TonyS Posted December 31, 2022 Share Posted December 31, 2022 (edited) I've been trying to build a 4 EDF model Vulcan for the best part of 5 years now, maybe longer. It took shape quickly but came to a screeching halt when I got to wiring it up and has sat on my workbench ever since. Every so often I pluck up enough enthusiasm to 'give it another go' and so, here I am. Basically the problem is this. No matter how I wire the system I can only ever get two fans to work. The set up was meant to build in some redundancy, one battery powers the two inboard fans, the other the two outboard fans. I did this such that if one battery gave up the model would still have two motors. Anyway, the set-up is as follows: The four speed controllers have four plugs each with a positive, negative and data wire. I have disconnected the orange data from three of these. So the four plugs then go into a 4 in 1 connector which then connects to the throttle port in the receiver. The power cables from the outboard EDF speed controllers (red and black) connect into a 2 into 1 and then into one battery, the inboards do the same into the other battery. I switch on my Tx (a Spectrum DX7) and then connect the two batteries. The two inboard motors then bleep and respond to throttle inputs from the Tx. The outboards EDFs are dead. I've just tried changing the battery set-up so that in place of the 2x 4S batteries I have 2x 2S batteries in series and all 4 of the motors then connect together. I did this in case the problem was connecting first one battery (which then primed 2 speed controllers) then connecting a second but at this stage the second pair of speed controllers wouldn't be recognised. Same outcome - 2 EDFs working, two EDFs dead. If I mess around I can get the 2 outboard EDFs to work and then the two inboard EDFs are dead. If anyone can provide any pointers as to what I could try next I'd be immensely grateful. I did by the way post about this (about 4 or 5 years ago I think though I've lost track of time). Thanks Edited December 31, 2022 by TonyS correction Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 31, 2022 Share Posted December 31, 2022 Tony, My immediate thought is that the speed controllers need data/signal and negative wire from the rx to function, not just the data/signal. A circuit diagram of how you have it wired up would be useful. Even a photo of a hand drawn one would work. Martin. Quote Link to comment Share on other sites More sharing options...
Martin Gay Posted December 31, 2022 Share Posted December 31, 2022 This might help if you have not already seen it: Microsoft Word - How to wire up a twin Brushless aircraft rev 2.doc (4-max.co.uk) Quote Link to comment Share on other sites More sharing options...
Andy J Posted December 31, 2022 Share Posted December 31, 2022 Tony, could you make a quick sketch of your electrical connections to the speed controllers and motors? Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted December 31, 2022 Share Posted December 31, 2022 (edited) 56 minutes ago, TonyS said: I have disconnected the orange data from three of these I assume this is a mis type? It's the positive power you need to disconect from three of the ESC's Edited December 31, 2022 by Philip Lewis 3 Spelling Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 31, 2022 Share Posted December 31, 2022 You should have disconnected the positive (red) from three of the four ESC`s, not the signal which they need, otherwise they will have no input and you will be powering the Rx four times over which is a no-no. The ESC leads need to go into a four into one connector which then goes to the throttle channel. Quote Link to comment Share on other sites More sharing options...
john davidson 1 Posted December 31, 2022 Share Posted December 31, 2022 (edited) Wiring a twin motor is one thing, wiring with twin batteries is some thing else. I made a Twin Mustang some years ago with a battery in each fuselage to balance ,and had I think the same weird results until I programmed one ESC as a slave to the throttle channel. There was a very slight delay winding up the second motor , not noticeable in the air Four could be done this way as long as there are spare channels Edited December 31, 2022 by john davidson 1 addition Quote Link to comment Share on other sites More sharing options...
Andy J Posted December 31, 2022 Share Posted December 31, 2022 Tony, this diagram may help. Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 So, here goes... The, ahem, wiring diagram Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 51 minutes ago, Philip Lewis 3 said: I assume this is a mis type? It's the positive power you need to disconect from three of the ESC's Yes, apologies, the power is what's disconnected. Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 56 minutes ago, Philip Lewis 3 said: I assume this is a mis type? It's the positive power you need to disconect from three of the ESC's Yes, a mistype. Oops! Quote Link to comment Share on other sites More sharing options...
Andy J Posted December 31, 2022 Share Posted December 31, 2022 For a starter for 10, the -ve's of Bat 1 & Bat 2 need to be interconnected to provide a common ground to all 4 ESC's. Quote Link to comment Share on other sites More sharing options...
Andy J Posted December 31, 2022 Share Posted December 31, 2022 Next query is how did you wire up the BEC supply to the RX? Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 52 minutes ago, Martin McIntosh said: 2 minutes ago, Andy Joyce said: For a starter for 10, the -ve's of Bat 1 & Bat 2 need to be interconnected to provide a common ground to all 4 ESC's. That may well be the issue........ The negatives aren't interconnected! Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 2 minutes ago, Andy Joyce said: Next query is how did you wire up the BEC supply to the RX? There's no sep. BEC supply - Quote Link to comment Share on other sites More sharing options...
Andy J Posted December 31, 2022 Share Posted December 31, 2022 So how is the Rx powered? Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted December 31, 2022 Share Posted December 31, 2022 As shown the batteries should all be grounded together via the negative leads to the receiver, but it's worth checking. It may well be that the throttle signal is too weak to power 4 ESCs, this is driven from the chip on the receiver, although the current is very small it could be that it is insufficient top drive all 4 ESCs, if you plug the ESC's in separately do they work? I know that a friend had a similar problem with some electric retracts they wouldn't work unless he was using the lead supplied with them which had an inbuilt signal amplifier. If you search servo signal boosters you'll see several inline signal boosters are available. The other option would be to use separate channels on your Rx, but you may not have enough channels to do that. Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted December 31, 2022 Share Posted December 31, 2022 8 minutes ago, TonyS said: That may well be the issue........ The negatives aren't interconnected! I think that is the likely issue, you need a common ground to all. Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 5 minutes ago, Frank Skilbeck said: As shown the batteries should all be grounded together via the negative leads to the receiver, but it's worth checking. It may well be that the throttle signal is too weak to power 4 ESCs, this is driven from the chip on the receiver, although the current is very small it could be that it is insufficient top drive all 4 ESCs, if you plug the ESC's in separately do they work? I know that a friend had a similar problem with some electric retracts they wouldn't work unless he was using the lead supplied with them which had an inbuilt signal amplifier. If you search servo signal boosters you'll see several inline signal boosters are available. The other option would be to use separate channels on your Rx, but you may not have enough channels to do that. Thanks Frank, I have put a signal booster in the circuit between the 4 in 1 and the Rx. The retracts work well - and they are quite chunky, so I'd be surprised if there was insufficient signal to power 4 ESCs but then, what do I know.... I've just connected all the negative leads from the batteries however I still only get the two inboard fans powering up. I'm using a Spectrum AR500 Rx which is small but there are spare channels. I'm not sure how to slave a separate channel to the throttle though? Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 12 minutes ago, Andy Joyce said: So how is the Rx powered? Andy, it's via the power wire from the ESC Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 8 minutes ago, Philip Lewis 3 said: I think that is the likely issue, you need a common ground to all. So I've just connected the negatives and still nothing? Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted December 31, 2022 Share Posted December 31, 2022 Silly but have you tried one by one on your RX, it could be a program problem on your controllers. Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 (edited) Latest attempt..... Edited December 31, 2022 by TonyS sent wrong pic! Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 2 minutes ago, Paul De Tourtoulon said: Silly but have you tried one by one on your RX, it could be a program problem on your controllers. No such thing as silly at this stage. Got to be worth a try. I have had the outward EDFs working but who knows.... Quote Link to comment Share on other sites More sharing options...
TonyS Posted December 31, 2022 Author Share Posted December 31, 2022 51 minutes ago, Andy Joyce said: Tony, this diagram may help. On this diagram is it right that only the white data wire is connected from each speed controller? Quote Link to comment Share on other sites More sharing options...
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