performance. Check out the flight logs below showing a head-to-head comparison of a Zippy-H 12s1p 5000mAh to the same Turnigy 15-20C pack. The cells are lock-step balanced, before and after my flights (except for one; see "The bad" below).
3. High capacity. My brand new Zippy-H packs measured a capacity of around 4900mAh when brand new. The Turnigy 15-20C packs exceeded 5000mAh and my charger (BC8DX) terminated the discharge cycle early due to the pre-programmed capacity limit. Good enough for me; I didn't continue the discharge cycle to see how far they would have gone.
4. They are very compact. I would say (estimating) at least 2cm (~0.75") shorter than the Zippy-H with the same width and height. I didn't compare weights.
5. 10G leads; hefty. I don't think that a 12s1p machine really needs these since the average current is below 50A but a nice touch.
The bad:
1. I ordered 4 packs and one of the 4 came in with a low cell. What I mean by low is 0.00V. Not 1V, not even 0.5V, but 0.00V. I nursed it back into the charging range by carefully charging just the bad cell through the balance connector and then charged the pack normally. I flew it in my 600E (didn't want to risk my 700E beauty) and it performed just fine. By the time I arrived home, though, it was looking lower than the other cells. I discharged it to storage voltage (3.7V/cell) and decided to watch it. By last night, it was down to 3.2V (0.5V lower than the other cells). This morning it was down around 2V. Yep, bad cell with a very small internal short. :( Based on what I've read, this is just a risk with HobbyCity so I won't even try to return it.
2. No other drawbacks yet. I'll report back after some more flights on my remaining 3 packs.
Bottom line? $59 is an amazing price for this type of performance. With the bad pack (total loss, I assume), the price jumped from $75 to about $100 each (with shipping). I'm bummed about the bad cell but I still paid less than Zippy-H, even including exhorbitant EMS shipping. There are still somewhere over 150 of these available from HobbyCity (down from over 600 initially, if I remember correctly) so I'm planning to order 3 more to get me back to an even set, hoping that my number doesn't come up again with any more bad cells.
Here's the flight log.
http://www.helifreak.com/attachment.php?attachmentid=102927&d=1245713250
On the left is a 7.5 minute flight with Zippy-H with 10 previous flights. If you look back at some of my other 700E posts, you'll see this flight is pretty much the same as the first ones on these packs. (Kontronik Pyro 30-12 first tests - HeliFreak) On the far right is another 7.5 minute flight with the new Turnigy 15-20C. In the middle, is the very first (and very short) flight with the Turnigy pack. Take a look at the 120A spike at the beginning of the Zippy-H flight. I love rocket take-offs; you know, now you see it, now you don't. Well, the first time I tried this with the Turnigy 15-20C, I ripped the teeth out of my MicroHeli M1.0 gear :shock: Very short auto. Good thing I already received Miro's new 115T gear. I quickly installed the new Miro (FAD) gear and then did the full flight test on the right. Notice that I decided against the rocket launch for at least this flight. :P
Here's the things that I notice in the comparison:
1. More vigorous current spikes showing more peak power to the motor.
2. The HV110 governor doesn't hold quite as well. I believe that this is caused by the higher torque from the larger currents described in 1. Okay, the differences are pretty tiny but look closely at the blue trace. You can see some extra blips with the Turnigys.
3. Less spikiness (variation) on the voltage trace, showing the battery voltage holding up better to current transients (lower cell impedance).
4. The second short failed-gear flight was using the same packs as the 7.5 minute flight on the right without recharging. Even with this extra lost charge, the Turnigy packs still ended up at a higher end of flight voltage than the Zippy-H flight on the left. After flight, they recover to exactly the same voltage.
Summary: One pack with a bad cell. :arggg: Otherwise, these things are the bomb and priced similar to a good T450 pack (okay: truth; I haven't bought a new pack for my 450 in over a year). Will they last? Stay tuned.
Here's the thread that first got my attention: $118 per 700e battery - HeliFreak
I ordered 4 of these to round out my collection of 6 Zippy-H packs that have been performing flawlessly in my 700E.
The good:
1. $59 each. :shock: Yes, boys and girls, 1/5 of the price of the 6s1p packs that I first bought for my 600E two years ago. 4 packs, with EMS shipping (about 4 days), set me back right around $300 for a real price of $75 each shipped.
2. These packs rock. Easily as powerful as the Zippy-H. I've never run some of the new uber packs (Hyperion v3, etc.) but I'm very happy with the performance. Check out the flight logs below showing a head-to-head comparison of a Zippy-H 12s1p 5000mAh to the same Turnigy 15-20C pack. The cells are lock-step balanced, before and after my flights (except for one; see "The bad" below).
3. High capacity. My brand new Zippy-H packs measured a capacity of around 4900mAh when brand new. The Turnigy 15-20C packs exceeded 5000mAh and my charger (BC8DX) terminated the discharge cycle early due to the pre-programmed capacity limit. Good enough for me; I didn't continue the discharge cycle to see how far they would have gone.
4. They are very compact. I would say (estimating) at least 2cm (~0.75") shorter than the Zippy-H with the same width and height. I didn't compare weights.
5. 10G leads; hefty. I don't think that a 12s1p machine really needs these since the average current is below 50A but a nice touch.
The bad:
1. I ordered 4 packs and one of the 4 came in with a low cell. What I mean by low is 0.00V. Not 1V, not even 0.5V, but 0.00V. I nursed it back into the charging range by carefully charging just the bad cell through the balance connector and then charged the pack normally. I flew it in my 600E (didn't want to risk my 700E beauty) and it performed just fine. By the time I arrived home, though, it was looking lower than the other cells. I discharged it to storage voltage (3.7V/cell) and decided to watch it. By last night, it was down to 3.2V (0.5V lower than the other cells). This morning it was down around 2V. Yep, bad cell with a very small internal short. :( Based on what I've read, this is just a risk with HobbyCity so I won't even try to return it.
2. No other drawbacks yet. I'll report back after some more flights on my remaining 3 packs.
Bottom line? $59 is an amazing price for this type of performance. With the bad pack (total loss, I assume), the price jumped from $75 to about $100 each (with shipping). I'm bummed about the bad cell but I still paid less than Zippy-H, even including exhorbitant EMS shipping. There are still somewhere over 150 of these available from HobbyCity (down from over 600 initially, if I remember correctly) so I'm planning to order 3 more to get me back to an even set, hoping that my number doesn't come up again with any more bad cells.
Here's the flight log.
http://www.helifreak.com/attachment.php?attachmentid=102927&d=1245713250
On the left is a 7.5 minute flight with Zippy-H with 10 previous flights. If you look back at some of my other 700E posts, you'll see this flight is pretty much the same as the first ones on these packs. (Kontronik Pyro 30-12 first tests - HeliFreak) On the far right is another 7.5 minute flight with the new Turnigy 15-20C. In the middle, is the very first (and very short) flight with the Turnigy pack. Take a look at the 120A spike at the beginning of the Zippy-H flight. I love rocket take-offs; you know, now you see it, now you don't. Well, the first time I tried this with the Turnigy 15-20C, I ripped the teeth out of my MicroHeli M1.0 gear :shock: Very short auto. Good thing I already received Miro's new 115T gear. I quickly installed the new Miro (FAD) gear and then did the full flight test on the right. Notice that I decided against the rocket launch for at least this flight. :P
Here's the things that I notice in the comparison:
1. More vigorous current spikes showing more peak power to the motor.
2. The HV110 governor doesn't hold quite as well. I believe that this is caused by the higher torque from the larger currents described in 1. Okay, the differences are pretty tiny but look closely at the blue trace. You can see some extra blips with the Turnigys.
3. Less spikiness (variation) on the voltage trace, showing the battery voltage holding up better to current transients (lower cell impedance).
4. The second short failed-gear flight was using the same packs as the 7.5 minute flight on the right without recharging. Even with this extra lost charge, the Turnigy packs still ended up at a higher end of flight voltage than the Zippy-H flight on the left. After flight, they recover to exactly the same voltage.
Summary: One pack with a bad cell. :arggg: Otherwise, these things are the bomb and priced similar to a good T450 pack (okay: truth; I haven't bought a new pack for my 450 in over a year). Will they last? Stay tuned.