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yous should also use lipos able too deliver 130amps continous or more,. and 12avg wires minimum and deans connectors is not good enough use 5.5mm bullets.. or the new connectors that comes with alot of batteryes sold here at ose rated a 120amps cont. deans is only rated at 70amps.
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I've heard of guys getting in the 70mph. range with their Miss Geicos using 4082 2200kv motors spinning x442 props on 6s. The Leopard 4082 motor is rated to 60,000 rpm. I would think occasionally hitting 48,800rpm on this motor should be ok. I would however not push it at wot. constantly. It would seem to me they wouldn't rate the motor to 6s if it wasn't safe to run it on 6s. All I can say is most companies will give you a refund if you use their product within the parameters they lay out and it fails. There usually is a safety margin calculated into their parameters.Comment
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DID YOU READ THIS THREAD?! There seems to be a reoccuring theme around here lately?Comment
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6s is not recommended with the 2200kv motor. Sure it can probably spin that for a few seconds. But if you try it for a couple of minutes you will get a brick back and companies dont warranty burnt up motors that have been overheated.Steven Vaccaro
Where Racing on a Budget is a Reality!Comment
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Motors are mechanically limited to a maximum rpm. They start throwing magnets above that. The bearings usually will stand more rpm. The voltage times the Kv determines the rpm. They are also limited to a maximum power that they can deliver. The power required to turn a prop varies as the rpm CUBED and the propeller diameter to the FIFTH power. If you go from 6S to 8S the rpm increases by 29.6/22.2 or 1.333. The power required by the same prop increases by 2.37. Since you increased the voltage by 1.33, the current will increase by 1.78 times with the same prop.
A spread sheet with these factors helps understand what happens in these situations. It gets complicated where you can change all the variables. The simple relationships only hold with the same hull over a limited range of changes, but can still give a good idea of what happens. You need to start with known (actually measured) inputs.
Lohring MillerComment
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Am I wrong or do the lower kv. ratings allow for more cells. I know with the Nemesis Gold which is the same thing as Leopard the 4082 1500kv motor is rated at up to 9s which would spin it at 49,950rpm. The truth is I wouldn't push it at that rpm. for long but for a few seconds for one speed run now and then it should be ok. I would limit it to 8s for balance as well as a safety margin. The 2200kv version rated at 6s translates to 48,840rpm. Again I wouldn't run it a wot for long on 6s but for a few short runs it should be fine.
As to the esc on the other hand. As someone said earlier in this thread the Turnigy or Seaking 180 is only rated to 6s so an other esc would be required fo 8s. Though I havn't run across this problem yet I can see how the high rpms. could be hard on the other drive train components but if it amounts to replacing barings and teflon tubing on occasion I'm ok with that.Comment
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Use 30-35,000 RPM as your target of what a motor/battery combination to use. 2200KV should be run on 4S, = 31,680 No Load RPM. 1500KV on 6S = 33,300 no load RPM. If you try spinning your motor up around 50K, it's gonna fail, probably sooner than later.Mini Cat Racing USA
www.minicatracingusa.comComment
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Will I still get the same amount of power out of 4s as with 6s? If not I guess I should have gotten the 1500kv version rather than the 2200kv version I'm stuck with now. If that's so why do they even make a 2200kv version? Is there a way I can reduce the max rpm of the motor without having to buy new lipos? I was thinking about reducing my throttle end point or something like that. I'm no electrician so that explains my stupid question.Comment
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If set up and propped right, the speed will be close to the same as with 6S. No, you can not just reduce the throttle. On brushless motors the same amount of voltage is constantly going to the motor, it is the variance in pulse speeds from the esc to the motor that varies the rpm of the motor. Voltage does not change. Running brushless at less than wide open throttle most of the time will burn up the motor.Mini Cat Racing USA
www.minicatracingusa.comComment
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I am running a leopard 4082 1500 kv on 5s2p and getting 53 mph on 140 amps in my mean machine (given its a different hull), I would try tweaking your setup first. Getting a data logger would be the best idea, it will give you all the info you need. My temps are about 115F on the esc and 95F on the motor and that's with an m445. I still could get more out of it by a simple strut adjustment and a higher pitch prop. You really can squeeze alot from you current set up...24 R/C vehicles and still counting...What budget?
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Here is the data to prove it.Last edited by Rich; 09-09-2011, 06:45 PM.24 R/C vehicles and still counting...What budget?Comment
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Thanks for your helpComment
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