Help with XL2 log data???
 

Since my tried and true MMMv2 decided to catch on fire...I stepped it up an purchased a XL2 for my Muggy conversion with a 1717 castle motor. So I did a short run today with a few blips of the throttle...no where near WOT. The XL2 is a beast; however, from the get go it does have some cogging. Settings are default.

I've read other posts and I am still not entirely sure if I'm calculating the ripple correctly.

Max ripple = 1.97V
Max voltage = 24.7 V, ave = 24.4, min = 19.4V
Max current = 239.3 amps
Max Watts = 4635

Temps were all low - logged max esc = 92 F

The run was with a 17T pinion with a 48T spur.

calculated ripple I get is 1.97/24.7 = 0.079 or 7.9% which I think is okay.

The only thing that worries me is the cogging, which is not horrible but it persists and my batteries are older Hyperion G3 Ex rated at 45C 5000Mah. I have the CC cappack, 8mm CC bullets on everything, and a CC pro BEC.

What do you guys think?

http://i44.photobucket.com/albums/f1...y/firstrun.jpg

Not sure but i belive you have to navigate in the graph where the highest ripple occurred and read the voltage there, like not the use the max voltage.

When I look at the graph for maximum ripple the voltage is 24.1, so calculated ripple is 8.0, which is still reasonable...I'm worried about the cogging...I just have a feeling my lipo has gotten old? Think I'll order a new TP G6...

239 Amps seems pretty high, what are you geared for 100mph? I have a 1717 for my Flux 5T conversion and have decided I don't trust the MMM on 6s Lipo so a MMXL is in order, would you even need a cap pack with the XL esc?

I do remember saying that some of the firmware operates better then others.
I not sure which ones are avilable for the mmxl.

My gearing is not radical for an E-muggy, again 17T pinion and 48T spur...I was using 16T with the MMM though my motor wires would heat up more than anything else...the 1717 is fairly large in the muggy and unless I mill down the fins adjacent to the center diff outdrive, there is no way to get less than 16T or I'll have to shim up the center diff and put a 50T spur?

I'll have to check the firmware version...not sure how many there are for the MMXL?

Wow, 240Amps is a very high current for a Muggy on 6s. 4635Watts is more power than I've put through my 19lb. stretched Muggy geared for 50mph. But your setup looks OK - temps are good and ripple voltage is acceptable.

What size tires are you running?

Thats mean its to much resistance, you may want to gear down ore check\re solder your connections.

Both 8% ripple and 240 amp (burst?)is a bit high to say atleast.

im not even pulling that in my baja with 2028

Hmmmmm....

I disagree with you guys that 240A is really high -- if he's drawing 240A at top speed, then yes. But during acceleration currents can get REALLY high.

An Erevo brushless edition draws 400A during acceleration. Average current is only about 80A, but peaks are 400A+.

I think the datalogging feature will open some eyes to how much power these cars use. :surprised:

OK Patrick, I'll take your word for it - I was just comparing his results to what I've logged on my larger (heavier) version of the same vehicle.

A question that (I think) has been raised before, but I'll ask you: How narrow are the current spikes that these trucks have on acceleration? If we are logging at the fastest rate available on the ICE controllers, could we still be missing the highest point of the spike?

And, as always, thanks for your input here.

high current
 

I am not surprised by a 240 amp burst - this current lasts way less than a half second and isn't unheard of with a 4wd truck in high traction. The average draw will probably be less than 40 or 50 amps throughout a typical run(a 5000mah battery at 30 amps average draw will last less than 10minutes).

When using the data log, the sample rate makes a big impact on the draw that you actually see in the log - 10 samples/second will show much higher peaks typically than 5 samples/second or less, for instance - the peaks last a very short period of time usually. The 240 amp burst, for example, may show up as 150 amps if only sampling once per second.

Yeah, forgot to include that I'm using huge wheels and tires - 55 series Cen snipers...this is probably really screwing up my gearing. They really are not much heavier than stock muggy.

I'll have to do a run with my stock wheels.

So overall, it looks like my numbers are not horrible...but again I'm concerned about the start up cogging...my wheels/tires may be the issue, so I'll put the stock wheels and tires back on and try that before I drop $200 on a new battery.

Oh, my motor wires stayed cool with the Mamba XL - I've shortened the wires as much as I can while still including the 8mm bullets..

Again, motor and ESC and wires stayed cool though it was a short run.

Based on my experience, I am completely surprised by your max current of 240amps! Especially in a medium sized vehicle. My 28lb Baja 5t pulls 215 amps on pavement with NO tire spin. Meaning I am putting all the power to the ground... That is with the 2028 motor on 8s and running the crap out of it hard.

My Brushless E-Revo (more closely realated to a muggy than my 5t) also with an XL2 and a 1518 motor only pulls 106 amps on 6s...ripple is 1.8v with cap pack. And that is running mine wide-open-throttle...all the time really hard!!! So 240 seem really high to me....especially if you are just blipping the throttle. If I were to guess, I would say your motor is malfunctioning which is what caused your MMM2 to fail. Neither of mine cog in anyway shape or form.

Again, That is just my experience. Your current numbers are WAAAAY higher and different than mine and I have been running my baja 5t for about a year now. I was one of the first owners of the Castle Baja Conversion kit with the original Mamba XL ver 1. I would say you have a problem somewhere.

My XL2s are doing great! Lots of fun now.

Your numbers are low(especially the Muggy). What sample rate are you logging data at? I have seen 200 amps on a 10 pounds truggy in testing with an average draw of less than 30 amps during the run. A low sample rate will mask the true peaks. Also, any punch control or expo settings on the radio can also lower the recorded peak draw.

Anything is possible, but I literally have 5 runs total on this motor which was purchased new from CC...over the past 6 months I have completely rebuilt my muggy from the ground up off of an IRC chassis, new HD diffs, new drive shafts, new bearings,etc.

However, the cogging I'm seeing feels like the kind with less than optimal batteries...cogs a few feet then kicks in and is ok, or if you roll it and come on the throttle it doesn't cog at all.

I did briefly test my system without a pinion on and the log was perfect without load, so could my motor really be bad??

I have a neu 1521 I could try if I have enough 8mm bullets left....

The logging is set at default (I'll have to hook it up and check).

All other settings are at default... No punch control and radio is set on linear with no end points.

What's the best setting to change to tell if it's my batteries...if there is a setting?

Sorry, forgot to ask Mike, what log sampling rate do you suggest?

I checked the 5t and it was 2 samplings per second. All other settings were stock. No punch control, etc... If you set the sample rate much more than 2 per second, you won't get the entire run into the logging memory....you will only get 7 minutes or 14 minutes. Most guys at the HPI baja Forum are all pulling anywhere from 200 to 240 in their Castle Creations bajas....so, I think that my data is right on the money with it being around 220ish.

My 11lb revo (GPSed at 62mph) is also on 2 samplings per second....and according to the data log pulled a max of 106.5amps. All other settings are stock.

So assuming Castle Bajas pull 230ish...it makes sense to me that a 10lb truck would pull about half the amps as a 28lb truck. Seems just about right to me.

A ten pound muggy pulling 200amps!!!...what the heck motor is in it?!?!?!

All I can say is at a sampling rate of 2/second, all other settings stock, I was pulling 106 in my 11lb revo and 225ish in my 28lb 5t according to the Data log from each mamba XL2.

You have to agree that if he was just blipping the throttle and already getting 240amps...something seems odd when compared to results I have...plus all the other baja owner who have converted to the XL2 and 2028 motor who are getting about 230ish amps as well. That is all I know. a 10 lb muggy pulling 240 amps just blipping the throttle seem high....with the little bit of data logging experience I have had and read about.

Don't know if this helps...I may try a higher sampling rate...but that sucks because I would only get 1/3 or 1/2 the run into memory. Do you think 2/second sampling rate is sufficient?

Was that muggy pulling 200ish using a MambaXL2? let us know.

data log rate
 

Kirkinsb - 2 samples per second data rate explains your low numbers for sure - you are simply missing the microsecond peak currents that happen. In my experience, the peak draw will ramp down very quickly once the car is rolling - a 200+ amp spike could be down to 120 amps within the same second. 2 samples/second frame rate will not show this, though. I understand that a higher frame rate will result less log time, but it will also yield higher data resolution so you can see more detailed data, albeit for s shorter time. Besides....do you really need to log the entire run every time? Please maximize your frame rate, gather some data, and report back. You can always change the frame rate back afterwards, but I think you will be surprised at what you see.

Also, while the Baja is a larger, heavier vehicle, it also typically is used under a higher voltage and will have less traction than an overgeared Muggy(4wd) with large, heavy tires. On the surface, logic may say that a car that is half the size will draw half the current, but in truth, there are many variables that will quickly dispell this logic. Also, a throttle "blip" can be no different than a full on drag race launch, but over a shorter time period. The actual peak current happens over a very short time period(1/10 second or even less) so it does not surprise me to see 200+ peaks on a heavy, overgeared 4wd monster truck.

magicald - The highest log rate will give you the highest resolution. In reality, the average draw is typically fairly low, but there are microsecond peak currents that are very high. Personally, I have only used the highest available frame rate, as I normally am only logging data when I am trying to dial in a setup or test a component(battery, motor, etc.). The highest resolution will provide the most information in a short period of time. The beautiful thing is that you can change the frame rate! I think it is wise to maximize the frame rate occasionally to properly visualize the truest data, but there is nothing wrong with a lower frame rate to gather more general data over a longer period.


In my opinion, you simply can't draw any accurate conclusions from data logged at different frame rates - logging at a low frame rate will mask peaks.

Thanks for the input Mike. I have went with my gut and ordered a new TP g6 65C 6S battery...why I keep going back to this is that the hyperion I have is used...I'm not sure how old it is, but I've had it for 1 year and even though it charges normally, is not puffed, and balances nicely, I don't think it has enough amperage for my set up.

I'm going to what to run it until I get the new lipo. I'll change my sampling rate and let you guys know what I find.

May need to with to 17mm truggy tires though I love the way the large 55 series wheels look on the muggy...it is a monster-truggy after all!!

Good info..makes sense.... I will try the highest frame rate one of these days and see what happens.... Also good info about how higher voltage and current affect each other. Sounds good. I am just glad the XL2s seem to have the bugs worked out. They perferm great. Thanks

Just for everyone's benefit--

The ICE datalogger (used in the XL/XL2) actually samples the current several times during each PWM cycle (synchronously), and then keeps a running average of the results. The samples are then written to flash memory at the programmed "sample rate."

So the sample rate is only the rate at which the averaged samples are written to memory -- not the rate at which the controller samples the current...

Make sense??

Ok, so my readings at 2/second are probably fairly accurate? And I am not missing any huge amounts of data by not using the 5/second setting? Yes/No? Hmmm, interesting. Is their much benefit to having the data written 5/second as opposed to 2/second since it is averaged? thanks Patrick.

No, your readings are more averaged than if you had the data written at a faster rate - so the real peak of the spike is averaged with lower currents on either side of the peak giving a lower average current written to the memory. Writing data at a faster rate should include less averaged data - so truer to the actual curve.

I think.

Yeah...what he said(brian015). :)

So I was bored tonight, waiting on my new battery to arrive (which will hopefully solve my start cogging problem) so I decided to log a run with only the load of the drivetrain - wheels off the ground. This is a very short run, but numbers don't look bad at all. I used 10 samples/sec for the logging.

I guess I'm trying to reassure myself that my motor is okay...

http://i44.photobucket.com/albums/f1...ggy/NoLoad.jpg

I don't have enough male 8mm bullets to try my 1521 motor, it would be too much trouble to swap them from my 1717.

Any other ideas to test my 1717? I don't have another rig to try it in...I read about the "drill" method on some aircraft sites to make sure that voltage was similar between all leads and check and make sure no lead shorts is in continuity with the motor case.

Also, I ordered some 17mm adapters to put truggy wheels on it to try that if the battery doesn't help.

A few quick pics...sorry for the phone quality images

http://i44.photobucket.com/albums/f1...y/IMG_0098.jpg

http://i44.photobucket.com/albums/f1...y/IMG_0099.jpg

Looks like a heck of a nice set-up you have! I still have to run mine at 10/second to see what I come up with. But perhaps with a 4wd that has big tires...it may pull that much current. If temps are reasonable....you are probably ok to proceed.

The only thing you may think about doing is getting a waterproof receiver box...like a traxxas stampede receiver box to protect from dirt and water splashes. Good looking rig! Run it hard with the 10/second and post what you get. I may have time tomorrow to get some data on mine at 10/s or whatever the highest is.

Thanks, I've spent a lot of time on this thing.

I do need a receiver box.

I just hope my new battery fixes the cogging...I think it will, it reminds me of when i tried the stock nimh pack with my old Rc18 with a 8000kv motor, which worked great on lipos

Ok, got a VERY good Hard run with lots of full throttle all the way through the RPM range....best of all, I used the 10 samplings per second setting on my Castle Mamba XL2 with 2028 motor in my baja 5t. I probably ran it harder than usual because I really wanted to see what was the MAX current recorded.....

And it was just about exactly as I suspected. I usual us the 2 samplings per second data setting and pull about 220amps... Now with the setting on 10 samplings per second i got a maximum of 240.6 amps. And i would most likely attribute the extra 20 amps to driving ultra aggressive this run. I was really throwing my 5t around!!!!

I feel my original readings at 2 samplings per second were fairly accurate...seems they were.... I will next run my Revo also with a XL2 that I will put at 10 samplings per second...and see if it is still close to the 2 sampling per second data I have always used.

Thanks for the update...I agree, numbers are not that much different.

I really want to see your Revo data and how it turns out. I'm still waiting on my new Battery, I also got some 17mm hubs to run truggy tires on my muggy as well. I want to see hard numbers as to how much larger/heavier tires really makes on the amp draw with the 1717.

http://i1183.photobucket.com/albums/...7/IMG_0045.jpg

Just ran the Brushless Revo with MambaXL2 and 1518 motor. Ran perfect as always...drove the crap out of it as always. I usually collect data at 2 writings per second.. this time I raised it to 10 readings per second and just as I had suspected the data was VERY similar to what I get at 2 per second. My MAX current was 109, Watts was 2128. this is basically the same data...which supports my suspision that I am NOT missing huge chunks of data by using the 2/second writing setting.

Keep in mind before you all blast me...this are my findings...you may get something completely different.

But this all started with a fellow RCer wondering if his 240amp current reading was accurate on his Muggy.....I said it seemed way high compared to my 110amp on my brushless revo. Another member suggested I was missing data not using the highest reading possible....I did not truly feel that I was missing huge chunks. And when I raised it to 10/second....the readings were very close.

Which brings me back to the original topic.....240amps seem really high to me for a Muggy. I ran the crap out of my 12lb revo and could only pull 110ish!!!! Draw your own conclusions....

but I hope this helps out some. Is good data according the Castle's Mamba XL2 data logger....both at 2/second and 10/second.

Nice to see that at least your data didn't seem to change much with sampling rate.

I know you pulling a lot less amps, but we are not comparing apples to apples. I know they almost weigh the same (I need to weigh my muggy, but its at least 12-13 lbs rtr)...Again, out of the electric components, my lipos are the only thing used that I don't have the whole history of. They always worked well, but again that was all of 5 runs and over 6 months ago is when I decided to buy an IRC 4mm chassis and completely rebuild it.

I've read a lot about testing brushless motors though it seems like a difficult thing to do without special equipment. Correct me if I'm wrong, but if my 1717 is bad, would the motor run flawlessly without load and running with wheels off the ground? If I had a couple more male 8mm bullets I would throw my 1521 in...new battery should be here 2/1.

Also, what firmware are you running on your XL2? I'm running the most recent, which was on it from CC. Just wondering if previous versions were better for cogging with the 1717? I know with my MMM, 1.21 had no cogging, but newer version did??

I don't really know of a way to know if a motor is OK, other than running it and seeing how it performs and checking temps. There are guys on this forum that know a whole lot more than I do about motors and escs....all i know is double the current that I have been seeing really caught me by surprise.

You may be totally fine pulling that current....I know my firmware must be stock...I have never updated it...since both mine were running good.

Get them Lipos installed and fire that big dog up...I am interested to see what kind of data you get.

I have not run my my Revo for a while...I forgot how outragous that thing is! Lots of fun! Keep us posted.

I think I was more trying to show some people that my data was fairly accurate even on the 2/sec setting.

Wow, just for giggles I downgraded my firmware to 1.24 (oldest available) and cogging is much, much less barely noticeable much like what it was with my old MMM!!! Its funny because the logo on the castle link now says "Mamba Monster" instead of "XL" but logging is on there. I quickly looked at the very short log of just tooling around my garage and the max amps was 58, but my ripple was 10%!!! However, my batteries were on the cooler side maybe 60 degrees and partially discharged...not quiet storage level, but definitely not fresh off the charger.

Why the hell does the newest firmware cog more?? I didn't try any of the other beta firmwares.

What's funny is this was the same deal with the 1717 and my MMM... old 1.21 worked best??

Will do more testing, but with that ripple my batteries do look like they need to be replaced. Otherwise, huge wheels and all I think it will be ready for a "real" run when I get my batteries...might start off with truggy wheels and same gearing, then stock muggy wheels, then the big Cen wheels to see how much of a difference big wheels and tires makes.

Well...got my new batteries and nothing but let downs and disappointment!!!

My muggy cogs worse with new TP G6 65C batteries!! About the same on the newest firmware. I was only able to drive a little in my garage...it was pouring rain tonight outside...

Then worst of all, I was trying other firmware when a dialog box of death popped up saying the "update didn't finish, disconnect and reconnect esc" Well now my XL2 is bricked!!!!!!!! The lights no longer flash on the Castle Link....WTFFFFFFFFFFFFFFFF!!!

I'm about ready to give up on my E-Muggy!!

Awww man, that is terrible news. Sorry to hear that crappy news. Dang, that sounds like it is fried.... Perhaps a call to Castle Support tomorrow may help...Otherwise, you will probably have to send it in...and the wait can be a long time....That is why I bought a second XL2 so if one goes....I have another... Castle will take care of ya...but it may take some time to get you a new one back in the mail...

Freakin sux though. I have been there with the Ver 1 & 2. Keep us posted.