Gary Murphy 1 Posted June 27, 2014 Share Posted June 27, 2014 New to elec`s and the bumph states 40-60 A esc required. I have a good quality 80a new in packet and wonder if I can use that. I do not know if a too large a esc can harm the other components? Quote Link to comment Share on other sites More sharing options...
Olly P Posted June 27, 2014 Share Posted June 27, 2014 Gary, should be absolutely fine, only penalty might be in size and weight terms. Olly Quote Link to comment Share on other sites More sharing options...
Gary Murphy 1 Posted June 27, 2014 Author Share Posted June 27, 2014 That will be ok then,its a semi scale wwi bibe so no lack of room or weight worries. I was not sure if I read something about the motor and esc should be well matched,dont even remember if the esc or motor suffers. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted June 27, 2014 Share Posted June 27, 2014 Personally (and within reason), I go for the biggest ESC that space and budget will allow. My flea fli has 60A ESC for a 30A (330W load). No harm in that at all. It also helps remove some of the cooling worries - but they still need to be cooled! M Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted June 27, 2014 Share Posted June 27, 2014 Yeap - if weight/cost are not an issue then I think a good big'un, operating well within its spec, has some advantages over a good little'un, that's just managing at the edge of its performance envelop! BEB Quote Link to comment Share on other sites More sharing options...
Allan Bowker Posted June 27, 2014 Share Posted June 27, 2014 Yep, I agree, I don't think it is possible to 'over ESC'. As as already said, the only penalties are weight, size and cost. Quote Link to comment Share on other sites More sharing options...
Gary Murphy 1 Posted June 27, 2014 Author Share Posted June 27, 2014 Thanks guy`s, I was given a brand new castle creations 80a ,so I will use that.Thinking back to what I read,it was something about its better to use full power rather than half? does that sound like something that does come into play somewhere? motors or cells,trying to find what I read. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted June 27, 2014 Share Posted June 27, 2014 There is a school of thought that says that under some circumstances an ESC heats up more at lower throttle settings than say full throttle. The theory being that it regulates by pulses so at half throttle it has to "hold the current back" more and so absorb the energy of doing so. Personally, I don't really get this argument and it doesn't seem to be backed up by my experiences with ESC's. But others know more about the internal functioning of ESC's than I do so I'll leave that point of detail to them. Because..... - even if its true its not relevant here. You are not setting up an overpowered system running at half throttle. Your situation is not that you have a system capable of generating more power than you need. You just have an ESC in the chain which is rated as capable of handling more current than your system will draw. Having an ESC capable of handling more current wont make your system actually draw any more current. It just means you could use that ESC in other more demanding situations and in this situation it will be well within its performance limits, that's all. BEB Quote Link to comment Share on other sites More sharing options...
John Privett Posted June 27, 2014 Share Posted June 27, 2014 Posted by Gary Murphy 1 on 27/06/2014 18:18:36: Thinking back to what I read,it was something about its better to use full power rather than half? does that sound like something that does come into play somewhere? motors or cells,trying to find what I read. OK, that's talking about something slightly different. That question is, does the ESC work "harder" when the motor is running at full-throttle or at half-throttle? And the answer is probably, at half-throttle. In the old days (not so many years ago!) when brushed motors were the norm, then certainly the ESC was more stressed running at part throttle, as it was switching the motor current on and off thousands of times a second to regulate the motor speed. Whereas at full throttle it just supplied the full battery voltage constantly to the motor. And it's the switching that causes losses and generates heat. Nowadays with brushless motors the ESC has two functions, it switches the power between the motor windings (so the motor can go round) as well as switching the power on and off (thousands of times a second again) to regulate the motor speed. Again, it's the switching that causes problems, but there's always switching going on in the ESC, even at full-throttle, so it's possibly not as clear cut with brushless whether full or half throttle causes the ESC most stress. [And once again BEB got in 20 seconds ahead of me! I knew I shouldn't have proof-read what I'd written a second time! ] Edited By John Privett on 27/06/2014 18:33:08 Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted June 27, 2014 Share Posted June 27, 2014 Snap John! BEB Quote Link to comment Share on other sites More sharing options...
Shaunie Posted June 27, 2014 Share Posted June 27, 2014 It is true to say that an ESC has more switching events at part throttle than full. When a transistor (MOSFET) is switched off the voltage across it is high but the current is negligible so power dissipated is low, When switched on the current is high but the voltage drop is low so again dissipation is relatively low,however when switching on or off the current is significant and the voltage drop is appreciable therefore the device gets hotter. This will create more heat in the ESC, but I wouldn't worry too much as the designer should have taken that into account and apart from arranging good cooling there is nothing you can do about it any way. Having an ESC with more headroom will however help reduce heat build up so in that respect it can only be a good thing.. Shaunie. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.