Sabre Flyer Posted July 9, 2017 Share Posted July 9, 2017 Hi all, I have a HK blue series esc 60amp and it has only about 21/2 inch wires from esc to go to battery. It would be ideal if I could lengthen these by about 6 inches but I have read that this is a 'no no'. Is it ok to go ahead and lengthen the wires? Many thanks. Quote Link to comment Share on other sites More sharing options...
John Robertson 3 Posted July 9, 2017 Share Posted July 9, 2017 I for one have. No problems noted. I simply made up correctly-gauged leads to the extra length required, soldered the appropriate connectors on them and made sure that they were safely shielded by heatshrink - you don't want any bare metal anywhere, or it will all end in smoke. Fair enough - extra wires and junctions could indeed lead to higher failure rates, but I doubt our planes are too critical in this respect. I wouldn't even consider trying to remove the short leads from the motor and, given that the 3 leads from the esc are carrying pulses, I would keep servo and Rx wires well clear. Quote Link to comment Share on other sites More sharing options...
onetenor Posted July 9, 2017 Share Posted July 9, 2017 No reason why not solder them and shrink tube it. Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 9, 2017 Share Posted July 9, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 9, 2017 Share Posted July 9, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
KiwiKid Posted July 10, 2017 Share Posted July 10, 2017 If you have to lengthen the battery wires, for whatever reason, it is advisable to add extra capacitors in parallel with ESC. As already mentioned, the reason for this is to catch voltage spikes that can occur when the wires are lengthened. Over time these spikes will degrade the on board caps and mos-fets and one day the ESC will fail. As a rule of thumb, (after the first 4inches/10cm) for every 4inches/10cm extra length/distance between battery and ESC, add a 220uF extra cap near the controller. Your local hobby shop might stock these or you can get them from an electronics store. In your case (with the battery lead) you may end up with 30cm of wiring, so we need to add a couple of caps – like so: Note that the negative terminals on the caps are denoted by the dashes along the silver line - they are soldered to the black negative wire with the terminals on the other side soldered to the red positive lead. Also, keep the positive and negative wires as close to each other as possible by taping them together - this is better than twisting the wires as twisting will give them extra length! We do this because, when the wires are close to each other, the series inductance will be reduced. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted July 10, 2017 Share Posted July 10, 2017 With all due respect, what a load of mumbo jumbo...This was an issue with ESC's years ago (which was resolved)or possibly very cheap ones. Buy an ESC form a British manufacture/suppler, if you have a concern discuss it with the owner (very helpful chap on the end of the phone/email) and allay your concerns. Number one rule don't add any more components in your chain of single points of failure than you need to, especially components that are not warranted/recommended by the manufacture. Number two extend motor leads in preference to ESC/battery leads Number three if you do need to extend them consult with your specific ESC's manufactures for guidance so recommend just to lengthen the leads. In the end you pays your money and take your pick with support/product quality PS I have a Vulcan with Lipos in the nose (for C of G, ESC's in the fuselage and pusher motors at the other end of the 6ft model...this issue is the least of my problems! PPS same issue with twins and multi motors, Motor in the wings, ESC's in the cowls (for air flow) & batteries in the fuselage for space & CofG adjustment....all ways a challenge! Quote Link to comment Share on other sites More sharing options...
Ray Farrimond Posted July 10, 2017 Share Posted July 10, 2017 Simple solution https://wheelspinmodels.co.uk/i/70639/ Other types of connector can be found with a search. Ray Edited By Ray Farrimond on 10/07/2017 08:24:08 Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 10, 2017 Share Posted July 10, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Dickw Posted July 10, 2017 Share Posted July 10, 2017 Increasing the length of a cable increases the inductance which increase the intensity of any spikes caused by the pulsed DC flowing in the motor circuits. That is not so much a problem on the motor side as the motor windings give the “spikes” something to dissipate in, BUT, on the battery side of the ESC it is the capacitor that absorbs the spikes. Increase the length – that increase the inductance - that increases the spikes - that makes the capacitor work harder. That is why any respectable ESC manufacturer recommends adding capacitors if you increase the battery to ESC lead length. It’s not just Hacker – I have seen that advice from others as well. You may well get away with a short length increase such as you are suggesting – but then it may depend on how close your ESC is to its limits now. Dick Quote Link to comment Share on other sites More sharing options...
KiwiKid Posted July 10, 2017 Share Posted July 10, 2017 Chris is right in saying that the best alternative is extend the motor wires. Assuming the OP did not have this option, then adding the caps is next best fix. As mentioned, not doing this is going to put added stress on the on board caps and mos-fets - they won't fail straight away, but are a ticking time bomb that will go off at some stage. If you are (very) lucky, you might get away with a loss of motor power and a quick landing, if not, power to the RX will be lost and it's then time to assume the crash position (curled up on the ground whimpering) I am not aware of these modern ESC's that do not need extra caps. Some high voltage ESCs do come with an extra cap, but will need extras based on wire length. Many ESC manufacturers like Castle provide extra cap boards that make it easy to attach multiple caps. Edited By KiwiKid on 10/07/2017 10:20:49 Quote Link to comment Share on other sites More sharing options...
Dickw Posted July 10, 2017 Share Posted July 10, 2017 YGE added capacitor options here:- http://www.yge.de/en/accessories/ Dick Quote Link to comment Share on other sites More sharing options...
Tony Kenny Posted September 16, 2017 Share Posted September 16, 2017 Good thread to read. I recently extended the battery cable to an ESC on an EDF model, the first flight out and I didn't have much power and something didn't feel right so I got on the approach to land and went dead stick. After landing I tried the throttle again and got blue smoke from the motor. Could that be a result of an ESC fault developing due to extending the battery cables? Quote Link to comment Share on other sites More sharing options...
Geoff S Posted September 16, 2017 Share Posted September 16, 2017 The only problem is that the capacitors you're adding look like aluminium electrolytic which can have quite a high inductance themselves if the aluminium plates are wound round the electrolyte as they often are. That means their ability to absorb high frequency spikes is limited. A better type of electrolytic is a solid tantalum, which is more expensive, but they have much lower inductance (no capacitor is perfect and they all have a resonant frequency, which in order to absorb fast voltage spikes needs to as high as possible). Even aluminium electrolytics vary and those with heavily etched plates (to increase plate surface area, hence capacitance) are much better as regards inductance. You need to check the spec. However, it is always better to extend motor wires and keep the battery wires as short as possible but a few centimetres isn't likely to be critical. After all battery leads vary in length themselves so an absolute length isn't standard. On a Depron Eurofighter cartoon scale model I'm just finishing I intend to extend the motor wires rather than the battery wires as the instructions suggest. Geoff Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted September 16, 2017 Share Posted September 16, 2017 Jeti also recommend adding capacitors "when the wires from your battery to your ESC need to be lengthened more than 20cm (8 inches). In case the wires are longer, use one for each 20cm (8 inch) section." They also mention that "another advantage of adding an additional capacitor is to reduce possible interference which may be caused by current moving through your power wires." I believe that low ESR capacitors are recommended although I don't know if this only includes the solid tantalum types - perhaps Geoff would know if low ESR aluminium capacitors normally have lower inductance than standard types? Edited By Martin Harris on 16/09/2017 22:56:17 Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted September 16, 2017 Share Posted September 16, 2017 Its voltage too guys, as a cap never runs at 100% capacity, They discharge at a very high rate at 2/3rds the voltage. So the 50v caps I see in the pics will discharge at 30v, hmmm ? Choosing a cap is like choosing an ESC, in that we choose one near and above our operating voltage. Caps come in various guises, and ours would be the 8v or 16v And would do their work between 6 and 10 volts. On reaching their case claimed voltage range, they immediately discharge and are ready again to fill. This is how they smooth circuits Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted September 16, 2017 Share Posted September 16, 2017 That's a new one on me - I thought that the maximum working voltage related to dielectric breakdown? How does a capacitor decide what voltage it will store - I thought it was simply when the two plates reached equal charge state i.e. whatever voltage it's supplied with? Edited By Martin Harris on 17/09/2017 00:09:54 Quote Link to comment Share on other sites More sharing options...
Geoff S Posted September 17, 2017 Share Posted September 17, 2017 Posted by Martin Harris on 16/09/2017 23:44:32: That's a new one on me - I thought that the maximum working voltage related to dielectric breakdown? How does a capacitor decide what voltage it will store - I thought it was simply when the two plates reached equal charge state i.e. whatever voltage it's supplied with? Edited By Martin Harris on 17/09/2017 00:09:54 It is. The voltage rating of a capacitor is the theoretical maximum after which the insulation breaks down. You're absolutely right, Martin except capacitors don't store voltage, they store energy and the energy (Q) in joules = voltage x capacitance (in Farads!). Obviously you can juggle the formula around to give the voltage. As I said in my earlier post the important thing is the speed of the voltage spikes (and hence how high the frequency) and how low the inductance is which resists changes in voltage. It's a complicated subject and one I haven't visited for 20 years since I retired. Geoff Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted September 17, 2017 Share Posted September 17, 2017 Posted by Geoff Sleath on 16/09/2017 22:28:13: The only problem is that the capacitors you're adding look like aluminium electrolytic which can have quite a high inductance themselves if the aluminium plates are wound round the electrolyte as they often are. That means their ability to absorb high frequency spikes is limited. A better type of electrolytic is a solid tantalum, which is more expensive, but they have much lower inductance Tantalum caps are very unreliable and best avoided where possible as they have a tendency to go short circuit. Much better is to look at the ESR and select an electrolytic cap with a low ESR value. Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted September 17, 2017 Share Posted September 17, 2017 Posted by Denis Watkins on 16/09/2017 23:20:12: Its voltage too guys, as a cap never runs at 100% capacity, They discharge at a very high rate at 2/3rds the voltage. So the 50v caps I see in the pics will discharge at 30v, hmmm ? Choosing a cap is like choosing an ESC, in that we choose one near and above our operating voltage. Caps come in various guises, and ours would be the 8v or 16v And would do their work between 6 and 10 volts. On reaching their case claimed voltage range, they immediately discharge and are ready again to fill. This is how they smooth circuits I'm not sure where you go this information Denis, but it's far from correct. The voltage rating of a cap is the maximum voltage it's guaranteed to withstand before the dielectric breaks down; when selecting a cap, choose one that exceeds the maximum working voltage, e.g. for a 3S pack, use a 16V or higher rated cap. You could use a 250V rated capacitor, it would work but it would be much larger than the 16V cap and would cost a lot more as well. Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted September 17, 2017 Share Posted September 17, 2017 Posted by Geoff Sleath on 17/09/2017 00:33:23:You're absolutely right, Martin except capacitors don't store voltage, they store energy and the energy (Q) in joules = voltage x capacitance (in Farads!). Obviously you can juggle the formula around to give the voltage. Geoff I'm going to be a real pedant here! Capacitors don't store energy, they store charge, Q is a measure of charge, not energy and it's measured in Coulombs. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted September 17, 2017 Share Posted September 17, 2017 Posted by Geoff Sleath on 17/09/2017 00:33:23: except capacitors don't store voltage, they store energy Sorry - didn't put that as I meant it - I was trying to clarify that the potential difference across the capacitor relates to the charging voltage and not the voltage rating on the case... Quote Link to comment Share on other sites More sharing options...
Lorenz Mueller Posted September 17, 2017 Share Posted September 17, 2017 Much better is to look at the ESR and select an electrolytic cap with a low ESR value. Rubycon for instance sells a series advertised as being low ESR. A respectable electronic retailer will carry them. Used them according advice by manufacturer Schulze Germany to lengthen battery wires for a pusher jet to about 1m with no ill effects. Lorenz Quote Link to comment Share on other sites More sharing options...
Geoff S Posted September 17, 2017 Share Posted September 17, 2017 Posted by Martin Whybrow on 17/09/2017 01:39:56: Posted by Geoff Sleath on 17/09/2017 00:33:23:You're absolutely right, Martin except capacitors don't store voltage, they store energy and the energy (Q) in joules = voltage x capacitance (in Farads!). Obviously you can juggle the formula around to give the voltage. Geoff I'm going to be a real pedant here! Capacitors don't store energy, they store charge, Q is a measure of charge, not energy and it's measured in Coulombs. You're right of course. It's over 20 years since I retired and had to design a smoothing circuit. However I would still claim that capacitors store energy. As a teen I got enough 7kv belts from the charge stored in the capacitor of cathode ray tubes from the EHT circuits. I took comfort that they were high voltage but very low energy - it's the volts that jolts but it's the mils that kills Geoff Quote Link to comment Share on other sites More sharing options...
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