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11-17-2010, 04:25 PM
| #1 |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
|  powering an HS-7980TH
So I bought this monster servo for my 1/6 campbell buggy knowing that I would need a separate power source for it. Now I'm new to the whole high voltage servo scene, so can someone tell me what bec I need to power this monster. I know castle has the the BEC pro, but I read somewhere that this still may not even be enough. Can I straight wire a 2 cell to it unregulated and just monitor the voltage or will I fry the battery or servo pulling too many amps? Whats the actual peak amp draw of the servo? I read somewhere it was 9 amps. Any help would be greatly appreciated. -Mike |
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11-17-2010, 06:27 PM
| #2 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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The regular CC BEC should be sufficient.... Here is the spec sheet for that servo: http://www.hitecrcd.co.jp/RC/servo/pdf/hs7980.pdf That sheet shows the stall current of 7.3A. Here is the spec sheet for the CC BEC: http://www.castlecreations.com/products/ccbec.html That sheet shows the max output for the regular BEC is 10A. Last edited by JeremyH; 11-17-2010 at 06:30 PM. |
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11-17-2010, 08:07 PM
| #3 |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
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It says the stall current is 7.3A at 6.0v its 9.0A at 7.4V so the regular cc bec wouldn't be sufficient. Im also running 6s which is 22.2v or 24v peaked, and the regular cc bed only puts out 5A at 24v. Thank you for the info, that will be very helpful.  Looks like the bec pro is my ony option at this point.
Last edited by supercrawlerfreak; 11-17-2010 at 08:12 PM. |
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11-17-2010, 08:12 PM
| #4 | ||
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
| Quote:
Quote:
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11-17-2010, 08:34 PM
| #5 |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
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From my experience running something rather close to its amperage limits would make it get hot rather fast. Its usually better to be over powered than underpowered. The rig is going to weigh in at about 25-30lbs running weight, so I can see hitting the stall amperage often. Does anyone else make a high amperage bec besides castle?
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11-17-2010, 08:38 PM
| #6 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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Well, from personal experience, I run three Futaba BLS152 servos in my super. When I was building the truck, I was unsure if I needed the regular or the pro BEC....so I called up Castle. One of their techs (Thomas) told me that the little blue one would be sufficient.... A local club member runs dual 7980THs in his super and I can guarantee that he either has the little blue (most likely) or the pro BEC in his truck and I have never seen either servo stall...... |
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11-17-2010, 08:39 PM
| #7 |
| Rock Crawler Join Date: Oct 2009 Location: SO CAL
Posts: 598
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11-17-2010, 08:54 PM
| #8 | |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
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11-17-2010, 08:57 PM
| #9 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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Here's his build thread: Team Y-Town SuperJuice |
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11-17-2010, 09:00 PM
| #10 | ||
| MODERATOR™   Join Date: Jul 2004 Location: Ohio
Posts: 18,928
| Quote:
Quote:
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11-17-2010, 09:09 PM
| #11 | |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
| Quote:
The BEC still has a peak output of 10A.... | |
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11-17-2010, 09:15 PM
| #12 |
| MODERATOR™ Join Date: Jul 2004 Location: Ohio
Posts: 18,928
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Not at higher voltages. Lemme look to see if I can back that up, been a while since I've read about all that.
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11-17-2010, 09:17 PM
| #13 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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Ahhh......duhhh.....24V. I guess I should read....  So then he might want to go with the Pro.... BTW, SCF, what motors will you be running on this beast? |
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11-17-2010, 09:27 PM
| #14 |
| MODERATOR™ Join Date: Jul 2004 Location: Ohio
Posts: 18,928
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Good then you know. I was looking for the perfect quote, but I drifted off reading about plane electronics...
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11-17-2010, 10:02 PM
| #15 | |
| Pebble Pounder Join Date: Jul 2010 Location: Colorado Springs
Posts: 183
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11-18-2010, 12:24 PM
| #16 | |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
| Quote:
 I'm running a 65mm out-runner I believe, I'll have to double check when I get home. I'm having a slight problem with it though. It has gobs of torque and will climb steep inclines with ease, but if you let off the throttle and it starts rolling backwards and you try to stop or go forward again, it wont. It just sort of cogs. But as soon as it stop spinning the motor backwards it has all its gobs of power back. Any ideas? I was thinking of having John make it censored for me, but I don't know if he ever got his censored out-runners working | |
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11-18-2010, 01:17 PM
| #17 |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
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found it  I think mine is a slightly higher kv (430 I believe) but its the same motor. KMS Quantum 5321/14 Bless Motor' Ref: M-KMSQ5321-14 Specification Max. Continuous Current (Amps): 32A NiCad/Ni-MH: 16-32 cells LiPo: 5-10 cells I0: 1.5A (10v) Turns: 14T KV RPM: 238 RPM Diameter: 63mm Max Current: 42A/ 60S Propeller Range: 18 x 12, 22 x 8, 23 x 11 Resistance: 63mohm Bearings: 3 Pole: 14 Pole ESC Timing Degrees: 20-30 (High) Length: 54mm Weight: 460g Max Efficiency: >90% Shaft dia: 8.00mm |
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11-18-2010, 01:18 PM
| #18 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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It's probably just the fact that it is not sensored. I've had the same issue with smaller outrunners in the past. Also, what KV is the motor??
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11-18-2010, 01:20 PM
| #19 |
| I wanna be Dave Join Date: Sep 2005 Location: Houston, TX
Posts: 16,952
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Ahh....humm....well, the is a pretty low KV...so it should be good.
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11-18-2010, 01:36 PM
| #20 |
| Rock Crawler Join Date: Mar 2005 Location: Murrieta
Posts: 806
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You think John would be able to make it censored. Theres plenty of room in it.
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Linear Mode
