So, if I get an hour of runtime I must be averaging a 2.2 amp draw. If it only had 2 wires on the output side, it would be for a brushed motor. Guys, thanks for speedy answers. This field is what interacts with the stator magnets in the motor shell, and that’s what causes the rotation of the motor. The XRC GEN3 is armed with a powerful, INDUSTRY-BEST 7.0 HP motor. Thanks for the responses....so if you want to get the maximum performance out of your motor how do you do that? So, remember P=VI and since we’re looking for amps, we’ll switch that around to P divided by V = I, so watts divided by volts equals amps. So I jumped in head first and bought a B6d. It’s a better idea to fly with a timer and use this safety feature as a last resort, but it’s a nice feature to have to save your li-po batteries from accidental over discharge without turning the whole airplane off. To use the RC LiPo Battery Power & … So, it straight up says on the website that it’s a comparable replacement for a 46 glow engine, and it is rated at 900 watts max. First thing we need to know is the weight of the airplane. So, let’s do some math and see how this motor will work for us. Let’s talk watts for a minute. To find the maximum continuous amp draw, we first convert the 5100mAh to 5.1Ah, and multiply that number by 10C, to give a total continuous output of (5.1 x 10) = 51A How to find the optimum C rating As choosing the battery is often the last step to building your own drone, we will already know what motors and ESC we are using. It’s labeled CF-2822/14 1200kv. yes but at that voltage other things start to fry like connectors solder joints and esc's. 100 amps, and if you exceed that, the ESC might be damaged etc. Sometimes the brake is used on airplanes with foldable props, like for glider pilots that turn off their motors to glide. Electric Off-Road - the amps, the amps! Since we’re only pulling 40ish amps out of it, that battery will work perfectly for our application. In the former case the switch is cycled in a periodic fashion (PWM), thousands to 25,000 times a second, in the latter case (VFD) the next coil in sequence is switched on. Since the armature and the commutator spun, the electricity delivered to it by the brushes was able to reverse polarity and continue to spin the motor. For all the racers that have played with stock 27 turn motors ,, is there such a thing as too much amp draw with this type motor? This means that if your capacity is 3000 mAh for a constant 3 Amp current draw, then your capacity will be less than 3000 mAh if you draw a constant 6 Amps or a constant 30 Amps. So, 7 minutes at let’s say 40.5 amps, divided by 60 is 4.725 amp hours, or 4725 mah. Posted on 9th April 2013 by Hobby Warehouse. Depending on the airplane, you may want to cut a hatch somewhere. The reserve capacity of a battery is the number of minutes for which it can run at 25 amps of current without its voltage dropping below 10.5 volts. I know this can be done but in a car? Another thing to consider is prop RPM. The problem with brushed motors is that they’re not as efficient as brushless, and they don’t last nearly as long because of the physical interaction of the brushes riding on the commutator; therefore brushes are a wear item, and the commutator can also go bad. If you have a bigger airplane, you’ll want to power your radio equipment with a separate flight battery, just like you were running a nitro engine. It does not say if it’s for a brushed or brushless motor on the label, but we can figure that out by looking at it. And generally speaking, the answer is no. Let’s look at this a little closer. Brushed motors have 2 external wires that you connect to your power source. All battery elimination circuits are just voltage regulators, so essentially with a UBEC, you’re just adding a separate voltage regulator from your battery to the receiver. The old fashioned general rule is to stick with the following guidelines. When do a quick search for a 6000 mah 3s lipo, I see one that has a 25c continuous discharge, with a 50c peak. 12th spikes up to 40 amps in stock and runs down to 10-15 amps at the end of the straight. RC Cars: T4, e-revo, 2x e-maxx, BL Baja, HPI Super 5sc flux! Many times in the RC hobby the measurement of Amp hours or milliamp hours is given close attention. For some perspective, 0.05 amps should be the usual power draw when a vehicle is off. I always had a problem remembering what the commutator did, but one day it hit me that the commutator communicates the electricity from the brushes to the windings. If your battery is rated at 5000mAh, that means it can hold a steady 5-amp load for a full hour. How to Convert Reserve Capacity to Amp Hours. On the newer brushless ESCs from Novak, I think they let you switch the direction electronically from the ESC. However, you don’t have to use the BEC to power your radio, and if you have a bigger airplane, you can’t use the BEC to power your radio. I'd wager 120 Amps tops, and that's geared up and on high voltage. Let’s use that analogy again to quickly walk us through what we’re going to do to figure out what electric motor, battery, and speed controller we need for our airplane. So, if an amplifier, for example, is rated at 500 watts (power) and your electrical system produces 13.8 volts (the average output for most cars), the current draw will be … The power and configuration calculator has been created to assist models in making sure they have all the information they require to purchase application matching battery packs. Share; Posted January 22, 2016. The only problem is that motor timing is still […] First thing I found was an E-flite 4250 brushless motor, 540kv. Use of this site indicates your consent to the Terms of Use. As long as the switch remains closed, the current increases at a rate directly proportional with the voltage and indirectly proportional with the inductance (more turns or lower KV = more inductance). Now, since we know that P, or power labeled as watts =VI or voltage multiplied by amps, let’s figure out how many amps the motor will draw based on the power we need. As the motor spins, the brushes make contact with different parts of the commutator, which reverses the polarity on the windings and pulls the motor farther through its rotation. 46 reviews of Ampdraw Hobbies "You can't beat their customer service or their prices here!!! Brushless motors, on the other hand, are 3 phase ac synchronous motors. We’ll talk about that in a minute, but once we know the size motor we need we have a starting point for the rest of the setup. Is the 200a motor rating the sum of the 3 motor wires and not the battery wires. This means that a car battery’s amperage is more than 300 amps. After digging around online, I found a couple motors, so let’s look at them. Brushed rc motors have 2 wire leads, and brushless rc motors have 3 wire leads. The spec sheet for this one also tells us some other important information. This is further amplified and is passed-on as an output of the second stage and is available at the collector terminal of Q 2 after being shift by 180 o in its phase. Each ESC’s programming sequence is going to be different. Some ESCs have brakes on them, and the brake is normally able to be switched on and off in the programming. I am running dual batteries for my ECU, and the battery extension leads are going to be long. We get “5” from “5000” because a milliamp is 1/1000 of an amp. Now, that’s a lot of information on the label, but it’s important information to understand. A 4s lipo is 14.8 volts, so that works out perfectly. It is an inexpensive hobbyking ESC. A higher turn motor (13.5t, 17.5t etc) will have more torque but less top speed or RPM. All rights reserved. Think of it like a car motor. After you have it all laid out and put together, you have to, and I can’t stress this enough… It is imperative that you recheck the center of gravity and make any necessary adjustments. How am i supposed to measure the real amp draw with evidence like this? We’ll talk about ESCs later, but the reason these motors are able to operate is because the electronics advanced to where they became in a loose sense a computerized brush. Even though it’s a fully electric airplane, he has to charge and take care of the flight battery the same way he would any of his nitro planes. Your brushless motor should have a watt rating on its spec sheet, something like “180W”.