KenC Posted June 29, 2023 Share Posted June 29, 2023 Can some kind poster offer a diagram of the correct circuit for this . If the ESC has its own circuit for RX and servos , should this just be left to preserve the main Lipo for power, or is it possible to use this as a backup. As you can see I am new to electric flight , when I last flew ( turn of century) it was IC all the way. We always used the NiCd 4.8v flight packs and 2300 mah was fine for a good few flights , now I feel after playing and setting up that the electric retracts drain power quite a bit. So my next question is what sort of second power would you suggest ? Quote Link to comment Share on other sites More sharing options...
Wookman Posted June 30, 2023 Share Posted June 30, 2023 If you want to use a separate power source rather than the bec in the ESC you simply disconnect the positive wire where the ESC plugs into the rx. You are then free to plug a normal rx battery into the rx in the same way you would for an ic model. It would also be possible to power the rx and primary flight controls from the bec in ESC or a separate battery and then use a another battery to power the high drain items like retracts. Basically the signal and the negative from the retract goes o the rx and the positive and the negative goes to the separate supply. Easy enough to create a Y lead from two extension leads to satisfy that requirement. Another possibillity might be to power the retracts via the bec and the main drive motor from the lipo and use a separate supply for rx and primary flight controls. As to which batteries to use, I like 2000 eneloops. If you need better current delivery you will have the go to a sub C Nimh or another Li battery of some sort. Careful what voltage the retracts are rated for if you are going Li. You might need a separate bec! 6 Quote Link to comment Share on other sites More sharing options...
Andy Stephenson Posted June 30, 2023 Share Posted June 30, 2023 I powered the retracts on an electric model by simply using a separate stand-alone BEC connected directly to the drive LIPO. This way, if the retracts jam, it can't pull power from the receiver supply. Using electric retracts which have an overload cut-off after 2 seconds, it's also never likely to deplete the main battery beyond the point of danger to the receiver supply. 2 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted June 30, 2023 Share Posted June 30, 2023 It's going to depend in some respects on the size of the model and ESC BEC, on several foamy models inc high power EDFs the ESC BEC powers everything, the receivers I am using monitor the receiver voltage and to.date they have all worked fine. Many ESCs have switched BECs rated at 5amps, more that a 4cell AA high capacity pack could deliver. 1 Quote Link to comment Share on other sites More sharing options...
Trevor Posted June 30, 2023 Share Posted June 30, 2023 In addition to the above, if you've got one or two spare receiver channels, it can be worth plugging the retracts into separate channels then using a time delay in the transmitter so they don't all operate at exactly the same time. This will reduce the peak current demand on your battery or BEC and so reduce the voltage sag. I have one tricycle u/c model where I had to 'de-sync' the nose wheel retract in this way otherwise it would stop when half retracted as the combined current peak with the mains caused enough of a voltage sag for the nose retract to conclude it had met with some kind of obstruction. 3 Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted June 30, 2023 Share Posted June 30, 2023 That's what I did on my Seafire, two separate channels and a servo delay on one, the retracts look more scale. Quote Link to comment Share on other sites More sharing options...
KenC Posted June 30, 2023 Author Share Posted June 30, 2023 (edited) Thank you gentlemen for your comments and wisdom. As I will most probably opt for a "SAFE" receiver, and have telemetry reporting Lipo voltage below a certain voltage , I quite fancy the idea of leaving the retracts on the BEC who's voltage will be audibly warned, and putting the safe receiver on a safe 6v supply with the servos guaranteed to last longer than a 10 minute flight . For those that queried, I am looking at a 80amp ESC and 6S 5000 50c Lipo with a 3Max 5065 - 360 motor. Edited June 30, 2023 by KenC Quote Link to comment Share on other sites More sharing options...
KenC Posted June 30, 2023 Author Share Posted June 30, 2023 6 hours ago, Wookman said: If you want to use a separate power source rather than the bec in the ESC you simply disconnect the positive wire where the ESC plugs into the rx. You are then free to plug a normal rx battery into the rx in the same way you would for an ic model. It would also be possible to power the rx and primary flight controls from the bec in ESC or a separate battery and then use a another battery to power the high drain items like retracts. Basically the signal and the negative from the retract goes o the rx and the positive and the negative goes to the separate supply. Easy enough to create a Y lead from two extension leads to satisfy that requirement. Another possibillity might be to power the retracts via the bec and the main drive motor from the lipo and use a separate supply for rx and primary flight controls. As to which batteries to use, I like 2000 eneloops. If you need better current delivery you will have the go to a sub C Nimh or another Li battery of some sort. Careful what voltage the retracts are rated for if you are going Li. You might need a separate bec! In your third option of ɓec to retracts and lipo to throttle, then a second power to all servos. ...please confirm the wiring just to make sure silly me does not screw it up. If I may ask , wire from escape to battery has live and neutral noreal heavy cable ,and also a secondary live taken off the main. What is this for ? Quote Link to comment Share on other sites More sharing options...
Wookman Posted June 30, 2023 Share Posted June 30, 2023 (edited) I will, but it it will be later in the weekend or very early next week. Edited June 30, 2023 by Wookman Quote Link to comment Share on other sites More sharing options...
KenC Posted June 30, 2023 Author Share Posted June 30, 2023 OK thanks for your help, the part of my question ( typed on a pad keyboard ) 😞 was speaking about the power cables out of the ESC to the lipo battery. It is the main power and there is BEC in a normal futaba plug with the red removed for secondary power. Here is a pic of the main power to battery Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted June 30, 2023 Share Posted June 30, 2023 I'm guessing there could be a resistor on the 2nd red wire underneath the heat shrink. Basically plug in the negative, then use the red lead with resistor to charge up the ESC capacitors avoiding the spark and then.make up the main lead, but this would require an extra connection on the battery. On my 6s setups I use the Jeti antispark connectors with the built in resistors. BTW you model seems.similar to my 82" span MR Hurricane, where I use a separate battery for the Rx, servos and retracts, but thats because my ESC is the Opto type with no BEC Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted June 30, 2023 Share Posted June 30, 2023 I agree with Frank, that looks like a spark suppression set up. As he says, connect up the black connector (and please add more black heat shrink so you cannot see the brass connector for safety sake), then connect up the red wire with the smaller connector before connecting the bigger red connector (and if the connector it plugs into is in the same state as the black one - once again apply more heat shrink). I would also cover BOTH red connectors which some silicone tubing to prevent shorting out during storage. The above comments assume the above is off the battery but the same comments apply if it is the other way around. "Safety is not an accident" Quote Link to comment Share on other sites More sharing options...
KenC Posted June 30, 2023 Author Share Posted June 30, 2023 Thanks to you both for your comments. Andy unless someone can tell me why I should not, I am almost sure to fit a more modern 90 connector to the ESC wires and also the battery. Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted June 30, 2023 Share Posted June 30, 2023 (edited) Connectors are the choice of individual modellers, and as can be seen in other threads there is no real agreement. 4mm connectors like the big ones in your photo are the connector of my choice as it gives me plenty of options when it comes to joining pack in serial or parallel depending on the model. If XT90 is your choice then that is your choice, I would not be putting you off of using them. One thing to add, try and fit them with the same polarity as the pre connected pack ones, that way you can charge, connect up and go fly with any new packs you purchase later. Edited June 30, 2023 by Andy Gates Quote Link to comment Share on other sites More sharing options...
KenC Posted June 30, 2023 Author Share Posted June 30, 2023 Great tip Andy , thanks. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 30, 2023 Share Posted June 30, 2023 11 hours ago, Frank Skilbeck said: Many ESCs have switched BECs rated at 5amps, more that a 4cell AA high capacity pack could deliver. Eneloop AA size 2000mAh cells can deliver 5A just fine. For about twenty minutes, anyway. That said, personally, I would run main servos from one bec, and the retracts from a secondary bec, all from the main flight pack. 1 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted June 30, 2023 Share Posted June 30, 2023 27 minutes ago, Nigel R said: Eneloop AA size 2000mAh cells can deliver 5A just fine. For about twenty minutes, anyway. Try it and see what the voltage is, on some packs I've got 2 amps causes a large voltage sag. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted July 1, 2023 Share Posted July 1, 2023 They'll keep over 1v per cell until around twenty minutes in, is my experience. I don't do this regularly. Usually I would periodically check a 2000mah aa pack at 2a and make sure I get a good amount of the rated mAh on a charge/ discharge cycle. Some tests here that concur with the 5a for 20min figures: https://lygte-info.dk/review/batteries2012/Eneloop AA BK-3MCCE 1900mAh (White) 2019 UK.html Quote Link to comment Share on other sites More sharing options...
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