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Thread: Castle XL-X data logs amp ratings - are they accurate?

  1. #1

    Default Castle XL-X data logs amp ratings - are they accurate?

    Hello all,

    I wanted to see if anyone has seen or personally used a amp meter with an XL-X esc before. There is a strong feeling that the amperage ratings within the XL-X data logs are way off.

    A little back ground on this... I run on-road RC cars. (I come here for great electronics advice)
    I ran the XLX on 8s datalogs showed around 350 amps (forgot to save the log so I cant post it)
    I then ran the exact same setup with the HobbyWing Max5 8s (rated at 200amps cont) and the speed was within 1% of the run using the XL-X

    I cam across this video comparing the Castle MM-x and the XL-X where he is alluding to the same possibility of amp ratings that are nearly imaginary.

    https://www.youtube.com/watch?v=7oBp0_AELmI&t=842s

    Around 10:00 he reviews the logs for the MMX and around 13:00 the XL-X logs.

    Please don't get me wrong on my intensions here, I love castle products due to the tuning and data log detail. In this scenario I am trying to build a high power project and need some accurate numbers to make the best decision. If the XL-X on software V1.78 is not cranking out over 350 amps I will have to choose a different ESC. (most likely a 12s or 14s option as the goal is around 11kW under load considering voltage drop)

  2. #2

    Default

    I am not sure what you are getting at, it seems to be 3 different issues and Castle don't even publish amp ratings for their car ESCs.

    You seem surprised that 2 similar 1:5th scale ESCs give similar speed with the same setup but this is as it should be, why are you expecting a Big difference? Because 1 is capable of loging 350A and the other one is rated for 200A? What an ESC is capable of loging has nothing to do with its amp rating, even what an ESC is rated for continiously isn't even accurately indicative of what peak current it can take, which is why Castle don't even give an amp rating to their car ESCs. Both ESCs main selling point is the size of the Vehicle they can drive, and to drive those same vehicles with enough overhead to give a reasonable reliability whilst maximising profit, they will both need paralleled MOSFETs to a similar amp rating, PCB traces, bus bars and wires of similar sizes to supply the peak amps, and a similarly effective cooling solution, this will result in a similar resistance, and thus similar performance.

    Due to the way cars are typically used cars amp ratings are nearly imaginary, which is why Castle don't use them. The only reason we know their ratings is that customers have taken the cooling solutions off and compared the boards to Castle's air or boat ESCs which do have published amp ratings.

    The video you linked to is not casting doubt on the ESCs ratings, he says the XL is much more capable than the monster as indicated by its much lower temperatures with the same load. What he is disputing is the accuracy of the amp readings in the datalogs, and I would have to partially agree with him. While I havent used a XL-X specifically, I have used many Castle ESCs from their car, boat and, air ranges, including the Phoenix Ice 200 and Hydra Ice 240 which are very similar to each other underneath their cooling solutions. I have found that generally the readings look accurate and are confirmed by runtimes, but I do see the occasional instantaneous spike which looks erronious similar to what he had on the 3rd pull with the XL-X you can see the even shape of the 3 pulls on his log, and then there is a single pixel blip up to 350A on the third, this is what I see from time to time too.
    I believe that it is erroneous and should be ignored, certainly its duration is too brief to significantly heat anything up. It does throw off the maximum ampage report on the left side, but you can always click on the real peak to get the instantaneous readings which will tell you what the actual maximum ampage was.
    I could be wrong though, and those could be actual peaks but of very short duration. If a surface drive boat hits a wave and fully submerges its prop, it could produce a huge current spike, likewise if a car is spinning its tyres and hits a bump it will put extra pressure on those contact patches, if it is enough to get traction there could be a huge spike in current. If the current spike is of short enough duration it will look atypical and make me think it is erronious, for example, if the spike is 1/1000second in duration and the logger works at 10hz it would only show up in 1 out of every 100 pulls, infrequent enough that I would assume it was a glitch as otherwise I am seeing the same thing every time.

    There was an issue with one of the Castle car ESCs where it was limiting current even when current limiting was switched off a while back. I don't recall if it was the XL or the monster but i do think castle were in on the discussion and IIRC there was a patch or a solution of some sort. I would do some searching on here if I were you, as I don't recall the details. Maybe someone else recalls the thread and can link it.
    Last edited by NativePaul; 05-15-2019 at 01:48 PM.
    Paul "tug Killer" Upton-Taylor, Cat lover.
    FastElectricBoats.co.uk

  3. #3

    Default

    Quote Originally Posted by NativePaul View Post
    I am not sure what you are getting at, it seems to be 3 different issues and Castle don't even publish amp ratings for their car ESCs.

    You seem surprised that 2 similar 1:5th scale ESCs give similar speed with the same setup but this is as it should be, why are you expecting a Big difference? Because 1 is capable of loging 350A and the other one is rated for 200A? What an ESC is capable of loging has nothing to do with its amp rating, even what an ESC is rated for continiously isn't even accurately indicative of what peak current it can take, which is why Castle don't even give an amp rating to their car ESCs. Both ESCs main selling point is the size of the Vehicle they can drive, and to drive those same vehicles with enough overhead to give a reasonable reliability whilst maximising profit, they will both need paralleled MOSFETs to a similar amp rating, PCB traces, bus bars and wires of similar sizes to supply the peak amps, and a similarly effective cooling solution, this will result in a similar resistance, and thus similar performance.

    Due to the way cars are typically used cars amp ratings are nearly imaginary, which is why Castle don't use them. The only reason we know their ratings is that customers have taken the cooling solutions off and compared the boards to Castle's air or boat ESCs which do have published amp ratings.

    The video you linked to is not casting doubt on the ESCs ratings, he says the XL is much more capable than the monster as indicated by its much lower temperatures with the same load. What he is disputing is the accuracy of the amp readings in the datalogs, and I would have to partially agree with him. While I havent used a XL-X specifically, I have used many Castle ESCs from their car, boat and, air ranges, including the Phoenix Ice 200 and Hydra Ice 240 which are very similar to each other underneath their cooling solutions. I have found that generally the readings look accurate and are confirmed by runtimes, but I do see the occasional instantaneous spike which looks erronious similar to what he had on the 3rd pull with the XL-X you can see the even shape of the 3 pulls on his log, and then there is a single pixel blip up to 350A on the third, this is what I see from time to time too.
    I believe that it is erroneous and should be ignored, certainly its duration is too brief to significantly heat anything up. It does throw off the maximum ampage report on the left side, but you can always click on the real peak to get the instantaneous readings which will tell you what the actual maximum ampage was.
    I could be wrong though, and those could be actual peaks but of very short duration. If a surface drive boat hits a wave and fully submerges its prop, it could produce a huge current spike, likewise if a car is spinning its tyres and hits a bump it will put extra pressure on those contact patches, if it is enough to get traction there could be a huge spike in current. If the current spike is of short enough duration it will look atypical and make me think it is erronious, for example, if the spike is 1/1000second in duration and the logger works at 10hz it would only show up in 1 out of every 100 pulls, infrequent enough that I would assume it was a glitch as otherwise I am seeing the same thing every time.

    There was an issue with one of the Castle car ESCs where it was limiting current even when current limiting was switched off a while back. I don't recall if it was the XL or the monster but i do think castle were in on the discussion and IIRC there was a patch or a solution of some sort. I would do some searching on here if I were you, as I don't recall the details. Maybe someone else recalls the thread and can link it.

    I suppose my whole point is will the XL-X get me to 11kW or should I look at a HV esc in the 12s to 14s range used in boats like the ZTW 300a for example.

    In my 1/5 scale example runs lasted around 10 full seconds of full throttle where the esc has time to reign in the amperage limits (I have also seen short bursts of high current). Generally after about 3-4 seconds the amperage is pulled down to some "safe" constant value. I was surprised that the HW 200A rated seemed to be similar results to the Castle 310 to 350A data log value. (zero traction issues fully loaded the whole time). It has always been my suspicion that those amp logs are bogus numbers.

    I spoke with a Castle rep who indicated the MMX does not have limiting on it (no adjustments available in the castle link software). Logs seem to always clip off at 180amps take that for whatever value that is worth. For the XL-X on software version 1.78 current limiting can be adjusted up to 400 amps under the "custom" setting.

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