Chris Bott - Moderator Posted October 21, 2014 Share Posted October 21, 2014 I have to disagree Peter, a standard chock block has the end of the screw bearing directly down on the wires, when using the fine stranded wire that we do, there's a high likelihood that a good few of the strands will be severed as the end of the screw spins down towards, and probably through the wires. If the bundle doesn't perfectly fill up the space, then the screw is likely to go through between strands rather than applying a tight squeeze. If the bundle does fill the space, then it's going to be quite hard to make sure every strand goes in the hole. In my opinion, chock blocks are a very poor second to either a soldered joint, or soldered on plug in connectors. Screw down connections on correctly sized solid copper mains cable, yes. Or in low current stranded cables if crimp ferrules are attached first. But not for extra flex multi stranded wire carrying heavy currents, sorry. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted October 21, 2014 Share Posted October 21, 2014 Sorry Chris, I disagree, Like most things in life if the correct component is used then there is seldom a problem, the choc block barrel should be of the correct size for the cable, and the strands twisted anti-clock wise before insertion. then the strands will not be parted but compressed, strands will seldom be cut unless the screw face is damaged or its significantly overtightened Used correctly it is unlikely to cause a problem Soldered joints are in most circumstances preferable I agree, but where the user is not an expert in soldering, or uses an Iron or too small or too large a wattage then dry joints can ensue or damaged insulation etc etc Nothing is perfect and the biggest point of failure is usually the squidgy organic thing holding the tools! Quote Link to comment Share on other sites More sharing options...
Phil Green Posted October 21, 2014 Share Posted October 21, 2014 Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 21, 2014 Share Posted October 21, 2014 Oi! - get off that fence, Phil.... Pete Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted October 22, 2014 Share Posted October 22, 2014 Pete B @21/10/2014 19:57:45 Yes indeed, Pete, these are entirely my sentiments, too, all the way in. So this is exactly why, as I’ve remarked on the forum before, when I started assisting kids to fly models, and that’s many moons ago now, I insisted that the battery / switch harness plug and socket was securely held together. Adults I just similarly advise, though, and with an explanation they invariable do likewise. I always did it with a piece of lacing twine; now usually with one of the plastic clips; sometimes a simple staggered soldered joint, covered by a piece of fuel tubing slid over. Models crash for all sorts of reasons, and a power loss should be very largely avoidable, but even so it’s still fairly popular. More importantly, to me anyway, is the fact that said power loss leaves the throttle servo where it was, as indeed with all the other servos, thus there is no form of control whatsoever, and a model could conceivably crash in the pits area with the motor at full throttle. I’ve never actually seen this happen, but I know for certain sure there have been some very near misses. Over the years, too, there’s been many words, discussions and arguments about the merits or otherwise of fail safe settings, but a radio power failure negates the term ‘fail safe’ (relating to model aeroplanes) in a micro second, rendering it all as totally obsolete; and as far as I’m concerned, something of a seriously misleading misnomer to boot. As it happens, I don’t think that I’ve ever seriously advised anyone, and particularly beginners, to use choc blocks in any circumstances; however, it might be in the form of a casual suggestion on the odd occasion, but beyond that I consider that other pilots are capable of making their own decisions. In general it seems to me that aeromodellers are going to do that anyhow… This, then, is one of my angles regarding new modellers, and trying to encourage an ethic of caution, safety and 'Best Practice'. Chris @21/10/2014 20:03:27 I have to say that I’ve never seen any particular evidence that choc blocks damage any wires, and I’d probably never consider doing anything with these finely stranded wires without twisting them together first anyway. I’d certainly agree with a good soldered connection, but many folks don’t seem to do this much now. And there’s a surprising amount of evidence to suggest that some soldering is less than perfect, too, sadly it does appear to invariably be mostly at the manufacturing level, there’s a couple of photos in the album regarding this, as I remember. For me personally a choc block, with it’s fairly secure method of keeping the cables joined together, and regarding a crucial power connection, beats hands down an unlatched plug and socket which can and occasionally does fall apart at any time. In terms of current carrying capacity, again I’ve never seen this to be a problem. It shouldn’t be very very difficult to measure the volts drop across a block, against the same length of the conductor, and I suspect that installing an in-line watt meter might have a bigger effect. It’s just a personal choice, as I said, aeromodellers are always going to make up their own minds what they want to do… No criticisms intended gentlemen, just part of my take on it all… PB Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted October 23, 2014 Share Posted October 23, 2014 Each to their own I guess, I will certainly never use a choc block myself. As for assisting a beginner, I'd much rather teach him to solder properly than suggest a chock block, as the latter may result in him never being able to solder for himself. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 23, 2014 Share Posted October 23, 2014 +1 You can actually buy choc blocks with "terminal protection" which interposes a small strip of sprung steel between the screw & the conductor to prevent the screw breaking the strands. The screw tip bears down on the metal strip & compresses the conductors beneath it.... Still wouldn't use one though..... Quote Link to comment Share on other sites More sharing options...
Simon Hall 2 Posted October 24, 2014 Author Share Posted October 24, 2014 I have decided to just get on and solder the standard EC3 connectors to the new ESC myself. I now have all the connectors and heatshrink. I have watched a couple of Youtube vids and feel confident enough. I have done basic soldering before and this is not much more difficult by the look of it. What's the point in not having a go on my own with a hands on hobby like this? I have a block of wood with holes drilled to hold the bullets and some crocodile clips to hold things in place and help make the job a little easier. I was just wondering about the ESC I have bought which is a Turnigy Plush 40A. Is it linear or switched? I read somewhere that the early versions were linear, but the design was revised and the ones with the ferrule ring are switched. Mine has what looks like a green ferrule ring on it. I don't really know what the difference is to be honest, just that the switched ones are supposed to be better somehow? Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 24, 2014 Share Posted October 24, 2014 Good decision, Simon... soldering is such an inherent part of leccy flight, it's best to grasp the nettle Talking of grasping, the drilled hole method of holding the bullets is fine, as is the croc clip method with the EC3 and similar connectors. When you solder a connector, always fit a matching connector to the one you are soldering. This ensures that if a tad too much heat is applied, the connector will not deform to the point where it will not fit... Despite what the product listing for the 40A Plush ESC states, it is a switching BEC, not linear. All the Plush/Pentium/Flyfun ESCs, originally from Hobbywing, have switching BECs from 40A upwards. This is confirmed by comments on the product page too. In simplistic terms, for I know no other, linear BECs lose the excess energy in the form of heat, rather than switching on and off rapidly, so a switching BEC should run cooler, at the expense of generating a little more electrical interference, which is the reason for the green ferrule. More of an issue with 35MHz than 2.4GHz in practice, so I tend to remove the ferrule, if only to tidy up the installation... Leccy-literate forumites are more than welcome to add to this... Pete Quote Link to comment Share on other sites More sharing options...
Simon Hall 2 Posted October 24, 2014 Author Share Posted October 24, 2014 Thanks Pete, I will certainly use your tip and connect the opposite end up before soldering. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted October 24, 2014 Share Posted October 24, 2014 Make sure you have an Iron capable of generating enough heat to achieve a decent joint Simon, too little heat and you will get a dry joint and a simple test is to give the soldered bullet a decent little tug, if it comes off its a rubbish joint! Make sure you move the heatshrink far enough down the wire to avoid it shrinking while you are soldering, heavy wires and very good at transferring heat along their length! If your using the bullet in the hole method, then you will (unless you are very neat) to file excess solder off the bullet below the joint - easy with females, but if you are doing males, if you let too much solder overflow it will get into the expanding flanges on the bullet and jam them open Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted October 26, 2014 Share Posted October 26, 2014 I think with EC3s you solder the contact to the wire & then push it into the plastic housing.....this makes Petes advise about fitting a mating half somewhat redundant in this case..... Petes comments are perfectly valid & highly recommened for connectors where the contact is integral to the plastic housing such as Deans or XT60/90 connectors however. Two things to remember when soldering....keep it clean & keep it hot....you really need to make sure the work is hot enough to alllow the solder to flow well & remember to apply the soldering iron & the solder to the work. You often see people melting solder on the iron & letting it drip onto the work....this is wrong....heat the work with the iron until the work is hot enough to melt the solder. Tin the wire (ie melt solder into the strands) then tin the solder bucket on the contact (ie melt some solder into the bucket) then apply the iron to the contact...once the solder melts push the tinned wire into the solder bucket & you should soon see the wire tinning melt....ad a little more solder to flow around the joint & then remove the heat....hold the joint absolutely still until it cools & solidifies. The joint should look smooth & reasonably shiny.....a "dry" joint looks dull & "grainy" & if this happens you should apply more heat to re melt the joint & add a little more solder to help the joint flow together. It isn't difficult to do but there is a bit of a knck to it & like most things in life...practise makes perfect.... As Pete sez soldering is so integral to electric flight you should give it a go & learn how to do it. Two more points.....ensure you get the polarity of the ESC to battery connection correct & (I know it doesn't apply here but bear in mind for future) be VERY CAREFUL when soldering connectors onto batteries......if the battery wires are shorted out you will get one heck of a flash & a bang. Do it once & I can guarantee you will NEVER do it again.... Quote Link to comment Share on other sites More sharing options...
PatMc Posted October 26, 2014 Share Posted October 26, 2014 Posted by Dave Hopkin on 21/10/2014 19:56:32: I think there is a great deal of "over engineering" of electrical circuitry in the installation side of electric flight, For example, I have here a 4-Max/Purple power PPPO-3548-790, quite a beefy beast rated at 850 Watts for a 60Amp ESC, when I put a Micrometer on the motor wires, they are 1.5mm (presumably multi conductor wires) Now forgive me, but would I wire up a 60Amp Circuit using 1.5mm Wires? According to British Standard 6004 (household wiring) the diameter of flexible cable (multi conductor) for 60Amp is around 15mm Mark and it doesn't change significantly be it DC, 2 Phase AC or 3 Phase AC...... So I remain totally confident that my chocolate block connector will be far less failure prone than home soldered bullet connectors with the potential for dry joints But its a personal choice The 3548-790 motor is rated at 40A max - so 50% less than the ESC. Comparing the motor wire with house wiring isn't valid as the length also has to be taken as a factor - E.G. look up the required size cable for a 30A cooker circuit then check the dia of 30A fuse wire that could be part of that circuit. Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted October 26, 2014 Share Posted October 26, 2014 The 30A fuse wire is a) of a different material b) is designed to melt when it reaches a specific current hence thinner The wiring itself will be designed to handle a higher current that normal usage On an ESC the amplitude of the output from the ESC doesn't change, the frequency of off/on does.... Length of wiring is crucial, the resistance of copper is about 0.02 Ohm per Meter, but on the motor side of the ESC we are not dealing with DC, we are dealing with a square wave form where the switching frequency controls the speed of rotation so given the relatively high frequency of switching the effective area of conductor will be reduced by skin effect, I'm not sure what the frequency of a typical ESC is, but if its in the 100 Khz area, then the skin effect will reduce the conductor to an effective 0.2mm (hence multi strand wire must be used) Quote Link to comment Share on other sites More sharing options...
PatMc Posted October 26, 2014 Share Posted October 26, 2014 David, I'm afraid your wrong on just about every point you make. Quote Link to comment Share on other sites More sharing options...
Simon Hall 2 Posted October 26, 2014 Author Share Posted October 26, 2014 I seem to have stirred up a hornets nest here! Some of your comments are going way over my head as a total beginner. I am trying to pool all this useful advice together as best I can. Maybe I should have posted this in the beginner section. The main thing that concerns me at the moment is if I heat up the factory bared ends on the Plush ESC to add a little solder to them, can I put too much heat on the wire by holding the iron on too long and damage the ESC? Edited By Simon Hall 2 on 26/10/2014 18:43:30 Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 26, 2014 Share Posted October 26, 2014 No problem, Simon, it happens frequently... Some people seem to be overlooking the fact that you're a novice, looking for a simple, straightforward answer to your questions, and I'll continue to try and do just that The answer is that you're most unlikely to damage the ESC when you're tinning the wire ends, provided you use a nicely hot iron and you complete the tinning quickly. You should be able to hold the tip to the wire ends for just a few seconds - say, 5 to 6 max, and that should heat the wire enough for the solder to flow. Once you seen it run, it's done. Pete Quote Link to comment Share on other sites More sharing options...
Simon Hall 2 Posted October 26, 2014 Author Share Posted October 26, 2014 Posted by Pete B - Moderator on 26/10/2014 18:55:27: No problem, Simon, it happens frequently... Some people seem to be overlooking the fact that you're a novice, looking for a simple, straightforward answer to your questions, and I'll continue to try and do just that The answer is that you're most unlikely to damage the ESC when you're tinning the wire ends, provided you use a nicely hot iron and you complete the tinning quickly. You should be able to hold the tip to the wire ends for just a few seconds - say, 5 to 6 max, and that should heat the wire enough for the solder to flow. Once you seen it run, it's done. Pete Thanks Pete. I appreciate your advice and clear instruction for me as a beginner. I also appreciate all the above posters for their kind input and detailed info. Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted October 26, 2014 Share Posted October 26, 2014 Simon, Similar little hornets nests have lightly simmered on the back burner for a long time now. We’ve been over similar ground a few times in the past. With regard to the soldering, and to repeat the excellent advise already posted, I’d personally spend some time practising, find a bit of spare fairly light weight three core mains wire, say, and use that to see how how easy you can get the solder to flow. The secret is how long, or rather less, time you need to spend to get the right heat, using a smokin’ hot iron. Then twist three or more cores together and try that. I always add a small amount of flux first, I’ve used Powerflow for years. The reason for this is so that when you touch the work with the tip of the iron a small amount of solder flows straight onto the work and instantly starts to transfer the heat. This can happen very fast, on small work it’s just a dab and away. I try to not go back and add more, this can start to go wrong. On bigger work, apply the iron to the biggest and heaviest piece. On anything except shiny bright items I clean with cellulose thinners, or perhaps even up to a file it if necessary! I use the universal piece of wet sponge to keep the iron tip clean, and generally it only needs to be lightly tinned. If the solder does start to pile up, and you really have to adjust it, clean all the old solder off first, solder wick is very useful for this. Another little dabble, find some old exhausted AA cells, clean both ends, tin the end of a piece of wire, then tin a small area on the cell with a small puddle of solder, then solder the wire to the cell. It’s not that easy, remember that doing it for real you have to work fast, this would normally be a brand new nickel cell, and you wouldn’t want to ruin it before you start! Although I always found they were pretty hardy anyway, as indeed are most items. Then when you’ve done all these practise pieces, try and break them apart. If the soldering is nice and shiny, feathered edges, a perfect ‘wet’ joint, it’s unlikely you’ll be able to do much damage without the aid of a bit of leverage. So then you use a lever until you do get it apart, the result will give you a lot of confidence in your subsequent soldering… Good Luck! PB Quote Link to comment Share on other sites More sharing options...
Simon Hall 2 Posted November 2, 2014 Author Share Posted November 2, 2014 Thanks all for the tips. All done and I am very pleased with the results. I enjoyed doing it too. The link below was what I think was the best of the Youtube video tutorials based on all the advice given. **LINK** Quote Link to comment Share on other sites More sharing options...
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