Help with XL2 log data???

[magicald]

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?

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.

[magicald]

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...

[fastbaja5b]

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?

[coolhandcountry]

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

[magicald]

Originally Posted by fastbaja5b

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?

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?

Originally Posted by coolhandcountry

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

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

[brian015]

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?

Originally Posted by magicald

though my motor wires would heat up more than anything else...

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

[Pdelcast]

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.

[brian015]

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.

[RC-Monster Mike]

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.

[magicald]

Originally Posted by brian015

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?

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.

[magicald]

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.

[magicald]

Originally Posted by freddy

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

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.

[Kirkinsb]

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.